Treeshrews as a potential reservoir: First detection of dengue virus serotype 2 in Malaysian treeshrew faeces

Arboviruses are transmitted to humans and animals by arthropods and can be fatal. Dengue fever remains a major mosquito-borne disease in tropical regions, primarily spread by Aedes aegypti and Aedes albopictus. Despite vector control and vaccine efforts, dengue virus (DENV) continues to pose serious public health challenges in Malaysia. While non-human primates are known reservoirs in sylvatic cycles, the role of other mammals like treeshrews (Tupaia glis) is poorly understood. This study screened wild treeshrews in suburban Semenyih, Malaysia, for DENV and its serotype. From 2023-2024, fecal and urine samples were collected and pooled for molecular screening. Viral RNA was extracted and tested via RT-PCR targeting the Capsid-Premembrane (C-prM) region. Of 11 samples, three (27.3 %) were positive for DENV-2. Sequence analysis revealed the cosmopolitan genotype II, typically linked to human transmission, rather than sylvatic strains. Virus isolation in Vero and C6/36 cells showed cytopathic effects, though contamination hampered results. These findings suggest treeshrews may serve as incidental reservoirs or amplifying hosts of DENV-2, highlighting the need for wildlife surveillance to better understand dengue transmission and guide public health responses.