Abortion Of Ewes Research Articles

Phylogenetic Analysis and Certain Risk Factors of Chlamydia Abortus in Ewes in Nineveh Governorate, Iraq

Chlamydia is an obligate intracellular Gram-negative organism that causes abortion, or "enzootic abortion of ewes", which is characterized by causing economic loss in sheep breeding. Chlamydia abortus spread could be stopped, and monitoring efforts could be more successful by gathering data on the condition of the disease. This ground-breaking study focused on the phylogenetic analysis and certain risk factors of Chlamydia abortus in ewes in Nineveh governorate, Iraq. 52 placenta samples were collected, representing 52 flocks (8660 ewes) who suffered from abortion in various Nineveh provincial locations between August 2022 and January 2023. Two local sequences were submitted to GenBank and assigned the accession numbers OR334580 and OR334581. The Chlamydia abortus 16S rRNA sequences were analyzed using the GenomeNet multiple sequence alignment tool (CLUSTALW), an online resource. After that, the sequences were compared to other Chlamydia abortus sequences that were accessible in the GenBank using NCBI BLAST (BLASTn) of NCBI. The Tamura-Nei model in the MEGA11 software program was used to create the phylogenetic trees. Results indicate that 15.38% (8/52) of the ewes had positive results for Chlamydia abortus, which was significantly affected by the increase in herd size and interspecies farming. Two sequences were put through individual sequence analysis, which revealed new Chlamydia abortus sequences, which were recorded for the first time in the governorate of Nineveh. We concluded that a higher risk of infection occurs in farms that contain more than 100 ewes and are mixed with other species of animals.

Knowledge, attitudes and practices of sheep owners regarding abortion in Northern Tunisia.

Abortion in ewes causes high economic losses and represents a threat for human health due to abortive zoonotic pathogens. The present study aimed to assess the knowledge, attitudes and practices (KAP) among sheep owners in the northern Tunisia regarding ewes' abortions. Between February 2021 and May 2022, a structured questionnaire containing both close and open-ended questions was applied to 120 sheep owners in northern Tunisia. The data collected were analysed by chi-square test using Epi info 6 software. The majority (75%) of participants reported a history of abortion in their sheep flocks. Sheep owners thought that the most frequent cause of abortion was physical factors, such as trauma, climate and stress (60%±5.5%; 48/80), followed by toxicity (15%±4%; 12/80), metabolic and nutritional conditions (12.5%±3.7%; 10/80), vaccination (5%±2.4%; 4/80) and infectious causes (7.5%±2.9%; 6/80) (p<0.001). The majority of animal owners reported that abortions occurred mainly during autumn (39.6%±5%; 38/96), followed by summer (27%±4.5%; 26/96), winter (23%±4.3%; 22/96) and spring (10.4%±3.1%; 10/96) (p<0.001). Approximately, half (45.8%±5%; 55/120) of interviewed farmers would not take any action if an abortion occurred. Half of the interviewed farmers (50.5%±5.1%; 48/95) did not apply any preventive measures when manipulating aborted ewes, and most of the sheep owners (77.3%±3.8%; 92/119) did not know that aborted ewes could transmit zoonotic pathogens. Our survey concluded that sheep owners in Northern Tunisia had poor knowledge and attitudes as well as applied limited actions concerning several health aspects related to abortion. Education programmes should be established in order to improve Tunisian sheep owners' KAP regarding abortion.

Seroprevalence and Risk Factors Associated with Chlamydia abortus Infection in Sheep and Goats in North-Western Italy.

Chlamydia abortus, although poorly recognized as a human pathogen, is a zoonotic microorganism that can cause many different symptoms in humans, including subclinical infection and fatal illnesses in pregnant women. C. abortus is one of the most common causes of ovine and caprine infectious abortion worldwide, known as the causative agent of the enzootic abortion of ewes (EAE) or ovine enzootic abortion (OEA). To estimate C. abortus seroprevalence and the risk factors related to C. abortus in small ruminants, the sera from 3045 animals (both sheep and goat) belonging to 202 herds were tested and a questionnaire investigating flock management was administered. At the herd level, the true seroprevalence was 56.6% (CI95%: 46.9-66.3%), at sheep-farm and goat-farm level, the true seroprevalence was 71.4% (CI95%: 54.6-88.3%) and 44.8% (CI95%: 41.3-57.0%), respectively. The true seroprevalence was significantly higher among the sheep than the goats. The logistic regression model identified four factors associated with Chlamydia seropositivity: flock size (i.e., farms with >50 heads), contact with cattle, introduction of animals, and Coxiella seropositivity. The study evidenced a high seroprevalence of Chlamydia abortus in small ruminant farms in the Piedmont region. Considering its zoonotic potential and the health consequences in humans, communication to farmers on the importance of vaccination, as well as the sensibilization of farm vets, seem to be strategical.

