Lots of buzz, no bite – authorities slap down proposal to rid China of mosquitoes

Jane Cai in Beijing, South China Morning Post

Posted at Sep 15 2022 08:04 AM | Updated as of Sep 15 2022 08:29 AM

An Aedes aegypti mosquito resting on a mosquito net. Nyein Chan Naing, EPA/file
An Aedes aegypti mosquito resting on a mosquito net. Nyein Chan Naing, EPA/file

Proposal to China’s top legislative body to eradicate the pests is technically impossible, authorities say

Online reaction to idea is mixed, with some commenters questioning NPC priorities

A proposal by deputies to China’s top legislature that called for mosquitos in China to be wiped out has created a lot of online buzz, but the idea has been swatted away as technically impossible, according to the National Health Commission.

The commission’s statement on Tuesday was in response to a proposal made by deputies to the National People’s Congress (NPC) earlier this year titled Suggestion on Comprehensively Carrying Out Mosquito Eradication.

In 2008, China listed the study and monitoring of pathogens among key research priorities for the country. Breakthroughs have been made in sampling, testing and related technologies. However, in general, “research on innovative mosquito control techniques remains relatively weak”, read a statement on the commission’s website.

Government departments are required to respond to proposals from NPC deputies, which become eligible if they are signed by 30 or more deputies or an entire delegation. Nearly 3,000 deputies belong to the current NPC, which consists of 35 electoral units or delegations from across the country. It is unclear which deputies signed the proposal.

Globally, there are about 3,500 species of mosquitoes. Scientists say mosquitoes are among the most common carriers of disease and can harbour a wide variety of viruses. Mosquito-borne viruses have caused many serious public health problems throughout the world, such as Japanese encephalitis, dengue fever, malaria and Zika virus.

Reaction to the idea on social media was mixed. An online survey run by the Phoenix Weekly web forum attracted more than 40,000 votes in five hours.

About 57 per cent of the respondents supported the proposal, saying that wiping mosquitoes out is necessary as they are "likely to transmit diseases". About 40 per cent argued it was not a good idea because the "creatures exist for a reason".

"I totally agree to kill all the mosquitoes. They are really irritating," read one post on Weibo, a Twitter-like social media platform. "Maybe someday they will carry unknown diseases as complicated as the coronavirus!"

Many commenters suggested the idea was shortsighted. "Have the deputies ever considered the biological chain? Once the balance is broken, consequences could be huge," wrote one Weibo user. "I doubt if human beings can defeat mosquitoes. Even if technologies allow us to do so, we have to measure the economic, social and environmental costs first", wrote another user.

Other people questioned the priorities of NPC deputies. "We are suffering from stringent Covid-19 control measures. Why no proposal to change that?" wrote a commentator.

The impact of mosquito extinction and its wider effect on ecosystems has not been fully evaluated. According to scientists, if mosquitoes were eradicated from the planet, hundreds of fish species would have to either find new sources of food or face extinction themselves. Likewise, species of birds, bats, spiders, salamanders, lizards, frogs and even other insects, which also depend on mosquitoes, would struggle to survive.

Still, some experimental eradication tests have seen success. In 2018, scientists from the Imperial College of London used gene-editing tools to render female mosquitoes sterile. In 2019, an experiment on two islands in Guangdong province in China, reduced the female Asian tiger mosquito population - the main source of bites and disease transmission - by up to 94 per cent, and reduced the number of reported bite to humans by 97 per cent.

One of the Chinese study's researchers, Xi Zhiyong, a professor at Michigan State University, said they attempted to limit the ability to reproduce of both male and females. "The radiation-based sterile insect technique has successfully suppressed field populations of several insect pest species, but its effect on mosquito vector control has been limited", the researchers wrote in an article published in Nature in 2019.

The National Health Commission said it would improve environmental sanitation and kick off a national clean-up campaign within key areas in villages, urban slums as well as public toilets, in a bid to "reduce the density of mosquitoes".

Copyright (c) 2022. South China Morning Post Publishers Ltd. All rights reserved.