Sheep Antibody Research Articles

Risk Factors Associated with Seroprevalence of Chlamydia abortus in Sheep Farms in Ceará, Brazil

Background: Chlamydia abortus infections (Chlamydiosis) can cause reproductive problems in sheep, such as abortions and birth defects, leading to farm productivity loss. The symptoms, which are similar to other reproductive diseases, and the microbial pathogenesis make the clinical diagnosis difficult. Chlamydia abortus is a zoonotic pathogen, making it a public health issue because it can infect and induce abortions in humans. This study investigated anti-C. abortus antibody levels and infection risk factors in sheep in the State of Ceará, Brazil.Materials, Methods & Results: Forty-three properties from 10 municipalities in 4 mesoregions in the State of Ceará, Brazil (Sertões, metropolitan Fortaleza, North Ceará and Northwest Ceará) with sheep, goats, cattle, and horses were visited. Five hundred and four serological samples from sheep were collected and tested for anti-C. abortus antibodies using an Enzyme-linked Immunosorbent Assay (ELISA) [IDEXX®, Australia] and all procedures were performed in accordance with the manufacturer's instructions at the Clinical Pathology Laboratory of EMBRAPA Goats and Sheep (Sobral, Brazil). Individual questionnaires were completed about sheep breeding practices and to identify possible C. abortus risks. Seropositive results were found in 18.45 % (93/504 individuals) of sheep, and 88.37 % (38/43 properties) of the herds had at least one seropositive animal. The number of seropositive individuals was significantly different between adults and ewes [P < 0.01; Odds Ratio (OR) = 0.510; 95% confidence interval (CI) = 0.306 - 0.850]. Logistic regression modeling identified a missing health certificate request for newly acquired animals as a chlamydiosis risk factor [P = 0.038; OR = 2.672; 95% CI = 1.058 - 6.749].Discussion: The prevalence of anti-C. abortus antibodies in sheep in the State of Ceara emphasizes the importance of testing and tracking the disease spread among herds; these results were similar to studies in other areas of Brazil. Adult sheep that spend more time on the property may have a higher exposure risk because of increased reproductive activity. Misinformation and technical limitations can influence the proper handling of animals avoiding contagion through the correct use of techniques and recommendations. Disease transmission occurs through the digestive tract and between mother and fetus. Therefore, seropositive (infected) sheep may be related to the breeding system practices, such as allowing contact between sheep and other species on the property (goats, cattle, and horses) during breeding. Acquiring animals from external sources without sufficient health information can increase the transmission risk. Contaminated pastures, water, food, and air also increase transmission risk. The lack of technical and practical knowledge regarding disease prevention and control also contributes to disease transmission, resulting in reproductive losses due to high abortion rates. Chlamydia abortus has zoonotic potential and may infect humans without proper safety information. Therefore, future epidemiological studies are required for a better understanding of the primary risk factors for disease occurrence and spread among herds in the region. Chlamydia abortus infection is present in sheep in Ceará, Brazil. Chlamydiosis information programs should be adopted, sanitary measures implemented, and the epidemiological surveillance of sheep herds strengthened.

Revisiting Brucellosis in Small Ruminants of Western Border Areas in Pakistan.

Brucellosis, globally known bacterial zoonosis, is endemic to Pakistan. B. abortus in bovines, B. melitensis in small ruminants and B. canis in dogs mainly cause this disease. A total of 1821 sera (1196 from sheep and 625 from goats) from animal herds near the Pakistan–Afghanistan border were collected. In parallel testing of sera for anti-Brucella antibodies (B. abortus and B. melitensis) was carried out by RBPT and indirect ELISA. The presence of Brucella DNA in sera was tested by real-time PCR. The overall percentage of seropositive samples was 0.99 (18/1821) by both tests. All positive samples originated from Baluchistan territory which translated into 1.76% (18/1021). None of the positive sera had signals for Brucella DNA and none of sera from goats carried detectable antibodies. Both tests showed an almost perfect agreement with Kappa statistics. The flock size was found to be associated with the presence of anti-Brucella antibodies. The samples of Khyber Pakhtunkhwa (KPK) tested negative in both serological tests and hence were not processed for real-time PCR. The present study shows the presence of anti-Brucella antibodies in sheep in the Baluchistan region of Pakistan. Diagnostic services need to be improved and test and slaughter policies might be implemented for eradication of Brucella infection in these areas. Awareness about the infection is needed at the farmer’s level. Isolation and molecular biology of the isolates could help with understanding the prevailing etiology in a better way.

