Experimental infection of calves with Escherichia coli O157:H7.
Three 3-month-old Japanese Black calves were experimentally infected with Escherichia coli O157:H7 to define the magnitude (CFU/g) and duration of fecal shedding of the organism. In two of the three calves, fecal shedding of E. coli O157:H7 ceased in 5 and 9 weeks. The remaining calf continued shedding E. coli O157:H7 for more than 31 weeks, and the magnitude of the shedding ranged from 10(1) to 10(4) CFU/g of feces. The possibility is suggested that a percentage of animals naturally infected with E. coli O157:H7 on farms may become long-term shedders, transmitting the organism to other animals in the herd and to the proximate environment.
Ohya
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Kyushu Research Station, National Institute of Animal Health, Kagoshima, Japan.
Ito
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H
D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D003967:Diarrhea / Q000662:veterinary; D004197:Disease Reservoirs / Q000662:veterinary*; D004927:Escherichia coli Infections / Q000382:microbiology / Q000517:prevention & control / Q000662:veterinary*; D019453:Escherichia coli O157 / Q000472:pathogenicity*; D005243:Feces / Q000382:microbiology*; D013997:Time Factors