China unleashes "cannibal" mosquitoes, killer fish to fight Chikungunya virus

China has deployed innovative biological controls, including ‘cannibal’ mosquitoes and larvae-eating fish, alongside surveillance drones, to combat an unprecedented outbreak of chikungunya virus in its southern Guangdong province.

Since July, over 7,000 cases have been reported, marking the largest outbreak since chikungunya was first detected in China in 2008, Caliber.Az reports via British media.

The surge is linked to factors such as international travel, unusually heavy rainfall, and high temperatures.

The outbreak’s epicentre is Foshan, a manufacturing city with a population of 10 million, about 105 miles from Hong Kong, which recently reported its first case. Chikungunya, often confused with dengue, is rarely fatal but causes severe fever, rash, and joint pain. The disease’s name derives from a Swahili word meaning “to bend over,” reflecting its debilitating symptoms.

To curb the mosquito population responsible for spreading chikungunya—the Aedes mosquito—Chinese authorities have introduced the predatory elephant mosquitoes (Toxorhynchites). Their larvae consume thousands of Aedes larvae and display “compulsive killing,” where they kill larvae without eating them.

Professor Eng Eong Ooi from Duke-NUS Medical School explains, “It is likely that the health authorities in China are hoping that, by releasing Toxoryhnchites mosquitoes, they would reduce the Aedes mosquito population and thus control the spread of chikungunya virus.”

The effectiveness depends on release frequency, mosquito numbers, and species used. Similar releases have been tried in the US, Malaysia, and India with varied success.

In addition, 5,000 larvae-eating fish have been introduced into city lakes to target mosquito larvae in their aquatic stage. “The idea is to have natural predators of mosquitoes at different stages of the lifecycle, to reduce the overall population, virus transmission and hence disease rates,” said Prof Ooi.

China’s approach also includes strict “patriotic public health” measures reminiscent of its zero-Covid policy: mandatory removal of stagnant water, drones to identify breeding sites, large-scale insecticide spraying, and enforced isolation of patients under mosquito nets.

Dr Yanzhong Huang of the Council on Foreign Relations commented, “This blend of implicit coercion and community enforcement highlights China’s enduring ‘patriotic public health’ model, [which prioritises] rapid containment over individual liberties.”

Globally, chikungunya has surged in 2025, with outbreaks reported in over 110 countries, including Europe. The World Health Organisation warns that rising temperatures and expanding Aedes habitats will likely drive more outbreaks.

Dr Andre Siqueira of the Drugs for Neglected Diseases initiative stresses the disease’s severity, noting, “The previous belief that acute chikungunya is a mild disease has been challenged by the severity of joint pain and reports of complications such as myocarditis and encephalitis, as well as evidence for excess mortality in locations experiencing outbreaks.”

He added that up to 60% of patients may suffer chronic joint pain lasting months or years, creating a significant health and economic burden.

By Aghakazim Guliyev