5% of all acute diarrheas; increased in gay males (Ann IM 1984;101:338)
Table 6.5 Characteristics of Acute Diarrheal Infections*
| Agent | Quantity of Inoculum to Cause Disease | Usual Mode of Transmission | Incubation Period | Usual Symptoms | Diagnostic Methods | Duration of Symptoms | Duration of Shedding | Probability of Human-to-Human Spread† |
|---|---|---|---|---|---|---|---|---|
| Salmonella typhi | High (105 CFU)‡ | Human contact, prepared food, contaminated water | 5-14 d | Fever, abdominal pain, diarrhea | Blood culture, fecal culture | 3-4 wk | 2-6 wk, rarely lifetime | High |
| Salmonella(nontyphoidal) | Low (102-103 CFU) | Poultry, eggs, meat | 24 h (8-24 h) | Diarrhea, fever | Fecal culture | 2-4 d | 5 wk, rarely lifetime | Very low |
| Shigella | Low ( 102 CFU) | Human contact, prepared food, contaminated water | 3 d (1-7 d) | Diarrhea, fever | Fecal culture | 3 d (2-6) | Days to weeks | Very High |
| Campylobacter | Low | Poultry, milk, tap water | 3 d (1-7 d) | Diarrhea, fever | Fecal culture | 3 d (1-7) | 50% negative after 3 wk | Very low |
| Calicivirus | Low | Human contact (feces, vomitus), prepared food | 1 d (1-2 d) | Diarrhea, vomiting fever | RT-PCR | 2 d (1-3) | 3 d (1 d to weeks) | Very high |
| Rotavirus | Very low | Human contact | 2 d | Fever, vomiting, diarrhea (in infants) | EIA, latex agglutination | 4 d (3-9) | 4 d (2-7) | Very high |
| Astrovirus | Unknown | Human contact | 1-2 d | Diarrhea | EIA (not commercially available) | 2-5 d (1-14) | 4 d (1 d to weeks) | High |
| Adenovirus types 40 and 41 | Unknown | Human contact (feces possibly vomitus) | 2-3 d | Diarrhea, vomiting, fever | EIA (not commercially available) | 2-4 d (1-7) | 5 d (3-11 d) | Low |
| Giardia | Low (102 organisms) | Tap water, human contact | 9 d (1-2 wk) | Abdominal discomfort, diarrhea | Microscopical examination of feces | 1-8 wk | 3 wk-6 mo | High |
| Cryptosporidium | Very low (1-2 cysts) | Tap water, human contact | 7 d (1-14 d) | Diarrhea, abdominal pain, headache, fever | Microscopical examination of feces | 10-12 d (3-60) | 7 d | Very low |
* This table is subject to the limitations of the medical literature (for some organisms, clinical studies are more detailed, whereas for other organisms the documentation may not exist, although the clinical syndromes may be very similar). In the entries in the columns “Incubation Period,” “Duration of Symptoms,” and “Duration of Shedding,” the numbers in parentheses indicate the range. “Shedding” is the time during which the infectious agent can be recovered from feces after the end of illness. CFU denotes colony-forming units, RT-PCR reverse-transcriptase–polymerase-chain-reaction assay, and EIA enzyme immunoassay.
† This column reflects the authors’ assessment of the likelihood of human-to-human spread, based on all the available sources of information as presented in the text.
‡ Experimental studies show a high inoculum, but some clinical observations suggest a low inoculum.
Musher D, Musher B. Nejm 2004;351:2417-2427.