Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Pestivirus”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

Detection of calves persistently infected with bovine pestivirus in a sample of dairy calves in south-eastern Queensland.

OBJECTIVE: To determine the proportion and incidence of calves persistently infected with bovine pestivirus in calves (n = 1521) supplied to the Tick Fever Research Centre and to assess the test regime to detect calves persistently infected with bovine pestivirus. DESIGN: Calves, 1 to 6 weeks old, selected for use in the production of the tick fever vaccine were collected from 21 properties in 56 separate groups between October 1990 and December 1996. Each group was examined for the presence of calves persistently infected with bovine pestivirus. PROCEDURE: All calves were routinely tested for antibody to bovine pestivirus and bovine pestivirus antigen using a serum neutralisation test and an antigen-capture ELISA, respectively. Pooled lymphocyte samples from calves were also monitored for bovine pestivirus by inoculation of sheep. Whole herd testing was carried out in eight herds, using a serum neutralisation test as a screen test followed by an antigen-capture ELISA of cattle with a serum neutralisation test titre of less than 32. RESULTS: Fourteen of the 1521 calves tested (0.9%), were detected as persistently infected and the incidence ranged from 0.0 to 3.0% per year over 6 years. Persistently infected calves were found in 13 of the 59 groups and originated from 7 of the 21 herds used. In whole herd testing on the properties of origin, cattle persistently infected with bovine pestivirus were detected in four of the eight herds tested. CONCLUSIONS: The proportion of calves persistently infected with bovine pestivirus is similar to that in other countries and indicates that bovine pestivirus could be a significant cause of economic loss in Australian cattle herds. In detecting calves persistently infected with bovine pestivirus, the combination of sheep inoculation, paired antigen-capture ELISA and serum neutralisation tests appeared to be highly sensitive and specific.

Animals↗

Further characterization of border disease virus isolates: evidence for the presence of more than three species within the genus pestivirus.

The molecular analysis of three ovine pestivirus strains revealed the existence of two distinct groups of sheep-derived pestiviruses, namely "true" border disease virus strains (BDV) and bovine viral diarrhea virus (BVDV)-like strains. As an extension of these studies RT-PCR and nucleotide sequencing of the autoprotease (Npro) and nucleocapsid protein (C) encoding regions of additional serologically defined ovine pestivirus strains were performed. A comparison of Npro and C revealed that three ovine isolates belong to the group of true BDV while two were clearly different from these as well as from BVDV and CSFV. The amino acid identity between the latter two ovine strains is 85% for Npro and 92% for C and thus similar to values found within the three pestivirus species defined so far. In order to allow comparison with additional pestiviruses the nucleotide sequences of a part of the 5' noncoding region were determined for the ovine pestivirus strains. The comparative analysis showed that recently described BVDV strains associated with acute lethal infection were very similar to two ovine isolates. The latter represent a fourth group within the genus pestivirus different from the so far defined pestivirus species BVDV, true BDV, and CSFV. The data lead to the question whether the current nomenclature of pestivirus species according to the host origin and the induced diseases is still appropriate.

Amino Acid Sequence↗

Genetic characterization of ruminant pestiviruses: sequence analysis of viral genotypes isolated from sheep.

Historically, the genus pestivirus was believed to contain three species of viruses; bovine viral diarrhea virus (BVDV), border disease virus (BDV) and classical swine fever virus (CSFV). However, based on limited sequence analysis of a small number of pestiviral isolates from domestic livestock, evidence has recently emerged indicating that at least four distinct genotypes exist. In an attempt to gain a better understanding of the degree of viral variation among ruminant pestiviruses, the entire structural gene coding region of an ovine pestivirus. BD31, genome encompassing 3358 nucleotides was cloned and sequenced. Sequence analysis revealed that BD31 shares less than 71% nucleotide similarity with other pestiviruses, suggesting, that BD31 is distinct from BVDV, CSFV as well as other ovine and bovine pestiviruses currently referred to as BVDV type II. Based on this data, BD31 is the first North American pestivirus isolate that falls under the category true BDV. Results from the analysis of the nucleotide sequence of the E0-E1 coding region of six additional ruminant pestiviruses identified the existence of three distinct virus genotypes in North America. Thus, among ruminent pestiviruses, bovine isolates can be grouped into two genotypes, namely types 1 and 4, whereas ovine isolates fall into genotypes 1, 3 and 4.

