Abortion In Sheep Research Articles

Campylobacter fetus subespécie fetus: abortamento e natimortalidade em ovinos

A bactéria do gênero Campylobacter está comumente envolvida em surtos de abortos ovinos em muitos países. No Brasil, até o presente momento, ainda não houve relato sobre a ocorrência de aborto em ovinos causado pelo C. fetus, subespécie fetus (C. fetus ssp. fetus). No presente trabalho, relata-se a detecção deste agente em fetos e natimortos ovinos naturalmente infectados. Desse modo, alerta-se para a possibilidade de novos casos de aborto em ovinos causados por C. fetus ssp. fetus.

Campylobacter as a cause of gastroenteritis in humans and animals

Campylobacter is a zoonotic microorganism in human and animal population which causes gastroenteritis; it is widespread in nature. Under the present systematics, Campylobacter (Campylobacteriaceae) family consist of 16 species and 6 subspecies. Illness can occur in various animals. It causes dysentery in swine, abortion and infertility in cows, abortions in sheep and goats, avian hepatitis in poultry, and enteritis in many species including primates and pets. Campylobacter do not produce toxins in food and it is known that Campylobacter jejuni produce endotoxin (unstable at higher temperature), enterotoxin and citotoxin. Humans can be infected if they have a direct contact with animals and contaminated food. Campylobacteriosis in humans caused by C. jejuni is also known as Campylobacter enteritis. Infective dose of less than 500 cells can cause infection. Key words: Campylobacter, gastroenteritis, humans, animals, food.

Rift Valley Fever: A Fatal Viral Disease of Neonatal Animals

Rift Valley fever (RVF), a mosquito-borne disease of animals and humans, is caused by Phlebovirus which belong to the family Bunyaviridae. The disease in animals is characterized by fever, anorexia, diarrhea, hepatitis and abortion. It causes high mortality in neonatal animals and high incidence of abortion in sheep and cattle. The disease is of great economic significance as losses mainly occur due to the death of young lambs and calves. Laboratory help is required to confirm the diagnosis of RVF. The immunization and vector control are the main strategies to reduce the incidence of RVF. It is considered as an occupational disease of livestock handlers, dairy farmers, abattoir workers and veterinarians. Hence, it is imperative to take all necessary precautions to protect from infection.

Conventional and molecular biotyping of Brucella strains isolated from cattle, sheep and human

Summary: In this study, the role of Brucella spp. in cattle and sheep abortions among Kayseri region was investigated and predominant subspecies and biovars in this region were determined by conventional and molecular biotyping methods. For this purpose, 61 cattle and 64 sheep abortion material and also 50 human blood isolates were examined. A total of 29 Brucella spp. 17 (27.9%) and 12 (18.7%) of which were isolated from cattle and sheep specimens, respectively) were isolated from animal sources. Both animal and human isolates were typed by conventional and Enhanced AMOS-ERY PCR methods. All Brucella spp. strains isolated from cattle were found to belong to B. abortus biovar 3 and biovar 3b using conventional and molecular typing methods, respectively. All sheep originated Brucella spp. strains and human originated Brucella spp. strains were found to belong to B.melitensis biovar 3 using both conventional and molecular methods. As a result, predominant biovars causing brucellosis in human, cattle and sheep in Kayseri, Turkey were detected. These findings were considered to be useful in prevention and controlling activities for Brucellosis in Turkey. Keywords: Biotyping,

Development of a Loop-Mediated Isothermal Amplification Assay for Rapid, Sensitive and Specific Detection of a <i>Campylobacter jejuni</i> Clone

