Herd distribution of seropositive reagents to Chlamydia in Danish cattle

19% of 733 cows and heifers in 25 Danish milking herds had CF antibodies against Chlamydia. The number of seropositive reagents in the individual herds varied from 0-45%. In one herd especially studied, the majority of reagents were among calves, while the number of reagents was reduced with increasing age, which indicated a coherence with enzootic pneumonia in calves. Apart from this and few cases of sporadic abortions, seropositive reactions could not be connected with any known chlamydial syndromes. A few old cows suffering from paresis puerperalis had titre increase or comparable high titres, indicating outbreak of a persistent infection. The demonstrated differences in serological results from individual herds and areas (Table II) may reflect a difference in the age of animals tested.     

Bovine respiratory syncytial virus (BRSV) pneumonia in beef calf herds despite vaccination.

The present report describes the clinical, pathological, serological and virological findings in calves from 2 larger Danish beef herds experiencing outbreaks of pneumonia. The calves had been vaccinated with an inactivated bovine respiratory syncytial virus (BRSV) vaccine 2 months prior to the outbreak. The clinical signs comprised nasal discharge, pyrexia, cough and increased respiratory rates. A total of 28 calves died in the 2 herds. The laboratory investigations revealed that BRSV was involved and probably initiated both outbreaks. Furthermore, the serological results suggested that the vaccine induced only sparse levels of antibodies probably due to the presence of maternally derived antibodies at the time of vaccination. Necropsy findings in 5 calves revealed changes typical for infectious pneumonia with involvement of BRSV. In conclusion, vaccination of calves against BRSV in 2 Danish beef herds failed to protect the calves against severe or even fatal BRSV mediated respiratory disease 2 months later.     

Detection of antibodies and risk factors for infection with bovine respiratory syncytial virus and parainfluenza virus 3 in dual-purpose farms in Colima, Mexico

A cross-sectional study was carried out, from November 2007 to March 2008, to estimate the prevalence of and to determine risk factors associated with bovine syncytial respiratory virus (BRSV) and parainfluenza 3 virus (PIV3) in dual-purpose herds in Colima, México. One hundred and seventy-six sera from 33 herds for PIV3 and 232 sera from 44 herds for BRSV were used. Sera were analyzed by indirect ELISA for the detection of antibodies against BRSV and PIV3 in cattle herds to determine the seroprevalence of respiratory diseases. The apparent and true prevalences for PIV3 were 60.8% and 54.4% and for BRSV 52.2% and 50.8%, respectively. The percentage of herds showing at least one positive animal was 78.7% for PIV3, and 93.2% for BRSV. Age (≤12, 13-48, and >48?months old) and respiratory signs (no, yes) showed significant association (P?相似文献   

Prevalence of antibodies to infectious bovine rhinotracheitis, parainfluenza 3, bovine respiratory syncytial, and bovine viral diarrhea viruses in cattle in Saskatchewan and Alberta

A total of 1745 healthy cattle from 295 farms in Saskatchewan and Alberta was tested by ELISA for antibodies to four viruses. Antibodies to infectious bovine rhinotracheitis (IBR) virus were found in 37.8% of sera (59.5% of properties), to parainfluenza 3 (PI3) virus in 93.9% of sera (99.7% of properties), to bovine respiratory syncytial (BRS) virus in 78.5% of sera (86.6% of properties), and to bovine viral diarrhea (BVD) virus in 40.6% of sera (66.7% of properties)

The prevalence of PI3 viral antibodies among Saskatchewan cattle was not affected by district of origin, breed, sex, age, or vaccination practices, though BRS viral antibodies appeared less frequent in young, male, and unvaccinated animals. Antibodies to IBR and BVD viruses were less prevalent in the Prince Albert/Tisdale districts and in young, male, and unvaccinated animals, but were more common in Holstein cattle. Antibodies to IBR virus appeared less frequent in Herefords. Antibodies were more prevalent in cattle which had been vaccinated against IBR, BRS, and BVD virus infections.

