Epidemiologic Notes and Reports Chronic Diarrhea Associated with
Raw Milk Consumption -- Minnesota
On July 10, 1984, the Minnesota Department of Health was
informed
by Brainerd, Minnesota, physicians that 20-50 patients in that area
had experienced onset of chronic diarrhea since January 1984; they
were unaware of any patients who had recovered. Initial
investigation
by the Minnesota Department of Health identified 23 persons who met
the case definition of acute onset of diarrhea, lasting at least 4
weeks, in a person with no underlying illness known to cause
chronic
diarrhea. A case-control study of these case-patients and 46
gender-
and age-matched neighborhood controls revealed that illness was
strongly associated with drinking raw milk from a local dairy (p
0.1
x 10))-5))); no other risk factors were identified, and the dairy
voluntarily stopped selling raw milk. Based on a study of 94
families
(394 persons) who were regular customers of the dairy, the attack
rate
for chronic diarrhea with onset between November 1, 1983, and
September 1, 1984, was 8%. All age groups were affected, but the
attack rate was lowest for children (3%) and highest for adults
61-80
years of age (23%).
A review of medical records for patients hospitalized with
diarrhea at the community hospital since January 1982 and
interviews
of regular and occasional customers of the dairy identified 122
outbreak-related case-patients. The first case-patient had onset
of
illness in December 1983 with onsets continuing through July 1984
(Figure 3). All case-patients had consumed raw milk from the
implicated dairy during the 3 weeks before onsets of illness. To
date
there is no evidence of person-to-person transmission of illness.
Illness was characterized by acute onset of watery diarrhea
(frequently 10-20 stools per day) often associated with marked
urgency
that greatly limited patients' activities. Over 50% of the
case-patients also experienced abdominal cramping. Nausea,
vomiting,
and/or systemic symptoms occurred infrequently. Seven patients who
drank raw milk only on 1 day or 2 consecutive days had onsets of
illness 4-23 days after exposure (median 15 days). Although many
patients have noted gradual improvement in the frequency of
diarrheal
episodes, only 11 (9%) have fully recovered. Twenty-two patients
have
received empiric therapy with at least one antimicrobial agent for
at
least 7 days. Metronidazole (14 patients), erythromycin (eight),
tetracycline (two), trimethoprim/sulfamethoxazole (two), and
cephalexin (one) were used; no one responded to treatment.
Continuing
microbiologic and toxicologic studies performed at CDC of clinical
specimens, raw milk samples, and environmental samples from this
dairy
have not yielded any known enteric pathogens or toxins.
Reported by Acute Disease Epidemiology Section, Minnesota Dept of
Health; Enteric Diseases Br, Div of Bacterial Diseases, Center for
Infectious Diseases, CDC.
Editorial Note
Editorial note: The etiologic agent of this illness has not yet
been
identified, but available data suggest an infectious etiology. Raw
milk was implicated as the vehicle of transmission in this
outbreak.
However, as with other enteric pathogens, such as Salmonella sp.,
and
Campylobacter jejuni, for which raw milk is an important vehicle,
other as yet unidentified vehicles may also be associated with this
illness. To aid in further understanding this syndrome, outbreaks
of
diarrheal illness similar to that reported here should be reported
to
CDC through local and state health departments.
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