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Population Health for Nurses

13.2 Types of Infectious Disease Outbreaks

Population Health for Nurses13.2 Types of Infectious Disease Outbreaks

Learning Outcomes

By the end of this section, you should be able to:

  • 13.2.1 Define the term infectious disease.
  • 13.2.2 Explain how infectious agents are transmitted.
  • 13.2.3 Describe the types of infectious disease outbreaks.
  • 13.2.4 Discuss the impact of vaccines on infectious disease control and prevention.
  • 13.2.5 Explain the nurse’s role in infectious disease control and prevention.
  • 13.2.6 Identify emerging infectious diseases and potential bioterrorism agents.

Diseases are infectious if they are easily transmitted between individuals. To understand how outbreaks of infectious diseases occur, community and public health nurses should understand disease communicability and transmissibility. Health promotion and disease prevention efforts are geared toward breaking the chain of transmission. To break this chain, nurses must implement appropriate public health measures based on the transmission mode and educate communities effectively on how to protect and prevent disease transmission. Public health nurses, like Sally, play a role in disease surveillance.

The Epidemiology (Communicability) of Infectious Diseases

Infectious diseases are caused by pathogenic microorganisms—agents such as bacteria, viruses, parasites, or fungi—that enter a human host, multiply, and cause infection that can spread via direct or indirect transmission (CDC, 2022ap). Epidemiology for Informing Population/Community Health Decisions introduced the epidemiological triad and the chain of infection; both are central in the transmission of infectious disease. The epidemiological triad includes the host, agent, and environment and describes the who, what, and where of the infectious process. The chain of infection builds on this triad; a disease is considered communicable or contagious (capable of spreading from one person to another) if the infected host has a portal of exit, a means of transmission, and a portal of entry into another susceptible host. Some infectious diseases can be spread by germs in the air, food, water, or soil and by vectors or by animals to humans. While these diseases are still considered infectious, as they are caused by bacteria, viruses, parasites, or fungi, they are not considered communicable from person to person.

The agent’s pathogenicity (the potential ability to cause disease in a susceptible host) depends on the agent’s infectivity and its ability to invade the host, destroy host body cells, and produce toxins that result in the virulence, or severity, of the infectious disease.

The susceptibility of a host is a key component in the epidemiological triad and chain of infection. Susceptibility depends on many factors, such as age, sex, physical health, and immune status. Portals of entry and exit can include the skin, conjunctiva, respiratory tract, GI tract, genital tract, and vertical transmission during the birthing process. The environment is a component common to both the epidemiologic triad and the chain of infection. It refers to reservoirs of infectious agents, which may be humans, animals, plants, insects, water, and soil. The environment and any environmental changes can have a significant impact on the transmission of waterborne, foodborne, and vector-borne agents. Transmission of infectious agents includes airborne, direct contact, indirect contact, and droplet transmission. If an environment is favorable for the survival of an infectious agent and there is an opportunity for the host to be exposed to the agent, infection and disease will ensue (The Alliance for Child Protection in Humanitarian Action, 2018).

Common Communicable Diseases

As the COVID-19 pandemic showed, communicable diseases are a major global health and security threat, negatively impacting social and economic development (WHO, 2023b). Older communicable diseases such as tuberculosis (TB) remain global public health threats. Public health nursing is founded on the practice of promoting health, preventing disease and disability, and protecting the health of populations (Association of Public Health Nurses, 2022). Public health nurses require knowledge of communicable diseases and basic epidemiological principles to promote the health of individuals and communities by implementing measures to prevent and control the spread of communicable diseases.


Influenza viruses cause influenza (flu) A and B, which result in a respiratory infection affecting the nose, throat, and lungs, causing mild to severe illness and sometimes death. Influenza viruses are categorized as follows:

  • Influenza A viruses cause the most severe and widespread disease, undergoing minor mutations (antigenic drift) each year and periodically undergoing a major mutation (antigenic shift), which results in a flu pandemic.
  • Influenza B virus often causes milder disease outbreaks, mutating gradually via antigenic drift but not undergoing antigenic shift.

Flu often occurs in the winter months but may be found year-round with testing. Each year, approximately 8 percent of the U.S. population becomes ill from flu viruses, with children twice as likely as adults over the age of 65 to develop symptomatic flu illness (CDC, 2022x). The seasonal incidence of flu changes based on the severity of the flu season. Seasonal flu is very different from pandemic flu. Seasonal flu viruses often undergo antigenic drift, necessitating an annual flu vaccine that is updated yearly to reflect current circulating influenza strains. In contrast, a major mutation resulting in a new influenza strain (antigenic shift), such as those that have occurred four times in the last 100 years, is often responsible for pandemic flu (CDC, 2022t). Hosts are more susceptible to these new disease strains as they often have little to no immunity against them (CDC, 2022t).

Flu is easily transmitted by droplets of infected material. When infected individuals talk, sneeze, or cough, infectious droplets can land in the mouths or noses of individuals nearby, spreading the disease. The flu can also be spread through indirect contact transmission (CDC, 2022x). Infected individuals are most contagious during the first three to four days of illness, but some are contagious beginning one day prior to symptom onset and up to seven days after becoming ill. Anyone can get the flu, and serious problems may occur at any age. Older adults, children under five, pregnant persons, and individuals with chronic conditions such as asthma, diabetes, and heart disease are at higher risk for developing flu-related complications. Flu symptoms include fever, chills, cough, sore throat, nasal congestion, body aches, headaches, fatigue, and sometimes vomiting and diarrhea (CDC, 2022x).


Pneumonia is a lung infection that causes mild to severe illness in individuals of all ages. Risk factors are age (older than 65, younger than five years), co-occurring chronic medical conditions, and cigarette smoking. Viruses, bacteria, and fungi are agents that can cause pneumonia. In the United States, the most common causes of pneumonia include:

  • Viral: Influenza, respiratory syncytial virus (RSV), and SARS-CoV-2
  • Bacterial: Streptococcus pneumoniae (pneumococcus), Mycoplasma pneumoniae, and Chlamydophila pneumoniae
  • Fungal: Coccidioidomycosis found in Southern California and the Southwest deserts, histoplasmosis mostly found in the Ohio and Mississippi River Valleys, and cryptococcus found in soil contaminated with bird droppings (American Lung Association [ALA], 2022)

Some types of pneumonia are contagious, spreading via droplet transmission similar to the flu. Individuals may also spread pneumonia through indirect contact transmission, and not everyone exposed to pneumonia will develop active disease (ALA, 2022). In 2021, over 40,000 individuals died from pneumonia in the United States. Many of these deaths could have been prevented or avoided with vaccines and appropriate treatments (CDC, 2022ab). Current vaccine options for bacteria and viruses that can cause pneumonia include COVID-19, Haemophilus influenzae type b (Hib), influenza, measles, pertussis, pneumococcal (PCV), and varicella. PCV protects against 13 or 15 (PCV-13 vs. PCV-15) of the most common serotypes and is a part of the routine infant vaccination schedule, while the 23-valent pneumococcal polysaccharide vaccine (PPSV23) is available for individuals in high-risk groups.

Pneumonia symptoms vary greatly but may include fever, chills, a productive cough, shortness of breath, rapid or shallow breathing, sharp or stabbing chest pain, chest pain worsening with deep breathing or coughing, loss of appetite, fatigue, nausea and vomiting, and confusion (ALA, 2022). In 2019, pneumonia killed 2.49 million individuals globally, one-third of whom were children under age 5 making it a leading cause of death in this population (Dadonaite & Roser, 2019). Within the United States, community-acquired pneumonia is a leading cause of hospitalization and results in significant mortality (Regunath & Oba, 2022).


Hepatitis is inflammation of the liver and may result from a viral infection. In the United States, its most common viral forms are hepatitis A, B, and C (Table 13.2). Viral hepatitis infections affect millions of people globally, with hepatitis B and C resulting in chronic infections and liver cancer, disproportionately affecting lower-income countries. However, progress in treatment is being made globally. Hepatitis C is curable with a three-month course of medication taken once a day, and medications are available to slow the progression of hepatitis B and prevent liver damage (CDC, 2021e). Both hepatitis A and B can be prevented with safe, effective vaccines.