The relatively small number of cattle sampled from Alberta had a similar prevalence of antibodies to PI3 and BRS viruses to that seen in cattle in Saskatchewan, though IBR and BVD prevalence rates were lower.

     

The serological response to foot-and-mouth disease vaccination is not affected by simultaneous infectious bovine rhinotracheitis/adenovirus/parainfluenza 3 vaccination

Young calves were simultaneously vaccinated by subcutaneous route against foot-and-mouth disease (FMD) and against infectious bovine rhinotracheitis/adenovirus/parainfluenza-3 (IBR/Adeno/PI-3) by intranasal route. The serological response against the 3 FMD virus types of the FMD vaccine was clearly positive. There was no significant difference between results of simultaneous FMD and IBR/Adeno/PI-3 vaccination and FMD vaccination only.     

Neutralizing antibodies to bovine herpesvirus 1 in reindeer

Serum samples from cattle and reindeer in Lapland were examined for neutralizing antibodies to the IBR/IPV virus. All the bovine sera tested were negative. The reindeer sera were tested using 2 different virus neutralization methods differing in the serum-virus incubation time prior to inoculation into tissue culture tubes. 12.6 % of the samples tested with a preincubation of 1 h at 37°C were positive, whereas 23 % of those tested with a preincubation time of 24 h at 37°C were positive. The fairly high prevalence of antibodies to IBR/IPV in the reindeer population in Finland indicates the occurrence of the IBR/IPV virus or a closely related cross-reacting herpesvirus.     

Prevalence and specificity of antibodies to bovine respiratory syncytial virus in sera from feedlot and range cattle

The specificity of serum antibodies for the polypeptides of bovine respiratory syncytial virus (BRSV) was examined, using sera obtained from feedlot and range cattle. Test results in sera from feedlot cattle indicated a 60% rate of seroconversion and 95% seropositivity to BRSV, associated with lack of clinical signs indicative of respiratory tract disease. Exposure to other common respiratory tract viruses also was high (greater than or equal to 92% to bovine herpesvirus type 1, bovine viral diarrhea virus, and para-influenza virus type 3). Test results in sera from range cattle indicated BRSV seropositive rates of 28% in calves, 49% in yearling cattle, and 70% in mature cows; clinical signs of respiratory tract disease were not observed in these cattle. Antibodies to BRSV in sera from cattle in both environments reacted predominantly with polypeptides of molecular weight 80,000 through 85,000, 40,000, and 28,000. Reactivity to a glycoprotein of molecular weight between 43,000 and 44,000 and to several glycopolypeptides of smaller molecular weight increased in serum specimens obtained from feedlot cattle between time of entry into the feedlot and slaughter.     

Serological and molecular diagnosis of bovine viral diarrhoea virus and evidence of other viral infections in dairy calves with respiratory disease in Venezuela

An investigation based on 2 studies was carried out to assess the involvement of bovine virus diarrhoea virus (BVDV), bovine herpesvirus type 1 (BHV-1), and bovine respiratory syncytial virus (BRSV) in calf respiratory disease in dairy farms in Venezuela. In the first study, 8 farms were selected and paired serum samples from 42 calves with respiratory disease were tested by ELISA for antibodies to the 3 viruses. Seroconversion to BVDV, BHV-1, and BRSV was found to 5, 2, and 6 farms out of the 8, respectively. The proportion of calves that showed seroconversion to BVDV, BHV-1, and BRSV were 19%, 14%, and 26%, respectively. In the second study, another farm having previous serological evidence of BVDV infection was selected. The decline of maternal antibodies against BVDV was monitored in 20 calves and the half-life of maternal antibodies was 34 +/- 12 days presumably indicating an early natural infection with BVDV. Furthermore, sera free of BVDV antibodies that were collected in studies 1 and 2 and were assayed for the presence of BVDV by nested RT-PCR. Two BVDV strains were detected and compared to those of ruminant and porcine pestiviruses. Both strains were assigned to subgroup Ib of type I BVDV. This investigation provides information on BVDV genotypes circulating in Venezuela and may contribute to the establishment of official control programmes against the viruses studied.     

