Leptospirosis is a disease first described in the literature nearly 70 years ago. In cattle the principal serovars of Leptospira interrograns are L. hardjo-bovis, L. pomona, L. canicola, L. icterhaemorrhagiae, L. grippotyphosa and L. szwajjizak. L. hardjo-bovis is the serovar most frequently associated with reproductive wastage in the United States. Of the remaining serovars, L. pomona is the most significant. Many aspects of the disease remain poorly understood, e.g. variation in disease pattern and disease impact associated with different strains of the same host-maintained serovor in different management systems and different parts of the world.
This presentation focuses on L. hardjo-bovis. Cattle are the maintenance host and the only reservoir. In general, a disease associated with infection of the maintenance host is sub-clinical, produces low antibody titers and affects young or pregnant animals with a very rapid transmission rate from animal to animal. Maintenance host diseases can be very difficult to diagnosis. L. hardjo-bovis is currently diagnosed using a combination of serology and identification of leptospires in the urine. A prevalence study indicated there is a high prevalence of L. hardjo-bovis in the rolling plains of Texas.
Control of this disease consists of implementing biosecurity measures, use of antibiotics to clear carrier states and use of a vaccine effective for L. hardjo-bovis.
