Corynebacterium pseudotuberculosis infection in Israeli dairy cattle

Abstract

Two forms of Corynebacterium pseudotuberculosis infection in Israeli dairy cattle herds during a survey period of 13 years (1989–2001) are described. The more common form, which was diagnosed in 45 herds, was characterized by ulcerative granulomatous lesions which occurred either sporadically – in 26 herds (with a morbidity rate of up to 5% – or in an epidemic course in 19 herds. Most (80·6%) of the affected animals were cows; the rest were first-calving cows (16·2%) and heifers (3·2%). The morbidity occurred mostly during the summer months. The ulcerative granulomatous lesions appeared in three clinical forms: cutaneous, mastitic and visceral. Mixed forms were also observed. The morbidity rate was 6·4% and the culling rate reached 16·3% of the affected animals. Most of the strains of C. pseudotuberculosis which were isolated from the abscesses in the cutaneous form of the disease and from milk samples failed to reduce nitrate. A decrease in milk production (6%) and an increase in bulk-milk somatic cell count were noted. Necrotic and ulcerative dermatitis on the heel of the foot occurred in an epidemic course in heifers in only two herds during the winter months, with morbidity rates of 7·5 and 76·2%, respectively. C. pseudotuberculosis isolates from skin lesions and from the soil did reduce nitrate. Clinical, epizootiological and microbiological aspects of the infection are described.