Prevalence of bovid herpesvirus-4 and its antibody in cattle in Minnesota

Serologic analyses and virus isolation studies were carried out to determine the role of bovid herpesvirus-4 (BHV-4) in infections in cattle, principally those of the reproductive tract. Serologic analyses were performed, using an indirect fluorescent antibody test on thoracic fluid specimens from aborted fetuses and on sera from 3 sources of adult cattle. Virus isolation was attempted from field cases of abortion, early embryo death, and postpartum vulvovaginitis/metritis, using uterine discharge and buffy coat preparations obtained from cows and tissues obtained from aborted fetuses. Of 420 fetal thoracic fluid specimens examined, 5 were positive for BHV-4 antibodies. Seventeen percent of adult cattle from 2 sources ie, clinically normal herds and abattoir cattle, were seropositive for BHV-4 antibodies. Cattle from a third source, 4 herds with high incidence of reproductive tract disorders, had a seroprevalence rate between 36 and 88%. Two isolates of BHV-4 were also obtained from this group. The overall incidence of BHV-4 antibodies in clinically normal cattle was higher than previously recognized, with relatively higher prevalence in herds having reproductive problems (chi 2 = 156.5, P less than 0.005). At least 10% of the BHV-4 antibody-positive sera did not have neutralizing antibody against bovine viral diarrhea virus and/or bovid herpesvirus-1, both important causes of bovine reproductive tract disorders.     

Virological and serological evidence of bovine herpesvirus type 4 in cattle in Northern Ireland

Bovine herpesvirus type 4 (BHV-4), a member of the genus Rhadinovirus, subfamily Gammaherpesvirinae, within the family Herpesviridae, was isolated in fetal bovine lung cells from samples of vaginal discharge taken from a dairy herd in which approximately 50 per cent of the cattle developed metritis after calving. The identity of the isolate was confirmed by immunofluorescent staining with a BHV-4-specific monoclonal antibody and partial sequencing of a portion of the glycoprotein B gene. Serological testing failed to demonstrate a significant association between the exposure of the cattle to BHV-4 and the metritis, but several cattle seroconverted during the periparturient period, consistent with the recrudescence and shedding of virus associated with the stresses of parturition and the onset of lactation. Despite the previous failure to detect BHV-4 in Northern Ireland, a serological survey of 999 cattle in 49 dairy herds and 51 beef herds found widespread evidence of exposure: 29 of the dairy herds and 35 of the beef herds contained one or more seropositive cattle, and 33.3 per cent of the dairy cattle and 23.3 per cent of the beef cattle were positive.     

The biology of bovine herpesvirus-4 infection of cattle

The biology of bovine herpesvirus-4 (BHV-4) infection of cattle is reviewed. The infection is distributed worldwide. Most of isolated viruses are non-pathogenic in cattle; some of them are able to produce a genital disease. Twenty-nine structural polypeptides were described; ten of them are glycosylated. Two major glycoproteins were characterized by monoclonal antibodies. Restriction maps of BHV-4 DNA are available for the enzymes EcoRI, BamHi and HindIII. The strain variations studied by restriction analysis are very weak. The virus is able to persist in a latent state after primary infection. The identified sites of latency are nervous ganglia and mononuclear blood cells. The immune response of cattle after BHV-4 infection is characterized by low or undetectable levels of neutralizing antibodies. Four envelope proteins are recognized by convalescent sera and are the main antigenic components. Skin test remains negative in immunized cattle. Bovine herpesvirus-4 is not strictly species-specific: infection was proved in American bison (Bison bison), African buffalo (Syncerus caffer), sheep and probably cat, because feline herpesvirus-2 is in fact a BHV-4 strain. Finally BHV-4 shares antigenic and genomic relationships with alcelaphine herpesvirus-1, the causal agent of the African form of malignant catarrhal fever.     

