Leptospirosis Diseases of Cattle in the Tropics

Abstract

Bovine leptospirosis is a disease of cattle caused by at least 23 serologically distinct serovars (serotypes) of Leptospira interrogans. Leptospires also cause disease in other domestic animals, wildlife and man.

Acute leptospiral infections in cattle are clinically recognized by fever, icterus, hemoglobinuria and agalactia. The signs vary extensively in incidence and intensity. Pregnant cattle infected during the last third of gestation frequently either abort or give birth to dead or weak calves. Chronic leptospirosis has been associated with infertility.

Diagnosis of leptospirosis is usually dependent upon serologic evidence correlated with an evaluation of clinical signs. Isolation of the leptospires from urine of recently affected cattle can often be accomplished with the use of special media or inoculation of laboratory animals such as the weanling hamster.

Cattle generally respond to treatment with streptomycin or tetracyclines if the administration occurs before lesions are advanced. Vaccination alone or in combination with antibiotic therapy can reduce spread of the disease when administered early in a herd infection. Vaccination with polyvalent leptospiral bacterins provides clinical protection if antigens of the homologous serovars of the region are contained in the bacterin.

Preventive measures should also include separation of the cattle from other livestock and fencing off pasture areas where surface waters have been contaminated by urine from other potential carrier hosts.