Guarding farm animals against Leptospirosis

Leptospirosis can infect most mammals including sheep, cattle, deer, goats and dogs. Picture supplied

by Dr Andrew Cribb, East Coast Farm Vets

With an incredible amount of rain over the last year it’s not surprising there have been cases of Leptospirosis in farm animals, as well as working dogs.

Leptospirosis is caused by the bacteria Leptospira interrogans that occurs throughout New Zealand and the world. There are over 150 serovars of L. interrogans, of which six are found in NZ and a 2012 study found Lepto positive animals on 97 percent of sheep and beef farms and 76 percent of deer farms.

Leptospirosis can infect most mammals including sheep, cattle, deer, goats and dogs. It is one of New Zealand’s most important diseases that can be transmitted from animals to humans by being in an infected area. It can have serious consequences, including damaging the kidneys, and as such, it should have a place in every on-farm health and safety policy.

In cattle, Lepto can cause severe disease. Clinical signs can include; loss of appetite, abortion, stillborn or weak calves, mastitis and possible future issues with infertility.

In sheep, if an outbreak occurs in lambing hoggets, some lambs will be found dead and others will be lethargic and not eating. They may have red-coloured urine that often stains the wool on the hocks and crutch area and may also have pale, muddy-coloured or yellow mucus membranes due to jaundice. It can also cause abortion in ewes.

Animals that recover from Leptospirosis continue to excrete Leptospires in the urine for a long period of time. Research shows sheep can excrete Leptospires in their urine for up to 11 months.

Leptospires survive in cool, wet conditions. Areas where there are stagnant water and contaminated effluent are the major sources of infection in the environment.

Infection in humans is relatively common in agricultural workers, rural veterinarians, abattoir workers and forestry workers. Infection typically occurs by contamination with infected urine (urine splashes into the eye, nose and mouth) and abortion or placental material entering through the skin. The consumption of raw milk, from a cow within the acute phase of infection can also pose a risk of infection.

In 90 percent of cases, severe flu-like symptoms are encountered with the immune system usually mounting an effective response. In 10 percent of cases, clinical signs are similar, but without medical intervention liver and kidney failure can occur.

To prevent an outbreak on your farm, discuss your vaccination programme with your veterinarian, ensure your rodent control is maintained, keep pigs away from cattle/sheep and fence off or drain any contaminated/stagnant water supplies.