Epidemiology and genetic characterization of BVDV,BHV-1, BHV-4, BHV-5 and Brucella spp. infections in cattle in Turkey

The aim of the study was to determine the epidemiological data of bovine viral diarrhea virus (BVDV), bovine herpesvirus-1 (BHV-1), bovine herpesvirus-4 (BHV-4), bovine herpesvirus-5 (BHV-5) and Brucella–associated cattle that were previously reported to have abortion and infertility problems in Ankara, Corum, Kirikkale and Yozgat provinces, Turkey. Whole blood and sera samples were obtained from 656 cattle, and antibodies against Brucella spp. were detected in 45 (6.86%) and 41 (6.25%) animals by Rose Bengal plate and serum tube agglutination tests, respectively. The seropositivity rates against BVDV, BHV-1 and BHV-4 were 70.89%, 41.3% and 28.78%, respectively. RT-PCR and PCR were performed to detect RNA and DNA viruses in blood samples, respectively. The BVDV 5′-untranslated region and BHV-1 gB gene detected in this study were phylogenetically analyzed. The BVDV strains analyzed in this study were closely related to those previously reported from Turkey. The nucleotide sequence from the BHV-1 strain detected in this study is the first nucleotide sequence of BHV-1 circulating in this area of Turkey deposited in the GenBank. The presence of Brucella spp. and prevalence of BHV-1, BHV-4 and BVDV in cattle should be further investigated throughout these regions.     

Studies on bovine herpesviruses. Part 1. Isolation and characterization of viruses isolated from the genital tract of cattle

Herpesviruses, previously isolated from cattle (Theodoridis, 1978), were further studied and provisionally placed in the bovid herpesvirus 4 (BHV-4) group. Major differences were found between IBR-IPV (BHV-1) and BHV-4 virus strains. In MDBK cells, all BHV-4 strains started growing at the edges of the culture, the process progressing slowly until destruction of the cells was complete by the 10th day. BHV-4 strains failed to induce neutralizing antibodies in cattle, goats and rabbits. Only the addition of mineral oil adjuvant induced neutralizing and complement fixing antibodies in goats. BHV-1 strains, in contrast, produced very potent antisera in all these systems. Cross-neutralization tests indicated the existence of 2 distinct serological groups representing BHV-1 and BHV-4. The BHV-4 strains appear to be interrelated and they could not be grouped. A BHV-1 strain showed fixation of complement with the antisera of 6 BHV-4 strains. Electron micrographs showed an accumulation of nucleocapsids in the cytoplasm and an early release of virus particles due to cell destruction. Variation in incubation temperature had a significant effect on the particle formation. At lower temperatures, the number of enveloped particles in the cytoplasm increased. On the basis of the characteristics uncovered in this study, it is possible that all the BHV-4 strains represent one and the same virus which has undergone certain biological changes, thus illustrating a phenomenon which appears to be a characteristic of the herpesviruses.     

Evaluation of an antigen-capture ELISA for the detection of bovine herpesvirus type 1 shedding from feedlot cattle

A total of 457 nasal swab specimens from cases of respiratory disease in 2 feed lots were evaluated for the detection of bovine herpesvirus Type 1 (BHV-1) by ELISA. Thirty-three were found to be positive for BHV-1 by the recovery of infectious virus and 21 of these were positive by ELISA, yielding a sensitivity of 64%. Fifteen other virus isolations were made and included bovine viral diarrhea viruses, rhinoviruses and parainfluenza Type 3 viruses; none of these cases were positive with the BHV-1 ELISA. Specificity of the ELISA was 100%. Eighty percent of the specimens with BHV-1 titers greater than 10(5) TCID50 were detected by ELISA; the median amount of virus in positive specimens that were detected by ELISA was 7 X 10(5) TCID50 and the median amount of virus in specimens not detected was 1.5 X 10(4) TCID50. BHV-1 infection was most frequently diagnosed in feedlot cattle that had been in the feedlot for 40-80 days. Approximately half of the infected cattle were carrying virus-neutralizing antibodies in their serum.     

