A herd level analysis of a Corynebacterium pseudotuberculosis outbreak in a dairy cattle herd.
Corynebacterium pseudotuberculosis infection in an Israeli dairy cattle herd is described. The disease was characterized by ulcerative granulomatous lesions, which occurred in an epidemic form. Thirty-two cows and two heifers were affected, the ratio of the number affected to number at risk being 17.5 : 1 and 9.5 : 1, respectively. The culling rate was 50% of the affected animals. Most of the affected animals were cows (91.2%), with one first-calving cow (2.9%) and two heifers (5.9%) also affected. The infection occurred during the summer to autumn months (August-December), and lasted 118 days. The incubation period is about 2 months. The disease appeared in two clinical forms - cutaneous and mastitic - or as a mixed form. C. pseudotuberculosis organisms that were isolated from the ulcerative granulomatous lesions and from milk samples failed to reduce nitrate. A decrease in milk production (4%) and an increase in the bulk-milk somatic cell count from a herd mean of 240 x 10(3) mL(-1) to 460 x 10(3) mL(-1) were noted during the morbidity period. The organism was isolated from milk samples of eight animals (25%). Clinical, epizootiological and microbiological aspects of the infection are described.
Yeruham
Israel
I
'Hachaklait' Gedera and the Koret School of Veterinary Medicine, the Hebrew University of Jerusalem, PO Box 12, Rehovot 76100, Israel. chkl1357@netvision.net.il
Friedman
Samuel
S
Perl
Samuel
S
Elad
Daniel
D
Berkovich
Yair
Y
Kalgard
Yoram
Y
D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology* / Q000209:etiology / Q000382:microbiology / Q000473:pathology; D003354:Corynebacterium Infections / Q000453:epidemiology / Q000662:veterinary*; D016925:Corynebacterium pseudotuberculosis / Q000302:isolation & purification*; D003612:Dairying; D004196:Disease Outbreaks / Q000662:veterinary*; D005260:Female; D007557:Israel / Q000453:epidemiology