This research verified the variation of the occurrence of herpesvirus bovine type 1 (BoHV-1) by its association with two viral infections: bovineviral diarrhea (BVD) and enzootic bovine leukosis (EBL). The following methodologies were used: virus neutralization test (VNT) for both BoHV-1 and BVD diagnosis, and agar gel immunodiffusion (IDGA) for EBL. Five cattle herds were selected in the states of São Paulo and Minas Gerais, three of them were dairy cattle herds, one beef cattle and one crossbred cattle. Every herd had a number of animals seropositive for BoHV-1. From 278 analyzed samples, 54,68% (152/278) were responsive to BoHV-1, 69,70% (194/278) to BVDV-1, and 34,33% (97/278) to EBLV. The statistical analysis showed significant difference (á=0,01) in infection occurrence according to the type of herd and animal age. Dairy cattle were more sensitive to BoHV-1 (81,31%) and to EBLV (49,53%), while in beef cattle the most frequent was BVDV-1 (94,74%). Age was a risk factor only for BoHV-1 and EBLV, the results showed that the older animals were more susceptible. The associative analysis also indicated that among BVDV-1 and/or EBLV infected herds the probability of finding BoHV-1 is higher than among herds where these two infections do not occur. KEY-WORDS: BoHV-1. BVD. EBL. Immunosuppression. Seroprevalence. Viral co-infection in bovine herds.
Abstract: BovineViral Diarrhea virus (BVDV) can infect pigs and lead to production losses. Data on the epidemiology of this virus in pigs are scarce. In order to obtain occurrence data of this disease, 600 blood serum samples of pigs from five farms in the northeast of the state of São Paulo were collected. Samples were divided into four categories: Weaning (W), Nursery (N), Finishing (F) and Sows (S), and were submitted to Virus neutralization (VN) test for BVDV-1 and BVDV-2. One (1/30) positive sample to BVDV-1 was detected in Property 2, showing 3.33% prevalence in (F) and a herd level prevalence of 0.84%. Regarding BVDV-2, in Property 2, 3.33% (1/30) of samples were seroreagent, obtained in (F) and 6.66% (2/30) in (S), with the herd prevalence of 2.44 %. Properties 3 and 4 presented, 3.33% (1/30) of seroreagent samples in the (S), with 0.84% at herd level, respectively. In Property 5, we found 6.66% (2/30) of seroreagent samples, both in (S), with a final prevalence of 1.66%. No risk factor was significantly associated. Despite the low prevalence, evidence of infection was found in different categories within the farms, showing that inefficiency in biosecurity can lead to infection in swine.
Bovineviral diarrhea virus (BVDV) is a widespread pestivirus infection affecting mainly cattle but also other ruminants (Carlsson 1991). The disease causes consid- erable economic losses in the dairy industry, mainly attributable to reduced milk production, reduced repro- ductive performance, delayed growth, increased suscep- tibility to other diseases, early culling and increased mortality among young stock (Houe 2003). Infections in susceptible adult cattle are often subclinical, although this depends on the causative virus strain. Normally, only transient mild fever and leukopenia can be observed in closely examined animals. Two to three weeks after infection, neutralizing antibodies are produced (Howard 1990). However, when the infection occurs in a susceptible pregnant cow, the fetus may be infected, and the conse- quences of this depend on the precise moment infection takes place. Thus, it could lead to embryonic death, abortion, congenital defects or stillbirth, or to the birth of persistently infected (PI) calves. The latter occurs when the fetus is infected in the first trimester of pregnancy (mostly from 30 to 90 days of gestation) due to the development of specific immunotolerance against BVDV (Moennig & Liess 1995). PI animals shed large amounts of virus during their lifetime, to the extent that they are the main infection source of BVDV (Meyling et al. 1990). Normally, in the presence of a PI animal, seroconversion will occur in all animals with which it comes into contact.
