Chlamydia abortus Detection in Post-Partum Secretions of Iranian Lori Breed Ewes

BACKGROUND AND ABJECTIVEChlamydia abortus is an intracellular gram-negative pathogen that has been reported as one of the main causes of abortion in sheep in many countries of the Middle East, causing enzootic abortion of ewe (EAE). Bacterium pose a zoonotic risk to workers, farmers, and veterinarians as well. In Human mild influenza-like symptoms can be brought on by ingesting contaminated food or inhaling infective droplets. in sheep the disease that results from C. abortus' initial invasion of mucosal membranes and subsequent genital system incursion manifests as abortion, particularly in the final two to three weeks of pregnancy, stillbirth, or lambing that appear to be healthy but are actually infected. Pneumonia, enteritis, encephalomyelitis, conjunctivitis, seminal vasculitis, and orchitis are additional clinical sign that frequently need to be treated in infected sheep. Before gestation, infected ewe does not exhibit any clinical symptoms of infection. The main sources of infection spread among susceptible flocks are genital secretions prior to abortion or during parturition, as well as the products of abortion including infected placentae, fetuses, and the coats of neonates. The most specific method for diagnosing EAE includes isolating the bacterium or DNA amplification from an abortive sample or vaginal discharge by molecular methods such as PCR, identifying the outer membrane genes (ompA). EAE has frequently been studied serologically reported in sheep in Iran. The purpose of this study is to look into whether C. abortus was present in the post-partum secretions of Lori breed sheep that had a full-term delivery. by using the real-time PCR method.MATERIALS AND METHODSSampling was done from the post-partum secretions of ۳۶ Lori ewes that had full-term and healthy lambing (by using swabs). These animals have a history of abortions. A cold chain system was used to transport the gathered samples to the lab after they had been stored in sucrose-phosphate glutamate (SPG) buffer. Until further use, the samples were kept at −۲۰ °C. The High Pure PCR Template Preparation Kit (Roche Company, Germany) was used to extract the DNA from samples in accordance with the manufacturer's instructions. The DNA was stored at −۲۰ °C pending analysis. Taq-man real-time PCR was used to amplify the ompA gene in order to qualitatively detect C. abortus. Cinacloon Co. (Iran) primers and probes of the target genes were employed. The TaqMan Universal PCR Master Mix (۱×), ۱ μl of DNA sample, ۱۰ pmol primers, ۵ pmol probe, and ۵ ng of IC template were used to perform the final ۲۵ μl reaction mixtures. On Rotor Gene Q ۱۸۲(QIAGEN Marseille S.A.), amplification was performed using the following temperature schedule: preheat at ۹۵ °C for ۱۰ minutes, followed by ۴۰ two-step cycles at ۱۵ and ۶۰ degrees Celsius for ۶۰ seconds. The cycle threshold (Ct value) was calculated automatically.RESULTS AND DISCUSSIONAccording to real-time PCR results, sixteen samples tested positive for C. abortus. The fact that C. abortus was positive in postpartum secretions in ewes who had a normal delivery with healthy lambs is crucial. The presence of C. abortus in samples obtained from ewes following parturition has been investigated in studies. including Livingstone et al.'s research in ۲۰۰۹. They discovered C. abortus DNA in placentas from ten ewes with a history of abortion. The ewes under study have healthy lamb in their subsequent lambing. They used the real-time PCR technique.in ۲۰۰۷ a British study reported ۳۰.۹% prevalence of C.abortus DNA among uterine tissue of three hundred and four ewes at an abattoir by conventional PCR. In ۲۰۱۸ Barkallah et al. detected C. abortus by PCR method in ۸.۷% of swabs from sheep in Tunisian and as described by Merdja et al., ۱۳ out of ۱۹۹ (۶.۵%) swabs were positive for C.abortus by Real-time PCR in Algeriam in ۲۰۱۵. Four out of the eleven fetal membrane samples collected in a ۲۰۱۱ study by Gutierrez et al. contained low numbers of C. abortus in subsequent parturition with EAE history. They claimed that low levels of ewes infection after primary infection can cause them to remain chronically or persistently infected. In the aforementioned study, no animals aborted in the second lambing season and the length of gestation was not different between pregnancy outcomes. Ewes are considered to be naturally infected with C. abortus via the oral–nasal route and may become persistent carriers, shedding during subsequent oestrous cycles and at lambing. According to studies, ewes with a history of EAE are thought to be immune to further lamb loss after having an abortion. In the case of present study, ewes with a possible EAE history all have full term delivering during subsequent pregnancy.CONCLUSIONThe findings of the current study demonstrate that C. abortus can still be excreted in post-partum secretion even after healthy, normal lambing. This issue emphasizes the possibility that the infection could spread among the herd if it is not properly managed. Infectious elementary bodies are shed into the environment and may be inhaled by exposed animals. This issue will become more important Since vaginal discharge can last up to three weeks after lambing. A characteristic feature of EAE is that ewes which abort following infection do not abort again in subsequent years. In the current study, it's possible that C. abortus was the cause of the previous ewes' abortion. The findings of the current study, along with the high rate of EAE in various Iranian regions, economic losses, and risk of human infection, call for extra focus in order to advance research and put preventive and control measures into practice. According to research like Esmaili et al. 's ۲۰۲۱ study, Small ruminant herds in Iran had a high prevalence of C. abortus, so vaccination is strongly advised for Iranian flocks. To lessen the adverse effects, ranchers must receive training and education in quarantine and sanitary practices. The implementation of a successful control program requires an understanding of epidemiologic features. It is advised to conduct additional research on different animal species to identify the role that C. abortus and other agents play in small ruminant abortions.

کلیدواژه ها:

Lori breed ، Chlamydia abortus ، Lambing ، Real-time PCR ، Ewes ، Enzootic Abortion of Ewe (EAE)