Loop-mediated isothermal amplification (LAMP) assay is a simple, rapid and specific detection method and has been used for detection and identification of different Campylobacter species. In this study, we develop a LAMP assay specific for detection of a particular clone (clone SA) of Campylobacter jejuni, associated with the vast majority of recent sheep abortions in the U.S. Using a set of specific primers for C. jejuni IA3902 (a clone SA isolate) and genomic DNA or boiled cell extract as template, the target DNA was amplified at 63 °C for 50 min in a water bath. A positive reaction was identified visually as white precipitate or fluorescence under UV, and confirmed by gel electrophoresis. Detection limit of the assay was comparable to that of conventional PCR. The LAMP was shown to be specific for detection of clone SA when tested on a number of C. jejuni strains of different genetic backgrounds. Applicability of the LAMP assay for specific detection of clone SA was demonstrated in animal tissues experimentally infected with IA3902 or genetically diverse C. jejuni strains. Since clone SA is the predominant cause of sheep abortions in the U.S. and is a zoonotic pathogen, the LAMP assay may be a valuable detection tool in future epidemiological studies.

Brucellosis in sheep and goat of Bogra and Mymensingh districts of Bangladesh

Brucellosis is the most important bacterial disease of livestock in Bangladesh. The present study was conducted to determine the seroprevalence of brucellosis in goat and sheep in Mymensingh and Bogra districts of Bangladesh using slow agglutination test and Rose Bengal test as screening test and indirect enzyme linked immunosorbent assay as confirmatory test. Questionnaire based data on age, gender, area, client's complaint, number of animals in herds, disease history, reproductive problems such as abnormal uterine discharge, abortion or previous abortion in sheep and goat and their reproductive diseases were recorded. A total of 200 sera samples were collected from 80 sheep and 120 goats. The prevalence of brucellosis in goat was 2.50% and 1.25% in sheep. Positive reactors were only detected in female of both goat and sheep. In this study, there existed a significant association among abortion and the prevalence of brucellosis (p < 0.01). The prevalence of brucellosis in sheep and goat in Bangladesh is not negligible, and it is therefore worth considering the adoption of preventive measures.

New challenges for vaccination to prevent chlamydial abortion in sheep

Ovine enzootic abortion (OEA) is caused by the obligate intracellular Gram-negative bacterium Chlamydia abortus. OEA remains a common cause of infectious abortion in many sheep-rearing countries despite the existence of commercially available vaccines that protect against the disease. There are a number of confounding factors that influence the uptake and use of these vaccines, which includes an inability to discriminate between infected and vaccinated animals (DIVA) using conventional serological diagnostic techniques. This suggests that the immunity elicited by current vaccines is similar to that observed in convalescent, immune sheep that have experienced OEA. The existence of these vaccines provides an opportunity to understand how protection against OEA is elicited and also to understand why vaccines can occasionally appear to fail, as has been reported recently for OEA. Interferon-gamma (IFN-γ), the cytokine that classically defines Th1-type adaptive immunity, is a strong correlate of protection against OEA in sheep and has been shown to inhibit the growth of C. abortus in vitro. Humoral immunity to C. abortus is observed in both vaccinated and naturally infected sheep, but antibody responses tend to be used more as diagnostic markers than targets for strategic vaccine design. A future successful DIVA vaccine against OEA should aim to elicit the immunological correlate of protection (IFN-γ) concomitantly with an antibody profile that is distinct from that of the natural infection. Such an approach requires careful selection of protective components of C. abortus combined with an effective delivery system that elicits IFN-γ-producing CD4+ve memory T cells.

Molecular Evidence for Zoonotic Transmission of an Emergent, Highly Pathogenic Campylobacter jejuni Clone in the United States