Amino Acid Sequence↗

5' and 3' untranslated regions of pestivirus genome: primary and secondary structure analyses.

Within the conserved 5' untranslated region (UTR) of the pestivirus genome three highly variable regions were identified. Preceding the polyprotein start codon, multiple cryptic AUG codons and several small open reading frames are characteristic for all the five pestiviruses. Inspection of the context of AUGs revealed that the polyprotein initiation AUG of pestivirus has a weak context for efficient translation initiation. The most favorable context was found in two of the cryptic AUGs. Two oligopyrimidine-rich tracts upstream to the conserved either cryptic or authentic AUG in the 5'-UTR of pestivirus were identified and 83.3% of their nucleotide sequences are complementary to the consensus sequence at the 3' terminus of eucaryotic 18S rRNA. A secondary structure model for the 5'-UTR of pestivirus was predicted. Nucleotide sequence comparison among five pestiviruses led to the identification of a variable region and a conserved region in the 3'-UTR. A deletion of 41 nucleotides was found within the variable region in Osloss. A secondary structure model for the 3'-UTR was also predicted. The structural similarity of the 5'-UTR between pestiviruses and picornaviruses and hepatitis C viruses was demonstrated and the possible implications of features of the 5' and 3'-UTR of pestiviruses are discussed.

Base Sequence↗

Outbreaks of border disease in goats induced by a pestivirus-contaminated orf vaccine, with virus transmission to sheep and cattle.

Five herds with a total of 276 female goats experienced severe outbreaks of reproductive failure due to a pestivirus-contaminated experimental orf vaccine given early in the breeding season. The reproductive failures comprised barrenness in 42 goats, abortion in 53 and, in 118, the birth of dead or weak kids. The incidence of female goats with such failures was 82 per cent overall, herd incidence rates ranging from 79 to 96 per cent. No progeny showed characteristic signs of border disease (BD). Microscopic lesions in the CNS were moderate, mostly characterized by hypercellularity, cell disorganization and decreased myelin content. Non-cytopathic strains of pestivirus were demonstrated in tissue or serum from two weak-born and two apparently healthy kids. Neutralizing antibodies against a bovine pestivirus were found in all 254 goats examined about 4 months after vaccination. At the end of the breeding season, all kids were removed and 74 young kids were introduced from presumably normal herds. Approximately 8 months later, 64 (86 per cent) of the bought-in kids had pestivirus antibodies. Two years after the outbreaks, such antibodies were found in all but three of 127 vaccinated goats still alive, and another 2 years later, in all 22 vaccinated goats in one of the herds. Sheep also were kept on the same five farms and cattle on one. Sheep in two of the flocks showed reproductive failure probably caused by pestivirus transmitted from infected goat offspring. A pair of twin lambs showed nervous signs and brain lesions characteristic of BD, while 17 other lambs had a very low growth rate. Virus was not isolated from any lamb. The prevalence rates of ewes with pestivirus antibodies in the two affected flocks were 33 and 72 per cent, respectively. One of nine cows aborted a pestivirus-infected foetus, and all were antibody-positive.

Abortion, Veterinary↗

Phylogenetic analysis of pestiviruses from domestic and wild ruminants.

Infections with pestiviruses occur in cattle, sheep, pigs and also in numerous other ungulate species. In the present study, pestiviruses from goat, buffalo, deer and giraffe were analysed at the molecular level; unusual strains from cattle and pigs were also included. A phylogenetic analysis of the respective pestiviruses was undertaken on the basis of a fragment from the 5' noncoding region as well as the gene encoding autoprotease Npro. Statistical analyses of the respective phylogenetic trees-based on the 5' NCR revealed low confidence levels for most of the branches, while the structure of the tree based on the Npro gene was supported by high bootstrap values. Accordingly, the isolates from goat, buffalo and deer can be grouped together with bovine viral diarrhoea virus (pestivirus type 1); within this genotype three subgroups and one disparate virus have been identified. One isolate from pig and one from cattle belong to the group of 'true' border disease virus (pestivirus type 3), which can be further subdivided into two major subgroups. Interestingly, the giraffe isolate does not belong to one of the four established pestivirus genotypes. The phylogenetic analysis strongly suggests that genotype 1 pestiviruses occur world-wide in many ruminant species. Furthermore, phylogenetic trees based on the Npro gene nucleotide sequences show that the respective sequences do not segregate into discrete lineages based on host-species origin.