Reduced likelihood of bovine coronavirus and bovine respiratory syncytial virus infection on organic compared to conventional dairy farms

The prevalence of antibodies to bovine coronavirus (BCV) and bovine respiratory syncytial virus (BRSV) infections was studied in 20 conventional and 20 organic dairy herds. The organic farms had produced 'certified' milk for at least 2 years. On two occasions, with a 1-year interval, 699 serum samples from 624 peri-parturient cows were tested by ELISA for antibodies to BCV and BRSV. Accompanying data relating to the sampled animals were collected in order to identify potential factors associated with increased antibody prevalence. The antibody prevalence was high at both sampling times with approximately 85% and 80% of animals positive for antibodies to BCV and to BRSV, respectively. Conventional herds had a significantly higher mean antibody prevalence to BCV and BRSV than the organically managed herds (P<0.01). Animal age was significantly associated with increased antibody prevalence (P<0.001). The findings of this study suggest that organic farm management may be effective in reducing the seroprevalence of these viruses relative to conventional farming methods.     

Seroepidemiology of Neospora caninum and Toxoplasma gondii in cattle and water buffaloes (Bubalus bubalis) in the People's Republic of China

A seroepidemiological survey of Neospora caninum and Toxoplasma gondii in cattle and water buffaloes was carried out in the People's Republic of China. Serum samples were obtained from dairy (n=262, 9 herds in 9 provinces) and beef cattle (n=10, 1 herd) and water buffaloes (n=40) in China. All sera were tested for antibodies to N. caninum and T. gondii by an enzyme-linked immunosorbent assay (ELISA) and an indirect agglutination test (IAT), respectively. The overall seroprevalence of N. caninum in dairy cattle was 17.2% (45/262), and the herds seroprevalence of N. caninum was 88.9% (8/9), and antibodies to T. gondii were present in 6 cows (2.3%). None of the cows had antibodies against both T. gondii and N. caninum. Antibodies to T. gondii or N. caninum were not found in beef cattle or water buffaloes. The seroprevalence of N. caninum in aborting cows (20.2%) was higher than that in non-aborting cows (16.6%) with an odds ratio of 1.26 (95% CI, 0.54-2.95), but the difference was not statistically significant (P>0.05). There was no apparent association of N. caninum seropositivity with age or number of pregnancies. This is the first report on the seroprevalence of N. caninum in cattle and water buffaloes in China.     

Studies of Coxiella burnetii infections in dairy herds with special regard to infections in men

Investigations of 1167 dairy cows out of 105 herds with fertility disorders on secretion of Coxiella burnetii (C. burnetii) by the genitals as well as serological studies of these animals using ELISA demonstrated that C. burnetii infections are significantly associated with abortions but not with repeated inseminations without success or vaginal excretions. The demonstration of an increased risk of infections for persons caring for those dairy herds could be shown by a total of 253 serological studies. A comparison of these studies of farmers caring for dairy herds suffering from abortions a seroprevalence of > or = 20% showed that these persons revealed significantly more frequent antibodies against C. burnetii than farmers of the group compared with. Further studies showed that in herds suffering from abortions a seroprevalence of > or = 20% means an additional risk of infections of farmers. Vice versa abortions of the cows in herds with a seroprevalence of > or = 20% imply an additional infectious risk.     

Coxiella burnetii infections and infections with bacteria of the genus Chlamydia in dairy cattle

Comparative studies on the prevalence of infections caused by Coxiella burnetii (C. burnetii) and Chlamydia were carried out with 592 cattle older than 2 years and 234 cattle younger than 2 years. Of these 477 originated from 24 dairy herds with considerable fertility problems (positive herds) and 349 from 14 dairy herds without major fertility problems (control herds). For the direct detection of these pathogens in the genitals capture ELISAs were employed, for the demonstration of antibodies the complement fixation test (CFT). Direct detection of C. burnetii and Chlamydia single as well as mixed infection revealed significant higher values for cattle from positive herds compared with those from the control herds. Animals revealing insemination ratios of > or = 2 showed significantly more frequent excretion of Chlamydia via the genitals and antibodies against C. burnetii than cattle with an insemination ratio of < 2. Investigations of cows which had had an abortion showed no indications of significantly more frequent C. burnetii or chlamydial infections. Inseminated but non-pregnant cows excreted significantly more C. burnetii and Chlamydia than pregnant cows. Clinical signs of endometritis were associated with an enhanced excretion of Chlamydia. Animals younger than 2 years excreted significantly more frequently C. burnetii but not Chlamydia via the genitals than animals older than 2 years. Indirect test showed results vice versa.     

