Ovine enzootic abortion disease seroprevalence in small ruminants around the world: a systematic review

Chlamydia abortus is a causative agent of Ovine Chlamydiosis or Ovine Enzootic Abortion (OEA) or Enzootic Abortion of Ewes (EAE) and can be transmitted to humans especially pregnant women during the lambing or kidding season, sheep, and goats from infected flocks represent a potential risk to pregnant women. Purpose: The objective of this study was to estimate the pooled prevalence of chlamydial abortus infections in small ruminants. Materials and Methods: The study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Relevant studies were retrieved from PubMed, Scopus, Web of Science, and Google Scholar. The retrieved studies were screened for eligibility. Then, important data were extracted from the included studies. The quality of each included study was evaluated. Results: Of 145 studies, 25 (with a total of 15663 samples) met the inclusion criteria and were included in the meta-analysis. The pooled prevalence of chlamydial infections in small ruminants was 14,46 % (95%, CI: 14,07±15,18). Among continents, the average prevalence of chlamydial abortus infections was highest in Asia (52%) (95% CI: 32,42±71,58) and lowest in North America (4%) (95% CI: 3,68±11,68). Conclusions: Few studies have reported the prevalence of chlamydia infections in small ruminants. Based on the available data, the prevalence of chlamydia infections in small ruminants was quite high (14.46%). Therefore, small ruminants could be potential reservoirs of Chlamydia and pose a risk to humans especially pregnant women, or other animal species, especially in the wild.