Survey on Carrier State of Sheep in Chlamydia pecorum Infection

Over the last 40 years, evidence has accumulated to suggest the ubiquitous presence of infections with intracellular bacteria of the genus Chlamydia in different livestock species. Different methods to clinical specimens substantiated such widespread, but mostly clinically unapparent, presumably low-level infections. In this initial epidemiological study, we addressed the question of chlamydial infection of conjunctiva and genital tract in apparently healthy sheep. In this research, 33 sheep and 20 goats which had previously been exposed to the possibility of sexual transmission of Chlamydia, examined by conjunctiva (53 swabs) and vaginal swab (53 swabs). After DNA extraction by boiling method, presence of Chlamydia pecorum was investigated by nested PCR. Chlamydia pecorum strain W73 was used as positive control. In this research, 10 infected swab samples (from 106 swab samples) contain of 7 vaginal (70%) and 3 conjunctival swabs (30%) were detected. All positive vaginal swabs and 3 positive conjunctival swabs were related to aborted and adult animals, respectively. According to higher percentage of Chlamydia pecorum infection in apparently healthy sheep,carrier state in sheep is more probable than goats. Vaginal secretion is more important route of chlamydial infection dissemination towards conjunctival secretion. Because of high risk of chlamydial infection in cows, attention to role of sheep in disease epidemiology was recommended.