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.

The Immune Response in the Uteri and Placentae of Chlamydia abortus-Infected Ewes and Its Association with Pregnancy Outcomes.

The enzootic abortion of ewes, caused by the bacterium Chlamydia abortus (C. abortus), is one of the main causes of abortion in sheep. There are multiple contributory factors, including chlamydial growth, host immune response, and hormonal balance, that result in different pregnancy outcomes, such as abortion, the birth of weak lambs that may die, or healthy lambs. This study aimed to determine the relationship between phenotypical patterns of immune cell infiltration and different pregnancy outcomes in twin-bearing sheep (both lambs born dead; one alive and one dead; both alive) when experimentally infected with C. abortus. Both the sheep uteri and placentae were collected after parturition. All samples were analysed for specific immune cell features, including cell surface antigens and the T-regulatory (Treg) cell-associated transcription factor and cytokines, by immunohistochemistry and in situ hybridisation. Some of these immunological antigens were evaluated in ovine reproductive tissues for the first time. Differential patterns of T helper/Treg cells revealed significant group effects in the placentae. It suggests the potential role that the balance of lymphocyte subsets may play in affecting different pregnancy outcomes in C. abortus-infected sheep. The present study provides novel detailed information about the immune responses observed at the maternofoetal interface in sheep at the time of pre-term abortion or lambing.

Immunopathology of early and advanced epididymis lesions caused by Brucella ovis in rams

Ovine brucellosis is an infectious disease that causes alterations in the reproductive tract in ram and abortion in ewes. Their negative economic impact in ovine production warrants a thorough understanding the interactions between B. ovis and the host. Here, epididymis lesions of rams infected by B. ovis were histopathologically staged into early and advanced. Expression by immunohistochemistry of Brucella antigens, inflammatory cell markers (CD3, CD79αcy) and cytokines (IFN-γ, TNF-α, TGF-β1) was assessed in both stages. Early lesions were characterized by epithelial changes, interstitial inflammation, and mild fibrosis; whereas advanced lesions displayed caseous granulomas containing numerous macrophages, multinucleated giant cells, lymphocytes, and plasma cells. Expression of Brucella antigens were observed in both stages. The cellular response in B. ovis lesions were predominantly of T-cells (CD3+) whereas low numbers of B-cells and plasma cells (CD79αcy+) were present in both early and advanced lesions. IFN-γ was expressed by lymphocytes in early lesions suggesting that the adaptive immune response against B. ovis is initiated by Th1 cells, this response was also preserved in advanced stages. Expression of TNF-α was observed in neutrophils of epithelial microabscesses and intraepithelial T-cells of early lesions suggesting a promotion of neutrophil phagocytosis triggered by TNF-α. On the other hand, advanced lesions showed a reduction of TNF-α expression which may permit B. ovis persistence in granulomas. Lastly, TGF-β1 expression (fibroblast, macrophages and less in lymphocytes) were increased with time, suggesting that B. ovis promotes TGF-β1 secretion promoting chronicity of the lesions.

SEROPREVALENCE OF CHLAMYDOPHILA ABORTUS IN SHEEP IN ТНЕ BELGRADE EPIZOOTIOLOGICAL AREA DURING 2019-2021

As one of the most important infective agents of abortion, Chlamydophila abortus takes an important place in pathology of ruminant reproductive tract. In sheep, the disease known as enzootic abortion of ewes or ovine enzootic abortion, and is manifested as abortion and accompanied reproductive disorders, thus resulting in significant economic losses worldwide. The characteristics of the pathogen and its zoonotic potential make this disease significant both for animal and public health. Therefore, the presented study aimed to obtain Chlamydophila abortus seroprevalence in sheep population in Belgrade epizootiological area. The study was done by testing 552 sheep sera samples from 10 municipalities of Belgrade city, during the 2019-2021 period. Serological examination was performed using ELISA assay (ID Screen® Chlamydophila abortus Indirect Multi-species, IDvet, Grabels, France). The obtained results showed Chlamydophila abortus seroprevalence of 6% in Belgrade epizootiological area. The largest number of seropositive sheep was found in municipality of Palilula. The detected antibodies against Chlamydophila abortus confirmed the circulation of the pathogen in sheep population in Belgrade epizootiological area. The obtained results show the need for further studies and continuous implementation of measures for detection, control, prevention and eradication of the disease.