Detection of Coxiella burnetii antibodies in sheep and cattle on a veterinary campus in St. Kitts: Implications for one health in the Caribbean region

Coxiella burnetii is a ubiquitous zoonotic bacterium reported worldwide that causes Q-fever. Infections result in profound economic losses to livestock producers by causing abortions and low birth weights. Current information about the disease in the Caribbean region is scarce. With multiple small islands and territories, it is often considered that the bacterium is absent or circulates at a low prevalence. Our study aimed to determine whether sheep and cattle housed at a veterinary campus in St Kitts had previous exposure to C. burnetii. Blood samples were taken from cattle (n = 63; 72% of the herd) and sheep (n = 133; 71% of the flock). Antibodies to C. burnetii were detected by a commercial indirect enzyme-linked immunosorbent assay (IDvet® ELISA) test. The seroprevalence was estimated at 26.3% (95% CI: 19.1–34.7%) in sheep and 0% (95% CI: 0–5.7%) in cattle. Sheep importation to St. Kitts is very rare, thus, these results suggest that C. burnetii is present on the island. The seronegativity of all the cattle highlights the absence of the bacterium on the veterinary campus. The high seroprevalence in sheep, however, has potentially important implications for animal health and public health as well as for wildlife conservation. Further investigation about animal seroprevalence and human exposure are warranted in St. Kitts and in the Caribbean region.

Validation and field evaluation of a competitive inhibition ELISA based on the recombinant protein tSAG1 to detect anti-Neospora caninum antibodies in sheep and goats

Neospora caninum is a protozoan parasite that causes abortion and reproductive failure in small ruminants. We validated and evaluated under field conditions a competitive inhibition ELISA based on the truncated SAG1 protein (tSAG1) from N. caninum for the detection of anti-N. caninum antibodies in sheep and goat flocks. The assay was validated using 80 positive and 142 negative serum samples from sheep and goats analyzed by IFAT and immunoblot (IB). ciELISAtSAG1 was then used to evaluate the prevalence of anti-N. caninum antibodies in 1449 goats from 143 flocks and 385 sheep from 40 flocks and compared to IFAT. The prevalence of anti-Toxoplasma gondii antibodies was evaluated by IFAT. The ciELISAtSAG1 cut-off was ≥ 36 percent inhibition, with a diagnostic sensitivity of 100.0 % (95 % CI = 95.4–100.0 %) and a diagnostic specificity of 98.6 % (95 % CI = 95.0–99.8 %) relative to the agreement between IFAT and IB. The field evaluation revealed a concordance between ciELISAtSAG1 and IFAT of 97.4 %, with an agreement (κ) of 0.90 for sheep sera, and a concordance of 96.5 % with κ = 0.85 for goat sera. The overall prevalence of anti-N. caninum antibodies in sheep was 14.3 % by IFAT and 15.8 % by ciELISAtSAG1. In goats, prevalence was 12.9 % by IFAT and 14.6 % by ciELISAtSAG1. The overall prevalence of anti-T. gondii antibodies was 28.8 % in goats and 43.8 % in sheep. The ciELISAtSAG1 could be useful for large-scale detection of anti-N. caninum antibodies in sheep and goats, and for seroepidemiological investigations due to its appropriate sensitivity and specificity, and the simplicity of production.

Detection of bluetongue virus antibodies in sheep from Paraná, Brazil

Bluetongue (BT) is an infectious and non-contagious disease caused by bluetongue virus (BTV) belonging to the genus Orbivirus. It is transmitted by a hematophagous vector, Culicoides sp., to ruminants, particularly to sheep, which are most susceptible to this disease. The main serological tests are agar gel immunodiffusion (AGID), which is recommended by the World Organization for Animal Health (OIE), and the competitive enzyme-linked immunosorbent assay (cELISA), which has the advantage of no cross-reaction with other orbiviruses. The aim was to compare the results of these two tests by conducting them on sera collected from sheep in the state of Paraná, Brazil. From March to October 2017, serum samples were collected from 270 sheep from 10 farms in six mesoregions of Paraná. The samples were subjected to AGID and cELISA to detect antibodies against BTV. Based on the test results, we classified the sheep as low, moderate, and high occurrence. The results demonstrated that 64.81% (175/270) of the sheep were seropositive through the cELISA test, showing a high occurrence, and 41.11% (111/270) were seropositive through the AGID test, indicating a moderate occurrence. The concordance between the tests was moderate (0.51) as determined by the Kappa coefficient. Among the studied farms, 90% (9/10) presented at least one seropositive sheep, and the number of animals tested positive by the cELISA test was higher than those by the AGID test. Favorable climate, which favors the presence and multiplication of the culicoid vector and the occurrence of infection, was the biggest predominant factor responsible for the obtained results. The low occurrence in farms with milder climate suggest that the presence of antibodies also occurs due to the low pathogenicity of circulating serotypes in the different mesoregions studied. It is concluded that BTV infection is present in the sheep herds in Paraná, and the occurrence was moderate detected by AGID test and high detected by cELISA test.

