Seroepidemiology of chlamydial infections of wild ruminants in Spain

Chlamydial infections were determined serologically among wild ruminants in the Nature Park of the Sierras de Cazorla, Segura y Las Villas (CNP; Spain ). Sampling was done during the period from 1990-95. There were 1,244 blood samples collected, consisting of 490 from fallow deer (Dama dama), 343 fro m mouflon (Ovis mussimon), 283 from red deer (Cervus elaphus) and 128 from Spanish ibex (Capra pyrenaica). Specific complement-fixing antibodies of Ch lamydia spp. were detected by means of microtechnique, using lipopolysaccha ride antigen. The relationship of biological (species, sex, age), temporal (year) and territorial (central and peripheral areas) factors to seropositi ve prevalence was examined, and preliminary data were collected on whether or not sheep and goat herds grazing in the peripheral areas of the park als o were infected with Chlamydia spp. Chlamydiosis was common in the four spe cies of wild ruminants in the CNP in all the years studied. The prevalence of Chlamydia sp. in mouflon (37%) was significantly greater than in fallow deer (30%), and both had a significantly higher prevalence rate than Spanis h ibex and red deer (both 24%). The four species of wild ruminants were sim ilar in that they act as reservoirs of Chlamydia spp., although their recep tivity may be different, and the infection can certainly be maintained amon g these animals by intra-group transmission. The differences in prevalences and geometric mean titers (GMT), both between the sexes (male versus femal e) and between different ages (adult versus juvenile), were insignificant i n all four species. For all species of wild ruminants both prevalence rates and GMTs were greater in populations occupying the peripheral areas of the park than in those inhabiting the central area. Herds of sheep and goats h ad a high prevalence of chlamydiosis. Intertransmission of Chlamydia sp. be tween wild and domestic ruminants occurred through grazing on the same past ures. The highest mean prevalence (44%) of patent infections (CFT titers of greater than or equal to 1:80) was detected in red deer, although this fre quency was not significantly different from those observed in mouflon (39%) , Spanish ibex (38%), and fallow deer (37%). The proportion of patent infec tion was higher in females than in males, and none of the juveniles (<2-yr- old) showed patent infections. The prevalence of predicted patent chlamydia l infections was always higher in the peripheral areas of the park, althoug h only among mouflon and fallow deer were the differences statistically sig nificant.