Use of a polymerase chain reaction assay to detect bovine herpesvirus type 2 DNA in skin lesions from cattle suspected to have pseudo-lumpy skin disease

Beef cattle from a herd in north Alabama were examined because of an outbreak of nonfatal skin disease characterized by discrete circumscribed areas of inflammation that developed on the skin from the neck to the hips. Areas of inflammation, which tended to be superficial, underwent necrosis and scabbed over. The scabs eventually dropped off leaving discrete, round, whitish, hairless lesions that were 1.2 to 2.5 cm diameter. Because clinical signs were consistent with those expected with pseudo-lumpy skin disease (PLSD) caused by bovine herpesvirus type 2 (BHV-2), samples from 16 representative animals were submitted for BHV-2 testing. All 16 animals were seropositive for BHV-2, but the virus could not be isolated from skin biopsy specimens or buffy coat samples. Results of a polymerase chain reaction assay incorporating primers designed to amplify 2 DNA sequences from BHV-2 were positive for 3 of the 10 cattle, suggesting that skin lesions in these cattle were a result of PLSD. Our findings suggest that PLSD may be more common and widespread in the United States than suggested by the frequency with which BHV-2 has been isolated from cattle with PLSD-like skin lesions.     

Genetic characterisation of bovine herpesvirus 1 in New Zealand

AIM: To genotype bovine herpesvirus type 1 (BHV-1) isolates from cattle in New Zealand. METHODS: Twenty-eight BHV-1 isolates were collected from clinical samples from cattle over 28 years. They were characterised and compared using restriction endonuclease analysis (REA), and polymerase chain reaction (PCR) and DNA sequencing. RESULTS: Twenty-four isolates were classified as bovine herpesvirus subtype 1.2b (BHV-1.2b) by REA. The remaining four isolates were distinct from the others in REA profiles of one of the major enzymes (HindIII) by which the classification was made. However, these four isolates were closely related to others when the REA profiles of other restriction enzymes were studied, and therefore were regarded as divergent strains of BHV- 1.2b. All BHV-1 isolates were detectable by PCR, and sequence analysis of selected PCR products did not indicate any significant differences between isolates. CONCLUSION: BHV-1.2b appears to be the predominant strain of BHV-1 in cattle in New Zealand. There was no evidence that more virulent strains of BHV-1, e.g. subtype 1.1 and BHV type 5, are, or have been, present in New Zealand. Genetic variations exist among these BHV-1.2b isolates.     

An acute outbreak of teat lesions affecting 38% of a dairy herd in Northland

Extract

Teat lesions are common in dairy cattle in New Zealand. Most of the infectious cases are caused by pseudocowpox virus, but lesions similar to those caused by bovine herpesvirus (BHV)-2 have been described clinically and confirmed serologically in New Zealand (Horner and Raynel 1988). BHV-2 and BHV-4 cause an acute viral disease in cattle known as bovine herpes mammillitis or ulcerative mammillitis (Hillerton et al 2001). Presumptive cases have been reported in New Zealand based on the nature and distribution of lesions (Daniel 1970). The disease is probably endemic in New Zealand but is poorly documented and generally considered to be mild and sporadic. The main differential diagnosis is pseudocowpox, which is often also present in herds affected with bovine herpes mammillitis, and dual infections of individual cattle have been reported (Gibbs et al 1972). To my knowledge, neither BHV-2 nor BHV-4 have yet been isolated in New Zealand.     

Prevalence of bovine respiratory syncytial virus (BRSV) and bovine herpesvirus-4 (BHV-4) in cattle from Ethiopia

A serological study was done to establish the occurrence and determine the prevalence of two important respiratory tract pathogens, bovine respiratory syncytial virus (BRSV) and bovine herpesvirus-4 (BHV-4), in cattle in Ethiopia. Prevalence rates for specific antibodies of 92.5% and 22.3% were recorded for BRSV and BHV-4, respectively. The presence of antibodies against these viruses in cattle from Ethiopia is recorded for the first time in this report. Our data suggests diseases caused by these viruses occur in Ethiopia but, perhaps because disease signs are not specific, they have not been recognized in the past.     

