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ANNEX K
Example of Case definition
1. Hemorragic Colits: Escherichia
coli O157:H7, EHEC.
2. Clinical description:
An infection, with variable severity, characterized by diarrhea
(sometimes bloody) and abdominal cramps. The vomits happen
occasionally and the fever doesn´t exist or is very low. In
some cases a watery diarrhea is observed. The duration of the
disease is on average 8 days. It can be complicated with a
Hemolytic Uremic Syndrome (HUS),
or Thrombotic Thrombocytopenic Purpura (TTP); also no symptomatic
infections can happen.
3. Criterion of the Laboratory
diagnostic:
• Isolation of E. coli 0157: H7
• Isolations of E. coli 0157: NM
4. Case Classification
Suspect: a HUS case or TTP
post-diarrheic (see HUS definition)
Probable:
- a case with E.coli 0157 isolation of hanging clinical sample to
confirm the presence of antigen H7 or verotoxin.
- a clinically compatible case that is related epidemiologically
with a confirmed or probable case.
Confirmed:
- a laboratory case confirmation.
5. Opportunity and notification
In agreement with national decisions
6. Complementary information
6.1.Incubation Period: 3 to 9 days, on average 4 days
6.2. Transmission: person to person by way of fecal-oral,
contaminated food or water with man or animals fecal material,
recreational water. The infection dose is not known but it is
presumed that 10 cells are sufficient to infect.
6.3 Reservoirs: man and animals intestine.
6.4 Food samples: suspected food are those without a sufficient
heating or raw (in general, ground meat, raw milk, apple juice,
cured buds of alfalfa, dry inlays, vegetables of leaf).
6.5. Clinical samples: fecal material for isolation of E.coli
until one week, after the symptoms beginning.
6.6 Measures of control: Identification of the associated food,
revision of the handling and heating process. In the cases of
boiled water, until a good process of chlorination would be
verified In order to avoid the transmission person to person,
indicate the frequent washing of hands and exclusion or isolation
of the patients in geriatrical and gardens or schools (consider the
possibility of closing of such until knowing the origin of the
outbreak). In the hospitals apply procedures of control of
infections.
6.7 Measures of prevention: Heating of the meat ground to a
minimum temperature of 70ºC (158ºF) (gray aspect, without
pink juice), pasteurized milk and apple juice, the water
chlorination, washing and disinfection the raw vegetable. Personal
hygiene and hygienic handling of foods to avoid the
cross-contamination.
7. Institutions of reference and
consult
Direction of the Institute or National Reference Laboratory:
- For clinical samples
- For food samples.
8. Mention of the Methods applied for
the laboratory diagnostics:
- Clinical laboratories.
- Bromatologics laboratories.
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