Amino Acid Sequence↗

Genetic diversity of pestiviruses: identification of novel groups and implications for classification.

The complete Npro coding sequences were determined for 16 pestiviruses isolated from cattle, pig, and several wild ruminant species including reindeer, bison, deer, and bongo. Phylogenetic analysis enabled the segregation of pestiviruses into the established species bovine viral diarrhea virus-1 (BVDV-1), BVDV-2, border disease virus (BDV), and classical swine fever virus (CSFV). For BVDV-1 five distinct subgroups were identified, while BVDV-2, BDV, and CSFV were each subdivided into two subgroups. The virus isolates from bongo and deer as well as one porcine virus isolate belong to BVDV-1. Interestingly, the isolates from reindeer and bison are distinct from the established pestivirus species. The Npro sequences from these two viruses are more similar to BDV than to the other pestivirus species. Calculation of the pairwise evolutionary distances allowed a clear separation of the categories species, subgroup, and isolate only when the reindeer/bison viruses were considered as members of an additional pestivirus species. Furthermore, the entire E2 coding sequences of a representative set of virus isolates covering all recognized species and subgroups were studied. Segregation of pestiviruses based on the E2 region was identical with that obtained with the N(pro) sequences.

Amino Acid Sequence↗

Enzyme-linked immunosorbent assay using a virus type-specific peptide based on a subdomain of envelope protein E(rns) for serologic diagnosis of pestivirus infections in swine.

Peptides deduced from the C-terminal end (residues 191 to 227) of pestivirus envelope protein E(rns) were used to develop enzyme-linked immunosorbent assays (ELISAs) to measure specifically antibodies against different types of pestiviruses. The choice of the peptide was based on the modular structure of the E(rns) protein, and the peptide was selected for its probable independent folding and good exposure, which would make it a good candidate for an antigenic peptide to be used in a diagnostic test. A solid-phase peptide ELISA which was cross-reactive for several types of pestivirus antibodies and which can be used for the general detection of pestivirus antibodies was developed. To identify type-specific pestivirus antibodies, a liquid-phase peptide ELISA, with a labeled, specific classical swine fever virus (CSFV) peptide and an unlabeled bovine viral diarrhea virus peptide to block cross-reactivity, was developed. Specificity and sensitivity of the liquid-phase peptide ELISA for CSFV were 98 and 100%, respectively. Because the peptide is a fragment of the E(rns) protein, it can be used to differentiate between infected and vaccinated animals when a vaccine based on the E2 protein, which is another pestivirus envelope protein, is used.

Amino Acid Sequence↗

Subdivision of the pestivirus genus based on envelope glycoprotein E2.

Conventionally, the genus Pestivirus of the family Flaviviridae has been divided into bovine viral diarrhea virus (BVDV), classical swine fever virus (CSFV), and border disease virus (BDV). To date, BDV and BVDV have been isolated from different species, whereas CSFV seems to be restricted to swine. Pestiviruses are structurally and antigenically closely related. Envelope glycoprotein E2 is the most immunogenic and most variable protein of pestiviruses. We cloned E2 genes of many different pestivirus strains, including those from a deer and a giraffe. The E2 genes were transiently expressed, characterized with monoclonal antibodies, sequenced, and compared. Based on these data, we can delineate six major groups within the Pestivirus genus. Four groups correspond to defined genotypes, whereas the two other groups could be new genotypes within the Pestivirus genus. One group comprises CSFV strains isolated from swine. A second group consists of BDV strains Moredun, L83, and X818, which have been isolated from sheep, and strain F from swine. A third group contains strain BD78 from sheep, strain 5250 from swine, and strain 178003 from cattle. On the basis of E2, these viruses are very similar to BVDV strains associated with acute severe outbreaks of bovine viral diarrhea, so-called type 2 BVDV. The fourth group consists of BVDV strains originating predominantly from cattle. This BVDV group can be divided into two subtypes or subgroups BVDV Ia and Ib: BVDV Ia contains viruses from the United States, such as like NADL and Oregon, and some others, such as 150022 and 1138 from Europe. Subgroup BVDV Ib contains strain Osloss and several Dutch isolates. The fifth and sixth "groups" could be proposed as two new genotypes and contain strains Deer and Giraffe, respectively.

