The following information was originally found on Zoetis website. Zoetis is a FarmShop Australia Partner.
Leptospirosis is an important public health and animal health issue. It is an infectious disease of cattle, other livestock and humans. The disease can infect family members, employees, consultants or visitors coming in contact with infected cattle. The productivity and reproductive performance of the herd can also be significantly reduced if infected with leptospirosis.
What is leptospirosis?
Leptospirosis, or “Lepto” as it is commonly known, is a bacterial infection that colonises in the kidney and genital tract of its host. Leptospires can be shed from these organs into the urine for more than 12 months, consequently releasing more bacteria into the environment.
What causes leptospirosis?
Leptospira borgpetersenii serovar Hardjo type Hardjobovis (L. Hardjo) and Leptospira interrogans serovar Pomona (L. Pomona) are the most common types of bacteria causing leptospirosis in Australian beef and dairy cattle. There are several other less common serotypes that are found in cattle co-grazing in areas where feral pigs are prevalent.
What are the clinical signs?
L. Hardjo may affect cattle of all ages but clinical signs are usually only seen in pregnant or lactating cows. Most cattle show no obvious signs of infection to L. Hardjo but may be shedding the bacteria. Infection has been reported to cause abortion, usually from 4 months gestation to term and the birth of weak or stillborn calves. Sudden milk drop and fever, infertility and mastitis are also clinical signs of infection. A flaccid udder with all four quarters affected may occur. Infection with L. Pomona can cause an acute septicaemia in calves, which may result in high mortalities. “Red water”, anaemia and jaundice may also occur and adult cows may abort.
What conditions are favourable for leptospirosis?
Survival of leptospires in the environment depends on moisture conditions in the contaminated area. This includes wetter areas around a dairy, waterways and irrigated pastures. Leptospires will survive for at least 6 months in water-saturated soil, several months in running water and several weeks in stagnant water. Introduced stock can be a source of herd infection, however closed herds are not completely safe either as water from other properties could carry the bacteria.
How is it diagnosed in cattle?
The diagnosis of leptospirosis is difficult and consultation with a veterinarian is required. Blood tests can be used but the best way to diagnose infection is to culture the bacteria from an aborted foetus, placenta or infected milk. However this is not usually very successful as leptospirae are difficult to culture.
How do people contract leptospirosis?
Humans contract leptospirosis from specific host animals. In people, the disease causes a “flu-like” illness that ranges from mild to severe. Infections due to L. Hardjo and L. Pomona are among the most common types of leptospirosis reported in people in Australia. The main source of exposure is through direct contact with infected urine, for example during milking, artificial insemination or when yarding and loading cattle. Assisted calving may also pose a risk as foetal fluids and placental material may be contaminated. Leptospires enter the body through the mucous membranes of the eyes and mouth, damaged skin due to abrasions or water softened feet.
Who is at risk?
A strong occupational link has been identified for many leptospirosis sufferers. Dairy farmers, beef producers, abattoir workers, meat inspectors, relief milkers, veterinarians, artificial inseminators (Al), herd testers, stock agents, stock transporters and visitors to farms have all been diagnosed with leptospirosis.
What are the symptoms of leptospirosis in humans?
Profound fatigue, severe headache, high fever, muscular aches and pains, sore eyes, nausea and vomiting.
Can leptospirosis be prevented in cattle?
Pfizer recommends the use of Ultravac® 7in1 or Leptoshield® because they are registered in Australia for the prevention of renal colonisation and urinary shedding of L. Hardjo and L. Pomona in uninfected animals. This means that following vaccination, animals which then come into natural contact with the organisms will not only resist infection, but they will also not excrete the organisms in their urine – true protection! Ultravac® 7in1 also provides protection against the five main clostridial diseases – black disease, blackleg, pulpy kidney, malignant
oedema and tetanus.
Ultravac® 7in1 and Leptoshield® are the only vaccines with an early calf vaccination program that is recommended from 4 weeks of age although it may be more practical to begin vaccination at 6 weeks of age to prevent the use of 3 doses (see vaccination schedule overleaf). This enables greater flexibility of calf vaccination and ensures protection against disease from the earliest possible age. It is important to have calves fully vaccinated before they are challenged. This will reduce the chance of cattle and human infection.
Early vaccination of calves is important to prevent infection and the development of urinary shedding in carrier animals. Animals that are already infected and shedding leptospires at the time of vaccination may continue to shed leptospires for 12 months or more.
Ultravac® 7in1 and Leptoshield® are also the only leptospirosis vaccines that can prevent reproductive tract colonisation and prevent foetal and placental infection with L. Hardjo.
What vaccination program is recommended?
The primary vaccination course consists of 2 doses of vaccine, with the second dose administered 4–6 weeks after the first. Annual booster doses are necessary to maintain protection.
Vaccination of calves
Ultravac® 7in1 and Leptoshield® are the only lepto vaccines that have been shown to be efficacious in the presence of maternal antibodies. Where calves are expected to have adequate levels of maternal antibodies, vaccination should be commenced at about 6 weeks to 3 months of age. If the level of maternal antibodies is expected to be low or absent, vaccination should be commenced at 4 weeks of age. If the second vaccination is given at less than 3 months of age, a booster should be given at 6 months. The recommended vaccination schedule is shown above.
All cattle on the farm can potentially be infected and shed leptospires if not vaccinated. This includes bulls and steers. When beginning a vaccination program or introducing new stock with an unknown vaccination history, it is essential to vaccinate all the animals with a primary vaccination course consisting of two doses,4–6 weeks apart. It should be noted that introduced animals already infected with leptospirosis may still excrete leptospires after vaccination and may require concurrent treatment with antibiotics.
Recommended vaccination program
Two doses 4–6 weeks apart, then a single booster dose annually. 1st Dose, 2nd Dose, Booster.