Dengue Virus turns mosquitoes hungrier

April 5, 2012

A new study from the Johns Hopkins Bloomberg School of Public Health shows that infection with dengue virus turns on mosquito genes that makes them hungrier and better feeders, and therefore possibly more likely to spread the disease to humans. Published in the journal PLoS Pathogens, the results showed that dengue virus infection of the mosquito’s salivary gland triggered a response that allowed the insects to smell odors better.

Dengue virus is primarily spread to people by the mosquito Aedes aegypti. About 3.6 billion people around the world are at risk of contracting dengue, with more than 70% of them residing in the Asia-Pacific region.

“Our study shows that the dengue virus infects mosquito organs, the salivary glands and antennae that are essential for finding and feeding on a human host. This infection induces odorant-binding protein genes, which enable the mosquito to sense odors,” said senior author Prof. George Dimopoulus from Bloomberg School’s Malaria Research Institute.

“In other words, a hungrier mosquito with a better ability to sense food is more likely to spread dengue virus,” he added.

For the study, researchers performed a genome-wide microarray gene expression analysis of dengue-infected mosquitoes and showed that infection regulated 147 genes with predicted functions in various processes including virus transmission, immunity, blood-feeding, and host-seeking.

Dimopoulos believes that with a better sense of smell, the virus may facilitate the mosquito’s ability to seek out human hosts, and could – at least theoretically – increase transmission efficiency.

More work still needs to be done to fully understand the relationships between feeding efficiency and virus transmission, he said.

“We have, for the first time shown, that a human pathogen can modulate feeding-related genes and behavior of its vector mosquito, and the impact of this on transmission of disease could be significant,” said Dimopoulos.

Health Care Asia
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