Chikungunya Emergence unit

Status: active - level 1

Last updated on 20 January 2025

Chikungunya: the situation in a nutshell

Chikungunya is an infectious disease caused by an arbovirus, the chikungunya virus.
Since August 2024, Réunion has recorded 192 confirmed native cases of chikungunya, spread across seven active outbreaks as of 13 January 2025.
This situation has led the authorities to activate epidemic level 3 of the ORSEC ‘Arboviroses’ plan, corresponding to a low-intensity epidemic [1].
The ANRS Emerging Infectious Diseases activated a level 1 Emergence cell on 16 January 2025.

Follow the latest scientific news on chikungunya !

As part of the ANRS MIE Emergence programme, the agency publishes a weekly scientific review on chikungunya, providing updates on the most recent research findings.

In particular, you will find in the scientific review available for download:

a summary of the epidemiological situation ;
recent scientific articles published in peer-reviewed scientific journals;
recent articles and press releases;
a brief overview of epidemiology, virology, clinical aspects, treatment and prevention;
an update on current research into treatments and vaccines, with an overview of current clinical trials;
official recommendations from health agencies.

Download the scientific review

Monthly Scientific Review on Chikungungya virus .pdf 237 KB

Epidemiological situation of chikungunya in Réunion

A major chikungunya epidemic between 2005 and 2006

Chikungunya is an infectious disease caused by an arbovirus, the chikungunya virus (CHIKV). Between 2005 and 2006, Réunion experienced a major chikungunya epidemic, with an estimated 266,000 symptomatic cases, or 34% of the island’s population. The epidemic was also marked by 258 deaths. An initial peak was recorded in May 2005, with 450 cases reported, before the incidence stabilised at around 100 cases per week during the austral winter. From October 2005, the incidence gradually increased, reaching a second peak in February 2006, with 47,000 cases reported weekly. The epidemic then slowly declined, with the last indigenous case recorded in December 2006. The end of the epidemic was officially declared in April 2007 [2].

The immunity acquired during this episode (estimated at 38% of the population of Réunion) declined over time, which could partly explain the resumption of chikungunya virus circulation in Réunion in 2024 [3]. After an absence of three years, 5 confirmed cases of chikungunya were reported in Réunion in 2009 [4]. Between 2010 and 2024, no indigenous cases were detected. [5]. This absence of cases ended in August 2024, marking a new turning point in the epidemiology of chikungunya on the island.

More about chikungunya

A resumption of viral circulation since August 2024

Between August 2024 and 13 January 2025, 192 native cases of chikungunya were confirmed in Réunion by PCR. Two new active outbreaks have been identified (La Vallée in Saint-Pierre and Bras Creux in Le Tampon), making a total of seven active outbreaks, of which Étang-Salé (ravine Sheunon district) is the most active with 90 cases. A number of isolated cases have also been reported, but no link with a known outbreak has been established.

This situation indicates that the virus is intensifying and continuing to spread across the island.

In response, the ARS of La Réunion activated epidemic level 3 of the ORSEC arbovirosis control plan on 13 January 2025 [1].