Seroprevalence of Paratuberculosis in Goats and Sheep in Arusha, Northern Tanzania

A retrospective crosssectional study was conducted to investigate the seroprevalence of paratuberculosis in small ruminants in the Arusha Municipality. A total of 383 samples comprising of 192 goat and 191 sheepsera from Arusha Municipality collected in the late 2010 and early 2011 by Tanzania Veterinary Investigation Agency Arusha for surveillance on peste des petits ruminants were tested for antibodies specific to Mycobacterium avium subspecies paratuberculosis using the commercially available PARACHEK2 indirect ELISA kit. Twenty one (21) of 192 (10.9 %: 95 % CI; 7.3 16.1 %) goat sera were positive; however none of 191 sheep sera screened were sero-positive for paratuberculosis. This is the first report on seroprevalence of paratuberculosis in goats in Arusha and in Tanzania as a whole. The fact that seropositive cattle were previously detected in samples collected in the same flock at the same time indicates the disease is well established in the Arusha. Furthermore, the co-infection of cattle and goats may have implication on the epidemiology of the disease in the area. The sero-negativity of all sheep samples tested is yet to be established but may be due one or a combination of factors. Since the Parachek ELISA kit is capable of detecting responses in sheep, one of the possible reasons may be that the prevalent M. paratuberculosis strain (s) in Arusha is type II or C strain that preferentially infects cattle and goats as opposed to type I or S strain which preferentially infects sheep. Alternatively, the prevalence and or the antibody titres in sheep may have been too low to be detected within the sensitivity of the Parachek ELISA kit.