Hepatitis A (HAV) Hepatitis B (HBV) Hepatitis C (HCV)
U.S. incidence in 2020 ~ 19,900 estimated infections
  • ~ 14,000 new infections disproportionately affect individuals of Asian Pacific Islander descent; an estimated 880,000 cases of chronic HBV infection in adults, a leading cause of liver cancer.
  • Most infants and 33% of children under age 6 with HBV will have lifelong chronic infection; children over 6 and adults usually recover completely.
  • ~ 67,000 new infections and an estimated 2.2 million adults with chronic HCV infection, a leading cause of liver cancer occured.
  • Rates of HCV-related deaths were highest in BIPOC individuals.
  • Ingesting the virus through contaminated food (fecal-oral route) or through person-to-person contact.
  • Hepatitis A outbreaks are rare in the United States but common in many countries, especially those without adequate sanitation and water.
  • Direct contact with infected blood, semen, other bodily fluids, or open sores, such as through the birthing process, sexual intercourse, sharing contaminated equipment (needles, syringes, toothbrushes, razors), and through poor infection control in health care facilities.
  • HBV is not spread through kissing, sharing utensils, sneezing, coughing, or breastfeeding or through food or water (CDC, 2023p).
  • Direct contact with infected blood such as through sexual contact, the birthing process, sharing contaminated equipment (needles, syringes), getting a tattoo or body piercing with contaminated instruments, or via poor infection control in health care facilities.
  • Transmission could also occur through a blood transfusion or organ transplant prior to 1992.
  • Mild to moderate illness, lasting several weeks to several months.
  • Most individuals recover without permanent damage, and death rarely occurs.
  • Acute infection occurs within the first 6 months of exposure.
  • Acute infection may be asymptomatic or result in mild to moderate disease, rarely causing severe disease. Up to two-thirds of all asymptomatic individuals may not know they are infected (CDC, 2023p).
  • Symptoms include fever, fatigue, appetite loss, nausea, vomiting, abdominal pain, arthralgias, and jaundice.
  • Acute infection can lead to chronic infection that could result in serious health issues of liver damage, cirrhosis, and liver cancer.
  • Acute infection may last a few weeks or become a serious chronic condition. Usually asymptomatic or mild symptoms such as fever, fatigue, nausea, vomiting, abdominal pain, or arthralgia.
  • Chronic disease develops in approximately half of adults yet usually remains asymptomatic or presents with nonspecific symptoms such as chronic fatigue and depression. 5–25% progress to cirrhosis over a 10 to 20-year period.
Prevention A highly effective vaccine is typically incorporated into the routine childhood vaccination schedule. Hepatitis B vaccination is a part of the routine infant and child vaccination schedule. There is no vaccine available for hepatitis C.
  • Vaccination for previously unvaccinated adults if at increased risk, such as individuals who experience homelessness, use illegal drugs, have occupational risk of exposure, travel internationally, or have chronic liver disease or HIV.
  • Men who have sex with men (MSM) are also identified as high risk.
  • Vaccination for all adults under age 60, but anyone may request it and receive it.
  • Universal screening at least once in the lifetime of all adults, and more often with ongoing risk factors such as pregnancy, hepatitis C infection, and individuals who are incarcerated, have a history of sexually transmitted infections, or have multiple sexual partners.
  • Universal screening at least once in the lifetime of all adults, and more often with risk factors such as pregnancy, IV drug use, concomitant HIV infection, children born to mothers with HCV infection, and any individual who received a blood transfusion or organ transplant prior to July 1992.
  • Available treatment involves once-daily medication for 2 to 3 months, resulting in 95% cure rates with minimal side effects.
Table 13.2 Comparison of Hepatitis A, B, and C in the United States in 2020 (See CDC, 2020f; CDC, 2022n; CDC, 2023e; CDC, 2023f; CDC, 2023p.)


Human immunodeficiency virus (HIV) is a virus that attacks the body’s immune system and, if untreated, progresses to acquired immunodeficiency syndrome (AIDS). No current cure or vaccine exists for HIV, but with proper treatment, it can be controlled and those affected can live long, healthy lives (CDC, 2022a). In the United States, an estimated 1.2 million individuals are infected with HIV, with almost 160,000 unaware of their HIV status (CDC, 2022s). Almost 40 percent of new HIV infections are transmitted by individuals who are unaware they have the virus. Risk factors include men having sex with men (MSM); individuals who have had anal or vaginal sex with an individual who is HIV+; having multiple sex partners; sharing needles, syringes, or other drug equipment; having a history of other STIs; and concomitant hepatitis or tuberculosis (TB) (CDC, 2022ah). The CDC recommends HIV testing for everyone between the ages of 13 and 64 at least once as part of routine health care and annual testing for individuals with risk factors (CDC, 2022r, 2022s).

HIV is transmitted through direct contact with infected blood and specific body fluids, most often through anal or vaginal sex or sharing needles, syringes, and other drug injection equipment. HIV transmission may also occur perinatally (pregnant person-to-child) during pregnancy, birth, or breastfeeding; however, this is now rare in the United States due to advances in HIV prevention and treatment (CDC, 2022a). The three stages of HIV infection include:

  • Stage 1, acute HIV infection: Heavy HIV load in the blood, flu-like symptoms occurring 2–4 weeks after initial infection and lasting days or weeks. Individuals are very contagious during this time.
  • Stage 2, chronic HIV infection (also called asymptomatic HIV infection or clinical latency): Individuals often have no symptoms but can transmit HIV. Individuals who adhere to prescribed HIV treatment may remain at this stage and never progress to stage 3. Without treatment, this stage may last a decade or longer, or may progress faster.
  • Stage 3, AIDS: individuals have a high viral load and damaged immune systems resulting in opportunistic infections or other serious illnesses. Without HIV treatment, individuals with AIDS generally survive 3 years (CDC, 2022a).

The three available HIV tests are antibody tests, antigen/antibody tests, and nucleic acid tests (NAT). While these tests are accurate, no test can detect HIV immediately after infection. HIV antibodies may be undetectable to existing tests for up to 90 days after infection. Antigen/antibody tests can detect HIV 18–45 days after exposure, and NAT can detect HIV 10–33 days post exposure. NAT should be considered for people who have had a recent exposure or possible exposure with early HIV symptoms (CDC, 2022s).

Antiretroviral therapy (ART) is an effective HIV treatment that reduces viral loads to undetectable levels, keeping the individual healthy and potentially at stage 2 (CDC, 2023g). ART is recommended for all individuals with HIV, as soon as possible after diagnosis, regardless of CD4 cell count levels, since it is associated with a large reduction in morbidity and mortality compared with those who defer treatment (CDC, 2023g). When ART therapy is taken as prescribed and in conjunction with undetectable viral loads, multiple studies have demonstrated no risk of oral, anal, or vaginal sexual HIV transmission (CDC, 2023g). ART therapy coupled with undetectable viral loads also reduces the risk of transmission during pregnancy, labor, and delivery by 99 percent (CDC, 2023g). Many individuals achieve undetectable viral loads within 6 months of beginning ART (CDC, 2023g). Treatment as prevention (TasP) helps keep individuals who are HIV positive healthy and helps them to avoid transmitting HIV to others. Some individuals with HIV refer to TasP as undetectable = untransmittable, or U=U (CDC, 2023g).

The Roots of Health Inequities


The U.S. HIV epidemic is marked by historical social injustices and disparate access to prevention, care, and treatment. The social determinants of health (SDOH) reinforce what the surveillance data demonstrate: inequities in HIV incidence, prevalence, and needs. Poverty, low education level, inequitable access to health care, and income inequality are factors related to HIV high-impact areas. Stigma, structural discrimination, and racism result in notable health disparities in individuals with HIV and AIDS. Deeper disparities are associated with intersectional identities such as being a Hispanic MSM or a Black woman living in the rural South.

  • Gay and bisexual men are most disproportionately affected by the HIV epidemic. MSM represent 2 percent of the total U.S. population but account for 61 percent of all new U.S. HIV infections.
  • Black individuals are the most affected racial/ethnic population, representing 14 percent of the total population but accounting for 44 percent of new infections, with an infection rate almost eight times higher than White individuals.
  • Latino individuals account for 20 percent of all new HIV infections, an HIV rate three times higher than that of White individuals.
  • Individuals who inject drugs represent 9 percent of all new HIV infections.
  • Individuals who are transgender have an average prevalence rate of 28 percent among male-to-female women.
  • The southern United States has experienced the highest rates of new HIV diagnoses over the past decade, and researchers have suggested that this may be attributed to the refusal of many of these states to expand Medicaid, the lack of access to health care providers in rural areas, low health literacy levels, high rates of sexually transmitted infections, and ongoing stigma associated with HIV.

(See CDC, 2020g and Sullivan et al., 2021.)


TB is caused by a bacterium, Mycobacterium tuberculosis (MTB), which often attacks the lungs but can attack any part of the body. TB is spread via airborne transmission. When inhaled, TB bacteria can settle into the lungs, grow, and spread to other parts of the body (CDC, 2022u). Anyone can become infected, but certain populations, such as BIPOC individuals, individuals experiencing homelessness, and those living in congregate settings (correctional facilities, detention centers) are at higher risk of TB disease than the overall population (CDC, 2022p). Because TB infection does not always result in illness, it is often classified as latent TB infection (LTBI) vs. TB disease (Table 13.3). Individuals infected with MTB have an estimated 5 to 10 percent lifetime risk of becoming ill with TB disease. Some will have LTBI, others will clear the infection, and some, such as those with weakened immune systems (for example, individuals living with HIV, malnutrition, or diabetes) and individuals with alcohol use disorder and tobacco dependence, will have a higher risk of becoming ill with TB disease (WHO, 2022b). See Caring for Vulnerable Populations and Communities.

Latent Tuberculosis Infection Active Tuberculosis Disease
Diagnostic Method Positive skin or blood test indicating TB infection Positive skin or blood test indicating TB infection
Chest X-ray and sputum culture positive for MTB
Description Presence of TB bacteria in the body, but the bacteria is inactive Presence of actively replicating TB bacteria in the body
Symptoms No symptoms; individuals are not ill and cannot transmit the bacteria to others Symptoms of weight loss, fever, night sweats, cough, chest pain, hemoptysis
Highly contagious
Treatment Can be given medication to prevent the development of TB disease Requires treatment
Prevalence Affected an estimated 13 million individuals in the United States in 2022 2.5 cases per 100,000 persons in the United States in 2022, an increase from 2021 levels
Table 13.3 Comparison of LTBI and TB Disease (See CDC, 2023n, 2023o.)