Amino Acid Sequence↗

Swine and ruminant pestiviruses require the same cellular factor to enter bovine cells.

Pestiviruses initiate infection of susceptible cells by receptor-mediated endocytosis. Cellular plasma membrane or endosomal molecules involved in translocation of these viruses into the cytosol have not been unequivocally identified. We reported previously that a mutant cell line derived from Madin-Darby bovine kidney (MDBK) cells, termed CRIB-1, was resistant to infection with bovine viral diarrhoea virus. CRIB-1 cells were also resistant to infection with classical swine fever virus and border disease virus of sheep, suggesting that entry of these three different pestiviruses into bovine cells requires a common cell membrane function. The resistance is pestivirus-specific: CRIB-1 cells were as susceptible as the parental MDBK cells to 14 other viruses of cattle and swine belonging to unrelated families. The resistance of CRIB-1 cells to pestivirus infection involves a block in virus entry since transfection of virus RNA or virus inoculation in the presence of PEG resulted in productive infection. Furthermore, quantitative analyses of the outcome of PEG-mediated infection of CRIB-1 cells indicated that the intracellular milieu was fully permissive for pestivirus replication. Binding studies revealed that virus attachment to CRIB-1 cells was not completely abrogated. These results indicate that entry of pestiviruses into MDBK cells depends on a common plasma membrane or endosomal function, which is lacking in CRIB-1 cells.

Animals↗

Pestivirus infections in ruminants other than cattle.

Pestiviruses infect a wide range of domestic, captive and free-living ruminants. Among domestic livestock, Border disease virus is a well recognised cause of an important congenital disease of sheep in virtually all sheep-rearing countries of the world. The clinical signs, pathogenesis, diagnosis, epidemiology and control of this disease are described in detail. One natural outbreak of Border disease in domestic goats has been described and there is serological and virological evidence that pestiviruses occur widely in this species. A pestivirus has been isolated from a farmed red deer (Cervus elaphus) and there is serological evidence of a widespread low prevalence of infection among this new domestic species. Pestiviruses have been associated also with outbreaks of disease among captive ruminants in zoological collections. Among free-living ruminants, pestiviruses have been recovered from dead roe deer (Capreolus capreolus), fallow deer (Dama dama), African buffalo (Syncerus caffer), giraffe (Giraffa camelopardalis) and wildebeest (Connochaetes spp.) but in all these instances the contribution of the virus to the cause of the disease was uncertain. Serological surveys have shown that many species of free-living ruminants in North America, Europe and Africa have varying prevalence rates of antibodies to pestiviruses.

Animals↗

Ovine pestiviruses: their taxonomic status revealed by palindromic nucleotide substitutions.

We examined previously identified border disease virus (BDV) strains by using a newly proposed genotyping procedure based on palindromic nucleotide substitutions (PNS) in the 5'-untranslated region (UTR), and found 22 (41.5%) out of 53 strains of BDV in the nucleotide sequence databases are not of BDV. All the 22 ovine pestivirus strains were allocated to the BVDV species according to the PNS, and were compared with reference strains of pestivirus 1 (BVDV-Ia,-Ib, and-Ic genovars), pestivirus 2 (BVDV-II genovar), pestivirus 3 (BDV) and pestivirus 4 (CSFV), respectively. Ten strains (Weybridge, A553, B1056, D771/1, D861, D1120/1, D1432/P, Q1161/1, Q1161/2, 114817) showed a palindromic structure in the 5'-UTR characteristic to the BVDV-Ia genovar, three strains (7535, 7546, 7548) were characteristic to the BVDV-Ib genovar, and nine strains (BD-78, 59386, SCP, Lees, C413, 167237, 168149, 173157, 175375) belonged to the BVDV-II genovar.

Animals↗

Adventitious pestivirus RNA in live virus vaccines against bovine and swine diseases.

