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B Thür

Publications and source records attributed to B Thür.

15 recordsLinked to original sources
PubMed2006

No evidence of bluetongue virus in Switzerland.

We report the results of the first survey for antibody against bluetongue virus (BTV) that was conducted in Switzerland in the year 2003. In a nationwide cross-sectional study with partial verification, 2437 cattle sera collected from 507 herds were analysed using competitive enzyme-linked immunosorbent assays (c-ELISA). To adjust for misclassification, 158 sera, including 86 that were recorded equivocal in Switzerland, were sent to the Office Internationale des Epizooties designated regional reference laboratory in the UK for confirmation. No BTV antibody was detected in any of these samples, confirming the absence of BTV from Switzerland in 2003. The specificity of the c-ELISA used in Switzerland for individual Swiss cattle was calculated to be 96.5%. The mean herd sensitivity achieved in our survey ranged from 78.9% to 98.8% depending on the with-in herd prevalence and test sensitivity used for the calculations. The cumulated confidence level achieved with the survey based on a minimal expected prevalence of 2%, was 99.99% and therefore it was concluded that there was no evidence of BTV circulation in Switzerland in 2003.

Animals↗
PubMed2001

Quantitative TaqMan RT-PCR for the detection and differentiation of European and North American strains of porcine reproductive and respiratory syndrome virus.

Since two different types of porcine reproductive and respiratory syndrome virus (PRRSV), the European (EU) and the North American (US) strain, occur or coexist in European swine herds, their rapid and reliable detection and differentiation is essential for disease surveillance. A quantitative TaqMan reverse transcription-polymerase chain reaction (RT-PCR) is described for PRRSV detection and strain differentiation. Sensitivity and specificity were compared with a conventional PRRSV RT-PCR and to the detection of both PRRSV types in cell cultures and both were found to be equal or superior to the reference methods. Reproducibility was tested and proved that the assay was very reliable. Standard dilutions included in each test allowed absolute quantitation of the amount of viral RNA. The TaqMan assay described below is time-saving, easy to handle, exhibits a decreased risk of cross-contamination and is highly sensitive and specific. It is, therefore, considered to be a powerful tool for the rapid detection and differentiation of PRRSV.

Animals↗
PubMed2000

Rescue of infectious classical swine fever and foot-and-mouth disease virus by RNA transfection and virus detection by RT-PCR after extended storage of samples in Trizol.

A method for storing samples containing classical swine fever virus (CSFV) or foot-and-mouth disease virus (FMDV), respectively, was developed, which abolishes the infectivity of both plus strand RNA viruses, and allows storage of samples above 0 degrees C for an extended time, yet preserves the viral RNA in a state which allows its detection by reverse transcription-polymerase chain reaction (RT-PCR), and even rescue of infectious virus after transfection of the extracted RNA into susceptible cells. Supernatants from infected cell cultures as well as organs from diseased animals were stored in Trizol(R) for 1-4 weeks at -20 degrees C, 4 degrees C, room temperature, or 37 degrees C. RNA was then extracted and used subsequently for RT-PCR, as well as transfection into susceptible cells to initiate the replication of progeny virus. Formaldehyde-fixed samples were also included in this study. Storage up to 4 weeks at 37 degrees C in Trizol(R) still yielded positive RT-PCR results and rescue of infectious virus upon RNA transfection. In contrast, formaldehyde fixation reduced drastically the detectability of viral RNA. This method represents a safe and inexpensive alternative to -70 degrees C (dry ice) storage or transport of samples, and abolishes the biosafety risks involved in shipping deep-frozen infectious materials.

Animals↗
PubMed1999

A survey of Newcastle disease in Swiss laying-hen flocks using serological testing and simulation modelling.

