Seroprevalence of antibodies to ruminant pestiviruses in sheep and goats in Tyrol (Austria)

In this study 2058 blood samples from sheep of 150 flocks from the province of Tyrol were tested by ELISA and serum neutralisation tests for antibodies to ruminant pestiviruses. In the ELISA, positive results were obtained with 34.9% of individual sheep sera and in 89.3% of the sheep flocks. The prevalence in sheep and sheep flocks varied according to areas. Seroprevalence of pestiviruses was significantly (p < 0.05) higher in small ruminants pastured during summertime on the Alps. Comparative neutralisation studies were carried out on all positive blood samples with BVDV-1, BVDV-2 and BDV. 443 seropositive sheep samples exhibited clearly the highest titre against one of the pestivirus strains tested. 413 revealed the highest titres (2 or more fold) to BVDV-1, 6 to BVDV-2 and 24 to BDV. In some areas a very high rate of pestivirus seroprevalence could be found. This fact could be harmful to the BVDV-Elimination and Controlling Program in cattle in Austria.     

Pestivirus infections in Norway. Serological investigations in cattle, sheep and pigs.

Serum samples from 1,133 dairy cows (187 herds), 3,712 ewes (103 flocks) and 1,317 adult pigs (877 herds), were tested for neutralizing antibodies against the NADL strain of bovine virus diarrhoea virus. The prevalence rate of seropositive animals was 18.5% in cattle, 4.5% in sheep and 2.2% in pigs, such seroreactors being found in 28% of the cattle herds and 18% of the sheep flocks. In all three species the rate showed considerable herd and geographical variation. In cattle the seroreactor rate was similar in herds with normal reproduction and in 62 herds with problems of repeat breeding. Of 31 pig sera containing antibodies against the NADL strain, 27 were also positive in a neutralization test for antibodies against swine fever virus (Baker strain). However, all sera showed a higher titre of antibodies against the bovine strain than against the swine fever virus. It was concluded that the immune response of the pigs had been induced by ruminant pestivirus, and not by swine fever virus.     

Serological survey for antibodies against pestiviruses in sheep in Austria

The prevalence of antibodies to pestiviruses was investigated in 4931 sheep, in 377 flocks, in four federal states of Austria, by means of an indirect elisa that detected antibodies to Border disease virus (BDV) and bovine viral diarrhoea virus (BVDV). The mean flock prevalence was 62.9 per cent and the mean individual prevalence was 29.4 per cent. Comparative neutralisation studies on the elisa-positive samples with BVDV type 1 (BVDV-1), BVDV type 2 (BVDV-2) and BDV recorded 336 samples with higher titres (more than four times average) to BVDV-1, three samples with higher titres to BVDV-2 and 55 samples with higher titres to BDV. The other samples did not show clear differences in antibody titres against the strains of pestivirus tested because of cross-reactions. The seroprevalence of pestiviruses in sheep was significantly higher on farms with cattle. There were significant regional differences between the prevalences in flocks and individual sheep, the highest prevalences being in the region of Austria where communal alpine pasturing of sheep, goats and cattle is an important part of farming.     

Seroprevalence of Borna disease virus in domestic animals in Xinjiang, China

To investigate the animals infected with Borna disease virus (BDV) in Xinjiang, China, we examined for BDV antibodies in the sera from groups of 20 horses, sheep and cattle, and from 165 wild rodents (18 species) by ELISA and immunoblot. The serological study disclosed the presence of antibodies to both BDV-p24 and -p40 in the horses (20%) and sheep (25%), whereas no apparent positive reaction was detected either in cattle or rodents. The results suggested that BDV is prevalent in horses and sheep in the district investigated.     

Flock-prevalence of border disease virus infection in Basque dairy-sheep estimated by bulk-tank milk analysis

Bulk-tank milk (BTM) samples from 154 sheep flocks were used to estimate BDV prevalence in the Basque Country in Spain using an ELISA and a RT-PCR test. The proportion of antibody-positive flocks was 68% but varied significantly between provinces and was 93% in Araba and 54-55% in Bizkaia and Gipuzkoa. Most ELISA-positive flocks had very low antibody inhibition percentage (AIP) indicating high seroprevalence and recent BDV exposure. However, only 9% flocks were PCR-positive suggesting few infected ewes were being milked at the time of sampling. Phylogenetic analysis of the 5' NCR sequences of BDV from seven infected flocks showed that all except one clustered within the group formed by BDV type C strains from a previous study in the region, whereas the remaining isolate was closest to BDV type A. These results suggest that BDV strains in most Basque flocks have a common origin and differences in prevalence between provinces are associated to recent events affecting BDV spread such as use of communal pastures and sheep trading. The widespread distribution of BDV in the region, advocates for the implementation of BDV control strategies and highlights the potential risk of sheep as a pestivirus reservoir for other species.     

