Corynebacterium pseudotuberculosis infection in Israeli cattle: clinical and epidemiological studies.

Morbidity due to Corynebacterium pseudotuberculosis infection occurred in 29 dairy herds in Israel during 1989 to 1995. The disease occurred sporadically in 17 of the herds with a morbidity of up to 5 per cent, and was epidemic in 12, with a morbidity of 5 to 35 per cent. Cutaneous abscesses were diagnosed in 609 animals. Young cattle appeared to be less susceptible to the disease than older cows. Beef cattle herds were not affected. The disease appeared in the cutaneous form in 92.5 per cent of cases, the cutaneous and mastitic form in 5.9 per cent and the cutaneous and visceral form in 1.6 per cent. The cutaneous form appeared as deep subcutaneous abscesses on various parts of the body, with granulating ulcers exuding pus and blood. In 10 of the herds, C pseudotuberculosis was isolated from 33 mastitic cows which also had cutaneous lesions. The visceral form of the disease was detected when severely affected animals were slaughtered. In 23 of the herds, the disease occurred during the spring and summer dry season, from March to October; the highest prevalence was in the semi-arid Negev region. In 25 herds, the infection lasted for up to five months. The skin lesions on individual cows healed on average in 23.4 days, after either local or parenteral treatment. No significant difference was observed between the effect of systemic antibiotic treatment and local antiseptic treatment. One hundred and two (16.7 per cent) severely affected animals were culled. There was a decrease in milk production and large increases in somatic cell counts in the 12 herds in which the disease was epidemic. None of the strains of isolated C pseudotuberculosis reduced nitrate.