Zoonotic TB may be public health threat in Zambia

Cross infection of tuberculosis between humans and animals in Zambia may be a considerable threat to public health in the country, according to a recent report from the Norwegian School of Veterinary Medicine.

Sidney Malama, a researcher with the school's department of food safety and infection biology, conducted doctoral research on the incidence of tuberculosis among humans and animals in Zambia. Malama found that Mycobacterium tuberculosis, the most common TB bacterium in humans, also occurs among cattle in Zambia's Namwala region.

According to the research, Namwala contains a large degree of genetic variation amongst M. tuberculosis strains in humans and the bacteria isolated from humans and cattle are respectively related. Because the bacterium is found in cattle, the animals may be a reservoir for human tuberculosis. Humans may become infected with M. tuberculosis and M. bovis by eating untested meat and by drinking unpasteurized milk.

Malama concludes that health authorities, cattle owners and wildlife managers must work together to stop zoonotic TB in Namwala and its bordering areas. He said a one health approach adapted to local needs should be employed to control the spread of TB in the area.

The incidence of all forms of human TB in Zambia is estimated to be 444 infections per 100,000 people.