2026-04-30-世界卫生组织-WHO_Rapid_Risk_Assessment_-_Chikungunya_virus_disease,_Global_v.2_15页_561kb

Chikungunya Virus Disease Global Summary

Core Content Overview

Chikungunya virus (CHIKV) disease is a mosquito-borne illness caused by the CHIKV, an RNA virus in the alphavirus genus. It is transmitted primarily by Aedes aegypti and Aedes albopictus mosquitoes, which are also responsible for dengue and Zika virus transmission. The disease is characterized by sudden fever and severe joint pain, which can persist for months or years. While the overall mortality rate is low, severe complications and long-term disability can occur, especially in vulnerable populations such as newborns, children, elderly individuals, and those with pre-existing conditions.

Main Points and Key Information

Overall Risk Assessment

• Overall Risk: Moderate
• Confidence in Information: Moderate
• The global public health risk is considered moderate due to widespread outbreaks in multiple WHO regions, the potential for further spread, and challenges in prevention and control capacities.

Global Transmission Trends (2025–2026)

• In 2025, a total of 502,264 cases, including 208,335 confirmed cases and 186 deaths, were reported from 41 countries and territories.
• As of March 2026, 18 countries and territories reported CHIKV transmission.
• The Region of the Americas accounted for the vast majority of cases, with Brazil and Bolivia representing 87% of total cases in the region. Argentina, Suriname, and Cuba together with these five countries make up 99% of reported cases.
• The European Region reported the second-highest number of cases, mainly from French overseas departments such as Mayotte and La Réunion.

Regional Transmission Details

• Africa & Eastern Mediterranean:

  • In Madagascar, 29 confirmed cases (0 deaths) were reported between January and February 2026.
  • Mauritius reported 1418 cases, with 1415 local and 3 imported.
  • Seychelles reported 53 confirmed cases in 2026, up from 37 in 2025, indicating increased vector activity.
  • Somalia reported 488 suspected cases, with 8 out of 10 samples confirmed, and no further cases since then.
  • Pakistan reported 18 cases in 2026, with Sindh province accounting for 16 cases.

• Europe:

  • France reported 788 cases across 78 clusters, with the last reported case in Antibes on 30 October 2025.
  • Italy reported 384 cases across 6 clusters, with the last case in Bellaria-Igea Marina on 11 November 2025.
  • French overseas departments such as La Réunion and Mayotte continue to report active transmission, with La Réunion having 54,500 confirmed cases and 45 deaths by December 2025.

• Americas:

  • Brazil reported 42,979 cases, including 15,579 confirmed, and 16 deaths.
  • Bolivia reported 23,145 cases, including 7,817 confirmed, and 7 deaths.
  • Cuba, Argentina, Suriname also reported significant cases, with Cuba experiencing an outbreak after 9 years of no circulation, and Suriname after 5 years of no reported cases.

• South-East Asia:

  • Bangladesh reported 19,490 suspected cases in Dhaka, with widespread urban transmission.
  • India reported 213,016 suspected cases and 9,177 confirmed, mainly in Maharashtra, Karnataka, and Tamil Nadu.
  • Thailand reported 1,405 cases, with a sharp peak in June–July, and the highest incidence in Chiang Mai.

• Western Pacific:

  • China reported 29,497 confirmed cases, mainly in Guangdong, with no severe cases or deaths.
  • Hong Kong SAR reported 82 confirmed cases, 11 local, and 2 imported as of March 2026.
  • Indonesia reported 3,608 confirmed cases in 2025, a significant increase from 1,399 in 2024.
  • Malaysia reported 74 cases, with no deaths.
  • Philippines reported 653 cases in 2025, a 78% decrease from 3,009 in 2024, with one death (0.15% case fatality rate).

Factors Contributing to Risk

• Vector Expansion: Aedes mosquitoes are spreading to new areas due to climate change and increased human mobility.
• Climate and Seasonal Patterns: Rainy seasons create favorable breeding conditions for mosquitoes, increasing transmission risk.
• Limited Population Immunity: Many areas have low immunity due to recent outbreaks or lack of prior exposure.
• Health System Challenges: Gaps in surveillance, diagnostics, and control efforts, especially in fragile or conflict-affected regions.
• Travel-Related Spread: Infected travelers contribute to the spread of the virus to new areas, including Europe and Asia.

Prevention and Control

• No specific antiviral treatment is available; management focuses on symptomatic relief and supportive care.
• Two CHIKV vaccines have received regulatory approval, but they are not yet widely available.
• WHO recommends continued support for surveillance, case detection, laboratory confirmation, vector control, and community awareness.
• WHO Regional Offices should coordinate response efforts, provide technical assistance, and support capacity building.
• WHO HQ will assist with vaccine recommendations and procurement of laboratory supplies.

Major Recommended Actions

• Refer the event for review by IHR Emergency Committee for potential Public Health Emergency of International Concern (PHEIC).
• Activate the ERF response mechanism immediately.
• Recommend setting up of grading call for funding access before full assessment.
• Support Member States in preparedness measures and response activities.
• Continue monitoring and conducting rapid risk assessments.
• Avoid declaring further risk assessment required at this time.

Conclusion

Chikungunya virus remains a moderate public health risk globally, with ongoing transmission in multiple regions and the potential for further spread. The disease poses a significant burden due to its prolonged symptoms and impact on healthcare systems, especially in areas with limited resources and weak surveillance. Continued international collaboration, surveillance, and vector control are essential to mitigate the risk and improve response capacities.