Dengue-Fighting Mosquitoes to the Rescue!


CM_DENGUE_FEVER_Defend-Against-DengueEven if you aren’t a fan of insects, you can usually come up with a benefit to having them around. Bees pollinate and spiders eat smaller bugs, but you would be hard pressed to find a positive for mosquitoes. Ruiner of many fine camping trips, and carrier of diseases such as the West Nile virus, malaria, and yellow fever, mosquitoes are rarely seen as beneficial. That’s all about to change though, thanks to a project that began at the University of Monash in Australia. Mosquitoes infected with a bacteria that suppresses dengue fever are being released 10,000 at a time in an attempt to prevent the spread of the disease.

Unlike malaria, there is no preventative medication for dengue, and mosquito nets and bug repellent can only do so much to stop infections. Dengue is a viral infection carried by mosquitoes that causes severe flu-like symptoms, and can develop into a fatal illness. Over the past few decades, dengue has been on the rise. Currently half the world’s population is at risk, especially those who live in urban and semi-urban areas in tropical and sub-tropical climates. A leading cause of death in children in some Latin American and Asian countries, dengue poses a serious challenge to health-care professionals.

NYT2008102207541667CCurrently being experimented with in Australia, Vietnam, Indonesia, and Brazil, the project takes mosquitoes infected with a bacteria and releases them in an attempt to prevent the further spread and devastation of dengue fever. The project in the Rio de Janeiro area of Brazil will release 10,000 mosquitoes monthly for four months.

The mosquitoes are infected with a bacteria called Wolbachia, which acts as a vaccine in mosquitoes with Aedes aegypti (i.e. dengue) by preventing the bacteria from multiplying. Unlike dengue, the bacteria cannot be transmitted to humans and is already found naturally in 60% of insects. Wolbachia has an interesting effect on the reproduction of mosquitoes. Fertilization is only possible if the female has the bacteria, and their offspring will also be carriers. If the the female does not have the bacteria but the male does, the eggs will not turn into larvae. The Wolbachia bacteria is thus able to quickly gain dominance in the population (even within a span of just ten weeks) without the constant need to release new mosquitoes into the environment.

Incidence of dengue in the world

Incidence of dengue globally

Researchers at the University of Monash tested the project for five years on their own bodies to ensure that Wolbachia cannot be transmitted to humans, so it seems that the project could only have a positive or neutral outcome. Hopefully the bacteria will help reduce cases of infection and death. Over the past five years in Brazil alone, 3.2 million cases of dengue infection have been reported, with 800 fatalities.

Sourced from the BBC and the WHO, pictures thanks to Health Risk Communication, Pangea Today, The New York Times, and Scitable.

Calondra Mainhart

Calondra Mainhart

Calondra is a writer, artist, and English teacher living in Turrialba, Costa Rica.

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