Infectious bovine rhinotracheitis (IBR) in Mediterranean water buffalo (Bubalus bubalis): prevalence of bubaline herpesvirus 1

Introduction Bovine herpesvirus 1 (BoHV1) andbubaline herpesvirus 1 (BuHV1) are ruminant alphaherpesviruses.BoHV-1 can provoke infectious bovine rhinotracheitis (IBR), genital disorders, conjunctivitis, abortions, encephalitis or immune suppression which may lead to secondary bacterial infections and cause pneumonia. Hence, BoHV-1 infection mightcause substantial economic loss and trade restrictions in cattle industry.IBR control and eradication programshave been implemented in many Europeancountries.Recent serological surveys described a prevalence of antibodies against BuHV-1 in water buffalo farms in Campania Region. Objectives The aim of this study was to compare the results of two different serological surveys, performed respectively in 2009 and in 2016, to evaluate the prevalence of BoHV-1 and BuHV-1 infections in water buffalo farms in the Province of Caserta, Campania Region (Italy), whereIBR control programs wererecently implemented. Animals and methods In both surveys, serum samples were collected from buffalo farms (precisely,862 animals/28 farms in 2009 and 309/16 farms in 2016).To detect antibodies for IBR,two commercial ELISA kitswere used, and,precisely, in 2009 IBR-gB and IBR-gE (IDEXX), in 2016 Eradikit Discrimination BoHV-1/BuHV-1 (IN3 diagnostic). Both tests provide the most correct diagnosis on serum samples (Nogarol et al., 2014;Tignon et al., 2017). Results and Discussion In 2009, we detected a seroprevalence of BuHV-1 (49,55%) vs. BoHV-1 (23,06%).In 2016, 57,60% of buffaloes were positive to BuHV-1 vs. BoHV-1 (1,62%), according with another survey carried out in the same Region (Caruso et al., 2016). Overall, we detected a time-dependent increase in BuHV-1 prevalence and a significantdecrease in BoHV-1 infection rates between the two surveys.To explain the difference in the decrease of BoHV-1, we suppose thata possible explanation could be in the existence of antigenic cross-reactionsbetween these viruses and in their abilityto crossthe speciesbarrier. Indeed,both BoHV-1 and BuHV-1 have been reported to cross the species barrier (Thiry et al., 2006). Conclusion Currently, the high percentage of sera reactive to BuHV-1 (57,60%) indicates that BuHV-1may be the main circulating alphaherpesvirus infection in Mediterranean water buffalo.