Monitoring of the shedding and serological dynamics of Bovine gammaherpesvirus type 4 in a dairy cattle herd

• Published in: Veterinary microbiology 2019-12, Vol.239, p.108495-108495, Article 108495
• Main Authors: Díaz, José Manuel, Prieto, Alberto, López-Lorenzo, Gonzalo, López-Novo, Cynthia, Iglesias, Antonio, Díaz, Pablo, Panadero, Rosario, Moral, Javier, López, Ceferino, Díez-Baños, Pablo, Morrondo, Patrocinio, Fernández, Gonzalo
• Format: Article
• Language: English
• Subjects: Animals; Antibodies; Antibodies, Viral - blood; BoHV-4; Cattle; Dairy cattle; Dairy farms; Epidemiology; Exudates; Exudation; Female; Heifers; Herpesviridae Infections - blood; Herpesviridae Infections - immunology; Herpesviridae Infections - veterinary; Herpesviridae Infections - virology; Herpesvirus 4, Bovine - physiology; Metritis; Parturition; PCR; Postpartum Period; Secretions; Seroconversion; Serology; Shedding; Tumor Virus Infections - blood; Tumor Virus Infections - immunology; Tumor Virus Infections - veterinary; Tumor Virus Infections - virology; Vagina; Vagina - virology; Virus Shedding; Viruses
• ISSN: 0378-1135; 1873-2542
• DOI: 10.1016/j.vetmic.2019.108495

•BoHV-4 was found in vaginal and nasal exudates and milk.•Cows with post-partum metritis shed BoHV-4 by several secretions.•8/10 heifers seroconverted after 6–10 months in the production lot.•ELISA-negative shedders were found.•Horizontal transmission may be present. Bovine gammaherpesvirus type 4 (BoHV-4) is increasingly related with reproductive disease in cattle, but its epidemiology is not fully understood. We monitored the serological response and shedding of BoHV-4 in a positive dairy cattle farm with metritis. First, we performed an ELISA to detect BoHV-4 antibodies in all the animals (n = 104). Afterwards, ten seronegative heifers introduced in the production lot and sera samples were monthly taken for four months and then 6–10 months after introduction to detect BoHV-4 antibodies by ELISA. Moreover, a vaginal swab was taken after calving to detect BoHV-4 by PCR. Concurrently, a weekly collection of vaginal and nasal swabs and milk was performed during the first month post-partum in multiparous cows with metritis (n = 14), heifers with metritis (n = 4), heifers without metritis but positive to BoHV-4 (ELISA or PCR) (n = 2) and multiparous cows without metritis (n = 3). Seropositivity was higher in older animals and in the production lot. Three heifers which shed BoHV-4 after parturition resulted seronegative at first but eventually seroconverted. In the same vein, most heifers seroconverted after 6–10 months in the production lot (8/10). Multiparous cows shed virus by various routes: 13/14 (93 %) in vaginal secretions, 7/14 (50 %) in nasal exudates and 7/14 (50 %) in milk. However, in the other groups, shedding was only detected in vaginal swabs from the first week post-partum. Our study describes BoHV-4 shedding in field conditions. Seronegative animals may become horizontally infected when moved to a contaminated environment.