Seroprevalence of Q fever among ewes and associated risk factors in Ain Defla region, North-central Algeria

Q fever is a zoonotic disease caused by Coxiella burnetii, which causes abortions in domestic ruminants. This study aims to assess the seroprevalence of Q fever among ewes and investigate the associated risk factors in the Ain Defla region (north-central Algeria). Blood samples from 184 ewes were randomly collected from 45 sheep flocks. Sera were tested for the presence of antibodies against C. burnetii using an ELISA test. Seroprevalence was 24.9% and 66.7% at the animal and flock levels respectively. Univariate analysis at the animal level indicated three factors significantly associated with C. burnetii seropositivity: presence of pigeons in farms (χ2 = 9.689; p = 0.008), abortion in ewes (χ2 = 11.209; p = 0.001), and abortion history in the flock (χ2 = 7.744; p = 0.005). Therefore, C. burnetii infection plays a major role in abortions in the sheep populations under study, and the presence of pigeons in farms plays a role in disease transmission.

Abortion in ewes in Nineveh governorate, Iraq: A systematic review and meta-analysis

The current study was designed to examine the evidence and knowledge gaps in studies investigating abortion in ewes in Nineveh, Iraq, and quantify the overall incidence of abortion and the prevalence of potential infectious etiology of abortion. PubMed, CABI, and GoogleScholar databases were used as search engines to track pertinent peer-reviewed studies. Additional relevant articles were identified by reviewing the reference lists of identified full-text articles and contacting colleagues who worked on pertinent topics. Identified studies were divided into two main groups, including studies that reported the abortion rate in ewes and studies that reported the potential infectious etiology of abortion. A meta-analysis was performed for each group.A total of 17 studies were qualified for review, including six studies that reported the abortion rate. All of the 17 studies examined the prevalence of potential etiology of abortion. The overall incidence of abortion was 7.32%, and the pooled prevalence of potential infectious etiology of abortion indicated that 51.43%, 31.92%, and 6.83% were for Toxoplasma gondii, Brucella spp., and other pathogens, respectively. In conclusion, it is essential to identify epicenters of abortion in Nineveh, the association between the incidence of abortion and parity, the effect of pregnancy season on the incidence of abortion, and confirm the prevalence of T. gondii in aborted ewes is high.

Expression Level of the mip, pmp18D, and ompA Genes in Chlamydia abortus Isolated from Aborted Ewes

In this manuscript, we report the proteins macrophage infectivity potentiator (mip, CAB080), major outer membrane protein (momp, CAB048), and polymorphic outer membrane protein (pmp18D, CAB776) that are expressed in different times of pregnancy in mice infected with Chlamydia abortus. Enzootic abortion of ewes (EAE) by C. abortus, an obligate intracellular pathogen, is a critical zoonotic disease-causing significant economic loss to livestock farming globally. This study was carried out for the detection and characterization of macrophage infectivity potentiator (mip, CAB080), major outer membrane protein (momp, CAB048), and polymorphic outer membrane protein (pmp18D, CAB776) using RT-qPCR. These proteins are believed to be expressed as virulence factors in C. abortus isolated from aborted ewes. BALB/c mice (pregnant and nonpregnant) were used as an animal model to be injected intraperitoneally with C. abortus culture in Vero cells since the endometrial lymphoid tissues of these animals resembles that of ewes. Also, the short duration of pregnancy in mice makes them a suitable animal model for obstetric studies. Tissue samples were taken from the mice after 10, 15, and 20 days of pregnancy to compare the expression of the genes mip, pmp18D, and ompA. Transcription level was quantified using RT-qPCR, the GAPDH transcription quantification, as a normalization signal. Abortion occurred in pregnant mice, and apparent differences between the transcriptional levels of the mip, pmp18D, and ompA genes in the samples taken during different time intervals of pregnancy were not observed (p > 0.05). The result indicated that the three bacterial genes, mip, pmp18D, and ompA, play a role as virulence factors in abortion and are differentially expressed in pregnant and nonpregnant animals. Inactivation of the genes is suggested to confirm the hypothesis.