Increased risk of hepatitis E virus infection in workers occupationally exposed to sheep.

Hepatitis E virus (HEV) is an enteric RNA virus from the family Hepeviridae with five genotypes (genotypes 1-4 and 7) known to infect humans. HEV infection is known to have a zoonotic swine origin in industrialized countries. The role of pigs and wild boars as major reservoirs for human infection is today well-established; however, the list of new animal reservoirs is ever-expanding as new HEV strains are continuously being found in a broad host range. The recent detection of HEV in sheep stools brings concerns on the possibility of HEV transmission from these animals to humans, particularly in those occupationally exposed. The present work investigated the potential occupational risk of HEV infection in shepherds and sheep milk cheesemakers-workers occupationally exposed to ovine (WOEOs; N=96)-from a region of the Centre of Portugal ('Serra da Estrela') based on the differences of anti-HEV IgG seroprevalence rates between these professionals and the general population (N=192). The presence of HEV-specific antibodies in sheep (N=90) from the same region was also evaluated. The HEV seroprevalence in WOEOs (29.3%) was found to be significantly higher (p=.0198) when compared with population controls (16.1%) which suggests an increased risk for HEV infection in these workers. HEV-specific antibodies were also found in 16.6% of the studied sheep showing that HEV circulates in these animals. Further studies are needed to confirm the zoonotic potential of sheep HEV.

Seroprevalence of anti‐Mycobacterium avium subsp. paratuberculosis antibodies in female sheep in Tunisia

Paratuberculosis (Ptb) is a widespread chronic infection caused by Mycobacterium avium subsp. paratuberculosis (Map) that affects both domestic and wild ruminants. Most of the studies focused on cattle while, the prevalence of Ptb in sheep in different regions of the world is not well investigated. This study aimed to address this gap of knowledge by screening adult female sheep for paratuberculosis antibodies in different geographical regions of Tunisia. A total number of 338 female sheep from 15 small to middle‐sized, extensively managed sheep farms in six regions across Tunisia were sampled. Animals were clinically examined before blood sampling. Sera were tested for the presence of anti‐Mycobacterium avium subsp. paratuberculosis antibodies using a commercial ELISA kit. Six farms out of 15 comprised at least one seropositive animal and 11 female sheep out of 338 tested animals (3.25%; 95% CI = [1.83–5.73]) were seropositive to M. avium subsp. paratuberculosis. The seroprevalence was significantly lower in 5‐year‐old females (p = .04) and animals that do not graze (p = .02). Due to its huge economic and social impacts, paratuberculosis represents a health problem in Tunisia and several other countries Further investigations are needed to rank sheep Ptb in Tunisia among other diseases and to assess the main risk factors using a larger nation‐wide survey.

Seroprevalence study of peste des petits ruminants in sheep and goats in the northern region of India

