Molecular screening for active severe acute respiratory syndrome coronavirus 2 infections among non-human primates in Indonesia.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses an ongoing public health concern, and its zoonotic nature increases the risk of cross-species transmission between humans and animals. Non-human primates (NHPs) are particularly susceptible because of the high similarity in angiotensin-converting enzyme 2 (ACE2) critical residues compared to those in humans, especially among catarrhine species. Therefore, surveillance of NHP populations is essential, particularly in Indonesia, a megadiverse nation hosting numerous primate species that frequently interact with humans. In this study, 237 NHPs representing multiple species, including long-tailed macaques (Macaca fascicularis), langurs (Trachypithecus spp.), gibbons (Hylobates spp.), and orangutans (Pongo pygmaeus), were sampled from both in-situ and ex-situ conservation settings across five provinces (Bali, East Java, West Java, Central Kalimantan, and West Sumatra). Paired nasopharyngeal and oropharyngeal swabs were tested for SARS-CoV-2 RNA using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). No molecular evidence of active SARS-CoV-2 infection was detected in any of the individuals sampled. None of the samples showed amplification of either the N1 or N2 gene targets, and no borderline Ct values (all Ct >35 or undetermined) or single-target reactivity was observed. These findings highlight the importance of ongoing surveillance of Indonesian NHP populations by expanding geographical coverage, increasing the sample sizes, incorporating serological testing, and evaluating additional sample types to better assess potential spillover and spillback risks.