Bovine herpesvirus 4 in bovine clinical mastitis

Abstract

CLINICAL mastitis has the largest economic impact on the dairy cattle industry. Despite intensive bacteriological research, 20 to 35 per cent of clinical cases of bovine mastitis have an unknown aetiology (Miltenburg and others 1996, Barkema and others 1998). Although viral infections have occasionally been associated with bovine mastitis (Siegler and others 1984, Yoshikawa and others 1997), it is generally considered that viruses do not play a role in the aetiology of bovine mastitis (Watts 1988, Radostits and others 1994 (BHV-1) per millilitre of milk, served as positive controls. A milk sample without viruses and a plain cell culture control, served as negative controls. After the second passage, a haemadsorption reaction, for the detection of, for example, Orthomyxoviridae and Paramyxoviridae, was performed on EBTr cells with 0-2 per cent guinea pig erythrocytes, and incubated at 370C for one hour. An EBTr cell culture inoculated with parainfluenza virus 3 was used as a positive control. Electron microscopy (EM) was performed after the second passages for all four cell types. A 400 mesh carbon-coated nickel grid with a collodion film was floated on a drop of the inoculated cell cultures for five minutes, drained onto filter paper and stained with 2 per cent phosphotungstic acid (pH 6-8). The grids were examined by transmission EM after drying.Serum samples collected from mastitis cows were examined for antibodies against BHV-1 by ELISA (Kramps and others 1994), against bovine herpesvirus 2 (BHV-2) by a 24-hour virus neutralisation test (Bushnell and Edwards 1988), against bovine herpesvirus 4 (BHV-4) by ELISA (Wellenberg and others 1999), against bovine respiratory syncytial virus (BRSV) by ELISA (Westenbrink and others 1985), against bovine viral diarrhoea virus (BVDV) by ELISA (Westenbrink and others 1986), against bovine leukaemia virus (BLV) by ELISA (Pourquier), and against adenovirus type 3 by ELISA (BIO-X). In case blocking percentages, ELISA coefficients or optical density values indicated a significant increase in antibody titre, the serum samples were titrated by serial two-fold dilution steps. The control cows were only examined for antibodies against BHV-4, because only a few cows with clinical mastitis seroconverted (where seroconversion is defined as a seronegative acute serum and a seropositive convalescent serum) against viruses other than BHV-4. Serum samples containing antibodies against BHV-4, were titrated by serial two-fold dilution steps. A four-fold (two dilution steps) higher antibody titre in convalescent serum compared with acute serum is defined as a significant increase.Bacteriological culture of the milk samples was performed according to standards of the National Mastitis Council (Harmon and others 1990). Milk samples (0-01 ml) were inoculated on 6 per cent blood agar plates (both aerobically and anaerobically), on TCT medium (Thallium sulphate, Crystal Violet, Staphylococcus f-toxin; Merck) and on MacConkey number 3 agar (Oxoid). The plates were incubated at 370C and bacteri...

The investigation of the presence of bovine herpesvirus type 4 (BoHV-4) in cows with metritis in a dairy herd

“…The pathogenesis of BoHV-4 infection was questioned due to the isolation of BoHV-4 from healthy individuals, and from cattle with a wide variety of clinical signs (12,19). The virus has been isolated from cattle with genital problems (metritis, mastitis) as well as healthy animals.…”

“…The virus has been identified in the respiratory tracts of infected animals in cases of vulvovaginitis, endometritis, mastitis, abortion and also from apparently healthy cattle (2,4,7,11,12,19). The role of BoHV-4 in infections occured the respiratory and genital tract has been studied by several researchers and the virus has been reported to be responsible for post-partum and chronic metritis problems alone or with other pathogens (12,18).…”

Prevalence of Bovine herpesvirus type 4 in aborting dairy cows

“…BHV-4 is related to many different conditions: infertility, postpartal metritis, abortion, vulvovaginitis, mastitis, encephalitis, calf pneumonia, keratoconjunctivitis, Correspondence to: -D. Cvetojević, e-mail: jaffvet@gmail.com; tel. : +381 11 285 10 65 cutaneous lesions, digital dermatitis (Castrucci et al 1986, Wellenberg et al 2000, Monge et al 2006, Costa et al 2011, Chastant-Maillard 2015. Beside that, the virus may also be isolated from clinically healthy animals (Frazier et al 2001).…”

Mammary Lesions Associated with Bovine Herpesvirus Type 4 in a Cow with Clinical Mastitis

“…Despite intensive bacteriological research, 20 to 35% of clinical cases of bovine mastitis have an unknown aetiology [2,8]. Although virus infection was suspected in such cases, the role of viruses in bovine mastitis has been generally ignored until Wellenberg et al [10] isolated bovine herpesvirus type 4 (BHV-4) in milk from cows with clinical mastitis in 2000. These samples did not, however, demonstrate an association between BHV-4 and mammary lesions in either natural cases [10] or experimental infections with BHV-4 isolate [9].…”