Background and Aim:Peste des petits ruminants (PPR) is a contagious, World Organization for Animal Health notifiable, economically important, transboundary morbilliviral disease of sheep and goats. Studying seroprevalence of PPR from different geographical areas under varying agro-climatic conditions may help in formulating effective and appropriate disease control strategies under the ongoing national PPR control program. The present cross-sectional study describes the prevalence of PPR virus antibodies in sheep and goats in the various epidemiological units in different states (Haryana, Himachal Pradesh [HP], Jammu and Kashmir [J&K], Punjab, Uttarakhand [UK], and Uttar Pradesh [UP]) of the northern region of India.Materials and Methods:A total of 5843 serum samples (sheep [n=2463] and goats [n=3380]) were collected by stratified random sampling method from 322 epidemiological units in the studied region during 2017-2018 and tested for PPR virus (PPRV) antibodies by competitive ELISA.Results:The results revealed that an overall seroprevalence of 44.05% (2574/5843) with 57.32%, 55.22%, 65.69%, 37.09%, 32.73%, and 29.35% prevalence of PPRV antibodies in small ruminants in Haryana, Punjab, UP, HP, J&K, and UK states, respectively. Further, Chi-squared test revealed an association of PPRV antibodies in goats (χ2=252.28, p<0.01) and sheep (χ2=192.12, p<0.01) across different states in the region.Conclusion:The seroprevalence in majority of the epidemiological units (n=130) in sheep and goats in the studied region had <30%. This necessitates comprehensive, rigorous, continuous vaccination and active surveillance programs for few more years to achieve the desired 70% seroprevalence level of PPRV antibodies in population and to make the northern region of India, as PPR free zone.

LEPTOSPIROSIS IN SHEEP IN SOUTHERN RIO GRANDE DO SUL, BRAZIL

Leptospirosis is a globally occurring zoonosis. The disease is often asymptomatic in sheep, but it is a major cause of reproductive losses. In Rio Grande do Sul state, commercial sheep herds total over 2,600,000 animals. In this light, our study aims to identify seroprevalence of anti- Leptospira antibodies in sheep in a slaughterhouse with state inspection level. Blood samples were taken at the time of bleeding at the slaughter line. Eighty-one serum samples were submitted to the Microscopic Agglutination Test (MAT), using a panel of 12 serovars. A total of 23 (28.39%) were reagents for at least one serovar. According to the most prevalent serovars (Autumnalis, Hardjo and Bratislava), grazing alongside cattle and the presence of rodents on the farm, may be influencing the transmission of the agent to the sheep. Although the prevalence was similar to the national average (26%), it is lower than that most recently described for the region (34.26%), which may indicate advances in technification and the elaboration of prevention policies

Prevalence and risk factors of some arthropod-transmitted diseases in cattle and sheep in Jordan.

Aims:The objectives of this study were to determine the prevalence and associated risk factors of bluetongue virus (BTV) in sheep and bovine ephemeral fever virus (BEFV) in dairy cattle in Jordan.Materials and Methods:A simple randomized study was designed to collect 600 serum samples from sheep and 300 serum samples from dairy cattle located in the Northwestern parts of Jordan. In addition, data regarding farm management were collected using a pre-tested questionnaire through personal interview to determine potential risk factors. The seroprevalences of BEF and BTVs were determined using serum neutralization test and BTV group-specific competitive enzyme-linked immunosorbent assay, respectively.Results:The overall seroprevalence of neutralizing antibodies against BEFV in dairy cattle was 45.37%. The overall seroprevalence of BTV group-specific antibodies in sheep was 47.8% (54% true seroprevalence). Logistic regression analysis identified geographic location (Irbid) (odds ratio [OR]=1.0; confidence interval [CI]=0.5-2.1), no use of disinfectants on the farm (OR=1.0; CI=0.05-0.1), and lack of veterinary services (OR=10; CI=3.5-13.2) as risk factors associated with high seropositivity against BTV in sheep. Geographic location (Jarash) (OR=3; CI=1.0-5.5), age of the animal (1-2 years of age (OR=1; CI=0.3-1.9), and lack of veterinary services (OR=9; CI=4-11) were identified as risk factors associated with high seroprevalence against BEFV in dairy cattle.Conclusion:Results of this study indicate that BEFV in dairy cattle and BTV in sheep are endemic in Northwestern regions of Jordan. Implementation of appropriate control measures is, therefore, required to reduce the adverse effects of these diseases on animal health and productivity.