Nineteen isolates of bovineviral diarrhea virus (BVDV) from Brazil were genetically characterized through partial nucleotide sequencing and analysis of the 5’UTR region. The isolates were grouped as BVDV-1 (11/19), BVDV-2 (6/19) or “atypical” pestivirus (2/19). Among the BVDV-1, eight isolates were classified as subgenotype BVDV-1a, whereas most (4 out of 6) BVDV-2 belonged to subgenotype 2b. Two isolates from aborted fetuses were not classified into any genetic group, being considered atypical BVDVs. Genetic diversity among Brazilian BVDV isolates may be responsible for vaccination and diag- nostic failure and therefore may influence the control strategies for BVDV infection in the country.
Acute infections of bovineviral diarrhea virus (BVDV) lead to a range of clinical presentations. Laboratory tests for detection depend on collection of samples during a short viremia. Acutely infected animals remain largely undia- gnosed. Transfer RNA halves (tsRNAs) are hypothesized to function like microRNAs to regulate gene expression during an immune response. The objective of this study was to identify tsRNAs in cattle that had been challenged with a non-cytopathic field strain of BVDV. Colostrum-deprived neonatal Holstein calves were either challenged with BVDV (n=5) or mock challenged (n=4). Sera was collected prior to challenge and days 4, 9, and 16 post challenge. RNA was extracted and read counts of small non-coding RNAs were assessed using next-generation sequencing. A total of 87,838,207 reads identified 41 different tsRNAs. Two 5’ tsRNAs, tsRNA ProAGG
Karl Ståhl 2 *, Alfredo Benito 3 , Ricardo Felmer 4 , Javier Zuñiga 4 , German Reinhardt 5 , Hermelinda Rivera 3 , Claudia Baule 2 and Jorge Moreno-López 6 ABSTRACT.- Ståhl K., Benito A., Felmer R., Zuñiga J., Reinhardt G., Rivera H., Baule C. & Moreno-López J. 2009. Genetic diversity of bovineviral diarrhoea virus (BVDV) from Peru and Chile. Pesquisa Veterinária Brasileira 29(1):41-44. Joint Virology Research and Development Division, National Veterinary Institute and Swedish University of Agricultural Sciences Uppsala, Sweden. E-mail: Karl.Stahl@bvf.slu.se
Calves born persistently infected with non-cytopathic bovineviral diarrhea virus (ncpBVDV) frequently develop a fatal gastroenteric illness called mucosal disease. Both the original virus (ncpBVDV) and an antigenically identical but cytopathic virus (cpBVDV) can be isolated from animals affected by mucosal disease. Cytopathic BVDVs originate from their ncp counterparts by diverse genetic mechanisms, all leading to the expression of the non-structural polypeptide NS3 as a discrete protein. In contrast, ncpBVDVs express only the large precursor polypeptide, NS2-3, which contains the NS3 sequence within its carboxy-terminal half. We report here the investigation of the mechanism leading to NS3 expression in 41 cpBVDV isolates. An RT-PCR strategy was employed to detect RNA insertions within the NS2-3 gene and/or duplication of the NS3 gene, two common mechan- isms of NS3 expression. RT-PCR amplification revealed insertions in the NS2-3 gene of three cp isolates, with the inserts being similar in size to that present in the cpBVDV NADL strain. Sequencing of one such insert revealed a 296-nucleotide sequence with a central core of 270 nucleotides coding for an amino acid sequence highly homolo- gous (98%) to the NADL insert, a sequence corresponding to part of the cellular J-Domain gene. One cpBVDV isolate contained a duplica- tion of the NS3 gene downstream from the original locus. In contrast, no detectable NS2-3 insertions or NS3 gene duplications were ob- served in the genome of 37 cp isolates. These results demonstrate that processing of NS2-3 without bulk mRNA insertions or NS3 gene duplications seems to be a frequent mechanism leading to NS3 expression and BVDV cytopathology.
