Diagnosis
Following on from our discussion last week as to what bovine tuberculosis is, today we look at further diagnosis, treatment and management.
While bovine TB generally takes a chronic debilitating course, it can be more severe and rapidly progressive.
Although there are several ways bovine TB can be diagnosed, the most common method is the tuberculin test. This involves antigen being injected into the skin and the animals' immune reaction being measured. To ensure a definitive diagnosis the bacteria is then grown in a laboratory over several weeks. This method has its drawbacks as its sensitivity can range from 48% to 95% and requires regular retesting. An article published recently www.farms.com/ag-industry-news/better-bovine-tb-te... suggests researchers in New Mexico have "made a breakthrough that could lead to a more efficient way of testing for bovine tuberculosis". This breakthrough is based on the test that was developed for human TB as in both cases "the disease is recognised by specific biomarkers." It is hoped this method will be able to easily distinguish between exposure and infection.
Another diagnosis method is smear testing material from the lining of the inner wall of a lesion.
While bovine TB generally takes a chronic debilitating course, it can be more severe and rapidly progressive.
Although there are several ways bovine TB can be diagnosed, the most common method is the tuberculin test. This involves antigen being injected into the skin and the animals' immune reaction being measured. To ensure a definitive diagnosis the bacteria is then grown in a laboratory over several weeks. This method has its drawbacks as its sensitivity can range from 48% to 95% and requires regular retesting. An article published recently www.farms.com/ag-industry-news/better-bovine-tb-te... suggests researchers in New Mexico have "made a breakthrough that could lead to a more efficient way of testing for bovine tuberculosis". This breakthrough is based on the test that was developed for human TB as in both cases "the disease is recognised by specific biomarkers." It is hoped this method will be able to easily distinguish between exposure and infection.
Another diagnosis method is smear testing material from the lining of the inner wall of a lesion.
Prevention and Management
While there is no preventative treatment to protect your cattle from M. bovis there are certain steps to reduce the risk of infection:
Approved property programs (APP) were introduced and implemented in the BTEC and TFAPs. These document the agreement between an owner and a state government on the implementation of a program. An APP is a prerequisite for any property that is involved in TB investigation or eradication.
Refer to the bovine tuberculosis case response manual for more information on dealing with bovine TB www.animalhealthaustralia.com.au/our-publications/...
Note: In Australia, you are legally required to report any suspected cases of bovine TB.
- Maintain a closed herd.
- When purchasing cattle, purchase from a reliable source and ask about the test history of the animals.
- Prevent contact with other herds by maintaining boundaries, grazing away from neighbouring herds and minimising return of cattle from markets.
- Minimise visitor contact with your herd
- Keep cattle housing and equipment clean and disinfected.
- Avoid sharing equipment, machinery and vehicles with other farmers.
- Don't rely on natural water sources for your cattle and prevent access where possible.
- Carry out required testings properly and on time.
- Have a strict biosecurity plan for your property.
Approved property programs (APP) were introduced and implemented in the BTEC and TFAPs. These document the agreement between an owner and a state government on the implementation of a program. An APP is a prerequisite for any property that is involved in TB investigation or eradication.
Refer to the bovine tuberculosis case response manual for more information on dealing with bovine TB www.animalhealthaustralia.com.au/our-publications/...
Note: In Australia, you are legally required to report any suspected cases of bovine TB.
Key Facts and Important Things to Consider
- In cattle, M. bovis can spread from other infected animals, or picked up from contaminated environments, food and water, milk, urine, faeces and other discharges such as from the nose or mouth.
- People can be infected by consuming unpasteurised products from infected animals, inhaling infectious air and from direct contact such as open wounds. Anyone at risk or who has been exposed to an infected animal should seek medical advice and treatment.
- The spread of the disease is often influenced by the density of the cattle.
- Tubercle bacillus was discovered as the cause of tuberculosis in 1881 by Robert Koch. M. bovis was identified over 15 years later in 1898.
- M. bovis is killed by sunlight but flourishes in moist warm conditions such as soil and faeces. It can survive for up to 8 weeks in cattle faeces.
- A commissioned report (Tolson and Jervois 1990) that examined national records including the National Tuberculosis Case Register found that the disease can reoccur up to 15 years after eradication.
- A revival of bovine TB in Australia is considered possible so monitoring and prevention requirements should be thoroughly maintained and carried out.
- The TFAP introduced definitions to establish the difference between 'TB incidents' and 'TB cases'. A 'TB incident' is when there is detection of any evidence of TB while a 'TB case' is a case of TB that has actually been confirmed by testing, laboratory findings or tracebacks.