Campylobacter jejuni is a major zoonotic pathogen. A highly virulent, tetracycline-resistant C. jejuni clone (clone SA) has recently emerged in ruminant reservoirs and has become the predominant cause of sheep abortion in the United States. To determine whether clone SA is associated with human disease, we compared the clinical isolates of clone SA from sheep abortions with the human isolates of the PulseNet National Campylobacter databases at the CDC and the FDA using pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and serotyping. The combined SmaI and KpnI PFGE pattern designations of clone SA from sheep were indistinguishable from those of 123 (9.03%) human C. jejuni isolates (total, 1,361) in the CDC database, among which 56 were associated with sporadic infections and 67 were associated with outbreaks that occurred in multiple states from 2003 to 2010. Most of the outbreaks were attributed to raw milk, while the sources for most of the sporadic cases were unknown. All clone SA isolates examined, including PFGE-matched human isolates, belong to sequence type 8 (ST-8) by MLST and serotype HS:1,8, further indicating the clonality of the related isolates from different host species. Additionally, C. jejuni clone SA was identified in raw milk, cattle feces, the feces and bile of healthy sheep, and abortion cases of cattle and goats, indicating the broad distribution of this pathogenic clone in ruminants. These results provide strong molecular and epidemiological evidence for zoonotic transmission of this emergent clone from ruminants to humans and indicate that C. jejuni clone SA is an important threat to public health.

A review of poisonous plants that cause reproductive failure and malformations in the ruminants of Brazil

The objective of this review is to provide a report on toxic plants causing reproductive problems in ruminants in Brazil. Aspidosperma pyrifolium causes abortion or stillbirth in goats, as well as most likely in sheep and cattle, in the semiarid regions of Northeastern Brazil. Intoxications by Ateleia glazioveana, Tetrapterys acutifolia and T. multiglandulosa result in abortion and neonatal mortality in cattle and sheep, and the same signs have been experimentally observed in goats. These three plants can also cause cardiac fibrosis and a nervous disease with spongiosis of the central nervous system. Other plants known to cause abortion include Enterolobium contortisiliquum, E. gummiferum, Stryphnodendron coriaceum, S. obovatum and S. fissuratum. These plants can also cause digestive signs and photosensitization. Abortions have been reported in animals intoxicated by nitrates and nitrites as well. Infertility, abortions and the birth of weak offspring have been reported in animals intoxicated by plants containing swainsonine, including Ipomoea spp., Turbina cordata and Sida carpinifolia. Trifolium subterraneum causes estrogenism in cattle. Mimosa tenuiflora and, most likely, M. ophthalmocentra cause malformations and embryonic mortality in goats, sheep and cattle in the semiarid regions of Northeastern Brazil.

Critical Role of LuxS in the Virulence of Campylobacter jejuni in a Guinea Pig Model of Abortion

Previous studies on Campylobacter jejuni have demonstrated the role of LuxS in motility, cytolethal distending toxin production, agglutination, and intestinal colonization; however, its direct involvement in virulence has not been reported. In this study, we demonstrate a direct role of luxS in the virulence of C. jejuni in two different animal hosts. The IA3902 strain, a highly virulent sheep abortion strain recently described by our laboratory, along with its isogenic luxS mutant and luxS complement strains, was inoculated by the oral route into both a pregnant guinea pig virulence model and a chicken colonization model. In both cases, the IA3902 luxS mutant demonstrated a complete loss of ability to colonize the intestinal tract. In the pregnant model, the mutant also failed to induce abortion, while the wild-type strain was highly abortifacient. Genetic complementation of the luxS gene fully restored the virulent phenotype in both models. Interestingly, when the organism was inoculated into guinea pigs by the intraperitoneal route, no difference in virulence (abortion induction) was observed between the luxS mutant and the wild-type strain, suggesting that the defect in virulence following oral inoculation is likely associated with a defect in colonization and/or translocation of the organism out of the intestine. These studies provide the first direct evidence that LuxS plays an important role in the virulence of C. jejuni using an in vivo model of natural disease.

Complete genome sequence of the animal pathogen Listeria ivanovii, which provides insights into host specificities and evolution of the genus Listeria.

We report the complete and annotated genome sequence of the animal pathogen Listeria ivanovii subsp. ivanovii strain PAM 55 (serotype 5), isolated in 1997 in Spain from an outbreak of abortion in sheep. The sequence and its analysis are available at an interactive genome browser at the Institut Pasteur (http://genolist.pasteur.fr/LivaList/).

