Epidemiologic study of chlamydial infection in sheep farms in Madrid, Spain

A cross-sectional study was conducted in a population of sheep in Madrid (Spain) to assess seroprevalence and to identify risk factors for chlamydial infection. Information from 57 flocks was collected and 512 animals were sampled. The effects on the seroprevalence of several variables, such as farm management practices, farmer characteristics, animal health and veterinary services were evaluated using a random-effects logistic regression model. The seroprevalence to Chlamydia spp. was 50.5% (+/- 4.5(95% CI)) using the Complement Fixation Test with a 1.32 cut-off titer. Fifty-five herds (96.5%) were positive. Three variables were associated with seroprevalence in the final model. Being a dairy animal was a risk factor (OR = 2.40, P = 0.067), Distance among farms greater than 500 m acted as protective factor (OR = 0.55, *P = 0.026). The third variable confirmed the endemic situation of chlamydiosis in the area: seropositive animals belonged to herds in which the observed percentage of abortions was greater than 5% (OR = 2.40, *P = 0.010). (C) 1998 Published by Elsevier Science B.V.