Chlamydia abortus is one of the most common abortive agents worldwide in sheep. Few studies have been reported C. abortus infection among sheep in Egypt but the available data is scarce. The objective of the present study was to determine the seroprevalence of C. abortus among sheep, the associated risk factors and its molecular characterization. The present study was conducted on 675 sheep in six Governorates at Northern Egypt. Data analysis confirmed the presence of antibodies against C. abortus in 93 out of 675 sheep. The logistic regression model was fitted to identify the associated risk factors with C. abortus infection. The results revealed that C. abortus increased significantly in ewes (OR = 4.04, 95 %CI: 1.44−11.28) during autumn season (OR = 3.6, 95 %CI: 1.64–8.28), in ewes with a history of abortion (OR = 1.4, 95 %CI: 0.87–2.50) and in farm where no lambing pen (OR = 2.2, 95 %CI: 1.30–3.94) or abscence of post abortion measures (OR = 1.96, 95%CI: 1.23-3.12). In addition, age, flock size and exchange of breeding ram had no significant effect on prevalence of chlamydiosis. Also, PCR assay was confirmed presence of C. abortus as accusative pathogen in aborted ewe and the genetic characterization of Egyptian C. abortus strain revealed 100 % identity with another strain from Iraq. A control program should be applied to reduce economic losses and risk of human infection.

流产衣原体是绵羊中最常见的流产剂之一。鲜有研究报道埃及羊中流产梭状芽胞杆菌感染，但现有数据很少。本研究的目的是确定绵羊中流产梭状芽孢杆菌的血清阳性率，相关的危险因素及其分子特征。本研究是在埃及北部六个省的675只绵羊上进行的。数据分析证实了675只羊中有93只存在抗流产梭状芽胞杆菌的抗体。使用逻辑回归模型确定与流产弯曲杆菌感染相关的危险因素。结果显示流产梭状芽胞杆菌在有流产史的母羊中，秋季（OR = 3.6，95％CI：1.64–8.28）的母羊显着增加（OR = 4.04，95％CI：1.44−11.28）（OR = 1.4，95％CI： 0.87–2.50）和没有羊羔笔（OR = 2.2，95％CI：1.30–3.94）或无人工流产措施（OR = 1.96，95％CI：1.23-3.12）的农场。此外，年龄，鸡群大小和繁殖公羊的更换对衣原体感染的发生率没有显着影响。同样，PCR分析证实流产母羊中存在流产弯曲杆菌作为可控病原体，埃及流产弯曲杆菌菌株的遗传特征显示与另一种来自伊拉克的菌株具有100％的同一性。应该应用控制程序以减少经济损失和人类感染的风险。