Abstract
Chlamydia abortus is one of the most common infectious and zoonotic bacteria, which causes abortion in different ruminants as well as other animals and humans. For the first time in Iraq, the current study aimed to identify the prevalence of C. abortus in cattle using the enzyme-linked immunosorbent assay (ELISA). A total of 276 venous blood samples were collected from November (2021) to January (2022), subjected to obtaining sera that ELISA tested. Infection severity and estimation of the relationship between serum positivity and risk factors (including age, sex and region) were evaluated. An overall 17.03% of samples were being positive for C. abortus, which classified as mild (63.83%), moderate (25.53%) and severe (10.64%) infections with OD values of 0.32710.0085, 0.5270.0139 and 0.70840.0256, respectively. The association of positivity to risk factors revealed that there was significant variation in their values as follows: for age, significant increases in prevalence and risk factors were detected in cattle aged <3 years when compared to 3-6 and >6 years; whereas, for sex, significant increases were found in females more than males. For the region, significant higher and lower prevalence and risk exposure to were reported in Al-Hai and Al-Kut, respectively. The association of mild, moderate and severe infections to risk factors showed that moderate infection was elevated significantly in cattle of <3 years, while the mild infection increased significantly in cattle aged 3-6 and >6 years with the absence of severe infection in both last age groups. In females and males and all study regions, mild infection appeared more significantly than moderate and severe infections (P<0.05). The present study was the first serological detection of C. abortus in cattle in Wasit province (Iraq); furthermore, studies are necessary to estimate the prevalence of C. abortus in cattle and other field animals.