Globally in 2021, 1.6 million individuals died from TB; it remains the 13th leading cause of global death and the second leading infectious killer after COVID-19 (WHO, 2022b).

TB may be detected through testing (Table 13.4).

TB Test Name Type of Test Mode of Test Interpretation
Mantoux tuberculin skin test (TST) Intradermal test for active TB or LTBI Requires two visits to a health care provider. First visit: injection of small amount of tuberculin into the skin of the lower arm. Second visit: must occur within 48 to 72 hours to read skin test for a reaction.
*Preferred test for children under 5 who have not received the bacille Calmette-Guérin (BCG), which may cause false positive reactions.
Positive skin test: individual has MTB but requires additional screening or testing to determine LTBI or TB disease.
Negative skin test: LTBI and TB disease unlikely.
QuantiFERON®-TB Gold Plus (QFT-Plus) and T-SPOT®.TB test (T-Spot) Blood tests for active TB or LTBI Interferon-gamma release assays (IGRAs) blood tests.
*Preferred for those who have received the BCG vaccine as it does not give false positive results in those vaccinated.
Positive TB blood test: individual has MTB but requires additional screening for symptoms of active TB, plus a chest X-ray to assess for signs of active disease.
Negative blood test: LTBI and TB disease unlikely.
Table 13.4 Tuberculosis Tests (See CDC, 2022al.)

Despite its global presence, TB is curable and preventable (WHO, 2022b). Treatment takes anywhere from four to nine months and can be expensive without adequate health insurance, creating barriers for clients who are unable or unwilling to take medication for that duration or who cannot afford the cost of treatment (CDC, 2023m; Viney et al., 2019). Treatment for active TB disease often consists of multiple drugs, some with a high side effect profile. Inadequate treatment may result in treatment failure, ongoing transmission to others, and the development of drug resistance. Drug-resistant TB, which occurs when the bacteria become resistant to the antibiotics normally used to treat it, is a public health crisis. Drug resistance is more common in individuals who do not take their TB drugs regularly, in those who develop TB re-infection after being treated for TB in the past, and in individuals from areas of the world where drug-resistant TB is common (CDC, 2022i).

Drug-Resistant Tuberculosis

The three classifications of drug-resistant TB are multidrug-resistant TB (MDR-TB), pre-extensively drug-resistant TB (pre-XDR TB), and extensively drug-resistant TB (XDR TB). In this video, Khayr reflects on his experience with LTBI that ultimately transformed into MDR-TB and his long journey to survivorship. The clip sheds light on the importance of adhering to medication treatment for LTBI.

Watch the video, and then respond to the following questions.

  1. What might have changed Khayr’s behavior when he first learned he had latent TB?
  2. What do you feel is the nurse’s role in preventing MDR-TB?

Role of the Nurse in Preventing Communicable Diseases

Educating the public is the nurse’s first priority in preventing and mitigating many communicable diseases. Primary prevention of illness and disease focuses on the individual and the health and well-being of the entire community. Table 13.5 shows examples of primary, secondary, and tertiary prevention interventions for communicable diseases.

Primary Prevention
Educate individuals and communities on the importance of these disease-prevention behaviors.
  Seasonal Influenza and Pneumonia Hepatitis A Hepatitis B and Hepatitis C HIV
  • Seasonal influenza, COVID-19, Hib, measles, pertussis, and varicella
  • Pneumococcal, PCV-13, PCV-15, and PPSV23
Hep A Hep B None
  • Frequent handwashing or hand sanitizing
  • Isolating oneself when ill
  • Staying away from ill individuals
  • Coughing or sneezing into the crook of the arm
  • Disease transmission; disease can be spread at daycare centers and restaurants from inadequate hygiene practices
  • Handwashing after changing diapers or using the bathroom
  • Not sharing needles, syringes, or equipment contaminated with infected blood
  • Not sharing toothbrushes or razors with an infected individual
  • Using appropriate protection if having sexual relations with an infected partner
  • Researching tattoo and body piercing parlors to ensure they have appropriate infection control measures in place
  • Everything listed for Hepatitis B and C
  • Treatment as prevention: HIV+ individuals who take ART as prescribed and have undetectable viral loads can help avoid transmission to their sexual partners. U = U.
  • Using appropriate protection if having sexual relations with an infected partner
  • Nurses also provide referrals for pre-exposure prophylaxis (PrEP) for HIV-negative sexual or drug-injecting partners
Secondary Prevention
Identify diseases early via screening, before the onset of signs and symptoms, allowing for early treatment to delay or avoid potential complications and helping decrease potential transmission to others.
Hepatitis B and Hepatitis C Tuberculosis HIV
Referrals for None. None. Pre-exposure prophylaxis (PrEP) for HIV-negative sex or drug-injecting partners
Screening for
  • Hep B and Hep C at least once, more if necessary for risk factors or exposures
  • Substance use
  • Risky sexual behaviors
  • STIs as this may indicate unprotected sexual activity, thereby increasing risk of disease transmission
  • TB with either the tuberculin skin test or one of the blood tests
  • HIV at least once, more if necessary for risk factors or exposures
  • Risky sexual behaviors
  • STIs as this may indicate unprotected sexual activity, thereby increasing risk of HIV transmission
  • Substance use
Tertiary Prevention
Treatment to manage the disease post-diagnosis to slow or stop disease progression:
  • Referrals for Hep A, B, or C treatment
  • Referrals for HIV treatment
  • Referrals for TB treatment
Table 13.5 Prevention of Communicable Diseases

Foodborne Diseases

Within the United States, foodborne illness is fairly common, with an estimated one out of every six individuals becoming ill from contaminated food or drinks and approximately 3,000 deaths related to foodborne illnesses each year (CDC, 2022b). Table 13.6 describes the top pathogens responsible for foodborne illnesses and death.

Pathogens Causing Food Poisoning Illness Pathogens Causing Food Poisoning-Related Deaths
Norovirus Salmonella (non-typhoidal)
Salmonella (non-typhoidal) Toxoplasma gondii
Clostridium perfringens Listeria monocytogenes
Campylobacter Norovirus
Staphylococcus aureus Campylobacter
Table 13.6 Top Five Pathogens Responsible for Foodborne Illnesses and Death (See CDC, 2022l.)


The highly contagious norovirus is the leading cause of vomiting and diarrhea from acute gastroenteritis in the United States across all age groups (CDC, 2023l). Each year, there are between 19 million and 21 million cases, with over 100,000 hospitalizations and approximately 900 deaths; these cases occur more commonly between November and April (CDC, 2021c; CDC, 2023l). Older adults and children under 5 are most likely to have complications related to norovirus. By age 5, one in 110,000 children will die from norovirus and one in 160 will be hospitalized (CDC, 2023k). Though they are often referred to as a “stomach bug” or “stomach flu,” none are related to influenza viruses (CDC, 2023l).

Norovirus is transmitted via the fecal-oral route through contaminated hands, food, or water or by contact with contaminated surfaces. The most common symptoms include nausea, vomiting, diarrhea, and stomach pain that often resolves within 48 hours (CDC, 2023l).

Common settings for norovirus outbreaks include hospitals, long-term care facilities, restaurants, schools, childcare centers, colleges, and cruise ships. Foods commonly implicated are leafy green vegetables, fresh fruits, and shellfish (CDC, 2021c).

Healthy People 2030

Safe Food Handling

Healthy People 2030 features many objectives related to safe food handling. These objectives highlight the importance of consumer education to prevent disease and focus on the importance of washing hands and surfaces and separating cutting boards when preparing food, cooking food to a safe internal temperature, and refrigerating food within two hours after cooking.

(See also CDC, 2022m.)

Non-typhoidal Salmonella

Salmonella bacteria are classified as “typhoidal” or “non-typhoidal.” Typhoidal salmonella serotypes cause typhoid fever. This discussion focuses on non-typhoidal salmonella, which causes an estimated 1.35 million illnesses and 420 deaths annually in the United States (CDC, 2022ae). For every confirmed positive lab test, an estimated 30 cases go unreported (CDC, 2022ad). Children under age 5 are more likely to become infected; this age group, adults over 65, and individuals who are immunocompromised are most likely to have severe infections (CDC, 2022ae).

Salmonella bacteria live in the intestinal tracts of humans, amphibians, reptiles, poultry, and other birds and in the feces of some animals (CDC, 2022ae) and infect individuals who do not wash their hands after contact with animals or animal feces. Salmonella can also be found in foods like chicken, turkey, beef, pork, eggs, fruits, and vegetables. Salmonellas contaminate an estimated one out of every 25 packages of supermarket chicken, infecting individuals if the contaminated chicken is not cooked thoroughly or if its juices leak onto surfaces or foods that are not cooked such as fruit and produce (CDC, 2022ad).

