Summer 2025 saw a significant increase in chikungunya virus cases in China’s Guangdong Province. The mosquito-borne illness has since spread from Southern China to other regions globally, including France and Italy, raising questions about whether China is the source of another potential pandemic.

A report in the journal Biocontaminant examines how a combination of travel and climate change has led to outbreaks outside the province.

“The outbreak reflects both the global spread of chikungunya and the favorable conditions for mosquito-borne diseases in southern China,” said lead author Guang-Guo Ying of South China Normal University in a press statement.

Also read: Chikungunya returns: WHO warns of global risk from mosquito-borne virus epidemic

The virus is not highly contagious and cannot spread from person to person. However, the rapid international spread has sparked concerns about disease control measures.

China-origin mosquito-borne virus spreads through international travel

According to the Centers for Disease Control and Prevention, over 100 countries have reported outbreaks of the chikungunya virus, with travel from China being one of the primary spreaders of the current outbreak.

The chikungunya virus transmits through bites of infected Aedes albopictus or Aedes aegypti mosquitoes, which exist in tropical and subtropical regions around the globe. The virus remains in the bloodstream and can be transmitted back to uninfected mosquitoes when they bite a human carrying the chikungunya virus.

In rare cases, some individuals have become infected with the virus after experiencing blood-to-blood contact in a laboratory or medical setting.

Europe reports hundreds of chikungunya cases linked to China outbreak

According to the European Centre for Disease Prevention and Control, as of Oct. 5, 2025, both France and Italy have reported a surge in chikungunya cases, with France reporting 700 cases and Italy reporting 353.

According to the Cleveland Clinic, patients bitten by an infected mosquito can start experiencing chikungunya symptoms within five to seven days. These symptoms typically include fever and joint pain. By this time, an infected person can be bitten by an uninfected mosquito and transmit the virus to it.

This infection and reinfection cycle is likely how smaller outbreaks are spreading in Europe and other parts of the world outside Southern China.

Travelers from these regions may have ventured to infected areas in China and brought the virus back with them, spreading it to local mosquitoes.

Also read: China enforces Covid-like measures amid Chikungunya outbreak

According to the European Climate and Health Observatory, over 90 percent of chikungunya virus cases are related to travel. After a mosquito bites an infected person, it can transmit the virus to an uninfected person in less than a week.

Southern China conditions create favorable environment for disease spread

As global temperatures continue to rise, populations of A. albopictus or A. aegypti could increase. These mosquitoes lay their eggs in still or standing water and have adapted well to urbanized environments, according to the press statement.

Southern China’s climate provides ideal conditions for mosquito breeding and virus transmission.

“Climate change can increase the likelihood of extreme weather phenomena, including heavy rainfall and prolonged droughts. This phenomenon has been linked to the spread of arboviruses in endemic regions and is now observed in previously unaffected areas, indicating a broader environmental impact,” the study authors wrote in their report.

Prevention methods include removing standing water and vaccines

Ways to mitigate mosquito populations include removing standing water sources or covering them after periods of heavy rainfall.

According to the CDC, there are two chikungunya vaccines available. Having them administered before traveling to regions with known infections, including Southern China, can help reduce the spread.

This article is not offering medical advice and should be used for informational purposes only.