Occurrence of chlamydiae in the genital tracts of sows at slaughter and their possible significance for reproductive failure

The aim of this study was to investigate further the role of chlamydiae as pathogens in the genital tracts of sows at slaughter. Genital tracts of 101 randomly selected sows were collected and specimens of genital tract local izations were systematically examined for chlamydiae using immunohistochemi stry and PCR. In the genital tracts of 10 sows, Chlamydia psittaci DNA was detected by PCR, and was further typed as 'serotype 1' in nine cases and as avian strain 6 BC in one animal. However, all specimens examined by immuno histochemistry were negative for chlamydiae. Pooled samples of scalding tan k water were additionally investigated for 95 animals. Of these samples, 63 .2% contained chlamydial DNA, mostly C. trachomatis, and in one sample C. p sittaci 'serotype 1'. Although in most cases contamination through influx o f faecally contaminated scalding water is a possible reason for thr positiv e PCR results in the genital tract, latent infection cannot be excluded. In conclusion, the results obtained suggest that chlamydiae are of no or only minor importance in the examined group of Swiss breeding sows. Nevertheles s, the role and significance of chlamydiae as pathogens in porcine reproduc tive disorders remain unresolved and require further investigation.