Salmonella illness, salmonellosis, results in a mild to severe diarrheal illness, acute gastroenteritis. Symptoms include sudden onset of diarrhea that may or may not be bloody, abdominal cramping, and fever. Less commonly, nausea, vomiting, and headache may be present. Diarrhea may last for days, increasing the risk of severe dehydration, especially in infants, young children, and older adults. Most individuals recover within seven days without antibiotic treatment; however, it can take months before bowel habits return to normal. Occasionally, salmonella infection can spread to other body areas, referred to as extra-intestinal infections, and it may be severe enough to cause disability and death (CDC, 2022ae).

Salmonella Illness Linked to Chicken

In this video, 14-year-old AJ and his mother tell their story of illness related to a multistate outbreak of salmonella from contaminated chicken.

Watch the video, and then respond to the following questions.

  1. What was the role of the public health nurse in responding to foodborne illnesses?
  2. What purpose did the actions of the public health department in response to AJ’s case serve?
  3. AJ’s mother mentions several food safety measures she takes in the kitchen. What other measures can you think of that she does not mention?

Listeria Monocytogenes

The bacteria Listeria monocytogenes causes listeriosis, a serious but rare infection. In the United States, an estimated 1,600 individuals become ill with listeriosis each year, and 260 individuals die from it (CDC, 2023i). Listeriosis most often infects and sickens pregnant clients, their newborns, adults over 65, and individuals with weakened immune systems. Listeriosis is usually a mild illness in pregnant people, but it may cause severe disease in the fetus or newborn. Sometimes listeriosis becomes invasive—causing sepsis, meningitis, or encephalitis—and affects other parts of the body (CDC, 2023i).

Listeria bacteria are difficult to remove from food processing facilities, where they will spread to food that touches contaminated surfaces (CDC, 2023i). Refrigeration does not kill Listeria, but the bacteria is easily killed by heating food to a high enough temperature (CDC, 2023i). Foods more likely to be contaminated with Listeria include soft cheeses; deli products such as sliced cold cuts or cheese; deli salads such as coleslaw, potato salad, tuna salad, and chicken salad; sprouts; unpasteurized milk and associated products; hot dogs; and fermented or dry sausages such as chorizo, pepperoni, and salami (CDC, 2023i).

Listeriosis often results in fever and diarrhea, similar to other foodborne illnesses, but it is rarely diagnosed. More often, it is only identified if it becomes invasive or occurs during pregnancy. Signs of invasive listeriosis are meningitis-like symptoms of headache, nuchal rigidity, fever, confusion, and convulsions. Invasive listeriosis is serious, requiring inpatient hospital care; it causes death in one in five infected individuals (CDC, 2023i). Pregnant people often experience fever and flu-like symptoms; however, listeriosis can lead to miscarriage, stillbirth, premature delivery, or life-threatening infections of the newborn. Listeriosis during pregnancy results in a fetal loss in 20 percent of the cases and results in newborn death in about 3 percent of the cases (CDC, 2023i).

Escherichia Coli

Escherichia coli (E. coli) bacteria are normally found in human and animal intestines. While most are harmless, some may cause diarrhea, respiratory illness, and urinary tract or bloodstream infections ranging in severity (CDC, 2022k). Older adults, children under age 5, those with weakened immune systems, pregnant persons, and individuals who travel to certain countries are at higher risk for infection, although it can affect anyone (CDC, 2022k). The six types of pathogenic E. coli strains that cause diarrhea are often called diarrheagenic E. coli. Of this group, Shiga toxin-producing E. coli 0157 (STEC) is most commonly associated with foodborne outbreaks. An estimated 265,000 STEC infections occur in the United States each year; however, the actual number is likely higher as many infected individuals do not seek medical care and, if they do, may not have their stool tested (CDC, 2022j).

STEC is transmitted through ingestion of tiny amounts of human or animal feces, such as through contaminated food, unpasteurized milk, untreated water, or contact with cattle or with the feces of infected individuals. The CDC recommends avoiding unpasteurized milk, unpasteurized apple cider, and soft cheeses made from raw milk as these carry a high risk of STEC infection. Individuals have contracted infections by swallowing lake water while swimming, touching the environment in petting zoos, not washing hands after changing diapers, and eating food prepared by people who did not follow hand hygiene after using the restroom. In the United States in 2021 and 2022, there were a total of seven STEC outbreaks. These outbreaks were associated with prepared food items such as packaged salads, baby spinach, cake mix, frozen falafel, ground beef, and other unknown food sources (CDC, 2022j).

STEC infections often cause diarrhea (which may or may not be bloody), stomach cramps, vomiting, and low-grade fever. Symptoms usually last five to seven days with illness severity ranging from mild to life-threatening. Typically, individuals will begin to feel ill three to four days after ingesting STEC. Between 5 and 10 percent of individuals will develop hemolytic uremic syndrome (HUS), a condition that can lead to kidney failure, about a week after symptoms first appear when the diarrhea is improving (CDC, 2022k).

Client Teaching Guidelines

Food Poisoning—Know the Signs

Recognize the following signs of mild to moderate food poisoning:

  • Fever
  • Diarrhea
  • Stomach pain or cramps
  • Nausea and vomiting

Recognize the following signs of severe food poisoning and see a health care provider:

  • Fever higher than 102°F
  • Bloody diarrhea
  • Diarrhea lasting more than 3 days
  • Frequent vomiting causing inability to keep liquids down
  • Dehydration

If you think you got sick from food, report it to your local health department.

(See CDC, 2023d.)

Role of the Nurse in Preventing Foodborne Diseases

Providing appropriate education to clients is the number one priority for the nurse in preventing and mitigating many foodborne illnesses. Primary prevention of illness and disease serves not only the individual but also the health and well-being of the entire community. Table 13.7 shows examples of primary, secondary, and tertiary prevention interventions for foodborne diseases.

Primary Prevention
Against Norovirus, Salmonella, and Escherichia coli Against Listeriosis
  • Educate individuals and communities on the following topics:
    • Follow the four steps to food safety: Clean, Separate, Cook, and Chill Guidelines
    • Wash hands well after using the restroom or changing a diaper
    • Wash hands well after touching animals or animal environments or visiting a petting zoo or farm (E. coli and salmonella)
    • Cook shellfish thoroughly (norovirus)
    • Take precautions with food and water when traveling abroad (E. coli)
    • Do not drink untreated water (E. coli)
    • Do not swallow water when swimming in lakes, ponds, streams, backyard “kiddie” pools, or swimming pools (E. coli)
    • Avoid unpasteurized dairy products, juices, and ciders (E. coli, Listeria)
  • Educate individuals and communities on the following topics:
    • Heat deli meats and cheeses prior to eating
    • Avoid eating soft cheeses or cheeses made with unpasteurized milk
    • Heat all raw sprouts prior to eating
    • Avoid consuming unpasteurized milk or juice and avoid eating deli salads if at high risk for severe listeriosis, such as pregnant or immunocompromised individuals
  • Decrease community spread
    • When ill and for 48 hours after symptoms stop, stay home and avoid preparing food for others
    • Disinfect potentially contaminated areas within the household
Secondary Prevention Against Salmonella and E. coli
  • Health department screening and initiation of food recalls
Tertiary Prevention Against Foodborne Illnesses Requiring Hospital-Level Care
  • Treatment and prevention of complications
    • Close monitoring for evidence of complications
    • Antibiotics as indicated or ordered
    • Oral hydrating solutions
    • Potentially IV fluid and electrolyte preplacement
Table 13.7 Prevention of Foodborne Disease

Vector-Borne Diseases

Vector-borne diseases are illnesses caused by infections transmitted by vectors, living organisms such as ticks and mosquitos that feed on human or animal blood (WHO, 2020). When vectors ingest infectious pathogens via blood from an infected host, they can transmit the pathogens to a new host. Once infectious, vectors can often transmit the disease for the remainder of their lives during each subsequent bite of a new host (WHO, 2020). Globally, vector-borne diseases are responsible for over 17 percent of all infectious diseases, causing more than 700,000 annual deaths (WHO, 2020). Global travel and urbanization have contributed to increasing vector-borne diseases, making everyone susceptible to diseases spread by mosquitos and ticks (CDC, 2019i, 2020b). In the United States, vector-borne diseases more than doubled from 2004 to 2018. The CDC reported nearly 650,000 cases between 2004 and 2016, with a high likelihood that the actual number was significantly higher due to underreporting.

Lyme Disease

Lyme disease is the most commonly reported vector-borne illness in the United States, with approximately 300,000 annual infections (CDC, 2019i). It is most often found in the Upper Midwest, Northeast, and Mid-Atlantic, where it is spread by the Ixodes scapularis tick. The Ixodes pacificus tick is implicated in cases in northern California, Oregon, and Washington (CDC, 2022y). The geographic range of the ticks that spread Lyme disease is expanding, due in part to a changing landscape and climate (Johns Hopkins Bloomberg School of Public Health, n.d.).