Survey to determine the seroprevalence of Toxoplasma gondii infection in British sheep flocks

A serological survey of Toxoplasma gondii infection in adult breeding sheep in Great Britain was conducted using surplus sera taken during a seroprevalence study of Brucella melitensis in 2009. Of the 3539 sera collected from 227 flocks, 2619 (74 per cent) were found to be positive for T gondii specific antibody when tested using latex agglutination. Multilevel logistic modelling suggested that the likelihood of infection increased with age and this effect appeared to be amplified in animals vaccinated against T gondii. The model also indicated that the odds of sheep being seropositive were increased on premises where cattle were also kept. These results suggest a high level of Toxoplasma infection in breeding sheep in Great Britain and provide further evidence to suggest that postnatal infection is more common than congenital infection in sheep.     

Epizootiologic study of bluetongue: virologic and serologic results

Heparinized blood and serum samples were obtained from 1,295 ruminants in herds or flocks with bluetongue virus (BTV) infection in 4 western states. Submissions were from herds or flocks with clinical bluetongue (BT), as well as from animals on premises with no history of BT disease. Insects, including Culicoides variipennis, were collected in areas enzootic for BT disease. Viral isolations were in 10-day-old embryonating chicken eggs that were then adapted to Vero cells for serotyping. Sera were tested from group-specific antibody to BTV by the micro agar gel precipitin (AGP) test. Viral isolations were from cattle (81), sheep (122), goats (9), antelope (2), and C varipennis (5). There were 7 isolates of serotype 120, 114 of serotype 11, 42 of serotype 13, and 56 of serotype 17. In herds or flocks from which BTV was isolated, 51% of cattle, 56% of sheep, 21% of goats, and 52% of antelope had AGP antibodies. Virus was isolated from 43% of the cattle and 23% of the sheep that had no demonstrable evidence of AGP antibodies. Viral isolations were seasonal, occurring from August until December. Approximately 30% of the herds or flocks from which virus was isolated had more than one serotype of virus causing infection.     

龙岩市部分地区牛、羊弓形虫病的血清学调查

目的：采集龙岩市部分地区牛、羊血清,检测福建省牛和羊弓形虫病的感染情况。方法：应用酶联免疫吸附试验检测牛和羊血清弓形虫IgG抗体。结果：49份牛血清弓形虫IgG抗体均呈阴性;35份羊血清中,8份弓形虫IgG抗体呈阳性,阳性率为22．86％（8／35）。结论：龙岩市部分地区羊弓形虫的感染率较高,应引起人们重视。     

我国部分地区牛羊弓形虫血清流行病学调查

为了解我国牛羊弓形虫病流行情况,应用间接血凝试验（IHA）对河南、山东、山西、内蒙古、云南、贵州6省区151份牛血清、50份奶样、490份羊血清进行了弓形虫病血清流行病学调查。结果显示：151份被检牛血清和50份牛奶样品,弓形虫抗体均为阴性。490份羊血清弓形虫抗体总阳性率5.71％,其中母羊、公羊血清阳性率分别为4.03％和9.79％;山羊、绵羊、杂交羊血清阳性率分别为6.58％、4.81％和5.13％;阳性率最高的为公山羊（13.2％）,最低的为母绵羊（2.96％）。28份阳性羊血清中,75％的抗体滴度为1：64,25％的抗体滴度为1：256。1岁后的羊,随年龄增长,血清阳性率升高。     

Prevalence of border disease virus in Spanish lambs

The prevalence of border disease virus (BDV) viraemia in Spanish lambs was determined from 2089 sera randomly collected at two slaughterhouses in 2001 and 2003, as well as in 126 sera obtained in 2004 from a fattening unit with an acute disease problem. BDV was detected with an indirect peroxidase monolayer assay (IPMA), and for the fattening unit sera also by an antigen ELISA. A subset of sera was additionally tested for BDV antibodies. The BDV prevalence in the slaughterhouse sera was 0.24%, whereas 7.1% of randomly selected and 38.6% of sera from clinically affected lambs in the fattening unit were virus positive. Pestivirus antibodies were found in 17.6% of the slaughterhouse sera and 28.6% of those from randomly selected lambs in the fattening unit. In total, 33 virus isolates and 3 antigen positive samples were identified. Genetic typing of 5'-UTR sequences classified all 36 pestiviruses as of BDV type 4. This shows that from a low BDV prevalence in apparently healthy lambs in the entire sheep population, clinical problems associated with BDV can develop when viraemic sheep are brought into intense rearing units.     

