Epidemiologic Notes and Reports Campylobacter Outbreak Associated with Raw Milk Provided on a Dairy Tour -- California
On October 3, 1985, students and teachers from northern California, and some of their family members, made a field trip to a San Joaquin County dairy. Of the 50 attendees from whom information was available, 23 (46%) became ill with Campylobacter jejuni infection.
Twenty-three (59%) of the 39 attendees who drank raw milk, and none of the 11 who did not drink it, became ill (p = 0.0005). Included among the cases was an infant who had been almost exclusively breast-fed and became ill after drinking a bottle filled with raw milk at the dairy. In addition, secondary cases occurred in two women who had not visited the dairy but who tended an infant who drank raw milk and developed campylobacter gastroenteritis. Stool cultures from one asymptomatic and eight ill persons grew C. jejuni. Neither the cows nor milk were cultured.
Of the 23 ill field-trip attendants, 96% reported diarrhea; 35%, abdominal cramps; 35%, fever; 26%, vomiting; and 22%, bloody diarrhea. Incubation periods ranged from 1 day to 10 days, but were 3 or 4 days in most cases. Symptoms most commonly lasted 5 days. Adapted from California Morbidity (February 7, 1986) as reported by B Benda, Contra Costa County Health Dept, J Pollak, R Benjamin, MD, T Livermore, MD, Alameda County Health Dept, H Mitchell, MD, San Joaquin Local Health District, SB Werner, MD, J Chin, MD, State Epidemiologist, California Dept of Health Svcs; Enteric Diseases Br, Div of Bacterial Diseases, Center for Infectious Diseases, CDC.
Editorial Note: Numerous outbreaks of enteric diseases have occurred among schoolchildren given raw milk while on field trips to dairies in the United States (1-5). As a result, in January 1985, the U.S. Food and Drug Administration (FDA) issued a "milk advisory" to all state school officers recommending that children not be permitted to sample raw milk on such visits.
Healthy lactating cows can carry C. jejuni in the intestinal tract, providing an extrinsic source of contamination. In one study of 193 healthy dairy cows at three dairies, 77 (40%) had positive rectal cultures (6). In another study of 477 dairy cows, 69 (14%) had C. jejuni cultured from bile (7). In addition, cows with no evidence of illness can excrete Campylobacter directly into their milk as a result of mammary infection (8). Fourteen (61%) of 23 Campylobacter outbreaks reported to CDC from 1980 to 1982 were traced to consumption of raw milk (5). Since culture of diarrheal stools for C. jejuni became common, many raw milk-associated Campylobacter outbreaks involving thousands of cases have been reported (9,10).
Milk is an excellent vehicle for infection, because its fat content protects pathogens from gastric acid and because, being fluid, it has a relatively short gastric transit time (11). Present technology cannot produce raw milk that can be assured to be free of pathogens; only with pasteurization is there this assurance (11). Since 1983, when Scotland banned the sale of raw milk, milkborne infection has decreased markedly (1). References 1. Korlath JA, Osterholm MT, Judy LA, Forfang JC,
References 1. Korlath JA, Osterholm MT, Judy LA, Forfang JC, RobinsonRA. A point-source outbreak of campylobacteriosis associated with
consumption of raw milk. J Infect Dis 1985;152:592-6. 2. CDC. Campylobacteriosis associated with raw milk consumption --
Pennsylvania. MMWR 1983;32:337-8, 344. 3. California Department of Health Services. Campylobacter outbreak
associated with certified raw milk products, L.A. County. California Morbidity #23, June 15, 1984. 4. California Department of Health Services. Campylobacter outbreak
after consuming raw milk on a field trip to a dairy . . . . FDA action on this recently identified public health problem. California Morbidity #9, March 8, 1985. 5. Finch MJ, Blake PA. Foodborne outbreaks of campylobacteriosis:
the United States experience, 1980-1982. Am J Epidemiol 1985;122:262-8. 6. Martin WT, Patton CM, Morris GK, Potter ME, Puhr ND. Selective
enrichment broth medium for isolation of Campylobacter jejuni. J Clin Microbiol 1983;17:853-5. 7. Warner DP, Bryner JH, Beran GW. Epidemiologic study of
campylobacteriosis in Iowa cattle and the possible role of unpasteurized milk as a vehicle of infection. Am J Vet Res 1986;47:254-8. 8. Hutchinson DN, et al. Evidence of udder excretion of
Campylobacter jejuni as the cause of milk-borne Campylobacter outbreak. J Hyg Cambridge 1985;94:205-5. 9. Jones DM, Robinson DA, Eldridge J. Serological studies in two
oubreaks of Campylobacter jejuni infection. J Hyg Cambridge 1983;87:163-70. 10. Robinson DA, Jones DM. Milk-borne Campylobacter infection. Br
Med J 1981;282:1374-6. 11. Potter ME, Kaufmann AF, Blake PA, Feldman RA. Unpasteurized
milk: the hazards of a health fetish. JAMA 1984;252:2048. 12. Sharp JCM, Paterson GM, Barrett NJ. Pasteurisation and the
control of milkborne infection in Britain. Br Med J 1985;291:463-4.
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