Newcastle disease (ND) is a highly contagious viral disease of birds particularly domestic poultry. Switzerland is currently declared free from ND; since vaccination is prohibited, the detection of antibodies against ND virus (NDV) results in the destruction of the respective flock (stamping-out policy). However, in 1995 and 1996, antibody-positive flocks were detected and sporadic ND outbreaks even occurred in Switzerland. Therefore, a serosurvey was done to look for evidence of NDV infections in Swiss laying-hen flocks. The survey was designed to provide 95% confidence of detecting at least one seropositive flock if the flock prevalence were 1%. Thirty blood samples from each of 260 commercial laying-hen flocks were collected during 1996 in a central poultry slaughterhouse. Sera were screened for NDV antibodies with a commercial blocking enzyme-linked immunosorbent assay (ELISA). Samples with a questionable or positive test result were retested with the same ELISA. A stochastic computer model was applied to define a cut-off number of test-positive samples to help to differentiate between true- and false-positive flocks and to estimate the true flock prevalence of infection. Four flocks were identified as NDV-seropositive and the NDV true seroprevalence among commercial laying-hen flocks in Switzerland was most likely between 1.35 and 1.55%. This indicates that Swiss laying-hen and parental flocks with more than 150 animals have been in contact with strains of NDV that cause subclinical infection in chicken, because no clinical symptoms have been observed. In this context, computer simulation was a useful technique to interpret survey results.

Animals↗
PubMed1999

[Molecular and immunodiagnostic studies of bovine neosporosis in Switzerland].

Cyst-forming coccidia may cause significant losses in livestock, primarily due to abortion, loss of young animals and neuromuscular diseases. Rather recently, Neospora caninum has been recognized as one of the major protozoal abortion-inducing parasites in cattle. The present study addressed the performance of different diagnostic tools (in vitro-cultivation; histology; immunohistochemistry; serology; PCR) suitable for the direct or indirect detection of N. caninum. By PCR, Neospora-DNA was detected in 24 brains (29%) from 83 bovine abortion, many of these brains were simultaneously characterized by histopathological findings typical for a protozoal, cerebral parasitosis. The diagnostic methods were furthermore assessed using samples of different tissues and body fluids from three experimentally Neospora-infected pregnant cows and their foetuses. The diaplacental passage of N. caninum to the foetus was successful in two of the three cases. In these two cases, PCR was positive for different foetal organs and, additionally, for the abomasal and amniotic fluid. The successfully infected cows developed anti-Neospora serum antibodies between 10 and 17 days post infection, foetuses remained serologically negative in all cases. The results obtained in the present study demonstrated the usefulness of PCR, complemented by serology, for the specific diagnosis of bovine neosporosis. Such tests may prove suitable to perform epidemiological investigations. Taken together, our data indicated that prenatal neosporosis may be an important cause of infectious bovine abortion in Switzerland.

Abortion, Veterinary↗
PubMed1999

[Classical swine fever in wild boars in Switzerland].

In May 1998, wild boars with classical swine fever (CSF) symptoms were detected in the southern part (Canton Ticino) of Switzerland. CSF virus was isolated from the submitted samples and RT-PCR followed by direct nucleotide sequencing of the 5' non-translated region showed that this virus was identical to the isolate previously recognized in wild boars from the area of Varese (Italy). In most animals, antibodies to CSF virus were detected as well. An immediate measurement was taken by limiting the movement of pigs and identifying both risk and surveillance zones. In order not to disturb potentially infected wild boars within their habitat a complete hunting prohibition for 2 months was enforced. The different possibilities of the control of CSF outbreaks in wild boars are discussed.

Animals↗
PubMed1999

[Newcastle disease--seroepidemiologic study of a highly contagious epizootic in poultry and in wild birds in Switzerland].

Newcastle disease (ND) is a highly contagious viral disease particularly of domestic poultry. Switzerland is currently declared free from ND. A serosurvey using an ELISA was performed to investigate infections with ND-Virus (NDV) in 260 Swiss laying hen flocks, 169 backyard poultry flocks and 1576 wild birds. For laying hen flocks, a stochastic model was applied to analyse the results from serological testing. Four laying hen flocks were identified as NDV-seropositive, and the true NDV seroprevalence in this population was most likely between 1.3 and 1.5%. NDV antibodies were also detected in five of the 169 backyard poultry-flocks. ND-antibody positive birds were found in 10% of all wild birds examined, with the highest proportions among cormorants, grebes, birds of prey, owls, and swifts. The study indicated that positive flocks must have been in contact with NDV strains causing sub-clinical infection, since no clinical signs had been observed. Moreover, trade of poultry or poultry eggs was considered to be an important factor associated with seropositivity in backyard poultry flocks. Contact to wild birds did not seem to be of major importance.

