EN
The following species of the family Chlamydiaceae are the most important in causing asymptomatic or symptomatic infections in swine: Chlamydophila abortus, Chlamydophila pecorum, Chlamydophila psittaci and Chlamydia suis. Mostly they cause asymptomatic infections or to an unknown percentage they participate in the etiology of multifactorial syndromes, usually with other species of facultatively pathogenic bacteria or viruses. Chlamydiaceae in pigs are not exclusive etiological agents of strictly defined diseases, as for example Chlamydia trachomatis in causing trachoma in humans, but are associated with different pathologies such as: conjunctivitis, pneumonia, pericarditis, polyarthritis, enteritis, return to estrus, abortion, mummification of fetuses or piglets before parturition, or abortion, delivery of weak piglets and increased perinatal or neonatal mortality. The mentioned chlamydial species also contribute to inferior semen quality. However, in comparison with infections or diseases of pigs caused by other microorganisms, Chlamydiaceae are at present considered as rather less important pathogens. Whether this evaluation is a proper one has to be considered in the future, since diagnostic laboratories rarely routinely investigate specimens from swine for Chlamydiaceae. In the review diagnostic tests for the identification of Chlamydiaceae were mentioned as well, with an indication of their diagnostic value. In the introduction, remarks concerning the taxonomy of Chlamydiaceae were presented.