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Bovine respiratory syncytial virus (BRSV) is a virus of the Pneumovirus genus belonging to the subfamily Pneumovirinae of the Paramyxoviridae family. BRSV is one of the main infectious agents causing bovine diseases of the upper and lower respiratory tract, affecting mainly young animals under the age of 9 months. It is responsible for high economic losses in the cattle industry around the world. The most effective and widely used method for limiting costs of infection with BRSV is immunoprophylaxis. Till now, this subject was rarely an object of interest in Polish scientific literature, therefore the aim of this article is to present current information on the types of available vaccines, their efficiency and safety. Additionally, a description of the variability of most immunogenic regions of BRSV and it is influence on the efficiency of the commonly used vaccines is included.
RT-PCR assays for detection of BRSV, based on four different sets of primers were optimized and evaluated for their sensitivity and specificity. Primers used in this study were specific for genes encoding three BRSV proteins, nucleoprotein N and glycoproteins F and G. Our results indicated that RT-PCR with primers B7:B8 for G protein was the most efficient in detecting BRSV. Starters B7:B8 reacted specifically only with BRSV strains, no cross-reaction with other closely related viruses to BRSV was observed. RT-PCR sensitivity was also high and amounted to 101.66 TCID50. Starters for F and N genes of BRSV were not sufficiently specific and cross-reacted with RNA of HRSV. RT-PCR with primers for the genes F and N of BRSV was characterized by a lower sensitivity than RT-PCR with primers B7:B8. In conclusion, RT-PCR specific to a sequence of glycoprotein G gene, seemed to be the most useful for BRSV detection.
The aim of the study was to evaluate the seroprevalence of BRSV in cattle in Poland. For the study, 3070 blood samples from cattle of both sexes were collected between 2007 and 2011. None of the animals had been vaccinated against BRSV. The samples came from animals from the whole area of Poland, which was divided into the following 4 macroregions: I - southern Poland, II - central Poland, III - western Poland and IV - north-eastern Poland. The samples were tested by the ELISA BRSV Ab test. The presence of BRSV antibodies was found in 61.4% of animals. Significant differences in the prevalence of BRSV infections were observed, depending on the origin of samples. The highest rate of infection (80.4%) was found in western Poland, and the lowest (29.6%) in southern Poland. The percentage of infected animals differed significantly between different age groups. Seropositive animals constituted, 54.9% of the group under 2 years of age and 66.1% of the older group. This study shows that BRSV infections are widespread in Poland and could have an important impact on the health status of cattle herds.
Three different rapid strip tests: TRU RSV, BinaxNOW RSV and RSV Respi-strip were compared with RT-PCR and ELISA BRSV Ag for the ability to detect bovine respiratory syncytial virus (BRSV) in nasal swabs collected from calves experimentally vaccinated with live vaccine Rispoval RS-PI3. The reference strains of BRSV (375 and A51908) were detected by ELISA BRSV Ag whereas the strains of human respiratory syncytial virus (HRSV) and bovine parainfluenza virus type 3 (BPIV-3) were not. All rapid strip tests as well as RT-PCR reacted positively both to HRSV and BRSV reference strains and negatively to BPIV-3. The detection limit for RT-PCR was 39.1 TCID50 (strain 375 of BRSV), whereas for each of the rapid tests it was approximately 156 TCID50 and 312 TCID50 for antigen ELISA. Diagnostic sensitivity in detecting BRSV in nasal swabs for TRU RSV and RSV Respi-strip tests was 33% and 50% for BinaxNOW RSV. Diagnostic specificity of TRU RSV was 100%, whereas for both BinaxNOW and Respi-strip it was 87%. We concluded that TRU RSV could be used as a supportive rapid test for BRSV screening in nasal swabs taken directly on a farm. However, due to the small group of animals used in the experiment, the results should be regarded as preliminary and the study should be repeated on a larger number of animals.
The genetic stability of ORF1a encoding non-structural proteins nsp1, nsp2, nsp3 and nsp4 of equine arteritis virus (EAV) has been analysed for nearly seven years in a persistently infected stallion of the Malopolska breed. Between November 2004 and June 2011, 11 semen samples were collected. Viral RNA extracted from semen of this carrier stallion was amplified, sequenced and compared with the sequences of the other known strains of EAV. Sequence analysis of ORF1a showed 84 synonymous and 16 non-synonymous mutations. The most variable part of ORF1a was the region encoding nsp2 protein with 13 non-synonymous substitutions. The degree of amino acid identity between isolates ranged from 98.91 to 100%. Only single non-synonymous mutations were detected in nsp1 (one substitution) and nsp4 (two substitutions). The most stable was nsp3 in which no amino acid substitutions were observed during the whole period of observation.
This paper describes the first characterisation of bovine respiratory syncytial virus (BRSV) detected in the nasal swabs collected from young yearlings with clinical signs of lower respiratory tract illness from the northern regions of Poland. RT-PCR products of the BRSV gene encoding glycoprotein G were sequenced and subsequently compared to the reference nucleotide sequences of 19 BRSV strains from all over the world. This comparison suggested a close relationship of Polish isolates to the strains isolated in THE Czech Republic in 2002-2003 and Danish strains from THE 80's and 90's.
