Leptospirosis is caused by infection with a bacteria of the species Leptospira.
At least five species of Leptospira have been found to affect cattle. The disease is associated with infertility, abortion and has been identified as a cause of milk drop.
How is the disease transmitted?
The bacteria localise in the reproductive tract and the kidneys and spreads when cattle are exposed to the urine of infected animals.
The disease can also be transmitted through contaminated water.
Sheep can also become infected and, although the disease does not manifest itself, they remain carriers.
Leptospirosis can be passed to humans. It is not a notifiable disease. Infection is passed through contact with urine, placental material or the aborted foetus of infected animals.
What are the clinical signs of the disease?
The first sign is often a drop in milk yield, but other signs are:
- loss of appetite
- sudden loss of milk with flaccid udder (flabby bag)
- abortion - usually 6-12 weeks after infection
Prevention & control measures
- do not mix cattle with sheep
- fence off contaminated water (all natural water courses should be assumed to be infected)
- treat all bought in animals with antibiotics until properly vaccinated
- vaccination is the best control method, significantly reducing the level of abortion and the risk of spread to man. Vaccines prevent the disease but do not eliminate the organism so yearly boosters are essential to keep the herd infection free.
Sources: NADIS; The Cattle Site; World Organisation for Animal Health