Symptoms of early localized disease, within a month after the tick bite, include fever, chills, fatigue, headache, myalgias, arthralgia, lymphadenopathy, and erythema migrans (EM), a red, ring-shaped rash at the bite site that expands over several days, often to sizes greater than five centimeters in diameter with a central clearing that results in a “bull’s eye” appearance, although the rash can appear different on darker skin tones (Figure 13.4, Figure 13.5). EM occurs in up to 80 percent of those infected with Lyme, but the classic rash is not always present (CDC, 2022y). Untreated or undiagnosed early Lyme progresses to disseminated disease in about 60 percent of clients, with symptoms appearing months after the tick bite. Disseminated disease may present with skin, neurologic, cardiac, or rheumatologic manifestations. Performing serologic testing for Lyme disease is recommended when disseminated Lyme disease is being considered. However, clinical diagnosis is recommended over serologic testing for clients who present with an EM rash after frequenting an area where Lyme is common (CDC, 2022y).

In a study by Ly (2021), the researcher found that Black clients with Lyme disease seem to be diagnosed later in the disease process than White clients. Black clients are more often diagnosed with disseminated disease upon initial diagnosis and appear to be diagnosed outside of the months that Lyme disease is most frequently diagnosed, reinforcing the idea that they are diagnosed later in the disease process. A study by Palmiere et al. (2019) looked into missed and delayed Lyme diagnoses in dark-skinned populations of Appalachia with findings that echo the work by Ly. A potential reason for these missed or delayed diagnoses may be related to the varying appearance of EM in individuals with dark skin (Minority Nurse, 2013). The EM is an early sign of Lyme disease, whereas late symptoms include arthritis and neurological symptoms. Ly (2021) found that 34 percent of Black clients were diagnosed with neurological symptoms in comparison to only 9 percent of White clients, reinforcing the earlier diagnosis in White clients (Eldred, 2022; Ly, 2019). Another study showed similar findings among Black children—that they were less likely to be diagnosed with Lyme disease and were more likely to be diagnosed with the arthritis manifestations related to Lyme disease and not the skin or cutaneous manifestations (Hunt et al., 2023). It is imperative that nurses remain aware of the risks of Lyme disease in all clients and educate clients who are darker skinned on the signs and symptoms of Lyme disease to be aware of. Early diagnosis of Lyme disease and proper treatment with antibiotics usually results in a rapid and complete recovery (CDC, 2022y). Education on tick bite prevention and tick removal can help prevent spread of the disease.

A bullseye-shaped rash spreads down a person's posterior shoulder. It is very dark in the center and gets lighter as it expands out.
Figure 13.4 A bull’s-eye rash (erythema migrans) is often a characteristic sign of Lyme disease. (credit: CDC, Public Domain)
A bullseye-shaped rash spreads over a person's shoulder. It is dark in the center and fades subtly as it expands out.
Figure 13.5 The appearance of erythema migrans can vary and appear different on dark skin tones, which may be a factor in the late diagnosis of Lyme disease in individuals with darker skin. (credit: modification of work by CDC, Public Domain)

West Nile Virus

Spread by the bite of an infected mosquito, the West Nile virus (WNV) is the leading cause of mosquito-borne disease in the United States. The disease is now considered native to the United States, with outbreaks reported each summer through the fall (CDC, 2019i). Mosquitos become infected with WNV by feeding on infected birds and then spread it to people and animals by biting them. In rare cases, WNV has been spread through blood transfusion, organ transplant, and perinatal transmission from mother to baby during pregnancy, delivery, or breastfeeding. It is not spread through droplets, by touching live animals or birds, or by eating infected animals (CDC, 2022am).

Although most infected individuals have no symptoms, one in five experiences fever, headache, body aches, vomiting, and diarrhea. Serious, sometimes fatal, disease occurs in one out 150 infected individuals, and of this group, one out of 10 die (CDC, 2022am). This severe infection often affects the central nervous system (neuroinvasive disease), causing encephalitis, acute flaccid paralysis, or meningitis. Recovery can take several months, and some effects may be permanent (CDC, 2022am).

WNV should be considered in any client with a febrile or acute neurologic illness with a recent exposure to mosquitos, blood transfusion, or organ transplant (CDC, 2023c). Lab diagnosis can be accomplished by testing the cerebrospinal fluid (CSF) and detecting WNV-specific IgM antibodies. Viral cultures and reverse transcriptase-polymerase chain reaction tests can be performed on blood specimens and confirm infection (CDC, 2023c). This is a nationally notifiable condition, a disease that, by law, must be reported to government authorities, allowing for case surveillance to assess transmission patterns and determine interventions to control outbreaks. Local and federal laws and regulations determine which diseases and conditions must be reported for case surveillance (CDC, 2022v). This will be discussed in more detail in the next section, Infectious Disease Prevention and Control.

Zika Virus

The Zika virus is caused by infected Aedes aegypti and Aedes albopictus mosquitoes found throughout the United States (CDC, 2019i). It can be passed from a pregnant person to their fetus, and fetal infection during pregnancy may cause birth defects such as microcephaly and other severe fetal brain defects (CDC, 2022aq). Zika can also be passed from an infected person via sexual activity including vaginal, anal, and oral sex and sharing sex toys, but male and female condoms can reduce this risk. Sexual transmission is especially concerning as many individuals infected with Zika are asymptomatic and may be unaware they are infected. Blood or urine tests can confirm infection. In 2015–2016, a large outbreak of travel-associated Zika cases occurred in the United States, along with local transmission cases of Zika in Florida and Texas. In 2017, the number of Zika cases in the United States started to decline, and no cases of Zika transmission by mosquitos have been reported since 2018; however, Zika remains a global health threat (CDC, 2022aq).

Clinical findings in symptomatic disease include acute onset of fever with maculopapular rash, arthralgia, or conjunctivitis (CDC, 2019m). Other symptoms may include myalgias and headaches with clinical illness lasting a week or less. Zika infection during pregnancy causes severe fetal brain defects, including microcephaly, a condition where a baby’s head is much smaller than expected, often resulting in abnormal brain development. Infants born to individuals with Zika infection during pregnancy must be evaluated for congenital infection and neurologic abnormalities (CDC, 2019m). Zika is a nationally notifiable condition reported to state and local health departments. No specific treatment for Zika exists as it is supportive in nature including rest, fluids, and use of analgesics or antipyretics. Those who are infected should be protected from further mosquito exposure for a few days after illness to prevent transmission to other mosquitos, thereby reducing the risk of local transmission (CDC, 2022aq).


A mosquito-borne disease, malaria is caused by a parasite (Plasmodium falciparum, P. vivax, P. ovale, P. malariae, and P. knowlesi) that frequently infects the Anopheles mosquito and is then transmitted to humans through this infected mosquito’s bite (CDC, 2022z). It can also be transmitted through a blood transfusion, through an organ transplant, perinatally, or by sharing needles contaminated with blood. Malaria can result in serious illness and death (CDC, 2022z). P. falciparum causes the most severe malaria and is common in many African countries. Individuals living in poverty or rural areas lacking access to health care are at the greatest risk for life-threatening illness (CDC, 2022z). An estimated 241 million malaria cases occurred globally in 2020, with over 600,000 deaths. An estimated 90 percent of these deaths occurred in children under age 5 in sub-Saharan Africa, where the disease perpetuates a cycle of disease and poverty (CDC, 2022z). Almost half of the world’s population is at risk for malaria, and lower-income countries are disproportionately affected (WHO, 2023a). Within the United States, approximately 2,000 cases are diagnosed yearly, with most cases occurring in immigrants and travelers returning from countries where malaria is endemic, such as sub-Saharan Africa and South Asia (CDC, 2022z).

Clinical findings in acute malaria include flu-like symptoms of fever, chills, headache, myalgias, fatigue, GI symptoms, and sometimes anemia and jaundice. Untreated malaria may cause kidney failure, seizures, mental status changes, coma, and death. P. vivax and P. ovale may result in relapsing malaria because these parasites can remain dormant in the liver and then come out of hibernation, resulting in acute illness (CDC, 2022z). Available malaria treatments are highly effective when started at the onset of symptoms (CDC, 2022z). Malaria is a nationally notifiable condition that must be reported to state health departments and the CDC through the National Malaria Surveillance System (NMSS). The CDC investigates locally transmitted malaria, such as transfusion malaria, and supports health professionals in preventing, diagnosing, and treating malaria (CDC, 2020a). In June 2023, the CDC issued a health alert advisory notifying clinicians, public health authorities, and the general public about the identification of a handful of cases of locally acquired P. vivax malaria in Florida and one in Texas (CDC, 2023j). This was the first time in 20 years that a case of locally acquired malaria was identified in the United States. Although the risk of locally acquired malaria remains low, vigilance is needed to prevent mosquito bites (CDC, 2023j).

Role of the Nurse in Preventing Vector-Borne Diseases

The community health nurse is crucial in stemming disease burden from vector-borne diseases. Primary prevention can help to decrease the number of individuals infected with vector-borne diseases through education campaigns. Because no known treatments aside from supportive care exist for WNV or Zika virus, education and interventions are essential to prevent the spread of these diseases. Table 13.8 shows examples of primary, secondary, and tertiary prevention interventions for vector-borne diseases.