Molecular Detection of Brucella ovis in Aborted Ewes in Sulaimani Governorate

Abortion causes substantial economic losses in sheep flocks. In addition to financial compensation, abortion is a sharp aspect of public health. Brucella, Campylobacter, Salmonella and Chlamydia are the most examples of diseases associated with the abortion of ewes. Brucellosis is a zoonotic bacterial infection produced by a variety of species of Brucella. It has a significant economic impact on domestic animals, primarily ewes. The current study investigated Brucella ovis from aborted fetuses and vaginal swab samples collected from sheep flocks in the Sulaimani governorate by the polymerase chain reaction. Thirty-eight aborted fetuses and 70 vaginal swabs were collected from sheep flocks in three districts of Sulaimani governorate (Kalar, Chamchamal and Said Sadiq) from March 2018 to June 2019. The pathogen was identified in clinical specimens using conventional PCR. Brucella ovis was isolated from 26 of 38 aborted fetuses (68.4%) and 21 of 70 vaginal swabs (30 %) of aborted ewes. The Brucella ovis gene ompA was sequenced, and phylogenetic analysis of the ompA gene sequences revealed that Brucella ovis isolated established a distinct branch and a lower relationship of Brucella ovis to the Brucella melitensis species. It has been concluded that Brucella ovis is the most pathogenic Brucella species and a major cause of ewe's abortion in the Sulaimani governorate.

Sheep abortion – a roundtable discussion

Foreword Abortion takes a heavy toll on the sheep industry, not only economically, but in emotional terms too. Enzootic abortion in ewes is consistently the most frequent diagnosis followed in descending order by infection with Toxoplasma gondii, Campylobacter spp., Salmonella spp. and Listeria spp. Causes of abortion also lead to increased barren rates, and the birth of weak lambs, so the impact of these pathogens is greater than just abortion. Fortunately there are vaccines for the two most common causes of abortion, providing farmers and the veterinary surgeons advising them with effective and sustainable tools in the control of enzootic abortion and toxoplasmosis. The uptake of these vaccines, however, remains lower than might reasonably be expected. In this roundtable discussion the barriers to the implementation of the extant measures of abortion control were discussed and suggestions made as to how abortion can better be prevented.

Efficacy of Two Chlamydia abortus Subcellular Vaccines in a Pregnant Ewe Challenge Model for Ovine Enzootic Abortion.

Chlamydia abortus, the aetiological agent of enzootic abortion of ewes, is a major cause of reproductive loss in small ruminants worldwide, accounting for significant economic losses to the farming industry. Disease can be managed through the use of commercial inactivated or live whole organism-based vaccines, although both have limitations particularly in terms of efficacy, safety and disease-associated outbreaks. Here we report a comparison of two experimental vaccines (chlamydial outer membrane complex (COMC) and octyl glucoside (OG)-COMC) based on detergent extracted outer membrane preparations of C. abortus and delivered as prime-boost immunisations, with the commercial live vaccine Cevac® Chlamydia in a pregnant sheep challenge model. No abortions occurred in either experimental vaccine group, while a single abortion occurred in the commercial vaccine group. Bacterial shedding, as a measure of potential risk of transmission of infection to naïve animals, was lowest in the COMC vaccinated group, with reductions of 87.5%, 86.4% and 74% observed for the COMC, OG-COMC and live commercial vaccine groups, respectively, compared to the unvaccinated challenge control group. The results show that the COMC vaccine performed the best and is a safer efficacious alternative to the commercial vaccines. However, to improve commercial viability, future studies should optimise the antigen dose and number of inoculations required.

Phylogenetic and molecular analysis based on genes 16S-rRNA, OMPA and POMP to identify Chlamydia abortus infection occurrence at the milk samples of goats and sheep in west Azerbaijan of Iran.