Detection of Toxoplasma gondii antigens reactive with antibodies from serum, amniotic, and allantoic fluids from experimentally infected pregnant ewes

Toxoplasma gondii, an intracellular protozoan parasite, is one of the major causes of infectious abortion in sheep. To further understand the pathogenesis of toxoplasmosis, serum, amniotic and allantoic fluids and foetal stomach contents were collected from experimentally infected pregnant ewes to determine pathogen numbers and other markers of infection. Fifteen pregnant ewes (90 days of gestation) were each orally inoculated with 3000 sporulated oocysts of T. gondii. Serum samples were collected weekly following challenge. Amniotic and allantoic fluids and foetal stomach contents were collected at 21, 25, 28, 33 and 35 days post-infection. Characteristic placental lesions were detected in 1 of 4 challenged ewes at day 25, 3 of 4 challenged ewes at day 28 and in all challenged ewes at days 33 and 35 post-infection. T. gondii was detected only sporadically in amniotic and allantoic fluids before 35 days of infection, by real-time PCR, and only in ewes with placental lesions. At 35 days post-infection, high numbers of parasite were detected in both amniotic and allantoic fluids. An increase in the number of fluids from challenged animals with IgM and IgG was detected over time, except for IgG in allantoic fluid, which was detected in all samples from day 21 post-infection. IgG in amniotic and allantoic fluids was shown to be specific for T. gondii, and reacted with antigens with an apparent molecular mass of approximately 22kDa and 30kDa. Results suggest a maternal source of immunoglobulin in the allantoic fluid and a foetal source of immunoglobulin in the amniotic fluid early in infection but that both sources may contribute immunoglobulin to both fluids at a later stage.

Prevalence of Coxiella burnetii in livestock abortion material using PCR

Coxiella burnetii , the cause of Q fever, is an important zoonotic bacterial pathogen that occurs worldwide and has been extensively reviewed by Angelakis and Raoult (2010). Q fever has assumed increased importance following the large human outbreak in The Netherlands linked to intensive goat farming which led to over 3000 cases between 2007 and 2010 and resulted in major veterinary interventions, including mass vaccination and culling (Delsing and Kullberg 2008, Van den Brom and Vellema 2009, Roest and others 2011). C burnetii infection does not usually cause significant economic losses to livestock farmers in Great Britain and there are no formal control schemes. It can cause abortion in sheep, goats and cattle but infection is mainly subclinical and very few confirmed diagnoses are recorded each year by the Veterinary Investigation Diagnosis Analysis database. In human beings, infection is mainly asymptomatic. The most common clinical presentation is a flu-like illness, but it can have serious consequences in high-risk groups. The main source of human infection is by aerosol exposure from infected livestock farms and particularly parturition products from infected animals, including aborted fetuses. Advice on Q fever was developed for farmers in Britain following an outbreak in Cheltenham in 2007 linked to airborne spread (Wallensten and others 2010; website reference). Since …

Diagnosis by PCR-REA of Chlamydophila species infections in late-term abortions of domestic ruminants

Veterinary RecordVolume 168, Issue 23 p. 619-619 Research Diagnosis by PCR-REA of Chlamydophila species infections in late-term abortions of domestic ruminants M. L. Tavares Clemente DVM, MSc, Corresponding Author M....

Development of inactivated trivalent vaccine for the teratogenic Aino, Akabane and Chuzan viruses

Aino, Akabane and Chuzan viruses are arthropod-borne (arbo) viruses transmitted by blood-sucking insects like mosquitoes and Culicoides biting midges. These arbovirus infections are mainly associated with abortion, stillbirth and congenital defects in pregnant cattle, sheep and goats, which induces a considerable economic loss in livestock industry. The viruses seem to be widely distributed in Southeast Asia and Australia. As a control strategy, an inactivated trivalent vaccine against Aino, Akabane and Chuzan virus was developed by using binary ethylenimine or formalin as an inactivating agent. The newly developed trivalent vaccine is evaluated for its safety and immunogenicity in animals such as mice, guinea pigs and cattle. The immune responses were significantly detected within 2-weeks after second vaccination without any side effects. Since the field application of experimental vaccine also revealed increased antibodies in inoculated cattle, we demonstrated that these trivalent vaccines could be used as a vaccine to control the arboviral infections in ruminants.