Live virus vaccines against bovine and porcine diseases were examined for the presence of adventitious pestivirus RNA or pestiviruses by reverse transcription-polymerase chain reaction (PCR). Pestivirus RNA was detected in the live virus vaccines against Akabane disease, Ibaraki disease, infectious bovine rhinotracheitis, porcine parvovirus infection, transmissible gastroenteritis and Japanese encephalitis. Pestivirus RNA or pestivirus in the fetal bovine serum used to grow the host cells used to prepare the bovine and swine viral vaccines is a likely source of the contamination. Nucleotide sequence analysis of the PCR products suggests that modified live virus vaccines being used for immunization of cattle against bovine viral diarrhoea was not responsible for the contamination of the vaccines examined.

Animals↗

Experimental pestivirus infections in pregnant goats.

Fifty pregnant goats, inoculated intramuscularly at different gestational stages with a non-cytopathic ovine pestivirus or a cytopathic bovine pestivirus, all developed pestivirus-neutralizing antibodies within 5 weeks of inoculation. The incidence of reproductive failure was similar for the two agents. Parturition at term with only healthy kids occurred in 13 (26 per cent) of the goats. Viable kids were not born to any of the 17 goats inoculated at about day 40 of gestation. Three of the 17 delivered dead or weak kids, seven aborted and three of seven which were necropsied during pregnancy had markedly underdeveloped and autolysed or mummified fetuses in utero, while four were barren. When inoculated at around the 60th day of gestation, two of 18 animals gave birth to only healthy kids, 12 to dead and/or weak kids, two aborted and, at necropsy, a small, decomposed fetus was found in one goat while one other was barren. In this group, one kid was ataxic and seven others had body tremors characteristic of border disease. One of the latter kids was viable. Of 15 goats inoculated at around day 100 of gestation, 11 gave birth to healthy kids only, three to dead and/or weak kids and one aborted. In 23 progeny, histological changes in the central nervous system (CNS) consisted mainly of cerebral white matter necrosis, cerebellar dysplasia, hypercellular areas in white matter and lymphocytic perivascular cuffings. All seven weak-born kids with signs of border disease had CNS lesions, particularly cerebellar dysplasia and/or hypercellular areas. Non-cytopathic pestivirus was isolated from tissues from all eight progeny examined in the 40-day inoculation group, from tissues and/or serum from 10 of 23 progeny in the 60-day group, and from four of 24 in the 100-day group. Persistent infection was demonstrated in a healthy kid, in a viable shaker and in two other kids which appeared normal at birth. Examination of offspring before ingestion of colostrum revealed pestivirus antibodies in one kid in each of the 40- and 60-day inoculation groups and in five kids in the 100-day group.

Abortion, Veterinary↗

Highly sensitive one-tube RT-PCR and microplate hybridisation assay for the detection and for the discrimination of classical swine fever virus from other pestiviruses.

Rapid, sensitive and specific laboratory diagnostic methods are necessary to confirm outbreaks of classical swine fever. The detection of classical swine fever virus (CSFV) and its discrimination from other pestiviruses can be achieved by virus isolation on cell culture, antigen detection, or molecular methods. To reduce the time and the number of steps in the diagnostic procedure a sensitive and rapid detection method based on specific amplification of the pestiviral RNA by one-step reverse transcription-polymerase chain reaction (RT-PCR) followed by detection and differentiation of the amplification products by pestivirus-, bovine viral diarrhoea virus- (BVDV-) and CSFV-specific capture probe hybridisation and colorimetric assay in microwell plates (enzyme liked immunosorbent assay (ELISA)) was developed. Two different methods using two gene regions for pestivirus RT-PCR amplification were carried out. One pair of primers was selected from the 5'-UTR region and the second one from the gene region coding for N(pro), C and E0 proteins. The designed oligonucleotide primers were used for several pestivirus reference strains as well as for some field isolates detection in cell culture supernatants and in clinical specimens. The specificity and sensitivity of both methods were compared using EZ rTth RNA PCR kit and ACCESS RT-PCR system for combined RT-PCR assay. The use of one-step RT-PCR eliminates the additional manipulations that are generally required for a two reaction system and limits the risk of carry-over contamination. Labelling of PCR products with digoxigenin (DIG) during the amplification reaction enables colorimetric assessment of hybridisation reactions. For solution hybridisation pestivirus-, BVDV- and CSFV-specific biotin-labelled capture probes were used. By serial dilutions of DIG-labelled PCR products the RT-PCR-ELISA was found to be 100-times more sensitive than the conventional agarose gel electrophoresis. Higher sensitivity of RT-PCR-ELISA detection using specific biotin-labelled probes offers the opportunity to eliminate strain specific nested PCR and to overcome the problems with contamination and false positive results.

