Seroprevalence and Risk Factors Associated with Chlamydia abortus Infection in Sheep and Goats in Eastern Saudi Arabia

Abstract

<i>Chlamydia abortus</i> (<i>C. abortus</i>) is intracellular, Gram-negative bacterium that cause enzootic abortion in sheep and goats. Information on <i>C. abortus</i> seroprevalence and flock management risk factors associated with <i>C. abortus</i> seropositivity in sheep and goats in Saudi Arabia are scarce. The objectives of this study were to (i) estimate the animal, flock, and within-flock seroprevalence of <i>C. abortus</i> among Eastern Province sheep and goat flocks and (ii) identify the flock management and animal risk factors associated with <i>C. abortus</i> seropositivity in Eastern Province, Saudi Arabia. A cross-sectional study with a two-stage sampling process was carried out in the Eastern Province, Saudi Arabia, between 2015 and 2016. A total of 1717 sheep and 1101 goat serum samples were collected from 21 sheep and 14 goat flocks, then were tested for <i>C. abortus</i> antibodies using a commercial ELISA Kit. In addition, vaginal swabs and aborted tissue samples were collected from sheep (n = 48) and goats (n = 15) with recent history of abortion for detection of <i>C. abortus</i><i>pmp</i> gene using PCR. A questionnaire was constructed to collect information about flock management and animal risk factors possibly associated with <i>C. abortus</i> infection in sheep and goats. The true sheep and goat-level seroprevalences were 11.1% (95% CI: 9.7-12.7) and 10.6% (95% CI: 8.8-12.5), respectively. The true flock-level seroprevalence was 100% for both sheep and goats. However, the average within sheep and goat flocks true seroprevalences were 9.6% (95% CI: 1.8-22.9) and 9.3% (95% CI: 1.8-19.5), respectively. Multivariable logistic regression revealed that introduction of new sheep to the flocks (OR = 2.6; 95% CI: 1.5-4.4), type of breeding system (OR = 1.8; 95% CI: 1.0-3.4), flocks allowing females in (OR = 1.9; 95% CI: 1.1-3.3) or females out (OR = 2.2; 95% CI: 1.1-4.3), and sheep age 1.4-2.8 years (OR = 1.9; 95% CI: 1.3-2.9) were potential risk factors for <i>C. abortus</i> seropositivity in sheep flocks. However, in goat flocks, the introduction of new goats to the flocks (OR: 1.9; 95% CI: 1.2-3.0) was identified as a risk factor, whereas good farm hygiene (OR: 0.3; 95% CI: 0.2-0.7) was identified as a protective factor. <i>C. abortus pmp</i> gene was identified in 45 (93.8%) and 15 (100%) of samples collected from sheep and goats, respectively. These results could be used to implement efficient management measures to prevent and control <i>C. abortus</i> infection in sheep and goats in Eastern Province, Saudi Arabia, but also could be used to reduce the risk of <i>C. abortus</i> infection in sheep and goat flocks with similar management practices in other regions.