Shedding of Coxiella burnetii in milk by Nigerian dairy and dual purposes cows.

Fresh milk from dairy cows kept at semi-intensive husbandry in governmental and institutional farms and dual purpose Fulani nomadic husbandry around Zaria, Nigeria were screened for Coxiella burnetii using the mouse inoculation test. Of the 20 herds from both management systems tested, 16(80.0%) contained dairy cows shedding C. burnetii in their milk. Of a total of 169 cows tested, 41(24.3%) were shedders. Eighteen (22.0%) of 82 cows kept under semi-intensive and 23(26.4%) of 87 cows kept under Fulani nomadic systems were shedding C. burnetii. The difference in frequency of shedding C. burnetii between both system was not statistically significant (P greater than 0.05, X2). Of the 88 dairy cows serologically tested for C. burnetii agglutinins by the capillary agglutination test (C.A.T), 48(54.5%) were sero-positive and 40(45.5%) were seronegative. Among Q-fever sero-positive cows, 11(22.9%) were shedders and 37(77.1%) were not shedding C. burnetii in their milk. Of the sero-negative cows, 6(15.0%) and 34(85.0%) were shedders and non-shedders, respectively. With milk from Fulani nomadic cows predominantly taken raw or made into unheated fermented milk products, the health risk to the consumers of such products cannot be over-emphasized.