Evaluation of a quadrivalent inactivated vaccine for the protection of cattle against diseases due to common viral infections

Efficacy of an inactivated quadrivalent vaccine containing infectious bovine rhinotracheitis (IBR) virus, parainfluenza type 3 (PI3) virus, bovine virus diarrhoea virus (BVDV) and bovine respiratory syncytial virus (BRSV) was assessed in naive bovine calves to evaluate short-term (4-18 weeks) and long-term (24-38 weeks) protection following the basic intramuscular vaccination regime of 2 inoculations a month apart. Vaccination was staggered between the long-term and the short-term groups by about 5 months so that both groups, along with a matched group of 6 unvaccinated (control) calves, could be challenged at the same time. Sequential challenges at intervals of 3-8 weeks were done in the order: IBR virus (intranasally, IN), PI3 virus (IN and intratracheally, IT), pestiviruses (IN) and BRSV (IN and IT). The IBR virus challenge produced febrile rhinotracheitis (FRT) in control calves but both the severity and the duration of FRT was significantly reduced in both vaccinated groups. The amount and the duration of IBR virus shed by the vaccinated groups was significantly reduced compared to the control group. Although PI3 virus, pooled pestivirus and BRSV challenges did not result in a noteworthy disease, challenge virus shedding (amount and duration) from the upper (all 3 viruses) and the lower (BRSV) respiratory tracts was significantly reduced in vaccinated groups. After pestivirus challenge, sera and leukocytes from all control calves were infectious for 6-9 days whereas virus was recovered only from leukocytes in vaccinated calves and only for 1.6-2.7 days. Thus a standard course of the quadrivalent vaccine afforded a significant protection against IBR virus, PI3 virus, BVDV and BRSV for at least 6 months.     

Antibody prevalence against respiratory viruses in sheep and goats in North-Western Turkey

Respiratory viruses may infect both small and large ruminant species, and can be transmitted among those of species. Present study reports presence and serological distribution of bovine respiratory viral infections in sheep and goats in Marmara region of Turkey. Total of 388 sera, 228 from sheep and 160 from goats collected from 4 provinces were analysed. Neutralising antibodies specific to BVDV, BHV-1, BRSV, PI-3, BAV-1 and BAV-3 were investigated. Among 388 serum samples 32.1% were positive for BVDV, 23.0% for BHV-1, 72.9% for BRSV, 13.2% for PI-3, 86.0% for BAV-1 and 93.0% for BAV-3. There were significant differences observed between seroprevalence rates detected in neighbouring provinces. Prevalence of BVDV specific antibodies was extremely higher (p = 0.0009) in sheep, however, BHV-1 (p = 0.0001) and PI-3 (p = 0.0038) were more prevalent in goats. BRSV antibody prevalence was closely related to data obtained from cattle. This study demonstrates that, like in cattle herds, BRSV and adenoviruses are the possible common reason of respiratory diseases in small ruminants in the region.     