A time-resolved fluorescence immunoassay for the detection of anti-Neospora caninum antibodies in sheep

Neospora caninum is a protozoan parasite (Phylum Apicomplexa) that has been recently suggested as a relevant cause of reproductive disorders in small ruminants. The aim of the present study is to develop and validate a new serological test based on time resolved fluorescency using N. caninum GRA7 recombinant antigen (GRA7-TRFIA) for the detection of N. caninum antibodies in sheep. A total of 346 serum samples (208 from experimentally infected sheep, 117 from a dairy farm with a previous history of Neospora-associated abortion, and 21 negative sera) were used. The validation of the new assay was performed by the evaluation of assay precision, analytical sensitivity (Se), accuracy and cross reactivity. In the experimentally infected sheep, antibody kinetics was compared between GRA7-TRFIA and an in house N. caninum tachyzoite soluble extract-based ELISA (NcSALUVET ELISA) by Wilcoxon matched-pairs signed rank test. The cut-off and diagnostic Se and specificity (Sp) of GRA7-TRFIA was estimated by ROC analysis with field samples. In addition, concordance and correlation between GRA7-TRFIA and a commercial ELISA and NcSALUVET ELISA were assessed by kappa value and Spearman correlation coefficient, respectively.Overall, GRA7-TRFIA showed an adequate precision, analytical Se and accuracy to detect anti-N. caninum antibodies in ovine serum, and no cross reactivity with the closely related protozoan Toxoplasma gondii. In naturally infected sheep, 100% Se and 95.35% Sp were obtained for a cut-off point of 62.68 Units of Fluorometry for N. caninum (UFN). Moreover, GRA7-TRFIA allowed earlier detection of N. caninum infection than NcSALUVET ELISA in experimentally infected sheep.

Quantitative Immunoprecipitation Free Light Chain Mass Spectrometry (QIP-FLC-MS) Simplifies Monoclonal Protein Assessment and Provides Added Clinical Value in Systemic AL Amyloidosis

Introduction Early diagnosis, effective therapy and precise monitoring are central for improving clinical outcomes in systemic light chain (AL) amyloidosis. Diagnosis and disease response assessment is primarily based on the presence of monoclonal immunoglobulins and free light chains (FLC). The ideal goal of therapy associated with best outcomes is a complete responses (CR), defined by the absence of serological clonal markers. In both instances, detection of the monoclonal component (M-component) is based on serum FLC assessment together with traditional serum and urine electrophoretic approaches, which present inherent limitations and lack sensitivity particularly in AL where the levels are typically low. Novel mass spectrometry methods provide sensitive, accurate identification of the M-component and may prove instrumental in the timely management of patients with low-level amyloidogenic light chain production. Here we assess the performance of quantitative immunoprecipitation FLC mass spectrometry (QIP-FLC-MS) at diagnosis and during monitoring of AL amyloidosis patients treated with bortezomib-based regimens. Methods We included 46 serial patients with systemic AL amyloidosis diagnosed and treated at the UK National Amyloidosis Centre (UK-NAC). All patients had detailed baseline assessments of organ function and serum FLC measurements. Baseline, +6- and +12-month serum samples were retrospectively analysed by QIP-FLC-MS. Briefly, magnetic microparticles were covalently coated with modified polyclonal sheep antibodies monospecific for free kappa light chains (anti-free κ) and free lambda light chains (anti-free λ). The microparticles were incubated with patient sera, washed and treated with acetic acid (5% v/v) containing TCEP (20 mM) in order to elute FLC in monomeric form. Mass spectra were acquired on a MALDI-TOF-MS system (Bruker, GmbH). Results were compared to serum FLC measurements (Freelite®, The Binding Site Group Ltd), as well as electrophoretic assessment of serum and urine proteins (SPE, sIFE, UPE and uIFE). Results Cardiac (37(80%) patients) and renal (31(67%) patients) involvement were most common; 25(54%) patients presented with both. Other organs involved included liver (n=12), soft tissue (n=4), gastrointestinal tract (n=3) and peripheral nervous system (n=2). Baseline Freelite, SPE, sIFE and uIFE measurements identified a monoclonal protein in 42(91%), 22(48%), 34(74%) and 21(46%) patients, respectively. A panel consisting of Freelite + sIFE identified the M-component in 100% of the samples. QIP-FLC-MS alone also identified an M-component in 100% of the samples and was 100% concordant with Freelite for typing the monoclonal FLC (8 kappa, 34 lambda). In 4 patients, QIP-FLC-MS identified an additional M-protein that was not detected by the other techniques. In addition, 4/8(50%) kappa and 4/38(11%) lambda patients showed a glycosylation pattern of monoclonal FLCs at baseline by mass spectrometry. Interestingly, the frequency of renal involvement was significantly lower for patients with non-glycosylated forms (25% vs 76%, p=0.01), while no similar relationship was found for any other organs. During the 1-year follow-up period, 17 patients achieved a CR; QIP-FLC-MS identified serum residual disease in 13(76%) of these patients. Conclusion In our series, QIP-FLC-MS was concordant with current serum methods for identifying the amyloidogenic light chain type and provided, against all other individual tests, improved sensitivity for the detection of the monoclonal protein at diagnosis and during monitoring. The ability to measure the unique molecular mass of each monoclonal protein offers clone-specific tracking over time. Glycosylation of free light chains is over-represented in AL patients which may allow earlier diagnosis and better risk-assessment of organ involvement. Persistence of QIP-FLC-MS positive M component in patients otherwise in CR may allow targeted therapy. Overall, QIP-FLC-MS demonstrates potential to be exploited as a single serum test for precise serial assessment of monoclonal proteins in patients with AL amyloidosis. Disclosures Wechalekar: GSK: Honoraria; Janssen-Cilag: Honoraria; Amgen: Research Funding; Takeda: Honoraria; Celgene: Honoraria.

