Ovine gammaherpesvirus 2 in asymptomatic water buffaloes (Bubalus bubalis) from Central-western Brazil and implications for infections in buffaloes worldwide.

Ovine gammaherpesvirus 2 (OvGHV2) is the cause of sheep-associated malignant catarrhal fever (SA-MCF) in which sheep are the asymptomatic carrier-hosts with subclinical infections and/or clinical SA-MCF occurring in susceptible mammalian populations worldwide. Although SA-MCF is endemic in cattle throughout Brazil, there is only one report of OvGHV2-associated disease in water buffaloes (Bubalus bubalis), and comparatively few descriptions of infections by OvGHV2 in buffaloes worldwide. This study describes the molecular detection of OvGHV2 infections in asymptomatic water buffaloes and discusses the implications of infections in buffaloes worldwide. All buffaloes originated from the same farm within the State of Goiás, Central-western, Brazil, had no contact with sheep, and did not present any clinical manifestation of disease. Pulmonary, renal, and intestinal tissue fragments were randomly collected from 37 buffaloes during slaughter and used in molecular assays to detect the OvGHV2 tegument protein gene. OvGHV2 DNA was amplified from 18.9% (7/37) of all buffaloes evaluated; direct sequencing confirmed the PCR results. This report adds to the few descriptions of subclinical OvGHV2 infections in buffaloes worldwide, since most previous cases occurred in clinical outbreaks of SA-MCF. The worldwide distribution of SA-MCF and/or infections due to OvGHV2 in buffaloes may be representative of the geographical regions where this ruminant species is predominantly reared. However, subclinical infections and confusion with other similar ruminant diseases may have contributed to the comparatively reduced cases identified in buffaloes relative to cattle. Therefore, OvGHV2 associated infections may be more frequent in buffaloes worldwide than previously described.