Comparison of an enzyme-linked immunosorbent assay and a complement-fixation test for the detection of IgG to bovine herpesvirus type 4 (bovine cytomegalovirus)

An indirect ELISA for the detection of bovine immunoglobulin to bovine herpesvirus type 4 (BHV-4) was developed. Three methods of antigen preparation were compared. They included (1) BHV-4-infected Madin Darby bovine kidney (MDBK) cells treated with glycine and then frozen and thawed, (2) BHV-4-infected MDBK cells treated with glycine and then sonicated, and (3) BHV-4-infected MDBK cells treated with a detergent. The antigen preparation that gave the highest reactivity was the first method. We obtained serum samples from 178 cattle in the field and assayed the serum by ELISA and the complement-fixation (CF) test. Eighty-six percent (153) of the serum samples were positive by ELISA, and 70% (124) were positive by the CF test. The ELISA had a higher degree of sensitivity than did the CF test. Also, the ELISA was specific, and the prevalence of BHV-4-infection was more common in beef and dairy herds than previously recognized.     

Research on antibodies against BHV-1, BHV-2, BHV-4, BVD-MD virus, bovine adenovirus A and B, rotavirus and coronavirus in cattle in western Zaire: complementary results

Two-hundred bovine sera from western Zaire were screened for antibodies to 8 viruses: BHV-1, BHV-2, BHV-4, BVD-MD virus, bovine adenovirus A and B, bovine rotavirus and bovine coronavirus. Positive sera were found to all these viruses. For animals whose origin was undoubted, the main features were the high prevalence of infections by rotavirus and BHV-4 and the low prevalence of infections by coronavirus and BVD-MD virus.     

Variation in the pathogenic potential and molecular characteristics of bovid herpesvirus-4 isolates.

Seven bovid herpesvirus-4 (BHV-4) isolates recovered from various clinical conditions of cattle were studied for their pathogenic potential in pregnant rabbits. These viruses were originally recovered from respiratory and reproductive tract infections of cattle. A virus dose of 4 x 10(6.8)TCID50 per fetus was inoculated via the intrauterine route in 10- and 17-day pregnant rabbits. Clinical, virologic, and pathologic data were collected to compare the effect of each isolate on does and fetuses/kits. Three isolates (LVR-140, QVR-3140 and 86-068) caused abortion, fetal reabsorption and/or mummification in inoculated rabbits. Virus was recovered from tissues of inoculated rabbits (especially the spleen, ovaries and uterus) by organ explanation and/or co-cultivation. Intravenous inoculation of isolate 86-068 did not produce any clinical signs in either 10- or 17-day pregnant rabbits. All seven isolates of BHV-4 showed a predilection for the reproductive tract of pregnant rabbits but varied in the severity of disease signs produced. Variation was also observed in the genome of various isolates on the basis of restriction endonuclease (RE) analysis. Relationship of RE patterns to the variation in the pathogenic potential of seven BHV-4 isolates is discussed.     

A serological survey of bovine herpesvirus-1 infection in selected dairy herds in northern and central Italy

Serum samples from a total of 6979 dairy cattle from 55 herds in northern Italy (51 herds) and central Italy (4 herds), were examined by the serum neutralization test for the presence of antibody to bovine herpesvirus-1 (BHV-1). It was found that 84.31% of the farms selected in northern Italy and all the farms from central Italy had seropositive animals at titers of 1:4 or higher. The prevalence of infection was essentially the same among the cattle populations of the two selected areas of the country, being of 34.99% in the north and of 38.65% in central regions. A comparison of the data from the present study with those obtained in a serological survey conducted in Italy in 1966, shows that the rate of seropositive cattle to BHV-1 has increased by about 5.0% in the last 30 years.     

A study of some biologic properties of Bovid herpesvirus-4.

This article summarizes the results of a study on several strains of Bovid herpesvirus-4 (BHV-4), isolated from cattle. The study had several objectives, namely, to verify (a) the disease-causing potential of the virus, (b) the possibility by BHV-4 to induce a latent infection in the natural host and (c) the entity of the relationships among strains of the virus isolated from different disease syndromes. The following data were obtained: (1) All strains tested were able to replicate in experimentally infected calves; however, only one strain (85/BH 16TV) caused an overt systemic disease. (2) The nervous system as well as the lymphoid structures appeared to be the target organs for replication of the virus. (3) BHV-4, like other herpesviruses, was able to establish latent infection in cattle. (4) When two strains of the virus, isolated from cattle affected by different disease syndromes, i.e. respiratory disease (strain DN-599) or vulvovaginitis (strain 85/BH 16TV), respectively, they resulted to be closely related to each other. In particular, they revealed a similar DNA pattern and both strains were able to cause respiratory disease in calves. Moreover, the two viral strains were mutually protective in that calves were generally found to be refractory to challenge inoculation with either the homologous or the heterologous virus. (5) All BHV-4 strains tested generally failed to evoke a significant production of neutralizing antibody in the experimental calves.     

