Seroprevalence of Chlamydia psittaci-specific antibodies in small stock in Namibia--epidemiological study with an enzyme-linked immunosorbent assay (ELISA).

Abstract

An IgG (H+L)-ELISA was applied as a screening test for antibodies against Chlamydia (C.) psittaci in sera of goats and sheep in Namibia. In 576 (27.3%) of a total of 2,107 sera (299 = 25.2% of 1,185 caprine and 277 = 30.0% of 922 ovine sera) chlamydial antibodies could be detected. 86% of all farms tested revealed seropositive animals. Chlamydial infections were prevalent in all the geographical regions tested. The infection rates per State Veterinary District varied from 12.0% (Otjiwarongo) to 50.0% (Otavi) in goats and from 13.3% (Otjiwarongo) to 41.7% (Windhoek) in sheep. The regional distribution of chlamydial infections was not related to geographical or climatic factors. Sera from herds showing symptoms indicative for chlamydial infections showed significantly higher antibody rates (35% in goats and 39% in sheep) than sera from herds without health problems (18% in goats and 24% in sheep). Considering only sera from farms with clinical history of chlamydiosis, high seroprevalences were correlated to the symptoms abortion and keratoconjunctivitis. As in other countries, enzootic abortion seems to be the main manifestation of chlamydial infection in small ruminants in Namibia. C. psittaci might also play a considerable role in the etiology of infectious keratoconjunctivitis, whereas association with other clinical entities seems to be rare.