Serological investigation of aborted sheep and pigs for infection by Neospora caninum

Serology for Neospora caninum was undertaken using direct ELISAs on sera from 660 aborted sheep and 454 breeding sows, which had aborted or were considered infertile. All ovine sera were further tested by indirect fluorescent antibody test (IFAT) for N. caninum, and a latex agglutination test (LAT) for Toxoplasma gondii was performed on 423 of the samples, including all those positive by ELISA. ELISA-positive porcine sera were tested by IFAT and an inhibition ELISA for antibodies to N. caninum and by LAT for T. gondii. Only 3 (0.45%) of the ovine sera were seropositive for N. caninum by both ELISA and IFAT whereas although 40 porcine sera were seropositive by ELISA all were negative by IFAT. The results suggest that environmental exposure to N. caninum occurs rarely in sheep and pigs.     

Seroprevalence of maedi-visna and border disease in Switzerland

3866 sheep from 226 flocks of breeding associations and 1218 sheep from 15 independent sheep owners were tested for the presence of serum antibodies against Maedi-Visna and Border Disease viruses. The flocks were randomly selected based on the relative proportion and the geographical distribution of the 4 predominant Swiss sheep breeds (Braunk?pfiges Fleischschaf, Schwarzbraunes Berg- und Juraschaf, Walliser Schwarznasenschaf, Weisses Alpenschaf). Additionally two smaller breeds were included in the study (Charollais Suisse, Milchschafe). Sera of all sheep older than 1 year were collected together with data characterizing host and management factors. The sera were tested using established ELISAs for detection of antibodies to Maedi-Visna and Bovine Virus Diarrhea/Border Disease viruses. ELISA results of Maedi-Visna serology were confirmed by immunoblotting. 9% of the sheep of breeding associations were antibody-positive for Maedi-Visna virus. The results of the different breeds varied between 0.4% and 36%. A multiple logistic regression procedure identified breed, age, airing in barns, herd size, pasturing on alps and way of keeping the animals during winter as associated factors with individual serostatus. The prevalence of antibodies to Border Disease was 20% in sheep of breeding associations and 65% in those of independent sheep owners.     

Seroprevalence of Toxoplasma gondii in cattle, sheep and goats slaughtered for food in Mazandaran province, Iran, during 2005

Serum samples from 290 cattle, 400 goats and 588 sheep slaughtered for food in various areas of the Mazandaran province, Iran were tested for antibodies to Toxoplasma gondii by the indirect immunofluorescence antibody test (IFAT), from December 2004 to April 2005. Antibodies to T. gondii were found in 30% (120/400) goats and 35% (206/588) sheep and 0% (0/290) cattle, at a dilution of 1:16 or more for goats and sheep and 1:128 or more for cattle. The highest titres observed in cattle, goats and sheep were 1:64 (0.7%), 1:128 (1%), 1:64 (2%), respectively. These results indicate that T. gondii antibodies are widespread in the animal populations and suggest that toxoplasmosis is a widely spread zoonotic infection in northern Iran.     

The humoral and cellular immune response of sheep against Borna disease virus in endemic and non-endemic areas

