First isolation and characterization of pteropine orthoreoviruses in fruit bats in the Philippines.

Pteropine orthoreovirus (PRV) causes respiratory tract illness (RTI) in humans. PRVs were isolated from throat swabs collected from 9 of 91 wild bats captured on the Mindanao Islands, The Philippines, in 2013. The nucleic acid sequence of the whole genome of each of these isolates was determined. Phylogenetic analysis based on predicted amino acid sequences indicated that the isolated PRVs were novel strains in which re-assortment events had occurred in the viral genome. Serum specimens collected from 76 of 84 bats were positive for PRV-neutralizing antibodies suggesting a high prevalence of PRV in wild bats in the Philippines. The bat-borne PRVs isolated in the Philippines were characterized in comparison to an Indonesian PRV isolate, Miyazaki-Bali/2007 strain, recovered from a human patient, revealing that the Philippine bat-borne PRVs had similar characteristics in terms of antigenicity to those of the Miyazaki-Bali/2007 strain, but with a slight difference (e.g., growth capacity in vitro). The impact of the Philippine bat-borne PRVs should be studied in human RTI cases in the Philippines.