Background and Objectives:Enzootic abortion in sheep and goats, also called ovine enzootic abortion (OEA) or enzootic abortion of ewes (EAE), is caused by Chlamydia abortus. The disease has a major economic impact as it represents the most important cause of lamb loss in sheep in parts of Europe, North America and Africa. This serious and potentially life-threatening zoonosis can also affect pregnant women after contact with lambing ewes, leading to severe febrile illness in pregnancy and loss of the foetus.Materials and Methods:The present study was conducted to the Phylogenetic and Molecular Analysis based on Genes 16S-rRNA, OmpA and POMP of C. abortus in milk samples collected from sheep and goats in West Azerbaijan province, Iran. During 2018, a total number of 360 milk samples were collected from sheep (n = 180) and goats (n = 180) of different regions of the province. All milk samples were subjected to DNA extraction and examined by PCR.Results:Among 360 milk samples collected from sheep and goats, 31 (8.611%; 95% CI=6.13–11.96) were positive for Chlamydia spp. The helicase, 16S-rRNA and ompA genes were examined and resulted in 8, 31, 31 of positive samples respectively. The accession numbers have been deposited in GenBank (NCBI) (MT367602 and MT367603).Conclusion:Phylogenetic analysis based on the gene of helicase showed that most of the isolates shared similarity > 99.97%.

Enzootic abortion in sheep: a review

Enzootic abortion of ewes (EAE) is the most commonly diagnosed cause of abortion in sheep in the UK. This document will review disease background, how to reach a diagnosis of EAE, and recent developments in diagnostics and preventative approaches. It also explores the scope for progress and how that may be achieved. There is significant scope for more widespread screening and vaccination against EAE to yield benefits to animal health, human health, antibiotic stewardship, individual farm profitability and the UK sheep sector.

Distribution and Severity of Placental Lesions Caused by the Chlamydia abortus 1B Vaccine Strain in Vaccinated Ewes

Chlamydia abortus infects livestock species worldwide and is the cause of enzootic abortion of ewes (EAE). In Europe, control of the disease is achieved using a live vaccine based on C. abortus 1B strain. Although the vaccine has been useful for controlling disease outbreaks, abortion events due to the vaccine have been reported. Recently, placental pathology resulting from a vaccine type strain (vt) infection has been reported and shown to be similar to that resulting from a natural wild-type (wt) infection. The aim of this study was to extend these observations by comparing the distribution and severity of the lesions, the composition of the predominating cell infiltrate, the amount of bacteria present and the role of the blood supply in infection. A novel system for grading the histological and pathological features present was developed and the resulting multi-parameter data were statistically transformed for exploration and visualisation through a tailored principal component analysis (PCA) to evaluate the difference between them. The analysis provided no evidence of meaningful differences between vt and wt strains in terms of the measured pathological parameters. The study also contributes a novel methodology for analysing the progression of infection in the placenta for other abortifacient pathogens.

The 1B vaccine strain of Chlamydia abortus produces placental pathology indistinguishable from a wild type infection.

Chlamydia abortus is one of the most commonly diagnosed causes of infectious abortion in small ruminants worldwide. Control of the disease (Enzootic Abortion of Ewes or EAE) is achieved using the commercial live, attenuated C. abortus 1B vaccine strain, which can be distinguished from virulent wild-type (wt) strains by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. Published studies applying this typing method and whole-genome sequence analyses to cases of EAE in vaccinated and non-vaccinated animals have provided strong evidence that the 1B strain is not attenuated and can infect the placenta causing disease in some ewes. Therefore, the objective of this study was to characterise the lesions found in the placentas of ewes vaccinated with the 1B strain and to compare these to those resulting from a wt infection. A C. abortus-free flock of multiparous adult ewes was vaccinated twice, over three breeding seasons, each before mating, with the commercial C. abortus 1B vaccine strain (Cevac® Chlamydia, Ceva Animal Health Ltd.). In the second lambing season following vaccination, placentas (n = 117) were collected at parturition and analysed by C. abortus-specific real-time quantitative PCR (qPCR). Two placentas, from a single ewe, which gave birth to live twin lambs, were found to be positive by qPCR and viable organisms were recovered and identified as vaccine type (vt) by PCR-RFLP, with no evidence of any wt strain being present. All cotyledons from the vt-infected placentas were analysed by histopathology and immunohistochemistry and compared to those from wt-infected placentas. Both vt-infected placentas showed lesions typical of those found in a wt infection in terms of their severity, distribution, and associated intensity of antigen labelling. These results conclusively demonstrate that the 1B strain can infect the placenta, producing typical EAE placental lesions that are indistinguishable from those found in wt infected animals.

