Dengue, Zika and Wolbachia

Townsville has been trialling an innovative way of eliminating Dengue, one of the nastier tropical diseases, for the past eighteen months. Its basis is infecting the Aedes aegypti mosquitoes (photo – wikipedia), which carry the virus, with Wolbachia bacteria which prevent the virus developing.

The April 2016 Field Trial Update (pdf no longer available) is full of good news:

A year and a half after releasing the first mosquito with Wolbachia in Townsville, we are excited to announce that almost all Aedes aegypti mosquitoes are now carrying Wolbachia across the Stage 1 area.

Wolbachia levels in Townsville City, South Townsville, North Ward, Belgian Gardens, Castle Hill, West End, Garbutt, Gulliver, Currajong, Vincent, Aitkenvale, Mundingburra, Hyde Park, Pimlico, Mysterton, Hermit Park and Railway Estate are all between 80% and 100% and we hope to see this trend continue long-term. … We are making strong progress towards our goal of establishing Wolbachia in Townsville’s mosquito population, and reducing the risk of dengue transmission in our city.

… We are grateful to the more than 6700 locals who have joined our team. Townsville is setting an example for what communities can achieve when locals lend a helping hand.

… Meanwhile, communities in Cranbrook, Heatley, Kirwan, Thuringowa Central and Mount Louisa have been the first to grow and release their own Wolbachia mosquitoes using DIY Mozzie Boxes. Wolbachia levels in these suburbs are increasing and we will continue to monitor the population as the release phase in these areas comes to an end.

When we signed up for the trial we (and most of the rest of the world) hadn’t even heard of Zika virus, but Zika is the reason those Mozzie Boxes have been in the international news recently:

For the past several years, researchers in Australia have been at work trying to develop a way to put a stop to dengue, a virus that — like Zika — is spread by way of a certain breed of mosquitoes.

The result is what’s called a Mozzie Box, and Susan Desmond-Hellmann, CEO of the Bill and Melinda Gates Foundation, recently demonstrated how it works.

The Mozzie Box works by intentionally breeding disease carrying mosquitos, with a twist.

In the Mozzie Box, Aedes mosquitoes — the same kind that transmit diseases like Zika, dengue, yellow fever, chikungunya, and more — are bred.

And how exactly is breeding more mosquitoes the solution to a mosquito-borne illness?

The Mozzie Box mosquito eggs contain a bacteria called Wolbachia, which renders the grown mosquitoes essentially harmless (minus a few itchy bites here and there).

The whole story of Dengue (which we’ve had in Townsville forever), Zika (which we’ve never had) and the mosquitoes is too long and complicated to tell here but this Wikipedia page covers the science well enough to ground further reading on the World Mosquito Program site and elsewhere.

One thought on “Dengue, Zika and Wolbachia”

  1. Success!

    Dengue fever virtually eradicated from Far North Queensland, scientists say

    In a research paper made public on Friday, scientists from the World Mosquito Program (WMP) declared that local transmission of the mosquito-borne virus had essentially disappeared from the Cairns population since an eradication program began in 2011.

    They said the program was the launch pad for an eradication program they hoped would save 100 million lives worldwide over the next five years.

    Far North Queensland has previously been regarded as a high-risk region for dengue.

    WMP director Scott O’Neill said they hoped the success of the eradication program would have implications for other diseases such as Zika virus and yellow fever, which are also transmitted via mosquitoes.

    “We’ve seen almost the complete collapse of locally acquired dengue in previously high-risk transmission areas in cities and communities across Australia’s far north,” Professor O’Neill said.

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