Serological prevalence of Toxoplasma gondii and its association with abortion in sheep in Saudi Arabia

The purpose of this study was to investigate serological prevalence and titers of anti-Toxoplasma gondii antibodies in ewes following waves of abortion and stillbirths in a commercial flock in Riyadh, Saudi Arabia. Serum samples from 168 aborted ewes and 52 breeding rams, were tested for toxoplasmosis using an indirect enzyme-linked-immunosorbent assay (ELISA) and indirect haemagglutination test (IHA). 71 randomly sampled sheep from an abortion-free flock (60 ewes and 11 rams) were also tested, which served as controls. 149 (88.7%) ewes and 42 (80.8%) breeding rams from the flock where abortions and stillbirths occurred were positive for anti-T. gondii antibodies by ELISA. 155 ewes (92.3%) and 44 rams (84.6%), including all of the ELISA positive cases, were also positive by indirect haemagglutination test (IHA). More than 80% of the ELISA positive ewes had O.D. exceeding 100% and nearly 25% of them had O.D. of ≥150%. The IHA results, on the other hand, indicated that more than 75% of the seropositive ewes had antibody titers ≥1:1024, including 58 (37.4%) ewes with IHA titer ranging between 1:4096-1:8192 Pyrexia, depression and vaginal discharge were recorded in some ewes shortly prior to abortion. Post-mortem examination of 5 aborted fetuses revealed blood-stained fluid in the abdominal and thoracic cavities and small inflammatory and necrotic foci in the brain, liver and lungs while the placenta was reddish and friable, and its cotyledons were speckled with small whitish foci of necrosis and mineralization. T. gondii tachyzoites were demonstrated in placental sections of two ewes. By contrast, only 7 (9.9%) out of 71 randomly sampled sheep from an abortion-free flock (60 ewes and 11 rams), were positive for anti-T. gondii antibodies by ELISA and 6 (8.5%) by indirect haemagglutination (IHA) test and most of these had significantly lower titers compared to the flock where abortions and stillbirths were recorded. These results constitute the first detailed serological study of ovine toxoplasmosis in Saudi Arabia and strongly implicate toxoplasmosis as the cause of the abortions and stillbirths in these sheep.

Levels of selected minerals, nitric oxide, and vitamins in aborted Sakis sheep raised under semitropical conditions

The serum levels of calcium, phosphorus, magnesium, copper, zinc and iron and of nitric oxide, retinol, and β-carotene were determined in Sakiz ewes that had experienced an abortion and in healthy controls. Ten healthy and 25 aborted Sakiz sheep were selected from Afyon zone in western Turkey. Their ages ranged between 2 and 4 years weighing between 40 and 60 kg at the time of experiment. All of the abortions occurred in October. The concentrations of retinol, β-carotene, phosphorus, and zinc were significantly lower and those of calcium and nitric oxide were increased in aborted ewes relative to healthy controls. The serum levels of iron, copper, and magnesium were not significantly different among the two groups. In conclusion, abortion is an important problem in commercially important species of ruminants in many regions in the tropics including of western Turkey. Deficiencies of retinol, β-carotene, phosphorus and zinc, and the increase of calcium and nitric oxide concentration may play an important role in the etiology of abortion in ewes. Prophylactic measures such as vitamin and mineral supplementation may be of help to prevent or reduce the incidence of abortion in sheep.