Borna Disease (BD) is a mostly fatal disease of horses and sheep endemic in central Europe. Antibodies to Borna disease virus (BDV) have been described in sheep and other species living in BD non-endemic areas. Meaningful clinical BDV serology is hampered by difficulties in defining serological cut-offs, which require the investigation of populations from endemic areas. Here we studied BD serology in sheep from endemic and non-endemic areas of similar geography in Switzerland. Antibodies to BDV antigens were detected by ELISA and indirect immunofluorescence analysis (IFA) only in sera from 3 of 6 sheep with autopsy confirmed BD. One serum was positive by IFA but not by ELISA, while 2 sera were negative in both assays, indicating that not all diseased animals develop BDV specific antibodies. Six % of clinically healthy animals (6/106) from an endemic area and 2% from a non-endemic area (4/192) had serum antibody to either BDV p40 or p24 as detected by ELISA. None of the animals showed a cellular immune response to BDV p40. In some healthy sheep from the endemic area, serum antibody titers to BDV p24 antigen remained elevated over several months without onset of disease symptoms. Infections with either BDV or related viruses may thus occur at low frequency in sheep from non-endemic areas leading to the production of antibodies to BDV antigens. We further propose viral strain differences or environmental factor(s) may determine the clinical outcome.     

Serological survey of antibodies to Toxoplasma gondii in goats, sheep, cattle and water buffaloes in Bahia State, Brazil.

Serum samples from 439 goats, 240 sheep, 194 cattle and 104 water buffaloes were tested for antibodies to Toxoplasma gondii by a latex agglutination test. Antibodies to T. gondii were found in 28.93% of goats, 18.75% of sheep, 1.03% of cattle and 3.85% of water buffaloes, at a dilution of 1:64. The highest titres observed in goats, sheep, cattle and water buffaloes were 1:2048, 1:2048, 1:64 and 1:512, respectively.     

Prevalence of Borna disease virus antibodies in healthy Japanese black cattle in Kyushu

Epidemiological studies have demonstrated that asymptomatic infection of Borna disease virus (BDV) is found in various species of animals in Japan. Recent reports have also revealed that neurological diseases caused by this virus could exist in horses, cattle, a dog, and cats in this country. In this study, we investigated seroprevalence of BDV antibodies in Japanese black cows reared in Kyushu, the southernmost main island of Japan, using ELISA and Western-immunoblotting. Of 101 serum samples, 11 (10.9%) and 21(20.7%) sera were identified as having antibodies to the BDV N and P antigens, respectively. Among the positive sera, three cows (2.9%) were seropositive for both of the antigens. Furthermore, interestingly, only female cows showed antibodies to P, whereas N antibodies were detected in male and female cows with a comparative ratio. Together with previous studies, our results indicate that BDV might be widely spread in cattle raised in Japan. Furthermore, this is the first report to show that beef cattle, Japanese black cattle, have antibodies against a possible zoonotic pathogen, BDV.     

Cross-sectional survey on Toxoplasma gondii infection in cattle, sheep and pigs in Serbia: seroprevalence and risk factors

Toxoplasmosis is a globally distributed zoonosis with a clinical impact in the unborn fetus and in the immunosuppressed individual. In Serbia, studies of risk factors for Toxoplasma gondii infection in humans have shown that the relatively high prevalence is associated mainly with consumption of undercooked meat and/or meat products. However, data on T. gondii infection in domestic animals mostly used for human consumption are scarce. We thus conducted a cross-sectional survey on the seroprevalence of T. gondii infection in a representative sample of cattle, sheep and pigs from different regions of Serbia between June 2002 and June 2003, and analyzed the main risk factors associated with the infection. Sera from 611 cattle (yearlings and adults of both sexes), 511 ewes, and 605 pigs (market-weight and sows), were examined for T. gondii antibodies by the modified agglutination test. The seroprevalences determined were 76.3% in cattle, 84.5% in sheep and 28.9% in pigs. The antibody levels ranged from 1:25 to 1:400 in cattle, and up to 1:25,600 in sheep and to 1:12,800 in pigs. Among the seropositive, the proportion of high antibody levels (> or =1:1600), suggestive of acute infection, was 10% in sheep, and 4% in pigs. Possible association of the infection with biologically plausible risk factors including gender, age, herd size/farm type, type of housing, feeding practices and region, was analyzed by univariate analysis, and variables significant at P< or =0.1 were included in multivariate logistic regression models. The results showed that risk factors for cattle were small herd size (odds ratio, OR=2.19, 95% confidence interval, CI=1.28-3.75, P=0.004) and farm location in Western Serbia (OR=2.04, 95% CI=1.10-3.79, P=0.024), while housing in stables with access to outside pens was protective (OR=0.37, 95% CI=0.21-0.67, P=0.001). In sheep, an increased risk of infection was found in ewes from state-owned flocks (OR=4.18, 95% CI=2.18-8.00, P<0.001) vs. private flocks, and, interestingly, also in those from Western Serbia (OR=4.66, 95% CI=1.18-18.32, P=0.028). In pigs, the risk of infection was highly increased in adult animals (OR=3.87, 95% CI=2.6-5.76, P<0.001), as well as in those from finishing type farms (OR=3.96, 95% CI=1.97-7.94, P<0.001). In addition to providing data on the current T. gondii seroprevalence in meat animals in Serbia, the results of this study show the main risk factors associated with infection, thereby pointing to the type of preventive measures to reduce T. gondii infection.     

