Dengue: These mosquitoes give hope

January 16, 2017


Even after several years of researches, dengue still continues to infect an estimated 390 million people around the world each year. Recently, the researchers have genetically engineered mosquitoes that have an increased resistance to infection by the dengue virus. 

According to the researchers, when a mosquito bites a person infected with Dengue Virus (DENV), the virus needs to complete its life cycle in the mosquito's gut, eventually infecting its salivary glands, before it can infect another person. 

The earlier studies proved that, the mosquitoes depend on a molecular pathway to fight DENV infection and stop this cycle. Dome and Hop are the proteins that are involved in turning on the pathway, when its DENV infected mosquito. 

George Dimopoulos from Johns Hopkins University and colleagues genetically engineered Aedes aegypti mosquitoes to turn on expression of either Dome or Hop in the fat body tissue. Through the research, it was found that the mosquitoes with engineered versions of DENV infected Dome or Hop, had 78.18% (Dome) and 83.63% (Hop) copies of the virus in their guts, as well as significantly less virus in their salivary glands.

When compared to the normal mosquitoes, the altered genes mosquitoes had normal life spans and produced fewer eggs. No impact was seen on infection, when the researchers conducted the similar experiment on Zika virus and Chikungunya virus. This suggests that the significance of the molecular pathway in the fat body tissue is unique to DENV. 

"It may be possible to achieve improved or total resistance to dengue and other viruses by expressing additional transgenes in multiple tissues that block the virus through different mechanisms. Recently developed powerful mosquito gene-drive systems, that are under development, are likely to make it possible to spread pathogen resistance in mosquito populations in a self-propagating fashion, even at a certain fitness cost," the researchers said.

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