Chapter 122. Acute Infectious Diarrheal Diseases and Bacterial Food Poisoning (Part 6) pptx

Acute Infectious Diarrheal Diseases and Bacterial Food Poisoning Part 6 Table 122-3 Epidemiology of Traveler's Diarrhea Etiologic Agent Approximate Percentage of Cases Comments Ent

Chapter 122 Acute Infectious Diarrheal Diseases

and Bacterial Food Poisoning

(Part 6)

Table 122-3 Epidemiology of Traveler's Diarrhea

Etiologic Agent Approximate

Percentage of Cases

Comments

Enterotoxigenic

Escherichia coli

15–50 Single most important

agent, particularly in summertime in semitropical areas; percentage of cases ranges from 15% in Asia to 50% in Latin America

Enteroaggregative

E coli

pathogen of worldwide distribution

Shigella and

enteroinvasive E coli

10–25 Major causes of fever

and dysentery

Salmonella 5–10 Causes fever and

dysentery

Campylobacter

jejuni

3–15 More common in winter

in semitropical areas; more common in Asia

Aeromonas 5 Important in Thailand

Plesiomonas 5 Related to tropical travel

and seafood consumption

Vibrio cholerae 0–10 Most common in India

and Asia; also common in Central and South America

Rotavirus and 10–40 Latin America, Asia,

and Africa; norovirus

norovirus associated with seafood

ingestion on cruise ships

Entamoeba

histolytica

5 Particularly important in

Mexico and Thailand

Giardia lamblia <2 Zoonotic reservoirs in

northern United States; affects hikers and campers who drink from freshwater streams; contaminates water supplies in Russia

Cryptosporidium 2 Affects travelers to

Russia, Mexico, and Africa; causes large-scale urban outbreaks in United States

Cyclospora <1 Affects travelers to

Nepal, Haiti, and Peru; contaminates water or food

Unknown 20 Illness improves with

antibacterial therapy, implicating bacterial diarrhea

Source: After Dupont

Location

Day-care centers have particularly high attack rates of enteric infections Rotavirus is most common among children <2 years old, with attack rates of 75–

100% among those exposed G lamblia is more common among older children,

with somewhat lower attack rates Other common organisms, often spread by

fecal-oral contact, are Shigella, Campylobacter jejuni, and Cryptosporidium A

characteristic feature of infection among children attending day-care centers is the high rate of secondary cases among family members

Similarly, hospitals are sites in which enteric infections are concentrated In medical intensive-care units and pediatric wards, diarrhea is one of the most

common manifestations of nosocomial infections C difficile is the predominant

cause of nosocomial diarrhea among adults in the United States Viral pathogens,

especially rotavirus, can spread rapidly in pediatric wards Enteropathogenic E

coli has been associated with outbreaks of diarrhea in nurseries for newborns

One-third of elderly patients in chronic-care institutions develop a significant diarrheal illness each year; more than half of these cases are caused by cytotoxin-producing C difficile Antimicrobial therapy can predispose to pseudomembranous colitis by altering the normal colonic flora and allowing the

multiplication of C difficile (Chap 123)