Seroprevalence to bovine immunodeficiency virus and lack of association with leukocyte counts in Italian dairy cattle

We report herein on the first serological detection of antibodies to bovine immunodeficiency virus (BIV) in Italy. According to criteria of a stratified-random sampling of dairy cattle reared in the Parma area (a province in the Po Valley, Northern Italy), sera from 3166 cows belonging to 272 herds were collected. In addition, sera of 138 bulls from eight artificial-insemination (AI) centres were sampled. Seventy-eight cows (2.5%) from 16 herds (5.8%) and seven bulls (5.1%) from two AI centres were positive for BIV-R29 antibodies in the IFA-test. IFA-positive sera assayed by Western blot had reaction to different viral proteins: 81 out of 85 sera showed antibody to p26 (considered the BIV major internal core protein); four sera reacted to other viral proteins but not to p26. Peripheral blood leukocytes of 60 seropositive and 60 seronegative animals, belonging to eight BIV-infected herds, were enumerated to assess any effect of BIV infection on white-blood cells. No significant differences were detected between the two groups. These data indicate that BIV infection is present in Italian dairy cattle – but the role of BIV in inducing disease remains unclear.     

重庆市部分地区牛传染性鼻气管炎和流行性牛白血病的血清学调查

为了解传染性鼻气管炎（IBR）和流行性牛白血病（BL）的流行情况，从重庆市辖区内11个区县（自治县）采集奶牛、黄牛、水牛血清共；369头份，用酶联免疫吸附试验（HLISA）检测IBR和BL抗体。结果从部分区县（自治县）检测出阳性样品，IBE阳性率介于2．70％～20．00％之间，总阳性率为4．61％；奶牛、黄牛、水牛总阳性率分别为5．34％、4．92％、0％。BL阳性率介于2．70％～52．50％之间，总阳性率为12．20％，奶牛、黄牛、水牛总阳性率分别为20．87％、1．64％、0％，提示该病在我市奶牛和黄牛牛群中存在，污染较广，应引起重视。     

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 screening for Coxiella burnetii infection and related reproductive performance in high producing dairy cows

The possible relationship between Coxiella-seropositivity and the reproductive performance of cows during the previous year to the serological screening was examined in three high producing dairy herds. The herds had a history of subfertility (<25% of pregnancies for the total number of AI), abortion (>18% abortions) and a positive polymerase chain reaction test for Coxiella burnetii in the bulk tank milk with an excretion higher than 10(4)Coxiella /ml for all three herds. Antibodies against C. burnetii were detected in 50.2% of the 781 parous cows analyzed. Coxiella seropositivity was linked to placenta retention, to changes in the interval from parturition to conception (with the lowest interval parturition-conception for cows with low level of seropositivity), early pregnancy (cows becoming pregnant before Day 90 postpartum) and maintenance of gestation during the early fetal period, while it failed to affect rates of abortion after Day 90 of gestation or stillbirth.     

Comparison of a newly developed enzyme-linked immunosorbent assay with complement fixation and neutralisation tests for serology of bovine respiratory syncytial virus infections

An indirect double antibody sandwich enzyme-linked immunosorbent assay (ELISA) was developed for the detection and titration of serum antibodies to bovine respiratory syncytial virus (BRSV). The ELISA was compared with a complement fixation (CF) test and a test for virus neutralising antibody in serum (virus neutralisation [VN] test). Testing sera collected in dairy herds revealed the closest correlation between the results of the ELISA and the CF test with respect to BRSV antibody titres. The VN test detected BRSV antibodies in a higher percentage of acute phase sera compared to the other two tests in field samples and in early bleedings of experimentally infected calves. However, the VN test was less effective in making a diagnosis of BRSV infections on the basis of a significant titre increase in paired sera. For this purpose the ELISA was found to be the most sensitive test.     

Prevalence of infectious diseases in ring-necked pheasant flocks in Poland

The health status of ring-necked pheasants in view of the prevalence of infectious diseases was estimated in Polish pheasantries in the years 1997-2000. Anatomicopathological, microbiological and serological examinations were carried out on birds derived from 26 pheasantries, including birds randomly selected from 18 flocks and sick or dead birds sent from 8 pheasantries. Antibodies specific to the following viruses were detected in serum blood samples: HE, AE, AP, REO, AI, Adeno group 1, MD, ND, as well as Mycoplasma gallisepticum specific antibodies. However, in none of the examined flocks was the presence of antibodies against reticuloendoteliosis virus found. Marble spleen disease and salmonellosis proved to be the most frequent cause of death during the growing period.