Animals↗
PubMed1998

Molecular and immunodiagnostic investigations on bovine neosporosis in Switzerland.

Neospora caninum has gained considerable attention through its role in the aetiology of bovine abortion. Due to its close phylogenetic relationship with Toxoplasma gondii, respective unequivocal differential diagnosis deserves special consideration. In order to evaluate the diagnostic performance of molecular and immunodiagnostic techniques and to provide insights into the epidemiological significance of bovine neosporosis in Switzerland, we conducted a study on 83 cases of bovine abortion: of these, 24 (29%) foetal brains were positive by Neospora-PCR, six of these foetuses were simultaneously seropositive in Neospora-IFAT and/or somatic antigen-ELISA. Conversely, four (5%) foetal brains were considered positive by Toxoplasma-PCR, two of which were also seropositive in the Toxoplasma-P30-ELISA and/or direct agglutination test. The seroprevalence in 1689 cattle sera obtained from 113 diary farms was 11.5% (95% confidence interval: 9.2-13.8) by Neospora-somatic antigen-ELISA were and 10.7% (95% confidence interval: 8.3-12.6) by Toxoplasma-P30-ELISA. From the same samples, 1.1%, less than statistically expected, were positive in both ELISA. Within selected groups of cow-calf farms, the seroprevalence determined using the Neospora-somatic antigen-ELISA was 14% (95% confidence interval 5.0-23.0) for dams and 15% (95% confidence interval: 3.0-28.0) for offspring calves. Seroprevalences determined by Toxoplasma-P30-ELISA were 8% (95% confidence interval: 4.0-12.0) for dams and 3% (95% confidence interval: 0.3-6.0) for calves. None of the sera gave a positive reaction in both ELISA. Our data indicated that prenatal neosporosis appears as an important cause of bovine abortion in Switzerland.

Abortion, Veterinary↗
PubMed1998

Comparative detection of classical swine fever virus in striated muscle from experimentally infected pigs by reverse transcription polymerase chain reaction, cell culture isolation and immunohistochemistry.

Classical swine fever (CSF) is a highly contagious viral disease, which can be transmitted by CSFV-contaminated swill. In 1993, four CSF outbreaks in Switzerland were caused presumably by feeding pigs with improperly heated swill. The aim of the investigations was to find a suitable method for CSFV detection in striated muscle samples of infected pigs in order to allow routine testing of meat for virus contamination. The sensitivity of virus detection in striated muscle was compared with the detection in target organs. Using reverse transcription polymerase chain reaction (RT-PCR), cell culture isolation and immunohistochemistry on samples from 14 experimentally infected pigs, CSFV was detected in target organs of ten, and in striated muscle of six pigs, respectively. Overall, only 58% of muscle samples from CSFV-positive animals were positive by RT-PCR and 40% by virus isolation in cell culture, whereas the virus was detected in target organs of these pigs. Virus detection from striated muscle was primarily successful in severely diseased animals infected with highly virulent CSFV strains. It is concluded that striated muscle is not suitable for sensitive CSFV detection, and additional organs have to be examined for reliable diagnosis.

Animals↗
PubMed1998

[Pestivirus as causative agent of abortion and perinatal mortality in cattle and sheep in Switzerland].

The causal involvement of bovine viral diarrhoea virus (BVDV) and border disease virus (BDV) infection in bovine and ovine abortion and perinatal mortality remain unclear. From 1992 until 1994, 213 bovine and 31 ovine foetuses as well as 36 calves and 25 lambs which had died perinatally were investigated. Tissue samples were tested for the presence of pestiviruses and serum or fluid from the body cavities were analysed for the presence of pestivirus antibodies. Detection of pestiviruses was performed by (i) cell culture isolation, (ii) antigen ELISA and (iii) immunohistochemical staining for viral antigen. For antibody-testing an indirect ELISA was used. In nine bovine foetuses and in two calves BVDV was isolated. Pestiviruses, most likely BDV were detected in one ovine foetus and three lambs. In 6% of the bovine and 11% of the ovine foetuses anti-pestivirus antibodies were detected. However, clinical features and history of bovine cases did not show a correlation with the diagnostic results, In contrast, the presence of central nervous system signs in neonatal lambs and the detection of BDV was correlated.

