USDA scientists find more effective commercial vaccine against leptospirosis

Tue, 2012-01-31 07:45 AM
By: Mark Rockwell

Agricultural scientists have found a more effective vaccine for a disease that can jump from cattle to humans.

Researchers at the U.S. Department of Agriculture said the new vaccine is more effective than existing treatments in preventing leptospirosis from being transmitted through cattle herds and possibly to humans .

The disease is the most common “zoonotic” bacteria that can be transmitted through animals to humans, although human infections are relatively rare. The infection is most commonly transferred to humans through water contaminated by animal urine coming in contact with unhealed breaks in the skin, the eyes, or with the mucous membranes. The contagious disease, which is caused by Leptospira bacteria, can also be spread through contact with food, water or soil contaminated with urine from infected animals. It can affect all farm animals, rodents and wildlife.

The new vaccine was developed by microbiologist Richard Zuerner, veterinary medical officer David Alt and their colleagues at the Agricultural Research Service (ARS) National Animal Disease Center (NADC) in Ames, IA, said USDA. The scientists tested a version of the vaccine and discovered that it induced some protection against experimental infection with Leptospira borgpetersenii serovar Hardjo, the main cause of leptospirosis in cattle.

ARS is USDA's chief intramural scientific research agency, and this research supports USDA priority of promoting international food security.

Alt and his colleagues, who work at the NADC Infectious Bacterial Diseases Research Unit, examined the vaccine's potency in reducing the shedding of bacteria, potentially affecting the spreading of leptospirosis in cattle herds, said USDA. They vaccinated cattle twice with this vaccine or twice with a standard or control vaccine. They also tested the vaccine's ability to induce short- and long-term immunity and found it appeared to be effective at both three-month and one-year period after vaccination, although, said USDA, improvements are needed. “Although the vaccine did not provide complete protection from shedding at one year after vaccination, it induced greater immunologic responses and protection against shedding of leptospirosis than the standard vaccine,” said USDA.

USDA scientists find more effective commercial vaccine against leptospirosis | Government Security News