Animals↗

A novel method for pestivirus genotyping based on palindromic nucleotide substitutions in the 5'-untranslated region.

A simple and practical method was developed for pestivirus genotyping based on analysis of the secondary structures in the 5'-untranslated region (UTR). Three stable stem-loop structures, V1, V2 and V3, predicted by computer in the 5'-UTR, included strictly conserved consensus base-pairings which are shared by all the genotypes of pestivirus or are characteristic to each genotype of pestivirus. On the basis of the palindromic nucleotide substitution at the secondary structural level, six genotypes have been identified among pestivirus strains, irrespective of the cytopathic and non-cytopathic biotypes. They are genotypes Ia, Ib, Ic and II in bovine viral diarrhea virus, genotype III in border disease virus, and genotype IV in classical swine fever virus. The stable stem-loop structures, which were maintained by palindromic nucleotide substitutions in the stem region, may represent references for the classification and identification of pestivirus species and/or genotypes.

Animals↗

Ruminant pestivirus infection in pigs.

Ruminant pestivirus infections of pigs have a worldwide distribution. The prevalence is varied and depends mainly on (i) contact with cattle, (ii) age of pigs and (iii) degree of homology of virus strains used for serology, with field strains of bovine virus diarrhoea virus (BVDV) infecting pigs. Emphasis should be laid on sources of BVDV other than cattle, e.g. contaminated vaccines and fetal calf serum. The need for differentiation of pestiviruses (hog cholera, bovine virus diarrhoea and Border disease viruses) is highlighted by the fact that clinical disease syndromes, e.g. growth retardation and wasting, are reminiscent of hog cholera. Monoclonal antibodies are available which differentiate between hog cholera virus (HCV) and ruminant pestiviruses, presumably BVDV. An up-to-date account of the antigenic relationship between pestiviruses is included in the review. Analysis of the in vitro host range of these viruses is considered to be important and may explain infections of pigs with pestiviruses other than HCV. Recent results have shown the existence of "specialists" amongst BVDV strains for bovine cells, and a few isolates also performed well in cultures of the PK15 cell line. In contrast, multipotent BVDV strains presumably have additional attachment sites for ovine and porcine cells. Identification of receptors on ovine and porcine cells could contribute to a clear distinction between BVDV and HCV infections of pigs. Immediate control measures for BVDV infections of pigs are not required. However, such infections may interfere with serologic surveys and surveillance on a herd basis and, therefore, impair eradication programmes and efforts to maintain the status in countries declared free of hog cholera.

Animals↗

Serological and antigenical findings indicating pestivirus in man.

An epidemiological survey for pestivirus was undertaken in Zambia and Europe, in view of the recent serological findings obtained by previous studies in Europe with humans. Collected sera were tested for anti-bovine viral diarrhea virus (BVDV) specific antibodies by IIF and Western Blotting. Of those individuals tested (n = 1272), 15.3% showed a seropositive reaction to the BVDV. Anti-BVDV antibody prevalence in immuno-depressed patients (e.g. HIV positive) was investigated. A higher prevalence was revealed in HIV patients suffering from chronic diarrhoea and in those having developed AIDS Related Complex (ARC). Our of 212 persons tested for pestivirus isolation, a non cytopathic virus strain was detected in 2 buffy coat samples using IIF with a specific anti-BVDV serum. The isolation could be repeated three times during 31 days in one person. The virus was identified as a pestivirus with radioimmuno-precipitation assays and IIF-flow cytometry. A doublet of 120 kD was identified only in cell lysates, indicating a non-structural protein. In order to rule out cross reactivity 30 sera from Hepatitis C seropositive patients were tested against the isolate by IIF-flow cytometry. No antigen-specific binding could be observed. These findings indicated the occurrence of a pestivirus in man and might suggest a relationship with a pestivirus of animal origin.

Animals↗