Human land-use changes linked to greater viral diversity in mosquitoes — UP study

Mosquitoes in human-altered areas carry a greater variety of viruses, underscoring the need for stronger surveillance systems to monitor potential emerging threats, according to a University of the Philippines (UP) study.

The study, conducted by researchers from the UP Diliman College of Science National Institute of Molecular Biology and Biotechnology together with a scientist from Institut Pasteur and Université Paris Cité, analyzed the virome of Aedes aegypti and Aedes albopictus mosquitoes collected from three barangays in Los Baños, Laguna with different land-use conditions.

Both mosquito species are known vectors of diseases such as dengue, chikungunya, and Zika.

Using viral metagenomics, the researchers identified viruses from 12 taxonomic groups, most of which were classified as insect-specific viruses (ISVs) that do not infect humans.

The team compared mosquito samples from Barangay Bagong Silang, a forested upland area, and Barangays Lalakay and Bayog, which have undergone long-term conversion from agricultural land to built-up areas.

The study found that mosquitoes from the more human-altered areas exhibited higher viral diversity and intensity than those from the forested site.

“These mosquitoes are usually disturbance-resilient and are more competent hosts for several viral isolates,” the researchers said in a statement.

No dengue, Zika, or chikungunya viruses were detected in the samples.

However, mosquitoes from two sites carried the Cell Fusing Agent Virus (CFAV), an insect-specific virus that has been observed in some studies to interfere with dengue and Zika virus replication inside mosquitoes.

The researchers said the findings highlight the importance of monitoring mosquito-borne viruses in areas undergoing rapid land-use change.

“Mosquitoes act like biological syringes, feeding on multiple kinds of hosts,” they said, adding that this makes them useful indicators of viral diversity across space, time, and species.

The study, titled Virome Sequencing and Analysis of Aedes aegypti and Aedes albopictus from Ecologically Different Sites in the Philippines, was published in Parasites & Vectors and supported by the Department of Science and Technology–Philippine Council for Health Research and Development and the UP Diliman Office of the Vice Chancellor for Research and Development. — Edg Adrian A. Eva