Abortion, Veterinary↗
PubMed1997

Immunohistochemical diagnosis of pestivirus infection associated with bovine and ovine abortion and perinatal death.

OBJECTIVE: To establish a reliable, rapid, economical method for detection of pestivirus infection in bovine and ovine fetuses and to examine participation of these viruses in abortions and neonatal mortality. ANIMALS: 213 bovine and 31 ovine fetuses, as well as 36 newborn calves and 25 lambs, which had died within 3 days after birth, were tested for bovine viral diarrhea virus (BVDV) and border disease virus by use of different methods. PROCEDURE: Detection of BVDV in fetuses was performed by immunohistochemical methods, using a panel of monoclonal antibodies against pestivirus antigens on cryostat and paraffin sections and by virus isolation in cell culture; in some instances, an antigencapture ELISA was performed. Results of the various methods were compared. RESULTS: Sensitivity of BVDV detection by immunohistochemical methods and virus isolation in cell culture was equal; however, it decreased in association with autolysis. In autolytic fetuses, use of formalin-fixed, paraffin-embedded brain sections was the most favorable method. Antigen detection by ELISA was less sensitive. CONCLUSIONS: Immunohistochemical analysis of cryostat sections of brain, skin, thyroid gland, abomasum, and placenta is a rapid, sensitive method for detecting pestiviruses in fetuses. In the presence of advanced autolysis, this method used on formalin-fixed, paraffin-embedded brain sections is recommended over the other described methods.

Abortion, Veterinary↗
PubMed1996

[Bovine virus diarrhea/mucosal disease in cattle--clinical findings in 103 calves and cattle].

One hundred and three calves and heifers persistently infected with BVD virus were examined. The most important clinical findings in order of frequency were weight loss, erosions of the oral mucosa, diarrhea, anorexia and fever. In addition, nasal discharge, lymph node enlargement, erosions of the nose, muzzle and interdigital cleft and bronchopneumonia occurred in less than half of the patients. Furthermore, crustaceous dermatitis was observed in three patients and petechial hemorrhage of the oral mucosa occurred in two other cases with severe thrombocytopenia. Haemoconcentration, leukocytosis, hyperfibrinogenemia and azotemia were the most important haematological findings. To confirm the clinical diagnosis, the serum antibody titre of 69 patients was compared with that of a clinically healthy control animal from the same herd. There was no positive antibody titre in 65 of the 69 patients, whereas 67 of the control animals had positive titres. In 34 patients, EDTA blood samples were collected for virus detection. In 20 of these, skin biopsy samples were also obtained for virus demonstration. Virus has been demonstrated in the blood of 32 of the 34 cases and in all 20 skin biopsy specimens.

Animals↗
PubMed1996

[Immunohistology as a reliable and efficient method for the diagnosis of BVDV infections].

Persistent infection with the Bovine Viral Diarrhea/ Mucosal Disease Virus (BVDV) can be detected using immunohistological methods. The experiments show that the LSAB (Labeled Streptavidin Biotin) peroxidase method is suitable to detect the BVDV in cryostat sections of unfixed tissue. For the diagnostic work up in living animals, skin biopsies give reliable results. In dead animals, organs such as thyroid gland, skin, mucosa of the mouth, esophagus and abomasum are well suitable for immunohistological BVDV detection.

Animals↗
PubMed1996

[Chylothorax in a calf].

A case of chylothorax caused by fracture of thoracal vertebrae in a two-day-old Swiss Braunvieh male calf ist described. The clinical symptoms were those of a unilateral, progressive pleural effusion. This was confirmed by radiological and ultrasonographic examinations. Thoracocentesis was performed under ultrasonographic assistance. The liquid obtained from the pleural cavity was turbid and contained chylomicrons, lymphocytes and neutrophilic granulocytes as well as a high concentration of triglycerides. These qualities go together with chylus. Immunohistological examination for BVD virus turned out to be positive. An intrauterine disturbance of osteogenesis due to BVD virus must be considered a possible cause for fracture of vertebrae during delivery.

Animals↗