Chikungunya Outbreak in China: Over 7,000 Cases Reported in Guangdong

Southern China is facing a growing health challenge as over 7,000 cases of the mosquito-borne viral disease chikungunya have been reported, primarily in Guangdong province. The outbreak, which began in mid-June 2025, marks one of the most significant public health events related to this disease in China since it was first detected in the country nearly two decades ago.

According to data from China’s Center for Disease Control and Prevention (CDC), the earliest known symptomatic case of chikungunya in the current outbreak was reported on June 16, 2025. Since then, more than 7,000 infections have been confirmed, with the majority concentrated in Foshan, a city of 9 million in southern Guangdong.

Between July 27 and August 2 alone, 2,892 new local cases were reported, with 95% of them in Foshan. The remaining cases have been detected in other cities and municipalities across the province, including Guangzhou, Shenzhen, Dongguan, and Zhongshan.

In response to the growing number of infections, Chinese health authorities have implemented strict containment and treatment measures, echoing strategies used during the COVID-19 pandemic. In Foshan, hospitals have been directed to discharge chikungunya patients only after a negative test result or after a mandatory one-week stay.

Over 7,000 mosquito-proof isolation beds have been added across hospitals in the region. Dozens of hospitals have been designated as treatment centers, and neighborhood-wide disinfection campaigns have been launched. Measures also include mass testing, contact tracing, and the isolation of infected individuals.

Unconventional approaches have also been explored:

• Larvae-eating fish have been released into lakes to reduce mosquito breeding.

• "Elephant mosquitoes"—a species that doesn’t bite humans but feeds on Aedes mosquitoes (the primary carriers of chikungunya)—have been introduced into mosquito-prone areas.

On August 4, Hong Kong reported its first imported case of chikungunya during this outbreak. The patient, a 12-year-old boy, developed fever, rash, and joint pain after visiting Foshan in July. Hong Kong health authorities have since stepped up surveillance efforts, particularly among travelers arriving from affected regions.

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What is Chikungunya?

Chikungunya is a viral disease caused by the chikungunya virus, which is transmitted to humans through the bite of infected female mosquitoes, particularly Aedes aegypti and Aedes albopictus. These mosquito species are also known to transmit other viruses such as dengue and Zika.

The World Health Organization (WHO) notes that symptoms typically appear between 4 to 8 days after being bitten. Common symptoms include:

• High fever

• Fatigue and nausea

• Severe joint pain, which can last for months or even years

The name "chikungunya" is derived from the Kimakonde language of southern Tanzania, meaning “that which bends up,” referring to the bent posture caused by extreme joint pain.

Importantly, chikungunya is not transmitted from person to person, and the disease is rarely fatal. According to a 2024 study in Nature, around 35.3 million people are infected globally each year, with a very low mortality rate of 0.01%—about 3,700 deaths annually. However, infants and elderly individuals are at higher risk of developing severe symptoms.

Past Chikungunya Outbreaks

Although relatively rare in China, chikungunya is endemic to tropical regions, including parts of South Asia, Southeast Asia, Africa, and some Pacific islands. The disease was first identified in Tanzania in 1952 and has since caused multiple significant outbreaks:

• 1967 – Urban outbreak in Thailand

• 1970s – Outbreaks in India

• 2004 – Major outbreak in Lamu Island, Kenya, infecting 70% of its population

• 2006 – India experienced a large-scale outbreak with 1.3 million suspected cases, especially in Karnataka and Maharashtra

• 2007–2010 – Spread to Mauritius, Seychelles, and Southeast Asia, including Singapore and Thailand

• 2014 – First locally-acquired cases in the U.S. reported in Florida, Texas, Puerto Rico, and the U.S. Virgin Islands

In China, the disease has appeared only through imported cases:

• 2010 – Cluster in Dongguan, Guangdong

• 2019 – Cases in Ruili, Yunnan Province

As of May 2025, La Réunion, a French island in the Indian Ocean, had reported over 47,500 cases of chikungunya, with sustained high transmission ongoing, according to the WHO.

Why Is the Outbreak Growing Now?

According to Kang Min, Director of the Institute for Prevention and Control of Infectious Diseases at the Guangdong Provincial CDC, the current surge is likely driven by imported cases combined with seasonal environmental factors. The flood and typhoon season in southern China has significantly boosted mosquito activity, making disease control more difficult.

A senior Chinese official recently visited the worst-affected district in Foshan and called for greater efforts to contain the spread, especially of imported cases. The government is aiming to prevent the spread of the virus both within and outside the province.

While officials have reported that 95% of patients recover within 7 days, the lack of public familiarity with chikungunya in China has caused concern and confusion among the population. The absence of a specific cure—with treatment limited to symptom management—makes prevention through mosquito control the most effective strategy.

With authorities now implementing large-scale interventions, and international health agencies closely monitoring the situation, the Guangdong outbreak underscores the growing global threat of mosquito-borne diseases—especially in urban and densely populated areas.