Düzce İlinde Koyunlarda Coxiella burnetii ve Chlamydia abortus Etkenlerine karşı Antikorların Araştırılması

Aim: The aim of this study is to investigate the Coxiella burnetii and Chlamydia abortus antibodies in sheep in Duzce province. These two pathogens are causative agents of Query fever and Enzootic abortion of ewes, respectively which are related to abortion in small ruminants. Economic loss due to the abortions which are caused by microbiological agents is considerably high in many countries. Material and Methods: Blood samples of sheep were collected from Duzce province of Turkey for serological tests. Commercial enzyme-linked immunosorbent assay (ELISA) was used for the detection of specific antibodies to C. burnetii and C. abortus . A total of 72 samples obtained from 14 herds located in 12 villages/districts of 5 towns in Duzce province were utilized in this study. Samples were collected from 2-5-year-old female animals without an abortion history. Results: Total seroprevalence of Enzootic abortion of ewes and Query fever was found to be 20.83% and 26.38%, respectively. However, the proportion of seropositive herds was found to be 42.8% for Enzootic abortion of ewes and 50% for Q fever, which is higher than total seroprevalence. 6 flocks out of 14 were found to be seropositive for both of the diseases simultaneously. Conclusion: This study confirms the exposure of sheep herds in Duzce province to C. burnetii and C. abortus and provides original seroprevalence data about Duzce. The data gathered are beneficial to evaluate the possible connection of two investigated abortogenic pathogens in sheep abortion cases in Duzce province.

Productive performance, blood biochemical variables and immune responses of laying hens fed diets containing various fat sources

This study was conducted to evaluate the effects of various fat sources on productive performance, blood biochemical variables and immune responses of laying hens. Laying hens were divided into seven groups, which received i) basal or control diet (no oil); ii) and iii) basal diets containing 1% and 3% soybean (SB) oil; iv) and v) basal diets containing 1% and 3% kilka oil (KO), and vi) and vii) basal diets containing 1% and 3% soybean fatty acids (SFA). Productive performance was evaluated from day 1 to day 84. Blood biochemical variables and immune responses were assessed on days 28, 56 and 84 of the trial. The study results indicated that the dietary inclusion of 1% and 3% KO and SFA and 3% SB oil could decrease the feed conversion ratio (FCR) and increase egg production and egg mass in comparison with the control group throughout the study. Immune responses of sheep red blood cells and antibody titre against hemagglutination inhibition (HI) were significantly higher in laying hens fed KO and SFA and 3% SB oil compared with the control group. The serum concentrations of low density lipoprotein-C (LDL-C), very low density lipoprotein-C (VLDL-C) and malondialdehyde (MDA) were not influenced by the inclusion of oil sources. The serum concentration of cholesterol was increased significantly in laying hens that were treated with oil on day 28. The inclusion of fat sources significantly increased the serum concentration of HDL-C. The use of KO and SFA could be recommended at lower levels to improve the performance, immunity and some blood variables in laying hens.Keywords: egg production, kilka fish oil, lipid profile, soybean oil

Presence of Bluetongue Virus Antibodies in Cattle and Sheep in Ogun and Osun States, Nigeria