Natural Cross Chlamydial Infection between Livestock and Free-Living Bird Species

The study of cross-species pathogen transmission is essential to understanding the epizootiology and epidemiology of infectious diseases. Avian chlamydiosis is a zoonotic disease whose effects have been mainly investigated in humans, poultry and pet birds. It has been suggested that wild bird species play an important role as reservoirs for this disease. During a comparative health status survey in common (Falco tinnunculus) and lesser (Falco naumanni) kestrel populations in Spain, acute gammapathies were detected. We investigated whether gammapathies were associated with Chlamydiaceae infections. We recorded the prevalence of different Chlamydiaceae species in nestlings of both kestrel species in three different study areas. Chlamydophila psittaci serovar I (or Chlamydophila abortus), an ovine pathogen causing late-term abortions, was isolated from all the nestlings of both kestrel species in one of the three studied areas, a location with extensive ovine livestock enzootic of this atypical bacteria and where gammapathies were recorded. Serovar and genetic cluster analysis of the kestrel isolates from this area showed serovars A and C and the genetic cluster 1 and were different than those isolated from the other two areas. The serovar I in this area was also isolated from sheep abortions, sheep faeces, sheep stable dust, nest dust of both kestrel species, carrion beetles (Silphidae) and Orthoptera. This fact was not observed in other areas. In addition, we found kestrels to be infected by Chlamydia suis and Chlamydia muridarum, the first time these have been detected in birds. Our study evidences a pathogen transmission from ruminants to birds, highlighting the importance of this potential and unexplored mechanism of infection in an ecological context. On the other hand, it is reported a pathogen transmission from livestock to wildlife, revealing new and scarcely investigated anthropogenic threats for wild and endangered species.

Molecular survey of Toxoplasma infection in sheep and goat from Fars province, Southern Iran

Toxoplasmosis is a widespread zoonotic disease that causes significant morbidity and mortality in human fetus and in immunocompromised patients. Moreover, it becomes a major cause of abortion in sheep and goats. Since consumption of meat of infected lamb and goat is considered as the main sources of human infection in Iran, this study was undertaken to determine the prevalence of Toxoplasma infection in edible tissues of sheep and goats in Shiraz in 2008. Samples of brain, tongue, liver, and muscles of neck, intercostals, and femoral were taken from 56 sheep and 22 goats and tested by PCR. The total prevalence of Toxoplasma infection among animals was found to be 33.3%. Five out of 22 goats (22.7%) and 21 out of 56 sheep (37.5%) were infected by Toxoplasma. Differences between the prevalence rate of infection among females (nine out of 14 = 46%) and males animals (12 out of 45 = 29.5%) was significant (P = 0.013). Furthermore, a positive correlation was found between the age of animals and the rate of infection; animals greater than 2 years old showed a higher rate of infection (47%) in comparison with those less than 2 years old (25%, P = 0.04). The highest infected tissue was tongue (21.8%) followed by brain (19.2%) and femoral and intercostal muscles (17.9%). This study demonstrated a high level of Toxoplasma infection in slaughtered animals in Shiraz and these should be considered as the main sources of infection for human population in the region.

Immunological Paradigms and the Pathogenesis of Ovine Chlamydial Abortion

Successful mammalian pregnancy involves complex immunological interactions between the mother and foetus that are not yet fully understood. A number of immunological paradigms have been established to explain the failure of the maternal immune system to reject the semi-allogeneic foetus, mainly based on studies in mice and humans. However, as placental structure, gestation periods and number of concepti per pregnancy can vary greatly between mammals, it is not always clear how applicable these immunological paradigms are to reproduction in other species. Here, we discuss the predictions of three important immunological paradigms in relation to the pathogenesis of ovine enzootic abortion (OEA), a common cause of infectious abortion in sheep and other ruminants. OEA is caused by the intracellular Gram-negative bacterium Chlamydophila abortus that exhibits a tropism for placental trophoblast. The paradigms of particular relevance to the pathogenesis of OEA are as follows: (i) intracellular bacterial infections are controlled by T(H)1-type CD4(+ve) T cells; (ii) indoleamine 2,3-dioxygenase is expressed in the placenta to prevent immunological rejection of the semi-allogeneic foetus; and (iii) pregnancy is a maternal T(H)2-type phenomenon. We discuss the relevance and validity of these paradigms for chlamydial abortion and reproductive immunology in sheep.