Role of water buffalo in the epidemiology of bovine herpesviruses

GRAZZIOTTO NOELIA; MAIDANA S. S; JUAN MANUEL SALA; ROMERA S.A.

Congreso; 18th Ecology and Evolution of Infectious Diseases (online) meeting; 2021

Water buffalo (Bubalus bubalis) raising is gaining popularity in Argentina as an alternative livestock production system and water buffalo and cattle can share the agroecosystem and are occasionally reared together on the same farm. At present, information on the epidemiological role of buffaloes in Bovine herpesvirus infection is limited. In the present work, controlled experimental infection and transmission studies with buffaloes and cattle were carried out. Eight male bovines and eight male buffaloes were strictly isolated in two equal groups of four buffaloes and four bovines each. Buffaloes from both groups were inoculated with 6 ml reference BoHV-1 or field BoHV-5 by intranasal aerosolisation. After 24 hours of experimental infection four buffaloes per group were contacted with four naive cattle to evaluate the transmission interspecies. During the next 21 days post-infection (dpi) or days post-contact (dpc), viral excretion and clinical signs were checked. To evaluate the viral reactivation, 60 dpi or dpc, an immunosuppressive treatment for 5 consecutive days was performed in the animals. Each dpi or dpc, nasal and ocular secretions were collected and inoculated into monolayers of MDBK cells.All the buffaloes inoculated with BoHV-5 or BoHV-1 shed virus. The maximum viral excretion titers were 105.5 TCID50 / ml or 107.5 TCID50 / ml for BoHV-1 and BoHV-5 group respectively. The buffaloes showed moderate clinical signs and no showed nervous signs. Three of the four contact bovines of buffaloes infected with BoHV-1 shed virus (102.5 and 106.5 DICT50 / ml) however particles were not detected in any of the bovines contacted with buffalo experimentally infected with BoHV-5. None of the groups of bovine contacts showed nervous signs. The results suggest that buffaloes are susceptible to BoHV-1 and BoHV-5. Preliminary results would indicate that buffaloes infected with BoHV-5 are capable of transmitting the virus to sentinel cattle where the virus doing latency and reactive. Results provided evidence of reactivation of these infections and they could play an epidemiological role in the circulation/transmission of the virus among domestic and wild ruminants and the impact in the occurrence of natural recombinant emerging viruses with unknown pathogenesis.