Primary Prevention
Lyme Disease West Nile Virus Zika Virus
Educate individuals and communities on how to avoid insect bites
  • Use Environmental Protection Agency (EPA)-approved insect repellants containing DEET, picaridin, or oil of lemon eucalyptus.
  • Wear clothing that covers the body and is treated with permethrin when entering grassy or wooded areas.
  • Check the body daily for ticks.
  • Shower after coming indoors.
  • Teach how to remove ticks safely.
  • Prevent ticks on family pets.
  • Keep grass short.
  • Create tick-safe zones by keeping play areas away from shrubs and bushes, clearing tall grass/brush around the home, placing wood chips or gravel between lawns and wooded areas, using tick pesticides, and discouraging deer.
  • Use EPA-approved insect repellants containing DEET, picaridin, or oil of lemon eucalyptus.
  • Keep body parts covered with loose-fitting, long-sleeved shirts and pants.
  • Use clothing treated with permethrin.
  • Control mosquitoes indoors and outdoors by using screens and removing any standing water from your property.
  • Use EPA-approved insect repellants containing DEET, picaridin, or oil of lemon eucalyptus.
  • Review geographic locations where Zika is more prevalent; pregnant persons and those who wish to become pregnant within a short-defined period of time should avoid these locations during travel.
Educate individuals and communities on sexual transmission N/A N/A
  • Discuss risk of transmission via sex with an individual infected with Zika and that the only way to eliminate the risk of getting Zika from sex is abstinence.
  • Educate on condom use to reduce the risk of transmission.
Secondary Prevention
Lyme disease West Nile Virus Zika Virus
Educate individuals and communities on signs and symptoms
  • For any bull’s-eye rash, get evaluated.
  • For any known tick bite and onset of symptoms such as fevers, chills, myalgias, etc., get evaluated by a health professional.
  • For any febrile illness with neurological symptoms and potential exposure to mosquito bites, blood transfusion, or organ transplant, get evaluated by a health professional.
  • Fever with a maculopapular rash, arthralgias, conjunctivitis, myalgias, and headaches.
  • For any symptoms in a pregnant client who has recently traveled to active Zika areas or had sex with someone who lives in or recently traveled to areas with a risk of Zika, diagnostic testing should be performed.
Routine screening
  • Routine screening is not recommended.
  • Routine screening is not recommended.
  • Screening is generally not recommended for asymptomatic pregnant clients regardless of travel status.
Tertiary Prevention
  • Lyme disease, WNV, and Zika require referral for treatment and support.
  • With confirmed Zika in a pregnant client, screening the newborn for any congenital or neurological deficits is imperative.
Table 13.8 Prevention of Vector-Borne Disease

Waterborne Diseases

Many individuals become ill each year from waterborne diseases (CDC, 2020h). In the early 20th century, pathogens in drinking water caused most waterborne illness such as cholera and typhoid, but consistent sanitation measures and drinking water treatment have made these conditions rare in the United States. The Safe Drinking Water Act of 1974 also allows the EPA to set and enforce standards for drinking water quality (CDC, 2022h).

The CDC estimates that one out of 44 individuals become sick from waterborne diseases each year, and an estimated 7,000 people die from waterborne-related illnesses (CDC, 2020c; CDC, 2020e). The two most common types are respiratory or intestinal in nature. Legionella is the leading cause of drinking water outbreaks, and cryptosporidium is a leading cause of intestinal waterborne disease (CDC, 2019j; 2019l; 2022ai).

Today in the United States, waterborne pathogens infect individuals when they breathe in contaminated water droplets (as in heating and cooling systems) or when infected water gets in the ears or nose from recreational water sports and swimming (CDC, 2020e).

Cholera: The Pandemic the World Has Forgotten

Globally, drinking water access and safety are not guaranteed, and clean water is scarce in many places. Safe drinking water is characterized by an adequate supply of affordable clean drinking water free of pathogens and chemicals located near the home (WHO, 2023c). According to the WHO (2019), one in three individuals, 2.2 billion globally, lack access to safely managed, contaminant-free drinking water. Cholera is responsible for seven distinct pandemics over the past two centuries (WHO, 2022a). In this video, Dr. Anita Zaidi discusses the origins, transmission, symptoms, treatment, and prevention and control efforts.

Watch the video, and then respond to the following questions.

  1. Why are so many individuals still affected today by this preventable disease?
  2. What is the link between cholera pandemics and the global social determinants of health?

Healthy People 2030

Environmental Conditions

Healthy People 2030 includes important objectives related to water safety under the priority area of social determinants of health and environmental conditions. The objectives highlight the need to increase the number of people who have access to water that meets the Safe Drinking Water Act. Objectives include:

  • Increase the proportion of people whose water supply meets Safe Drinking Water Act regulations.
  • Reduce health and environmental risks from hazardous sites.
  • Reduce the number of toxic pollutants released into the environment.

Legionnaires’ Disease

Legionnaires’ disease is a dangerous type of pneumonia caused by Legionella bacteria. Normally found in lakes and streams, Legionella become a health concern when they grow and spread in water systems, such as sink faucets, centralized building cooling towers, decorative fountains, hot water tanks, and heaters. As Legionella grow and reproduce, water containing the bacteria can spread in droplets (CDC, 2021f). Individuals can also become ill by aspirating drinking water containing Legionella. Legionnaires’ disease symptoms often begin within two weeks post exposure, are similar to other types of pneumonia, and include cough, shortness of breath, fever, myalgias, and headaches; some individuals experience diarrhea, nausea, and confusion (CDC, 2021f). While easily treated with antibiotics, Legionnaire’s disease causes death in one in 10 individuals who contract it (CDC, 2021f).


Cryptosporidium (Crypto) is a microscopic parasite that causes cryptosporidiosis, a diarrheal disease. Protected by an outer shell, the parasite can survive outside a host’s body for long time periods and avoid disinfection with chlorine (CDC, 2019j). Crypto parasites are found worldwide and in every U.S. region, where an estimated 823,000 cases occur each year. Anyone can become sick with crypto, but individuals who are immunocompromised are more likely to have severe symptoms (CDC, 2019j). High-risk populations include children attending childcare centers, childcare workers, older adults, hikers who drink unfiltered and untreated water, individuals who drink from untreated shallow wells, swimmers, individuals who handle infected cattle, and international travelers (CDC, 2019j).

Crypto is transmitted by the fecal-oral route. The parasites live in an infected host’s intestines; the host will shed millions of Crypto parasites in a bowel movement. Many community outbreaks have been linked to consuming municipal or recreational water (CDC, 2019j). Causes of cryptosporidiosis may include:

  • Swallowing recreational water contaminated with crypto
  • Drinking water contaminated by stool from an infected individual
  • Swallowing something that has come in contact with an infected individual’s stool
  • Touching the mouth with hands after coming in contact with an infected individual’s stool (CDC, 2019j)

Symptoms of cryptosporidiosis begin about a week following infection and include watery diarrhea, stomach cramping, dehydration, nausea, vomiting, fever, and weight loss; they usually persist for one to two weeks. Those who are immunocompromised may develop a more severe and sometimes fatal illness. Healthy individuals generally recover without treatment.

Role of the Nurse in Preventing Waterborne Diseases

The nurse, utilizing primary prevention, can educate individuals and communities on how to avoid waterborne diseases, similar to the role of the nurse in foodborne diseases. Table 13.9 shows examples of primary, secondary, and tertiary prevention interventions for waterborne diseases.

Primary Prevention
Educate individuals and communities on water safety.
  • Drink only treated or filtered water.
  • Have private home wells checked regularly for water safety reasons.
  • Ensure the water in swimming pools, hot tubs, and splash pads is treated.
  • Avoid swallowing the water while swimming.
  • Require all individuals to take a quick shower to rinse off the body prior to entering any pools.
  • Educate families to ensure children who are not toilet trained wear swim diapers and are taken for bathroom breaks every hour to avoid defecation in the water.
  • Reiterate that anyone with any diarrheal illness should be excluded from swimming in any recreational body of water.
  • The CDC offers more guidelines on Diarrhea and Swimming.
Secondary Prevention
No screening tests or secondary prevention measures are recommended for waterborne diseases, but reinforcing the signs and symptoms that require follow-up from a health care provider can help ensure ill individuals receive timely assistance.
Tertiary Prevention
Tertiary prevention efforts focus on reducing the burden of disease by treating illnesses promptly and avoiding complications.
Table 13.9 Prevention of Waterborne Diseases (See CDC, 2021d.)

Sexually Transmitted Infections

Sexually transmitted infections (STIs), also called sexually transmitted diseases (STDs), are infections that transmit from person to person through vaginal, oral, and anal sex and less commonly through intimate physical contact (CDC, 2022f). An estimated one in five individuals in the United States are affected by STIs, with 26 million new STI cases in 2018 (CDC, 2022af). STIs are preventable, and many are easily treatable if diagnosed promptly. Some STIs do not cause obvious symptoms, while others only cause mild symptoms; therefore, screening is extremely important for sexually active individuals. Untreated STIs are associated with increased risk of HIV, chronic pelvic pain, and reproductive issues associated with pregnancy. In the United States, those most affected by STIs are people ages 15 to 24, gay and bisexual men, pregnant individuals, and racial and ethnic minority groups (CDC, 2022af). The eight most common STIs are chlamydia, gonorrhea, hepatitis B, herpes simplex virus type 2, HIV, human papillomavirus, syphilis, and trichomoniasis (CDC, 2022af).


