Chinese health officials are struggling to contain an outbreak of the chikungunya virus (CHIKV), a mosquito-borne infection that causes severe pain in the muscles and joints of its victims.
Chikungunya, which flares up periodically in Africa and Asia but can also be found in Europe and the Americas, derives its name from a Tanzanian word that means “bent over.” The name is a fair description of the chikungunya’s effect on humans, as the severe pain it causes in joints and muscles can leave victims contorted with agony.
CHIKV outbreaks usually fade when the infected population develops natural immunity, which tends to happen faster in small communities. This has proven to be a problem with the new outbreak in southern China, which spread into the densely populated city of Foshan, a metropolis with about 9.5 million inhabitants.
The people of Guangdong province grew alarmed when the number of reported CHIKV cases began approaching 5,000. Municipal officials in Foshan launched a major health campaign on Monday that requires all government agencies, private companies, and individual citizens to help eliminate mosquito breeding grounds.
“Measures include draining standing water, removing garbage, and using insecticides to reduce the density of disease-carrying organisms,” China’s state-run Global Times reported on Monday.
“Additionally, all organizations and individuals must strictly adhere to relevant legal regulations and actively cooperate with epidemic prevention measures implemented by authorities in accordance with the law. Those who fail to cooperate or obstruct the execution of these measures will be held legally accountable,” the Global Times added, giving a hint of how nervous local officials have become.
China’s CDC rushed to assure the public on Tuesday that CHIKV does not spread through casual human contact. Since China has no licensed vaccines, China CDC said the only way to reduce the risk of infection was “avoiding mosquito bites by using repellents, wearing permethrin-treated clothing and long sleeves and pants, installing window screens and sleeping under bed nets.”
On Tuesday, Foshan officials poured thousands of fish that eat mosquito eggs and larva into city parks. It was the city’s first attempt to combat mosquito-borne viruses with larvivorous (i.e. larva-eating) fish. City health officials hoped for a 60 percent decrease in the mosquito population within 90 days.
“Although the effects of mosquito-eating fish take longer to manifest, the strategy is pollution-free, environmentally friendly, and sustainable compared to traditional chemical disinfection and sterilization methods,” China’s state-run Xinhua news service noted.
Virologists commonly refer to the virus as CHIKV. Infections are very unpleasant, but rarely fatal. Patients who are very young, very old, or have certain pre-existing medical conditions sometimes experience long-term complications from CHIKV, such as neurological disorders.
Similar in many ways to the better-known Zika and dengue viruses, chikungunya is spread mostly through infected mosquitoes. Visible symptoms of CHIKV resemble those of Zika and dengue, including fevers and rashes, so it is often misdiagnosed. CHIKV was first diagnosed in Tanzania in the 1950s, but has now spread to over a hundred countries.
There is no fully-approved vaccine for CHIKV as of yet, although two candidates have received limited regulatory approval, including in the United States. One of them, IXCHIQ, uses a weakened strain of the CHIKV virus to create a strong immune response in patients. The other, VIMKUNYA, uses an artificial molecule that tricks the human body into generating an immune response against chikungunya.
The U.S. Centers for Disease Control (CDC) advises travelers who visit an area with a high risk of CHIKV infection to consider getting vaccinated, but neither vaccine is manufactured or used in large quantities. The live-virus vaccine, IXCHIQ, has been known to produce adverse reactions in patients younger than 18 or older than 60.
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