Seroprevalence of ovine progressive pneumonia virus in sheep in the United States as assessed by analyses of voluntarily submitted samples.

Ovine progressive pneumonia (OPP) is a lentivirus-induced disease of sheep in the United States that is similar, if not identical, to maedi/visna in many other countries. Prevalence estimates of seropositivity to this virus in sheep in the United States have been confined to limited groups or flocks of sheep and have varied from 1 to 90%. In this study of detection of antibodies against OPP virus, we found a lower general prevalence of antibodies to OPP virus in sheep than was previously reported. Of 16,827 sheep from 29 states in the United States, 26% were seropositive and 48% of 164 flocks that were tested had 1 or more seropositive sheep. Seropositivity to OPP virus for sheep within special categories was determined, although nonrandom samples that were available may have biased the results. Within regions of the United States, prevalence was highest in the Rocky Mountain region at 49% and lowest in the northern Atlantic region at 9%. Seropositive sheep were not evenly distributed among flocks, but were clustered in a few flocks of sheep. A high number of flocks had no or few seropositive sheep. Prevalence increased with age from 4% at less than 1 year to a plateau of 34% at 4 years. Seropositivity was variable among breeds and was not associated with sex, wool class, or place of origin of ancestors.     

Field observations during the Bluetongue serotype 8 epidemic in 2006. II. Morbidity and mortality rate, case fatality and clinical recovery in sheep and cattle in the Netherlands

Data collected in the Netherlands during the Bluetongue serotype 8 (BTV-8) epidemic indicated that in outbreak cattle herds, predominantly dairy and nursing cows were clinically affected and not young stock, beef cattle, beef calves, or breeding animals. In outbreak sheep flocks, mainly ewes and - if present - rams, were clinically affected and not the lambs. Median morbidity rate in outbreak herds was 1.85 per 100 sheep-month at risk and 0.32 per 100 cattle-month at risk for sheep and cattle, respectively. The mean proportion of BT-affected animals in outbreak herds that recovered from clinical disease was approximately eight times higher for cattle compared to sheep in the Netherlands. Median mortality rate in outbreak herds was 0.5 per 100 sheep-month at risk of dying and 0 per 100 cattle-month at risk of dying for sheep and cattle, respectively. Median recovery time of both sheep and cattle that recovered from clinical disease in outbreak herds was 14 days. Median case fatality was 50% in sheep outbreak flocks and 0% in outbreak cattle herds. It is concluded that morbidity and mortality in outbreak cattle herds was very limited during the BTV-8 epidemic in the Netherlands in 2006. In outbreak sheep flocks, morbidity was limited, with exceptions for a few flocks. However, almost 50% of the clinically sick sheep died in outbreak sheep herds.     

Serologic and virologic investigations into pestivirus infection in wild and domestic ruminants in the Pyrenees (NE Spain)

An outbreak of disease associated to a border disease virus was described in the Southern chamois (Rupicapra pyrenaica) in Spain in 2002. Sera and/or spleen samples from 57 mouflon, 15 red deer, 21 roe deer, 3 fallow deer, 55 sheep, 32 cattle, and 68 goats sharing the chamois habitat were studied. An antibody ELISA test yielded an inconclusive result in 2 mouflon and positive results in 5 goat sera. Comparative virus neutralization tests were performed on the 2 inconclusive mouflons, 3 of the 5 seropositive goats, 55 sheep and 32 cattle, using 6 pestivirus strains. Positive results were obtained in 1 mouflon, 2 goats, 69% of sheep and 78% of cattle. Virological investigations performed with an antigen ELISA test yielded negative results in 21 goats and 39 mouflons, the result in 1 mouflon being inconclusive. PCR performed on 12 goats and the inconclusive mouflon gave negative results. These results suggested that it is unlikely that chamois BDV is infecting wild and domestic ruminants.