The variability of the ORF2a, ORF2b, ORF3, and ORF4 genes of the equine arteritis virus (EAV) was analysed during a seven year observation of persistent infection in a stallion of the Małopolska breed. A total of 11 semen samples were collected between 2004 and 2011. RNA of EAV isolates obtained from the semen of the stallion was amplified, sequenced, and compared with the sequences of other strains available in GenBank. Multiple nucleotide substitutions were found in sequences of the analysed regions, however, neither deletion nor insertions were detected. The highest number of point mutations (11-6 synonymous and 5 non-synonymous) were found in the ORF2b gene, and the lowest number of substitutions (6-5 synonymous and one non-synonymous) were found in the ORF2a gene. None of the identified mutations affected any of the glycosylation or phosphorylation sites of the minor EAV protein. Phylogenese analysis of the ORF3 gene of EAV isolates showed that they grouped together within the cluster of European strains of EAV. Additionally, the ORF3 gene sequences of the isolates showed high (86.4% - 98.3%) similarity to the previously isolated Polish EAV strains.
Bovine herpesvirus-1 (BoHV-1), a causative agent of Infectious Bovine Rhinotracheitis (IBR), is responsible for high economic losses in cattle farming industry. The use of testing methods that allow early detection of BoHV-1-infected animals is a key element of each program of IBR eradication. The aim of the study was to design and evaluate two variants of LAMP isothermal tests with SYBR Green fluorescence probes, specific to the genes encoding gD and gE glycoproteins of BoHV-1. LAMP gE BoHV-1 assay was able to distinguish between gE- and gE+ strains of the virus. Both LAMP gD and gE assays were specific to BoHV-1 and did not react with other related to BoHV-1 alphaherpesviruses. Sensitivity of LAMP gD was 2x10⁴ copies of the viral genome whereas for LAMP gE it was 2x10⁵. Diagnostic sensitivity calculated for LAMP gD was 64.7% whereas for LAMP gE it was 80%. Diagnostic specificity for LAMP gD and LAMP gE was 78.9% and 89.3%, respectively. LAMP assay can be a rapid and simple method of diagnosis of acute BoHV-1 infections and discrimination of gE⁻ strains. However, relatively low diagnostic sensitivity of the method can limit its use in routine diagnostics.
The purpose of the paper was to present current knowledge on the epizootiology and diagnosis of respiratory infections caused by BRSV. This virus is one of the major infectious agents causing diseases in young cattle. BRSV can be the main cause of a respiratory infection or it can be one of the etiological agents of respiratory disease complex. The results of serological examinations and virus isolation showed that BRSV is widely distributed in cattle population all over the world. Economic losses caused by BRSV are associated mainly with high costs of treatment, decreased growth rates and calf mortality. A rapid diagnosis of the disease is crucial for further therapeutic management and the treatment should be concentrated on limiting losses within the herd. During recent years several papers concerning the diagnosis of BRSV have been published. This review describes not only the classical methods of virus detection (virus isolation in a cell culture, immunofluorescence, immunohistochemistry) but also the recently applied PCR assay.
The aim of this study was to determine the subtype of bovine herpesvirus 1 (BHV1) strains currently circulating in the cattle population in Poland. Altogether 224 nasal swabs, 36 lung tissue samples and 14 samples of fluid after embryo washing in cows were tested by virus isolation test. Five field strains of BHV1 were isolated. These isolates as well as 4 archival and 2 reference strains of BHV1 were subjected to restriction enzyme analysis. Viral DNA was cleaved with Hind III, Hpa I and Pst I enzymes. After digestion with Hind III typical patterns for BHV1.1 subtype were observed in all field strains. Among archival strains 2 belonged to BHV1.1 and 2 others to B-HV1.2a subtype. These findings were confirmed by digestion with other enzymes. The presented study showed that strains of BHV1.1 subtype are dominant in cattle in Poland.
Shedding time of bovine respiratory syncytial virus (BRSV) and bovine parainfluenza virus 3 (BPIV3) in calves vaccinated intranasally with modified live Rispoval RS-PI3 vaccine was determined. Blood and nasal swabs were collected on selected days before and after vaccination. Antibodies against BRSV and BPIV3 were tested by Respiratory ELISA Pentakit and the viral RNA was detected by RT-PCR. Twenty eight days after administration of the vaccine, a marked increase of specific antibody titres to BRSV and BPIV3 was detected in vaccinated calves. All animals were RT-PCR positive both for BRSV and BPIV3. Both viruses were excreted with nasal discharges within 8 d after vaccination but the course of shedding in individual calves was variable.
The study was performed on nasal swabs, tracheal samples, and sera obtained from young beef heifers aged between 6 and 12 months, from farms in eastern and south-eastern Poland. The samples were evaluated using bovine herpesvirus 1 (BHV-1) ELISA kits (ELISA BHV1 antibody and ELISA BHV1 antigen) and PCR. Among all the animals examined, 37 (32.2%) were positive in the ELISA BHV1 antigen test. The presence of BHV-1 was confirmed by PCR in 42 (36.5%) animals. In the ELISA BHV1 antibody test, 39 (33.9%) seropositive animals were identified. The presence of BHV-1 positive samples was observed in all the examined breeds of young cattle. There were no significant differences (P ≤ 0.05) in BHV-1 positive samples. The results indicate that the incidence of BHV-1 infections in feedlot cattle herds studied was 32.2%-36.5%, which suggests that preventive measures should be implemented in order to limit transmission of the virus.
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