Spread
How is leptospirosis spread?After clinical leptospirosis with Lepto Hardjo, infection localises in the kidney, Leptospira are then shed in the urine for a variable amount of time until the cow develops immunity to the disease. This can take up to 2 years. A small percentage of cows will continue shedding indefinitely. These cows, that are not showing signs of disease, but are shedding the bacteria, are called carriers.
Carrier cows will spread massive numbers of leptospira every time they urinate. The bacteria cannot withstand drying and will not last long in the environment. Therefore direct contact with infected urine as liquid or splashed into aerosol form is the main mode of transmission.
Leptospira will readily invade mucous membranes. The nose, mouth and eyes are particularly susceptible. Non-immune animals including humans are at risk of infection any time a carrier cow urinates nearby. The dairy is an ideal place for transmission.
As the number of carrier cows in the herd increases, so does the risk of infection to both humans and cows.
What are the symptoms of leptospirosis in humans?
Leptospirosis causes severe influenza-like symptoms that persist longer than a normal case of the flu. Symptoms include fever, headache, sore muscles and general malaise.