Nairobi — The high incidence of bovine tuberculosis (BTB) in cattle on large dairy farms in central Ethiopia threatens farmers' incomes and public health, according to a study.
As a result, the study calls for a concerted effort to control the disease and prevent the transmission of Mycobacterium bovis, the bacteria that causes it, to humans consuming dairy products from these farms.
Around 30 per cent of the nearly 3,000 dairy cattle from 88 herds around the capital, Addis Ababa, that were investigated for the study tested positive for BTB, while more than half the herds contained cattle that gave positive tests.
According to the authors, livestock is extremely important for people's livelihoods in Ethiopia and so the disease's impact on cattle increases their financial burden.
"It has been suggested that cattle with BTB have a reduced productivity affecting milk yield and carcass value," says the paper published in PLOS One.
The authors say that the high infection rate in the dairy farms is "likely to pose a serious risk to public health and deserves a targeted intervention as early as possible".
The researchers suggest that "government and policymakers should work together with stakeholders to design methods for the control of BTB in intensive farms in Ethiopia".
Mesfin Sahile, director of the National Animal Health Diagnostics and Investigation Center in Ethiopia and one of the paper's authors, says that separating sick animals from the herd for slaughter is a good way to tame the disease.
According to Sahile, farms where infected animals have been culled should be cleaned and proper follow-ups carried out to check that the rest of the herd remains healthy.
The disease, he says, poses a high risk to those working with these animals as herders, milkers and butchers, as well as to those eating their products, especially unpasteurised milk.
Henry Kiara, an epidemiologist and senior research officer at the International Livestock Research Institute in Nairobi, Kenya, agrees that the most effective control measure is to test and cull animals that test positive for BTB.
"There would have to be some form of compensation for farmers who volunteer the sick animals for this to succeed, hence the critical role of the Ethiopian government," he tells SciDev.Net.
This article has been produced by SciDev.Net's Sub-Saharan Africa desk.
PLoS ONE doi: 10.1371/journal.pone.0052851 (2012)