Biology of bovine herpesviruses

Cattle are the natural host of herpesviruses. Since now four different bovine viruses have been described as members of the family Herpesviridae. The prototype of the bovine herpesviruses, Bovine Herpesvirus type 1 (BHV-1), is the causative agent of infectious bovine rhinotracheitis (IBR), infectious pustular vulvovaginitis (IPV) and infectious balanoposthitis (IBP). The related BHV-5 is an exotic neurovirulent agent and like BHV-1 a member of the genus Varicellovirus, within the subfamily Alphaherpesvirinae. BHV-2, also an alphaherpesvirus but grouped into the genus Simplexvirus is the causative agent of bovine herpes mammilitis and pseudolumpy skin disease. In contrast, BHV-4, a member of the subfamily Gammaherpesvirinae, is not known to cause any disease. Beside bovine herpesviruses there are few other herpesviruses which can infect cattle. Infections of cattle with these herpesviruses have either clinical or diagnostic importance, based on a close antigenic relationship to BHV-1 of some ruminant herpesviruses. This article deals with the molecular virology of bovine herpesviruses and the pathogenesis of bovine herpesvirus infections and provides an overview over herpesviruses that can infect cattle.     

Studies concerning etiology of sheep-associated malignant catarrhal fever in Europe.

The etiological agent of sheep-associated malignant catarrhal fever (MCF) in Europe has not been isolated directly from sheep. The occurrence of antibodies against the African bovine herpesvirus (BHV-3, WC 11) in cattle and sheep was examined using recently modified indirect immunofluorescence test (IIFT) and neutralization test (NT) methods. Studies revealed that sheep and cattle sera in Europe were free from neutralizing antibodies of BHV-3. The IIFT could not establish the presence of antibodies to African BHV-3 in cattle but revealed that about 22.4% of sheep sera reacted to it. Apart from the well known ovine herpesvirus (BHV-5), occurrence of another herpesvirus in Europe had been expected. This virus is not identical with the WC 11 strain, but it is in antigenic relationship to it. We had for the first time substantial serological evidence to the effect that sheep-associated MCF in Europe is a herpesvirus related to the African strain.     

Bovine herpes virus expressing envelope protein (E2) of bovine viral diarrhea virus as a vaccine candidate.

The gene encoding the envelope protein (E2) of bovine viral diarrhea virus (BVDV) was expressed under the thymidine kinase (TK) promoter of Korean bovine herpesvirus 1 (BHV-1) isolate. Thymidine kinase negative (TK-) BHV-1 recombinants expressing E2 of BVDV were constructed and the expression of E2 was identified by immunofluorescence and Western blotting. Compared to wild type BHV-1, the recombinant BHV-1 had a delayed cytopathogenic effect in cells. The immunogenicity of the recombinant BHV-1 was examined in guinea pigs and cattle. Although an increase in body temperature was detected for a few days, the inoculated cattle returned to normal temperature with the development of neutralizing antibodies to BVDV.     

An association exists between bovine herpesvirus-4 seropositivity and abortion in cows

The prevalence of cattle seropositive to bovine herpesvirus-4 (BHV-4) is high in Belgium. In Belgian farms, clinical signs associated with BHV-4 infection essentially involve the genital tract and consist mainly of postpartum metritis or metroperitonitis. The role of BHV-4 in abortion has not been definitively demonstrated but epidemiological and experimental facts suggest its involvement. A seroepidemiological investigation was therefore conducted as a case-control study to compare the seroprevalences of BHV-4 infections in the aborted-cow population and in a randomly selected control group in the province of Liège (Belgium). The seroprevalence (17.2%) in aborted cows was significantly higher than that of the control group (10.0%). The odds ratio (OR) was 1.87 (1.06 < 3.30). BHV-4 infection is therefore considered as a risk factor for abortion in cows.