Acute infectious gastroenteritis is a common illness that affects persons of all ages worldwide. It is a leading cause of mortality among children in developing countries, accounting for an estimated 0.7 million deaths each year, and is responsible for up to 10–12% of all hospitalizations among children in industrialized countries, including the United States. Elderly persons, especially those with debilitating health conditions, also are at risk of severe complications and death from acute gastroenteritis. Among healthy young adults, acute gastroenteritis is rarely fatal but incurs substantial medical and social costs, including those of time lost from work.
Several enteric viruses have been recognized as important etiologic agents of acute infectious gastroenteritis (Table 98-1, Fig. 98-1). Although most viral gastroenteritis is caused by RNA viruses, the DNA viruses that are occasionally involved (e.g., adenovirus types 40 and 41) are included in this chapter. Illness caused by these viruses is characterized by the acute onset of vomiting and/or diarrhea, which may be accompanied by fever, nausea, abdominal cramps, anorexia, and malaise. As shown in Table 98-2, several features can help distinguish gastroenteritis caused by viruses from that caused by bacterial agents. However, the distinction based on clinical and epidemiologic parameters alone is often difficult, and laboratory tests are required to confirm the diagnosis.
TABLE 98-1VIRAL CAUSES OF GASTROENTERITIS AMONG HUMANS |Favorite Table|Download (.pdf) TABLE 98-1 VIRAL CAUSES OF GASTROENTERITIS AMONG HUMANS
|VIRUS ||FAMILY ||GENOME ||PRIMARY AGE GROUP AT RISK ||CLINICAL SEVERITY ||DETECTION ASSAYS |
|Group A rotavirus ||Reoviridae ||Double-strand segmented RNA ||Children <5 years ||+ + + ||EM, EIA (commercial), PAGE, RT-PCR |
|Norovirus ||Caliciviridae ||Positive-sense single-strand RNA ||All ages ||+ + ||EM, RT-PCR |
|Sapovirus ||Caliciviridae ||Positive-sense single-strand RNA ||Children <5 years ||+ ||EM, RT-PCR |
|Astrovirus ||Astroviridae ||Positive-sense single-strand RNA ||Children <5 years ||+ ||EM, EIA, RT-PCR |
|Adenovirus (mainly types 40 and 41) ||Adenoviridae ||Double-strand DNA ||Children <5 years ||+/+ + ||EM, EIA (commercial), PCR |
Viral agents of gastroenteritis. NV, norovirus; SV, sapovirus.
TABLE 98-2CHARACTERISTICS OF GASTROENTERITIS CAUSED BY VIRAL AND BACTERIAL AGENTS |Favorite Table|Download (.pdf) TABLE 98-2 CHARACTERISTICS OF GASTROENTERITIS CAUSED BY VIRAL AND BACTERIAL AGENTS
|FEATURE ||VIRAL GASTROENTERITIS ||BACTERIAL GASTROENTERITIS |
|Setting ||Incidence similar in developing and developed countries ||More common in settings with poor hygiene and sanitation |
|Infectious dose ||Low (10–100 viral particles) for most agents ||High (>105 bacteria) for Escherichia coli, Salmonella, Vibrio; medium (102–105 bacteria) for Campylobacter jejuni; low (10–100 bacteria) for Shigella |
|Seasonality ||In temperate climates, winter seasonality for most agents; year-round occurrence in tropical areas ||More common in summer or rainy months, particularly in developing countries with a high disease burden |