The Govt. of India proposes to declare India free of Tuberculosis probably by 2025. TB being a zoonotic disease and Mycobacterium bovis being known to be resistant to first line anti-tb drugs, poor milk and meat hygiene all make a case for parallel animal TB eradication program if we really intend to eradicate the disease.
Communicable TB among humans is associated with Mycobacterium tuberculosis. There are many other species of mycobacteria in the environment and humans exposed to these appear to develop sensitivity (as detected by reactivity to skin tests with antigens for those bacteria) which might provide some degree of cross-protection against M. tuberculosis. Yet to my knowledge only M tuberculosis is prone to be transmited efficiently among humans. I suppose the real challenge to elimination of TB in humans is not TB as a zoonosis but rather the huge burden of 'silent' carriers of M tuberculosis that exist in the population. In some regions, up to 50% of the population is asymptomatically infected and may become infectious many years later.
@Manuel C Gomes: TB is also caused by Mycobacterium africanum and M. bovis, both of which also can be transmitted between humans.
Tuberculosis is an important bacterial zoonotic disease, which is endemic in many nations of the world including India. In my opinion, total elimination of disease in India and other countries is not possible without its eradication in animal population. I strongly recommend the permanent involvement of Public Health Veterinarian in the control of zoonoses including tuberculosis.
Prof.Dr.Mahendra Pal
MVPH, Ph.D., D.Sc.
TB is only a zoonosis if caused by Mycobacterium bovis (a very rare condition!!). It is not considdered a zoonosis if, as normally (in 99% of cases) is the case, by M. tuberculosis or, in some parts of Africa, by M. africanum. Public Health Veterinarians are not really required in the fight against TB.
Hi,
I agree with the opinion of Prof. Pal; It has to start from eradicating the disease in animals before we actually report complete eradication. Animals, though may not be the only major reason for its spread, are predominantly cited for the spread of TB. Hence, the government and related organizations should work on all the factors responsible for the complete eradication of such a disease.
Sorry and with all respect: this is not true. TB is in more than 99% of cases spread from human to human, not from animals to humans.
I agree: animals are not the issue in so far as TB elimination in humans is concerned. The real issue is to surpass two common obstacules in TB control and then deal with latent infection in humans. The two well-known huge obstacules are (1) to achieve early detection of most humans (>90%?) who become infectious and then (2) to warrant that their follow-up treament is fulfilled. Once this is achieved, incidence is expected to decline *gradually*. But if the goal is elimination, how to cope with the enormous burden of population that is infected (and assymptomatic) with M tuberculolsis? WHO used to claim that 1/3 of the human population is infected (though the vast majority will never have disease). As Christian pointed out, transmission of M tuberculsos from animals to humans is negligible, that is a diversion from the real issues.
A further obstacle in control or even elimination is MDR-, XDR- and TDR-TB.
Although in principle it should be possible to eradicate infectious diseases if humans are the only hos of the pathogen (as is the case for M. tuberculosis, not though for M. bovis) I doubt that TB will be eradicated in the next 100 years. Please consider that 1/3 of the worlds population are infected, albeit not clinically diseased.
The number of unpasteurised milk and infected meat being consumed by the population plays an important role in the transmission of bovine tuberculosis to human beings. the condition is not as rare as you think. a lot of butchers in abattoirs in Nigeria are currently infected with bovine tuberculosis and the population has somehow adopted the consumption of tuberculosed lungs as a delicacy. it is called "fuku elegusi".
There is a constant rise in the cases of bovine tuberculosis being mistaken for human tb in clinics in Nigeria. So there is a need of a multidisciplinary approach to tackle this growing problem. Christian G Meyer
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