TB testing

Tuberculosis is a major disease problem in England, especially in the South West and causes considerable amounts of stress for all those involved. The routine tuberculosis skin test works by measuring the skin reactions to 2 injection; one of avian tuberculin and one bovine tuberculin. This test has been used for a long time but can only measure the animal immune reaction to the injections. The quirks of the test are

• It will detect infected animals before they have easily visible signs of infection on post-mortem.
• It can not predict how fast the time course of the infection will be. e.g. in human we can become infected and carry the disease but show no signs for many years.
• Cattle that have a reduced immunity due to severe tuberculosis infection do not always react to the test.

All cattle that fail the tuberculosis test are removed from the herd and slaughtered. On post-mortem they are check for tuberculosis lesions which often are only the size of a pin head and may not be very numerous.

Tuberculosis can affect any mammals, though some are more resist to the infection and so it is rare to see infection in them e.g horse. Cattle, badgers, llama and alapaca are more susceptible to contracting tuberculosis.

The vast majority of cattle infected with tuberculosis are removed quickly from herds due to regular tuberculosis testing; unfortunately infected badgers can survive up to 3 years with tuberculosis.

The tuberculosis infection rate in England has reduced slightly over the last 6 months compared to the previous year at the same time period but locally we are still seeing the same number of tuberculosis reactors.

.