Preventing Spread Of Cattle Tuberculosis To Humans

In recent years, there has been an upsurge in the population of people infected with tuberculosis in Nigeria. And the country has been ranked fourth among the countries with the highest burden of tuberculosis in the world.

According to World Health Organisation (WHO), 349 people out of a population of 100,000 Nigerians are infected with tuberculosis and the mortality rate is 89 out of 100,000 people.

Tuberculosis constitutes a big threat to the society, as an infected person is capable of infecting 10 to 15 people annually. Tuberculosis is a zoonotic infection which means that it is transmissible from animals to humans, and vice versa.

Researches by veterinary scientists in the country have indicated that the prevalence of tuberculosis in cattle is 10 per cent, and that the consumption of infected milk and meat from tuberculosis-infected cattle is a major source of infection of humans with tuberculosis.

In some developing countries like Nigeria, efforts to control human tuberculosis by stakeholders in the health sector are mainly directed at human-to-human transmission. This is because the occurence and severity of transmission from infected cattle to humans is undermined; therefore, such efforts are limited in effectiveness.

In Germany, for instance, successful eradication of human tuberculosis by the government was preceded by terminal policy implementation for the control of the disease in cattle. Terminal policy approach includes slaughtering and destruction of all tuberculosis-infected cattle in the country and the provision of financial compensations to owners of all slaughtered cattle.

In addition to undermining of the importance of implementing effective control policy for cattle tuberculosis, the inability of developing countries to effectively control human tuberculosis is majorly due to government budget constrain, arising from prioritisation of government’s efforts towards construction of roads, buildings and settlement of political conflicts.

Thus, governments of developing countries are unable to adopt terminal policy for effective control of cattle tuberculosis. Hence, the adoption of partial or total condemnation of carcass policy for slaughtered tuberculosis- infected cows or bulls at abattoirs to prevent the sale of infected meat to the public.

This policy approach includes inspection of carcass of slaughtered cows or bulls at abattoirs by veterinarians or trained animal health technologist for organs with tuberculous lesions. Organs such as the lungs and liver detected to have tuberculous lesions are severed from the whole carcass and confiscated for destruction.

In cases where tuberculous lesions are detected to be generalised on the carcass, the whole carcass is confiscated for destruction. Owners of confiscated infected meat or whole carcass are usually not compensated financially. They are expected to bear the financial loss.

This policy for the control and prevention of the transmission of cattle tuberculosis to humans is ineffective and prone to leakage of infected organs from the abattoir to the market. Unsuspecting people that buy such infected organs as meat, and consume the organs, particularly as poorly cooked delicacies in peppersoup, are predisposed to infection with tuberculosis, as in the case of people who are sold unpasteurised local milk from from tuberculosis infected cows.

Current human tuberculosis control policies in Nigeria and some other developing countries are immunisation and Directly Observed Therapy Short course (DOTs) and these are limited and not holistic for the gradual eradication of human tuberculosis.

A holistic policy approach to the control of human tuberculosis in these countries is to scale up the effectiveness of the current control policy for cattle tuberculosis, in addition. In order to achieve this goal, model effective control policy for zoonotic diseases in developing countries should be adopted and implemented.

For instance, an effective zoonotic disease control policy utilised in Brazil is the animal disease-free zone establishment policy. Under this policy, an animal disease free-zone is established and only animals certified to be healthy and free of diseases that are transmissible to other animals and man are allowed to exist within the zone.

Also, to scale up the current control policies for human tuberculosis in Nigeria, relevant agencies of the health sector should launch a national campaign in the mass media to enlighten the public as to the danger of consuming unpasteurised cow milk.