Caused by infection with Chlamydia trachomatis, chlamydia is the most frequently reported bacterial STI, resulting in cervicitis, urethritis, and proctitis. In 2018, there were an estimated 4 million chlamydia infections in the United States (CDC, 2022c). Many individuals are asymptomatic and do not seek testing. Screening is necessary to identify most infections and can reduce the rates of adverse outcomes in women. In women, untreated infections can lead to pelvic inflammatory disease (PID), tubal infertility, ectopic pregnancy, and chronic pelvic pain (CDC, 2022c). In men, untreated infections rarely result in major health problems but may cause infertility. Chlamydial infections are most common in young people ages 15 to 24 and BIPOC individuals. In 2020, chlamydia rates for Black individuals were six times the rate seen in White individuals (CDC, 2022c).

Chlamydia is transmitted via vaginal, anal, or oral sex with an infected partner. Ejaculation is not necessary to transmit the infection. It can infect the pharynx, cervix, urethra, upper reproductive tract, rectum, and conjunctiva. Symptoms in women may include abnormal vaginal discharge and dysuria. Symptoms may include penile discharge, dysuria, and pain and swelling in one or both testicles in men. Symptoms of rectal chlamydia may include rectal pain, discharge, and bleeding. Pregnant individuals can pass chlamydia to their baby during childbirth, resulting in pre-term delivery, conjunctivitis, and pneumonia in the neonate (CDC, 2022c).

When used correctly and with each sexual encounter, condoms can reduce the risk of chlamydia. Avoiding oral, vaginal, and anal sex is the only way to prevent chlamydia. Being in a mutually monogamous relationship with a partner who does not have chlamydia also lowers one’s risk (CDC, 2022c).


Caused by Neisseria gonorrhoeae, gonorrhea is the second most commonly reported bacterial STI. Approximately 1.6 new infections occurred in the United States in 2018, with more than half among individuals ages 15 to 24. Because many infections are asymptomatic, the true number of cases may be much higher than reported (CDC, 2022o). Any sexually active individual can become infected, but most cases are among teenagers, young adults, and Black individuals (CDC, 2022o).

Gonorrhea is transmitted via sexual contact with the penis, vagina, mouth, or anus of an infected partner. Ejaculation is not needed for transmission. It infects the mucous membranes of the reproductive tract in women and of the mouth, throat, eyes, and rectum of both men and women (CDC, 2022o). Gonorrhea can also be spread during childbirth. Infection in newborns may result in blindness, joint infection, or sepsis; treatment of gonorrhea in pregnant individuals reduces the risk of these complications.

Symptoms in women are often mild, nonspecific, and mistaken for bladder or vaginal infections. Initial symptoms include dysuria, increased vaginal discharge, and bleeding between menses. Symptoms in men occur one to 14 days after infection and include dysuria; white, yellow, or green urethral discharge; and potential testicular or scrotal pain indicative of concomitant epididymitis, a complication of urethral infection (CDC, 2022o). Rectal infection may also be asymptomatic or cause discharge, anal itching, pain, bleeding, or painful bowel movements. Pharyngeal infection may result in a sore throat or may be asymptomatic (CDC, 2022o). Complications of gonorrhea include PID in women, which may lead to chronic pelvic pain, infertility, or increased risk of ectopic pregnancy. In men, complications include epididymitis and infertility. Untreated gonorrhea can potentially spread to the blood, resulting in disseminated gonococcal infection (DGI), a life-threatening infection characterized by arthritis, tenosynovitis, and dermatitis (CDC, 2022o).

When used correctly and with every sexual encounter, latex condoms reduce the risk of gonorrhea. Avoiding oral, vaginal, and anal sex is the surest way to prevent gonorrhea. Being in a long-term, mutually monogamous relationship with a partner who does not have gonorrhea is another way to lower one’s risk (CDC, 2022o).

Healthy People 2030

Sexually Transmitted Infections

Healthy People 2030 has a focused goal of reducing sexually transmitted infections and improving access to quality STI care. Data demonstrates worsening rates for three of the 22 objectives that apply to this goal: reducing syphilis rates in females, reducing gonorrhea rates in male adolescents and young men, and reducing congenital syphilis rates. These worsening rates have led to a push to increase screening for these diseases and to provide updated STI treatment guidelines for providers.


Rates of syphilis, a bacterial STI caused by Treponema pallidum, have steadily risen over the past 20 years. In 2021, the United States reported 176,713 cases, an approximately 73 percent increase over a four-year period (CDC, 2022ak). MSM accounted for 43 percent of all primary and secondary cases, but cases are increasing among heterosexual individuals. Congenital syphilis, another growing concern, occurs when a pregnant person passes syphilis to the fetus. Over 2,800 cases of congenital syphilis were reported in 2021, a 185 percent increase since 2017 (CDC, 2022ak).

Syphilis spreads through direct contact with a syphilitic chancre (sore) that is usually located on or around the penis, vagina, anus, rectum, lips, or mouth (CDC, 2022ak). It is also transmitted during vaginal, anal, or oral sex and pregnancy. When a pregnant client has syphilis, the infection can spread to the fetus, resulting in a high risk of stillbirth or death shortly after birth. Untreated syphilis in pregnant clients results in infant death in up to 40 percent of cases (CDC, 2022ak). A newborn with congenital syphilis may be asymptomatic, but without immediate treatment, serious problems such as developmental delays, seizures, and death may ensue (CDC, 2022ak).

Often beginning three weeks after initial infection, symptoms may resemble those of many other diseases, yet they follow a typical progression, with each stage potentially lasting for weeks, months, or years. At any stage of infection, syphilis can invade the nervous system (neurosyphilis), the visual system (ocular syphilis), and the auditory and vestibular systems (otosyphlis). The four stages are as follows:

  • The primary stage starts with a single or multiple firm, round, painless chancres located where syphilis entered the body that last three to six weeks and then heal, regardless of treatment. Without treatment, syphilis will progress to the secondary stage (CDC, 2022ak).
  • In the secondary stage, lesions develop in the mouth, vagina, or anus, and skin rashes that are not usually itchy and may appear as rough red or reddish-brown spots appear on the palms of the hands and soles of the feet. They can be very faint, making them difficult to see. Condyloma lata—large, raised gray or white lesions—may develop in moist, warm areas such as the mouth, axilla, and groin. Other symptoms are fever, swollen lymph nodes, sore throat, headaches, weight loss, myalgias, fatigue, and patchy hair loss. These symptoms will resolve with or without treatment, but an untreated infection will progress to the latent and potentially tertiary stage of disease (CDC, 2022ak).
  • In the latent stage, there are no visible symptoms, and without treatment, it will remain in the body. This stage can last for years.
  • Tertiary syphilis may develop in some untreated syphilis infections, appearing 10 to 30 years after initial infection and affecting multiple organ systems. This stage is rare, but it can be fatal.

Condoms, when used correctly, can reduce the risk of syphilis; however, transmission can occur if the condom does not cover the lesions. Avoiding oral, vaginal, and anal sex is the only way to avoid syphilis. Being in a mutually monogamous relationship with a partner who does not have syphilis is another way to lower one’s risk of getting syphilis (CDC, 2022ak).

The Roots of Health Inequities

The Tuskegee Syphilis Study

In 1932, the U.S. Public Health Service (USPHS) authorized a study to evaluate the effects of untreated syphilis. Six hundred Black men from Tuskegee, Alabama, were selected to be a part of the study. These men were mostly poor sharecroppers with limited education. They were recruited under the false pretense that were being treated for “bad blood.” Two-thirds of the men were confirmed to have syphilis but did not receive treatment despite the availability of penicillin, which by 1943 was the treatment of choice to cure syphilis.

Watch the video, and then respond to the following questions.

  1. Why do you think the USPHS and the Tuskegee Syphilis Study investigators allowed this study to continue for 40 years while withholding treatment for 32 of those years?
  2. Do you think these investigators would have conducted this study on higher-income or White individuals? Why or why not?
  3. What role, if any, does nursing have in preventing this type of unethical medical research from occurring?

Role of the Nurse in Preventing Sexually Transmitted Infections

The nurse has an important role to play in preventing STIs, identifying them early, and getting them treated appropriately. The CDC provides guidelines for teaching clients about reducing the risk of getting or transmitting STIs. Table 13.10 shows examples of primary, secondary, and tertiary prevention interventions for STIs.

Primary Prevention
Education regarding the transmission of STIs and how to avoid them
  • Abstinence is the only way to be sure to avoid contracting an STI.
  • If sexually active, correctly and consistently using protection, such as a condom, with every sexual encounter can significantly decrease the risk of contracting an STI but does not eliminate the risk.
  • Any contact with a syphilitic chancre may result in transmission of syphilis.
  • Instruct clients to have conversations with their sexual partner(s) regarding the number of sexual partners and testing frequency.
Secondary Prevention
Screening for STIs
  • Screen all sexually active women under the age of 25 for chlamydia and gonorrhea and retest three months after treatment for these infections.
  • Screening sexually active MSM annually at sites of contact (urethra, rectum) for chlamydia, at sites of contact (urethra, rectum, pharynx) for gonorrhea, and for syphilis. Additionally, screen every three to six months if at increased risk.
  • Adapt screening recommendations for transgender and gender diverse persons to anatomy, meaning extend the annual routine screening for chlamydia in cisgender women under the age of 25 to all transgender men and gender diverse individuals with a cervix.
  • Educate client at every visit that for any signs and symptoms of an STI, it is important to get evaluated and screened.
Tertiary Prevention
Prompt referral for treatment for any positive STI screening.
Table 13.10 Prevention of Sexually Transmitted Infections (See CDC, 2022w.)