Fulton, R.W., R.E. Briggs, M.E. Payton, A.W. Confer and J.T. Saliki et al., 2004. Maternally derived humoral immunity to BovineViral Diarrhea Virus (BVDV) 1a, BVDV1b, BVDV2, bovine herpesvirus-1, parainfluenza-3 virus bovine respiratory syncytial virus, Mannheimia haemolytica and Pasteurella multocida in beef calves, antibody decline by half-life studies and effect on response to vaccination. Vaccine, 22: 643-649. DOI: 10.1016/j.vaccine.2003.08.033 Galli, I., A. Monje, S. Vittone, D. Sampedro and C. Busto,
The genus Pestivirus, belonging to the family Flaviviridae, has viral species of great importance for animal production, such as the bovineviral diarrhea virus (BVDV) 1 and 2, classical swine fever virus (CSFV) and the border disease virus (BDV). As classified by the ICVT (International Committee on Taxonomy of Viruses), these species are today named as Pestivirus A, B, C and D, respectively. The bovineviral diarrhea virus (BVDV) can be classified into two different biotypes according to the effect of viral replication on cultured cells: cytopathic (CP) and non- cytopathic (NCP) (LINDENBACH & RICE, 2001). NCPs are capable of producing persistent infection in infected bovine fetuses between 40 and 120 days of pregnancy, and are most commonly found in the field, while CPs are considered a mutation of the NCP biotype and are
Three Brazilian isolates of bovineviral diarrhea virus (BVDV), anti- genically distinct from the standard North American isolates, were selected to immunize BALB/c mice in order to obtain hybridoma cells secreting anti-BVDV monoclonal antibodies (mAbs). Two hybri- doma clones secreting mAbs, reacting specifically with BVDV-in- fected cells (mAbs 3.1C4 and 6.F11), were selected after five fusions and screening of 1001 hypoxanthine-aminopterin-thymidine-resistant clones. These mAbs reacted in an indirect fluorescent antibody (IFA) assay with all 39 South and North American BVDV field isolates and reference strains available in our laboratory, yet failed to recognize other pestiviruses, namely the hog cholera virus. The mAbs reacted at dilutions up to 1:25,600 (ascitic fluid) and 1:100 (hybridoma culture supernatant) in IFA and immunoperoxidase (IPX) staining of BVDV- infected cells but only mAb 3.1C4 neutralized virus infectivity. Fur- thermore, both mAbs failed to recognize BVDV proteins by IPX in formalin-fixed paraffin-embedded tissues and following SDS-PAGE and immunoblot analysis of virus-infected cells, suggesting they are probably directed to conformational-type epitopes. The protein speci- ficity of these mAbs was then determined by IFA staining of CV-1 cells transiently expressing each of the BVDV proteins: mAb 3.1C4 reacted with the structural protein E2/gp53 and mAb 6.F11 reacted with the structural protein E1/gp25. Both mAbs were shown to be of the IgG2a isotype. To our knowledge, these are the first mAbs produced against South American BVDV isolates and will certainly be useful for research and diagnostic purposes.
This study was designed to evaluate the extent of the protection for bovineviral diarrhea virus type 2 (BVDV-2) infection, afforded by vaccination with a combo inactivated vaccine, which contains bovineviral diarrhea virus type 1 (BVDV-1) and infectious bovine rhinotracheitis virus (IBRV). Five 3–4- month-old calves were intramuscularly vaccinated with a single dose of the combo vaccine and boosted with same dose three weeks after the first vaccination, with five mock immunized calves serving as a control group. Twenty-one days after the second vaccination, all calves were challenged with BVDV-2 SX08 strain by spray into nostril. The unvaccinated animals developed typical clinical signs of high rectal temperature, diarrhoea with erosions and a dramatic drop in leukocyte counts. These signs occured markedly less in all vaccinated animals, the rectal temperature, leukopenia and virarmia of which, were significantly less than the mock immunized calves. It can be concluded that vaccination with the combo inactivated vaccine affords cross-protection against clinical effects of a challenge-infection with BVDV-2 SX08 strain, although it was part protection.
