The common disease of Dairy cows and treatments
Transmissible spongiform encephalopathy (TSE) overview
Overview
| Cause |
There has been a lot of debate over the cause of this group of diseases and whether an infectious agent is involved. An abnormal protein, known as a prion protein, accumulates in the tissues of affected animals and is thought to be associated with the development of the disease. |
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| Description |
A group of progressive neurological disorders that are transmissible and affect a number of animal species and people. The significant TSEs in animals are:
Other less common TSEs in animals are:
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| Where scrapie and BSE occur |
Scrapie has occurred in Europe for over 200 years. It is also seen in the US, Canada and a few other countries. It is not known to occur in Australia. BSE was first described in the UK in 1987 and has since been identified in smaller numbers in many other countries in the world. Australia is internationally recognised as having a negligible risk for this disease. |
| Scrapie in sheep |
Scrapie is a fatal, chronic disease of adult sheep and goats, characterised by pruritus, abnormalities of gait, and a very long incubation period. It is thought that scrapie is associated with an infectious agent, but that the susceptibility of the host animal is determined by genetics. The main signs of scrapie in sheep are:
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| BSE in cattle |
BSE is a neurological disease affecting adult cattle. It was first described in the UK during 1987 but was thought to have been present for some years before that. The source of the disease was the feeding of manufactured feedstuffs. Studies suggest that meat and bone meal was the carrier of the disease agent and changes in the rendering processes had allowed the agent to be available to infect cattle. Bans on the feeding of meat and bone meals to ruminants resulted in a decline in the epidemic. The main signs signs of BSE in cattle are:
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| Australia's TSE freedom assurance program |
BSE has had a major economic affect on international beef trade. Consumers worldwide have often expressed their concerns for the public health risk associated with BSE in cattle. Australia, with its recognised negligible risk status for BSE has a considerable trade advantage. Australia protects its status and ensures continued freedom from these diseases through the national TSE freedom assurance program. Australia ensures that it remains free of these diseases by controlling the import of live animals, animal products and animal feeds, having a legislated ruminant feed ban in place and conducting targeted surveillance of cattle and sheep. |
| Can people can get the disease? |
In other countries, there are several spongiform encephalopathies occurring rarely in people. Variant Creutzfeldt-Jakob disease (vCJD) of people is thought to be caused by the same agent as BSE in cattle. There is no evidence that scrapie can be transmitted to people. |