Bluetongue is an infectious, arthropod-borne viral disease principally affecting ruminants. The occurrence of bluetongue virus (BTV) antibodies in sheep and cattle from backyard farms, cattle markets and abattoirs in Ogun and Osun states of Nigeria was investigated. Three hundred and forty (340) plasma samples comprising 205 from sheep and 135 from cattle were collected from March to September 2017, noting the sex, breed and age of the animals. The samples were screened with a commercial enzyme-linked immunosurbent assay (ELISA) kit that detects BTV antibodies in ruminant plasma or serum. All cattle tested from both states were positive for BTV antibodies giving a seroprevalence of 100% while 95% seroprevalence was obtained for sheep. In Ogun state, prevalence of 90.5% and 98% were obtained for male and female sheep respectively while 95.6% and 95% prevalence were also obtained for male and female sheep respectively in Osun state. Based on breed, 94%, 95%, 95% and 96% prevalence were obtained for Yankasa, Balami, Ouda and West African Dwarf (WAD) sheep respectively in Ogun state while 93%, 95.5%, 100% and 93% prevalence were obtained for Yankasa, Balami, Ouda and WAD sheep respectively in Osun state. Furthermore, prevalence of 92% and 96.7% were obtained for age groups of ≤ 1 year and &gt; 1 year respectively in Ogun state, while prevalence of 96% and 94.7% were obtained for age groups of ≤ 1 year and &gt; 1 year respectively in Osun state. Since vaccination against bluetongue disease is not practiced in Nigeria, the detection of high prevalence of BTV antibodies observed in apparently healthy animals in this study indicates natural, albeit subclinical, infection with the virus and sustained activity of the Culicoides vector. These findings suggest that bluetongue is widespread in southwestern part of Nigeria and highlight the need for continuous surveillance of the disease in the country as well as isolation, identification and characterisation of currently circulating BTV strains in Nigeria.

Serological Epidemiology of Foot-and-mouth Disease among Sedentary Mixed-species Herds in Adamawa Region, Cameroon

Foot-and-mouth disease (FMD) is an economically important viral disease of domestic animals and wildlife. High circulation occurs during outbreaks but little is known about the current transmission dynamics in sedentary cattle and sheep herds. To investigate on this, samples from cattle and sheep located in the Vina Division of the Adamawa region of Cameroon, during FMD outbreaks were collected. Non-Structural Protein (NSP) and antigen detecting/serotyping FMD ELISAs were used for sample screening. The NSP serological data of cattle was used to estimate transmission parameters in catalytic and reverse catalytic models. The Akaike’s Information Criteria (AIC) revealed the reverse catalytic model as the most parsimonious for the NSP serological data and was used to estimate the force of infection (FOI), the rate of waning immunity and to estimate historic periods of sustained transmission. Four serological types of FMD notably O, A, SAT 1 and SAT 2 were identified from cattle vesicular epithelia tissues. Seroprevalence findings revealed 65.14% and 15.71% FMDV antibodies in cattle and sheep respectively with highest prevalence in both populations occurring in Mbidjoro. The FOI (λ) in sedentary herds was constant; the rate of waning immunity (ω) was 0.32 meaning cattle are generally immune for 3.12 years post natural infection. The reproductive number (Rt) was 7.33, meaning approximately 87% of cattle always need to be effectively immunized to prevent outbreaks. Therefore, FMD circulates in sedentary cattle and sheep populations in the study area with four serological types detected in cattle.

Seroprevalence of Toxoplasma Gondii antibodies in sheep and goats slaughtered at the Kumasi Abattoir, Ghana

ABSTRACTToxoplasmosis, caused by T. gondii, is an important zoonosis worldwide. In Ghana, information on the disease in humans abounds but scanty in animals. This study was therefore conducted to estimate the seroprevalence of T. gondii infection sheep and goats sampled from the Kumasi Abattoir in Ashanti Region, Ghana.A total of 347 serum samples collected from 170 sheep and 177 goats were analyzed for the presence of T. gondii antibodies using a commercial ELISA kit. Results of this study estimated the seroprevalence of 23.7% in goats an, 35.9% in sheep. In sheep, 24 (35.82%) out of a total of 67 male samples were positive and 37 (35.92%) out of a total of 104 female samples were positive while in goats, 6 (8.2%) bucks out of a total of 73 were positive while 36 (34.6%) does out of a total of 104 were positive. There was a significant difference in the rate of seropositivity of female goats (p-value 0.01).This study confirms the existence of T. gondii infection in small ruminants in Ghana and it showed that sheep and dogs are more at risk to T. gondii infection hence meat from such animals could be a potential risk to public health if consumed raw or undercooked.

