Investigators sampled 182 fruit bats from animal markets and suppliers across Java, Indonesia, during 2020–2021 and identified species using external morphologic criteria and photographic records. The team cultured rectal swab specimens on Vero cells and monitored cultures for cytopathic effects (CPEs). Two isolates that produced prominent CPEs were recovered from Rousettus amplexicaudatus bats sold for human consumption in Cianjur, West Java. Those isolates were selected for genomic characterization by next-generation sequencing. The study reported the presence of Pteropine orthoreovirus (PRV) in this medium-sized fruit bat species, linking virus detection to animals in the wildlife trade supply chain.
Whole-genome sequencing recovered nine of ten genomic segments for both isolates. Comparative segment analysis showed near identity across nine segments (>99%–100%), while the S2 segment diverged more substantially, with 88.9% nucleotide identity between the two isolates. The authors reamplified and confirmed the presence of S1 and S2 segments by RT-PCR as part of genomic confirmation. The sequence dataset used for assembly and analysis derived from Illumina NextSeq 550 paired-end reads generated by a commercial sequencing provider; the paper specifies that library preparation and sequencing were outsourced but does not provide additional vendor details beyond the platform used.
Field sampling was nonlethal; the Institutional Animal Care and Use Committee of the Indonesian Agency for Agricultural Research and Development approved handling protocols. Rectal swabs were placed in Dulbecco’s modified Eagle medium with antibiotics and stored at −20°C in a portable freezer prior to transport to the Indonesia Research Center for Veterinary Science laboratory in Bogor. The laboratory workflow included RNA extraction with the QIAamp Viral RNA Mini Kit and RT-PCR screens targeting influenza A and bat coronavirus RdRp and spike genes. The team also performed a SARS-CoV-2 qualitative assay targeting N1 and N2 regions with RNase P as an internal control; that assay was used only for detection and not for viral load quantification. For virus isolation, samples were inoculated onto Vero cell monolayers and incubated at 37°C with 5% CO2; cultures were observed daily for CPE. Two isolates with clear CPE were reextracted from clarified culture supernatant for whole-genome sequencing via Illumina NextSeq 550, with paired 150-bp reads. Bioinformatics detection and assembly used the EsViritu pipeline and a database of GenBank virus sequences.
Phylogenetic analysis placed the two Indonesian isolates in close association with several previously described bat-associated PRVs. Specifically, the isolates clustered with Nelson Bay, Melaka, Kampar, Pulau, and Garut-69 strains. The source article notes close genetic relationships but reports the observed S2 divergence between the two isolates, suggesting segmental heterogeneity that may reflect reassortment or divergent evolution within local PRV populations. The paper references prior reports of PRV diversity from Indonesia and neighboring regions, including earlier isolations from Pteropus spp. and other fruit bats, but it does not describe direct epidemiologic links to human cases for these particular isolates.
PRVs have been increasingly associated with human respiratory illness in prior reports cited by the authors; the first zoonotic recognition occurred in 2006 with the Melaka virus, and multiple related viruses have since been isolated from patients with respiratory disease. The current detections in market-sourced Rousettus amplexicaudatus bats reinforce the potential for zoonotic exposure at the human–bat interface, notably where live bats are sold for consumption. The authors recommend continued surveillance of PRVs at points of contact between humans and bats to detect emergence of novel strains and to mitigate potential spillover. The article does not present data on human infections tied to these two isolates nor on seroprevalence in exposed people.
The authors note that this report documents virus isolation and genomic analysis from bats but does not evaluate pathogenicity in humans or provide clinical case data. Details such as viral loads in original swab specimens, comprehensive segment recovery for one missing genomic segment, and linkage to human exposure outcomes were not reported. The study therefore emphasizes surveillance at the human–bat interface as a priority to assess emergence of novel PRVs and to inform risk mitigation measures. Continued genomic monitoring, targeted epidemiologic studies among people with bat exposure, and characterization of any missing genome segments are among the specific unanswered questions the paper identifies for follow-up work.