The natural infection by bovineviral diarrhoea virus (BVDV) was monitored in three cattle herds through blood serum samples, obtained in several harvests undertaken in each herd, and submitted to virusneutralization test (VN) against BVDV-1 and BVDV-2. The samples not reagent to at least one of the genotypes and also in those collected from calves of less than six month of age, the BVDV research was undertaken by reverse transcription polymerase chain reaction (RT-PCR). In two herds, the BVDV was not detected in any sample and the number of reagent animals to VN test, especially in young animals, decreased as the harvests were conducted. However, in third herd, the infection remained during the monitored period, because the BVDV was detected in two persistently infected animals (PI) and also in one transiently infected animal (TI). The cattle breeding systems, as well as the intense movement of animals, were favorable to the permanence of infection in this last herd. The dynamics of BVDV infection was variable in the analyzed herds, highlighting the probable self clearance of BVDV in the herd 1 and the risk factors related to transmission of BVDV, as the frequent purchase of animals from different origins for the herd 4, as well as the probable hypothesis of infection of herd 17 have originated from the neighboring herd.
Samples of 114 bovine fetuses and 10 calves, which dead in perinatal period, were examined for detection of DNA. The most common detected agent was Brucella spp. in 17 samples (13.7%) followed by Leptospira spp. in 4 cases (3.2%),bovine herpesvirus (BHV) and bovineviral diarrhea (BVDV) in 3 animals (2.4%) each, and 1 for the association of BVDV and BHV. In 77.4 % (96/124) of the samples it was not possible to detect any agent.
Nineteen Brazilian isolates of bovineviral diarrhea virus (BVDV) were characterized antigenically with a panel of 19 monoclonal anti- bodies (mAbs) (Corapi WV, Donis RO and Dubovi EJ (1990) Ameri- can Journal of Veterinary Research, 55: 1388-1394). Eight isolates were further characterized by cross-neutralization using sheep mono- specific antisera. Analysis of mAb binding to viral antigens by indirect immunofluorescence revealed distinct patterns of reactivity among the native viruses. Local isolates differed from the prototype Singer strain in recognition by up to 14 mAbs. Only two mAbs - one to the non-structural protein NS23/p125 and another to the envelope glyco- protein E0/gp48 - recognized 100% of the isolates. No isolate was recognized by more than 14 mAbs and twelve viruses reacted with 10 or less mAbs. mAbs to the major envelope glycoprotein E2/gp53 revealed a particularly high degree of antigenic variability in this glycoprotein. Nine isolates (47.3%) reacted with three or less of 10 E2/ gp53 mAbs, and one isolate was not recognized by any of these mAbs. Virus-specific antisera to eight isolates plus three standard BVDV strains raised in lambs had virus-neutralizing titers ranging from 400 to 3200 against the homologous virus. Nonetheless, many antisera showed significantly reduced neutralizing activity when tested against heterologous viruses. Up to 128-fold differences in cross-neutraliza- tion titers were observed for some pairs of viruses. When the coeffi- cient of antigenic similarity (R) was calculated, 49 of 66 comparisons (74.24%) between viruses resulted in R values that antigenically distinguish strains. Moreover, one isolate had R values suggesting that it belongs to a distinct serologic group. The marked antigenic diversity observed among Brazilian BVDV isolates should be considered when planning diagnostic and immunization strategies.
Natural infection by bovineviral diarrhea virus (BVDV) was monitored in blood serum samples of three cattle herds. The samples were drawn in several harvests from each herd and submitted to virus neutralization test (VN) against BVDV-1 and BVDV-2. The non reactive samples to at least one of the genotypes and also those collected from calves younger than six months, were analyzed by reverse transcription polymerase chain reaction (RT-PCR). In two herds, BVDV was not detected in any blood sample and the number of reactive samples to VN test, especially young animals, decreased as the blood sample harvests were conducted. However, in the third herd, the infection remained during the monitored period, because BVDV was detected in two persistently infected animals (PI) and also in one transiently infected animal (TI). The cattle breeding system and intense movement of animals were favorable to the permanence of infection in this last herd. The dynamics of BVDV infection changed in the analyzed herds, highlighting the probable self clearance of BVDV in herd 1 and the risk factors related to transmission of BVDV, such as the frequent purchase of animals from different origins for herd 4, as well as the probable hypothesis that infection of herd 17 may have originated from the neighboring herd.
infection, transmission route and sensitive animals) must be well understood in order to control and eradicate pestiviruses. The objective of this work was to evaluate the role of swine (domestic and feral) as reservoir of pestiviruses in general and bovineviral diarrhea virus in particular, persistent infection being described in pigs (Terpstra & Wensvoor 1997). Thus 527 pigs and wild boars were tested for pestivirus using one step RT-PCR reaction with 324 and 326 panpestivirus primers (Fig.2). The eleven positive RNAs were sequentially tested for detection of CSFV, BVDV-1 and BVDV-2 using specific primers. As a result, for all samples were obtained specific amplification signals (211bp PCR product) to BVDV-1 (Fig.3). No positive PCR product was detected after amplification with specific primers for CSFV and BVDV-2.
