Leptospirosis in Livestock
By : Dr. Cody Egnor, State Vet’s Office
Leptospirosis is a bacterial disease caused by the Leptospira bacteria. Unfortunately, Leptospirosis is a zoonotic disease meaning it can infect multiple species including humans. There are many species or serovars of Leptospirosis and many of those serovars can infect multiple species and show different clinical signs. Two main serovars of Leptospirosis include Hardjo bovis and Pomona.
These serovars often present in a wide range of wildlife populations, including rats and mice. Leptospirosis can survive in surface water, stagnant ponds, streams, or moist soil for long periods. Once it infects the host it will survive indefinitely inside the kidneys. While there, Leptospira will be shed in the urine and infect other animals.
Signs of Leptospirosis in livestock generally include; high fever, abortions (fetal loss), weak offspring, and retained placenta. Its primary effects devastate the liver and kidneys. Unfortunately, the two serovars may infect a susceptible animal at the same time and present with different concurrent clinical signs. Abortion with the hardjo bovis serovar usually occurs within 2-3 months after infection while infections with the Pomona serovar usually occurs within 6 weeks. In cases where cows aren’t getting pregnant and bull issues are ruled out then Leptospirosis should be considered in addition to other diseases like Tritrichomonas feotus.
In the last 10 years there have been great advances in vaccine production technology specifically for Leptospirosis. These newer vaccines have expanded the range of serovars the vaccines cover as well as help prevent the colonization of Leptospira into the kidneys. This greatly reduces Leptospira shedding as well as helps prevent fetal loss and increases survival of livestock.
The prevalence of Leptospirosis in Arizona is lower than the levels of other places in the country that have a more favorable environment. However, Leptospirosis is still present in Arizona in livestock and wildlife, and a vaccination regimen should be discussed with your Veterinarian and added to a yearly herd vaccination plan.