Chikungunya outbreak in Foshan begins to ease

Guangdong province has made progress in curbing the spread of Chikungunya fever, particularly in the city of Foshan, where a recent surge in cases has shown signs of slowing, a senior provincial disease control official said.

Kang Min, director of the institute for prevention and control of infectious diseases at the Guangdong Provincial Center for Disease Control and Prevention, said 2,892 new local cases were reported in the week ending Saturday, a decrease of 48 cases from the previous week.

In Foshan's Shunde district, the hardest-hit area, the number of new cases has declined over five consecutive days, Kang said. He added that despite the progress, both Chikungunya and dengue fever remain in their peak seasons.

"Guangdong, with its high volume of international exchanges, continues to face persistent risks of imported cases," Kang said.

He warned that the ongoing flood season, along with typhoons, heavy rainfall and other weather conditions, have increased mosquito activity — making the next few weeks particularly challenging for disease prevention and control.

Kang urged both government departments and residents to step up efforts to eliminate mosquito breeding grounds through effective, concrete measures.

Chikungunya fever is an acute infectious disease caused by the chikungunya virus and transmitted by infected Aedes mosquitoes, commonly known as spotted mosquitoes. The disease can affect people of all ages, Kang said.

Zhou Huiling, a senior infectious diseases physician at the First People's Hospital of Foshan, said patients are currently being treated in isolation wards to prevent further transmission.

Patients can be discharged only after testing negative on nucleic acid tests or after receiving hospital treatment for at least a week, she said.

"Most of the current patients have mild symptoms, and by the time of discharge, symptoms are mostly relieved, with only a few reporting lingering mild joint pain," Zhou said.

She explained that the joint pain is caused by the virus directly invading joints, infecting osteoblasts and synovial tissues, and triggering the release of pro-inflammatory cytokines that can lead to bone damage.

The pain typically affects small joints in the ankles, fingers and wrists, but can also extend to larger joints such as the knees and shoulders. Symptoms tend to worsen with physical activity, and Zhou advised patients in the acute phase to stay in bed and limit movement.

"Being bitten by a mosquito doesn't necessarily lead to infection — only bites from virus-carrying mosquitoes pose a risk," she said.

Although no serious cases have been reported, experts warn that high-risk groups include infants, seniors over age 65, pregnant women, patients with chronic illnesses and those on immunosuppressive treatments, such as organ transplant recipients, AIDS patients and long-term users of immunosuppressants.

"There is still no vaccine available. Mosquito prevention remains the most important control measure, and early screening and isolation are key to preventing community transmission," Zhou said.

Her hospital currently offers free nucleic acid testing for Chikungunya, with seven testing rounds conducted daily and results available within three to four hours.

As of Monday, Foshan — located about 20 kilometers from Guangzhou, the provincial capital — has reported more than 7,000 cases of Chikungunya, the highest in Guangdong, China's most populous province with more than 127 million people.