Presence of Antibodies against Bluetongue Virus (BTV) in Sheep 5 to 7.5 Years after Vaccination with Inactivated BTV-8 Vaccines.

Thirty-six female sheep, previously vaccinated against Bluetongue virus serotype 8 (BTV-8) using inactivated vaccines, were included in this field study. In Germany, vaccination was compulsory in 2008 and 2009, voluntary in 2010 and early 2011, and later, was prohibited in 2011. Due to their age, eighteen sheep had been vaccinated for two or more consecutive years, while a further eighteen animals had only been vaccinated once or not at all. The sheep were blood sampled five (n = 31) to 7.5 years (n = 5) after their last vaccination. All serum samples (n = 36) were tested for BTV group-specific antibodies by an ELISA (IDScreen® Bluetongue Competition assay, ID Vet). In five of the animals, the BTV-8 serotype-specific antibody titers were measured by serum neutralization (SN). The majority of sheep that were vaccinated annually for two or more years showed a positive ELISA (14/18 sheep) and a SN (two of two sheep) result 5 years after their last vaccination. Most of the sheep vaccinated fewer than twice showed a negative ELISA result 5 to 7.5 years after their last vaccination (13/18 animals). The three animals in this group tested by SN showed one negative and two positive results. This short communication is the first to describe the presence of BTV antibodies in sheep 5 to 7.5 years after vaccination with inactivated BTV-8 vaccines.

Serological survey for anti-Toxoplasma gondii antibodies in sheep of northeastern Algeria

Although T. gondii is of considerable both public and veterinary importance worldwide, studies on its existence in sheep in Algeria, either through serology and or parasitology is scarce. To this end, a cross-sectional study was carried out in Tébessa, an Algerian eastern province, to, firstly, investigate the seroprevalence of T. gondii infection in sheep and, secondly, determine the potential risk factors that may be associated with seropositivity. A total of 376 serum samples from 39 flocks, collected between September 2015 and October 2017, were tested for anti-T.gondii antibodies via the enzyme-linked immunosorbent assay technique (ELISA). A T. gondii seroprevalence of 35.37% (95% CI 30.54-40.21%) was recorded, and 84.61% (95% CI 73.29-95.94%) of the flocks sampled had, at least, one seropositive animal. The multivariable logistic regression analysis showed that abortion during the latest pregnancy (OR = 1.56; 95% CI 1.02-2.44; p =0.05), presence of goats in sheep flocks (OR = 1.76; 95% CI 1.04-2.98; p =0.037), and the sampling period were the variables significantly associated with seropositivity. The present study reports, for the first time in this part of Algeria, the seroprevalence of T. gondii infection and bears out the highly dissemination capacity of the parasite. This is of a great importance for veterinarians in charge of veterinary public health, veterinary practitioners, and breeders in order to improve the control and prophylactic measures of toxoplasmosis. Nevertheless, further study should be conducted to explore the impact of the parasite on public and animal health.

Enzootic nasal adenocarcinoma in sheep: An update

Enzootic nasal adenocarcinoma of sheep (ENAS) is a contagious tumor of the ethmoid turbinate mucosa. The disease occurs naturally in all continents except Australia and New Zealand. Similar disease has been described in goats. ENAS is aetiologically associated with enzootic nasal tumor virus 1 (ENTV-1) a type Beta retrovirus and closely related to jaagsiekte sheep retrovirus (JSRV) and enzootic nasal adenocarcinoma virus of goats (ENTV-2). Clinical signs include continuous nasal discharge, respiratory distress, exophtalmus and skull deformations. The tumors have been classified histologically as low grade adenocarcinoma. ENTV-1 can be demonstrated in tumors by immunohistochemistry using several antisera developed against JSRV antigens which cross-react with ENTV-1 ones. ENTV-1 shares a oncogenic mechanisms with JSRV and ENTV-2 and active replication of the virus is required because oncogenic proprieties are associated with env gene products. Information about immune reactions in relation to ENTV-1 is scarce and controversial. Some early studies indicated absence of immune reaction although more recent studies have detected the presence of neutralizing antibodies in sheep with tumors and in contact sheep. However, the sensitivity and specificity of these tests are very low to be used in field studies. Several specific PRC techniques are available to detect viral genome in tissues and tumors. ENTV-1 can be detected in nasal secretion but is rarely found out of the tumor. The utility of PCR tests in control or eradication plans is discussed.