The work on developing a satisfactory test for bTB in camelids has moved a stage further with the release of some of the results for the second stage of the research into a PCR test. This test essentially looks for the DNA of the bTB bacillus in nasal swabs or the faeces of an animal suspected of having the disease.
The research is now showing that the PCR test can detect bTB at quite an early stage in its development in a camelid. This work has been initiated by the TB Support and Advisory Group and both British Camelids and BLS have contributed significantly to the work which is being done by the VLA in their Starcross Laboratory.
If this develops well then a PCR test offers a relatively cheap and easy way of testing for TB. It is non-invasive and provided care is taken in taking the faecal samples then there is no risk of false positives.
You can find out more on the TBSRG website at www.alpacatb.org and click on the PCR tab and then explore the associated PCR pages.
The same website also offers a nice explanation of the recent VLA research on the various anti-body tests – click on the bTB tests tab.
DEFRA advice to owners regarding the use of anti-TB drugs on
camelids suspected of having TB
Members are urged to take heed of the advice from DEFRA given below for the welfare of themselves, their own animals and the national alpaca herd.
DEFRA’s advice is that suspect clinical cases of TB should be notified to Animal Health and culled rather than treated with anti-TB drugs.
Owners need to be aware of the risks posed by treating suspect cases. Effective treatment of TB in humans is quite a complex, long and costly process involving a six-month course of at least three different drugs. To our knowledge, the effectiveness of such drugs and protocols has never been properly evaluated in South American camelids.
Assuming that an infected camelid will consistently receive the right dose of the appropriate drugs over a long enough period, it may remain infective to humans and other animals for some time.
Many treatment regimes, whilst seemingly capable of resolving the clinical signs of TB, will not result in a complete microbiological cure (elimination of all the bacilli) and may result in latent infections and potentially the development of drug resistance, resulting in serious public and animal health risks.
Additionally, owners need to be aware that by treating animals for TB they are jeopardising the only method of control currently available to infected herds (testing and slaughter of any positives) due to the suppressive effects the drugs may have on the immunological responses detected by the ante-mortem diagnostic tests. Animal Health may, therefore, be unable to undertake any TB testing of infected camelid herds if they become aware that owners are administering anti-TB drugs to some of their animals.
Vice Chairman BLS & Health & Welfare Representative