Healthy People 2030

Infectious Disease

Healthy People 2030 includes many objectives related to infectious diseases, STIs, and vaccination. Reducing the rates of hepatitis B and C deaths and the overall rate of viral hepatitis diseases along with decreasing the incidence of tuberculosis and pertussis are major goals. Healthy People also includes objectives related to increasing the number of individuals who get recommended vaccines and the maintenance of these vaccination records in an information system.

Vaccine-Preventable Diseases (VPDs)

The introduction of vaccines is a significant public health victory as many notifiable infectious diseases, such as diphtheria, measles, polio, tetanus, and rubella, have nearly been eliminated in the United States (CDC, 2022q). By the time a child reaches age 2, they can be vaccinated against 14 potentially life-threatening illnesses if the vaccine guidelines have been followed (CDC, 2022q). In adolescence, additional vaccines are available to prevent pertussis, meningococcal disease, and human papillomavirus. Since 2020, COVID-19 has remained in the top 10 leading causes of death, in the number three spot behind heart disease and cancer (CDC, 2023h). This illustrates the importance of monitoring for communicable disease and the role of public health in keeping individuals and communities safe.

The CDC (2022g) recommends vaccines to prevent the following vaccine-preventable diseases (VPDs):

  • Hepatitis A
  • Hepatitis B
  • Human papillomavirus
  • Influenza
  • Hib (Haemophilus influenzae type b)
  • Measles
  • Meningococcal disease
  • Mumps
  • Pertussis
  • Pneumococcal disease
  • Polio
  • Rotavirus
  • Rubella
  • Tetanus
  • Varicella
  • COVID-19

While vaccines are considered the best way to prevent diseases and outbreaks, not everyone gets vaccinated. Only 70 percent of children born in the United States in 2016 received their recommended vaccines by age 2 (CDC, 2022q). Non-Hispanic Black children were less likely to receive their early childhood vaccine series than non-Hispanic White children (CDC, 2022q). As fewer children are vaccinated, the United States has seen the reemergence of VPD outbreaks. Unvaccinated children risk becoming infected and transmitting these infectious diseases to others, including to individuals who are too young or too immunocompromised to be vaccinated.

Get Vaccinated and Prevent Measles

Globally, measles remains a highly contagious disease, and each year, unvaccinated Americans contract it while traveling abroad and then spread it to other individuals who are unvaccinated (Vaccinate Your Family [VYF], 2022). Measles outbreaks have occurred more frequently in the United States over the past decade, often in communities with groups of unvaccinated individuals. In 2019, the CDC reported almost 1,300 cases of measles in 31 states, and of these individuals, 10 percent were hospitalized (VYF, 2022). This is concerning, especially for children under age 1 who are unable to be vaccinated. Prior to the measles, mumps, rubella (MMR) vaccine, three to 4 million individuals in the United States contracted measles, and about 500 died (VYF, 2022).

This video from the CDC demonstrates how unvaccinated individuals can transmit VPDs to the most vulnerable individuals in our communities—babies, individuals who are immunocompromised, and older adults.

Watch the video, and then respond to the following questions.

  1. Which populations are most at risk of contracting measles? What makes them vulnerable?
  2. As a nurse, what is your responsibility in relation to preventing measles?
  3. How would you explain the importance of getting a measles vaccination to a client who is hesitant to get a vaccination?

An endemic disease in the United States, whooping cough (pertussis) is transmitted easily from person to person, with outbreaks occurring in schools, childcare centers, hospitals, and even in large geographic areas (CDC, 2022ao). Like any endemic disease, whooping cough may cause an outbreak, during which public health officials focus on protecting those at higher risk of getting sick and dying. Outbreaks are often difficult to identify; many cases go unreported because a variety of other illnesses cause similar symptoms. Whooping cough is a nationally notifiable disease with local and state health departments taking the lead on investigations. During an outbreak, public health nurses may be involved in active screening at schools, hospitals, and childcare centers to reduce exposure to individuals with pertussis, recommend timely medical evaluation, and promote prompt use of antibiotics to high-risk close contacts.

In the United States, up to 20 babies die each year due to pertussis (VYF, 2022). To decrease the risk in young babies, the CDC recommends women receive Tdap vaccination during each pregnancy, preferably between the 27th and 36th weeks (CDC, 2022ao). Before routine vaccination, pertussis was one of the most common childhood diseases and a major cause of death in children. While the vaccine has decreased its incidence, immunity diminishes, highlighting the importance of receiving recommended vaccinations at the recommended times.

Nurses play a critical role in educating individuals and communities about the importance of adhering to the recommended vaccination schedule. This includes being fully informed of the vaccine schedule, indications, contraindications, and types of available vaccines. The CDC has published You Call the Shots, an interactive, web-based immunization training course for nurses and other health care professionals discussing VPDs and current recommendations for vaccine use. Holding immunization clinics, visiting clients in their homes, providing pre–school entry immunization reviews, and offering accessible and convenient community information sessions are pivotal to gaining acceptance by vaccine-hesitant individuals. Nurses should follow the guidelines on nationally notifiable diseases and prepare accordingly by ordering the appropriate vaccines and necessary supplies to administer them.

Emerging Infectious Diseases

Emerging infectious diseases (EIDs) are those that are newly affecting populations or existing diseases that previously only caused isolated disease but are now significantly increasing in incidence and geographic range (National Institute of Allergy and Infectious Diseases [NIAID], 2018; Wang et al., 2021). Bioterrorism Category A, B, and C priority pathogens are also considered EIDs (Table 13.11) (NIAID, 2018). Because these diseases are new or were once less common, there are often minimal effective treatments and no cures. Without the benefit of prior knowledge and a lack of immunity, health care providers often contract EIDs as they tend to ill clients (WHO, 2014). Many EIDs are zoonotic in origin, emerging from animals and crossing the species barrier to infect humans (WHO, 2014). EIDs remain a global health threat as they can spread rapidly, posing a risk to the health and development of every country. As the COVID-19 pandemic has demonstrated, infectious diseases can cause significant death and disability and wreak havoc on the world economy, disrupting every level of society. Table 13.12 lists some emerging infectious diseases (Wang et al., 2021).

Category A Pathogens Category B Pathogens Category C Pathogens
Definition Organisms/biological agents that pose the highest risk to public health and national security Pathogens that are the second-highest-priority organisms Pathogens that have the third-highest priority; include emerging pathogens that could be engineered for mass dissemination
Characteristics Easily disseminated and transmitted from person to person, resulting in high mortality rates and potentially causing public panic and social disruption, requiring special action for public health preparedness Moderately easy to disseminate, resulting in moderate morbidity rates and low mortality rates, requiring enhanced diagnostic capacity and disease surveillance Easily available, easy to produce and disseminate, with the potential for high morbidity and mortality rates resulting in a major health impact
  • Bacillus anthracis (anthrax)
  • Clostridium botulinum toxin (botulism)
  • Yersinia pestis (plague)
  • Variola major (smallpox)
  • Francisella tularensis (tularemia)
  • Viral hemorrhagic fevers
  • Burkholderia pseudomallei (melioidosis)
  • Coxiella burnetii (Q fever)
  • Brucella species (brucellosis)
  • Epsilon toxin (Clostridium perfringens)
  • Ricin toxin (Ricinus communis)
  • Typhus fever (Rickettsia prowazekii)
  • Food and waterborne pathogens such as Diarrheagenic E. coli, pathogenic vibrios, Shigella species, Salmonella, Listeria monocytogenes, hepatitis A, Cryptosporidium parvum, Giardia lamblia, and Toxoplasma gondii
  • Mosquito-borne viruses such as WNV, Eastern Equine Encephalitis, Japanese encephalitis virus, yellow fever virus, and Chikungunya virus
  • Nipah and Hendra viruses
  • Hantaviruses
  • Tick-borne hemorrhagic fever viruses such as bunyaviruses and flaviviruses
  • Tick-borne encephalitis complex flaviviruses
  • Tuberculosis, including drug-resistant TB
  • Influenza virus
  • Rabies virus
  • Prions
  • Severe acute respiratory syndrome associated coronavirus
  • Antimicrobial resistance
Table 13.11 Bioterrorism EIDs/Pathogens
Infectious Disease Pathogen Primary Transmission
Hantavirus pulmonary syndrome Hantavirus Zoonotic
Hendra virus infection Hendra virus Zoonotic
Nipah virus infection Nipah virus Zoonotic
Highly pathogenic avian influenza H5N1, H7N9 influenza virus Zoonotic
Severe acute respiratory syndrome SARS-CoV-1 Respiratory droplet
Middle East Respiratory Syndrome MERS-CoV Zoonotic
Lyme disease Borrelia Vector-borne
Bartonellosis Bartonella Zoonotic
Cryptococcus gattii infections Cryptococcus gattii Environmental
Cyclosporiasis infections Cyclospora cayetanensis Foodborne, waterborne
Variant Creutzfeldt-Jakob disease Prion Zoonotic, foodborne
Table 13.12 Emerging Infectious Diseases

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