Evidence that Chlamydia abortus vaccine strain 1B produces indistinguishable placental lesions to wild type strains

Chlamydia abortus is the most commonly diagnosed cause of abortion in small ruminants around the world [1]. Control of chlamydial abortion is achieved in several European countries using an attenuated live 1B C. abortus vaccine strain, which can be distinguished from virulent wild-type strains by PCR-RFLP analysis [2]. Application of this method has provided molecular evidence that the 1B strain can cause abortion in ewes [3, 4]. The objective of this study was to define the distribution of lesions and bacterial load in cotyledons from ewes vaccinated with the 1B strain compared to normal wild-type infections. A Chlamydia-free flock of 75 multiparous adult ewes were vaccinated twice, two years apart, each prior to mating, with the commercial 1B vaccine. In the second lambing season following the last vaccination, placentae (n=116) were collected and analysed by C. abortus real-time qPCR [3]. Only two of the placentae, both from the same ewe, were found to be positive. Viable organisms were isolated from these placentae and confirmed by RFLP-PCR [3] to be vaccine-type. All cotyledons from these placentae were analysed by histopathology and immunohistochemistry [5], and compared with those from wild-type infected placentae. The lesions in the vaccine-type infected placentae were indistinguishable from the wild-type infected placentae in terms of their severity, load and distribution. These results suggest that the 1B vaccine strain of C. abortus can cause chlamydial abortion in ewes producing typical placental lesions to wild-type infected animals, and could be circulating with the potential to cause natural infection and disease.

Seroprevalence and associated risk factors of Chlamydia abortus infection in ewes in Tunisia

Enzootic abortion of ewes (EAE) caused by Chlamydia abortus is a disease of ruminants that results in serious economic losses in livestock industry. The zoonotic potential of the pathogen adds a public health concern on the efforts to control the disease. We report herein a cross-sectional study that was conducted during the lambing season (June and July) in Tunisia to estimate the seroprevalence of C. abortus infection in large sheep herds with abortion history. A total of 803 ewes were sampled and tested using indirect enzyme linked immunosorbent assay (iELISA). The overall apparent seroprevalence at herd and individual levels were 58 % (95 %CI = 39–74.5 %) and 6.6 % (95 %CI = 4.9–8.3 %), respectively. Significant risk factors investigated using univariate and multivariate analyses were history of infertility (OR = 5.7; 95 %CI = 3.05–10.66), the number of reproductive ewes (OR = 2.1; 95 %CI = 1.12–3.94), the control of new animals at introduction (OR = 4.35; 95 %CI = 2.46–7.68), the sharing of drinking water (OR = 2.18; 95 %CI = 1.22–3.9), the exchange of breeding males (OR = 2.56; 95 %CI = 1.003–6.54), the disposal of abortion materials without precaution (OR = 4.36; 95 %CI = 2.42–7.87), the lack of lambing barn (OR = 2.39; 95 %CI = 1.13–5.04), the non-application of hygienic post-abortion measures (OR = 10.35; 95 %CI = 5.28–20.26) and the manure management (OR = 11.35; 95 %CI = 3.26–39.48). To the best of our knowledge, this is the first sero-epidemiological survey conducted on an abortive disease in Tunisian ewes that investigated the risk factors of C. abortus infection.

Transcriptome Landscape of Intracellular Brucella ovis Surviving in RAW264.7 Macrophage Immune System

Brucella ovis infection results in genital damage and epididymitis in rams, placental inflammation and rare abortion in ewes, and neonatal mortality in lambs. However, the mechanism underlying B. ovis infection remains unclear. In the present study, we used prokaryotic transcriptome sequencing to identify the differentially expressed genes (DEGs) between wild-type B. ovis and intracellular B. ovis in RAW264.7 macrophages. Gene ontology (GO) term enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed, and quantitative reverse transcriptase PCR (qRT-PCR) was used to validate the top 10 upregulated and downregulated DEGs. The results showed that 212 genes were differentially expressed, including 68 upregulated and 144 downregulated genes, which were mainly enriched in 30 GO terms linked to biological process, cellular component, and molecular function. KEGG analysis showed that the DEGs were enriched in the hypoxia-inducible factor 1 (HIF-1) signaling pathway, mitogen-activated protein kinase (MAPK) signaling pathway, beta-alanine metabolism, and quorum sensing pathway. BME_RS01160, BME_RS04270, BME_RS08185, BME_RS12880, BME_RS25875, predicted_RNA865, and predicted_RNA953 were confirmed with the transcriptome sequencing data. Hence, our findings not only reveal the intracellular parasitism of B. ovis in the macrophage immune system, but also help to understand the mechanism of chronic B. ovis infection.