Mozzies to the Rescue

Singapore has seen an outbreak of the Zika virus, with 258 confirmed cases of local transmission in less than two weeks, and 2 pregnant patients. Sales of mosquito repellents have accordingly seen a frenzy, jumping as much as 10 fold. While the government recognises Zika is here to stay, it’s not waiting around to be bitten, and is turning to double agents in the fight: modified mosquitoes.

While mosquitoes have been infecting people around the world with Zika, scientists have been infecting mosquitoes with Wolbachia, in a tit-for-tat that could help turn the tide of the pandemic.

The Wolbachia bacteria is a naturally occurring organism that can spread from male mosquito to female through mating, and stops the resulting eggs from hatching. Tested as early as May, Brazilian scientists found that this useful germ reduced the Zika virus count inside mozzies, and made the virus present in their saliva non-infectious, thus lowering Zika transmission.

Now this miracle mozzie is coming to Singapore in October test trial across three sites: Yishun Street 21, Tampines Avenue 4, and Jalan Riang/Jalan Sukachita in Serangoon, when an average of 1-3 Wolbachia-carrying mozzies per person will be released. Over six months the male mosquitoes will be assessed, much like athletes at the recent Games, on their physical abilities (flight distance and height), along with an additional test for their – ahem – amorous ability to pass on Wolbachia to female mosquitoes. All this information goes towards planning a suppression trial, coming as early as 2017.

Such a biological strategy might also be invaluable as a longer-term solution. While fogging does kill adult mosquitoes in a large area, its insecticide plumes only last for about 10 minutes, and have a reduced impact on newcomers that fly in after that.

As we look to a future where Zika blooms and spreads seasonally in Singapore like dengue, it is more pertinent than ever to match official efforts by removing still water or planting an anti-mozzie garden to reduce the number of these winged insects taxiing Zika across Singapore.

By Vincent Tan