Swine can be infected by bovineviral diarrhea virus (BVDV). However, transmission routes among pigs are still unknown. The objective of the present study was to induce experimental infection of BVDV-1 in weaned piglets and to assess the potential transmission through pen back pond water, used to facilitate heat exchange of the pigs housed in barns. Two repetitions (BP1 and BP 2) were performed using 12 piglets proven to be free BVDV (n=6 per repetition) allocated into three groups: control, sentinels and infected with two piglets each. The piglets were placed in stainless steel isolators. The infected group received an inoculum containing BVDV-1, Singer strain. The piglets remained in the cabinets for 25 days, during which samples of nasal swab were collected daily and blood sampled weekly. At the end, the piglets were euthanized, necropsied and organ fragments were collected for histopathology, immunohistochemistry and RT‑PCR. In the first experiment (BP1) the infected animals shed the virus between days 6 and 21 post-infection. Regarding the sentinel group, shedding occurred in only one piglet, on the 20th day after infection, and seroconversion was observed on the 25th day post-infection. In BP2, infected piglets I3 and I4 shed the virus on days 4 and 21 post-infection, respectively. Only one sentinel piglet (S3) she the virus on day 13 post-infection. Therefore, it was concluded that pigs can become infected with BVDV-1 and shed potentially infectious viral particles consequently, being able to transmit the virus to other pigs through back pond water.
The open reading frame of a Brazilian bovineviral diarrhea virus (BVDV) strain, IBSP4ncp, was recombined with the untranslated regions of the reference NADL strain by homologous recombination in Saccharomyces cerevisiae, resulting in chimeric full-length cDNA clones of BVDV (chi-NADL/IBSP4ncp#2 and chi-NADL/IBSP4ncp#3). The recombinant clones were suc- cessfully recovered, resulting in viable viruses, having the kinetics of replication, focus size, and morphology similar to those of the parental virus, IBSP4ncp. In addition, the chimeric viruses remained stable for at least 10 passages in cell culture, maintaining their replication efﬁciency unaltered. Nucleotide sequencing revealed a few point mutations; nevertheless, the phenotype of the rescued viruses was nearly identical to that of the parental virus in all experiments. Thus, genetic stability of the chimeric clones and their phenotypic similar- ity to the parental virus conﬁrm the ability of the yeast-based homologous recombination to maintain characteristics of the parental virus from which the recombinant viruses were derived. The data also support possible use of the yeast system for the manipulation of the
Bovineviral diarrhea virus (BVDV) is an insidious, complex and ubiquitous pathogen that can affect cattle of all breeds and all ages, as well as others domestic and wild ruminants. 1 The disease caused by BVDV ranges in severity from asymp- tomatic to acute infection and fatal mucosal disease, with a mortality index of approximately 5%, which leads to an eco- nomic impact of BVDV infections of up to £993 per cow per year. 2
During a series of experiments attempting to reproduce clinically apparent bovine herpesvirus type 5 (BoHV-5) infections, a group of calves was inadvertently infected with bovineviral diarrhoea virus (BVDV). Another group of calves was infected with BoHV-5 only. This paper reports the outcome of such infections. Two out of six calves solely infected with BoHV-5 displayed moderate to severe clinical signs. Three out of four calves of the group co-infected with BoHV-5 and BVDV developed severe clinical signs, two of them died. BoHV-5 virus was isolated to higher titres and for a longer period from the group of calves infected with both viruses. These results suggest that BVDV may enhance clinical signs induced by BoHV-5 and may also play a role in extending the period of BoHV-5 shedding.