Since the first cases of chikungunya were detected in August 2024, a total of 192 cases have been reported. The dispersion continues, with 47% of cases detected in week 1 of 2025 being isolated. Two new active outbreaks have been identified. Public Health France also notes an increase in the number of visits to the emergency room due to influenza-like illness, while health indicators remained stable regarding acute gastroenteritis. We publish the bulletin below (Illustrative photo www.imazpress.com)
• Chikungunya
192 cases recorded since August 23. The dispersion of cases is intensifying: we are observing an intensification of the circulation of chikungunya in the territory, with a worrying geographical dispersion. In fact, the proportion of isolated cases increased from 23% in week 51 to 38% in week 52, reaching 47% in week 1, reflecting the continuation of geographic dispersion and the increased risk of the establishment of new outbreaks. .
Two new active outbreaks identified (La Vallée in Saint-Pierre and Bras Creux in Tampon), bringing to 8 the total number of outbreaks detected since the end of August 2024. Seven outbreaks remain active to date, including that of Ravine Sheunon, which is the most active with 90 cases recorded in total. The transition to epidemic level was officially announced.
• Acute respiratory infections and influenza viruses
A significant increase in visits to the emergency room for reasons of influenza syndrome was noted in S02/2025 (+88% with 51 visits in S02 versus 27 in S01) compared to the previous week. Three serious cases have been admitted to intensive care in the last two weeks, including one death.
With the end-of-year holiday period, the arrival of tourists and the return of vacationers from France where the flu is circulating with high intensity can explain this increase in emergency visits in Reunion.
Hospitalizations for this reason remained stable (7 in S02 versus 4 in S01). The share of emergency activity for a “flu syndrome” was 1.3% of total activity in S02 versus 0.7% in S01.
In community medicine, Acute Respiratory Infections (ARI) decreased with an activity share of 3.5% in S02 compared to 4.8% in S01. The share of IRA activity was above the 2013-2023 average.
Virological surveillance implemented with virology data from the CHU microbiology laboratory (CNR Arbovirus Associated, CNR Virus respiratory Associated, La Réunion) identified a co-circulation of influenza viruses A(H3N2) and A(H1N1)pdm09 with a positivity rate increasing from 7.7% in S01 to 10.4% in S02.
-• Bronchiolitis (in children under 2 years old)
Health indicators continued to decline. Emergency visits totaled 32 visits versus 47 for the previous week, a drop of 32%. Hospitalizations were also decreasing with 11 hospitalizations in S02 versus 19 in S01, a drop of 42%. The share of activity for a reason for bronchiolitis fell by 3 points and stands at 10% compared in S02 to 13% in S01.
Current weather conditions, with a very dry atmosphere, could explain the low number of cases of bronchiolitis.
• Acute gastroenteritis (GEA)
In S02, the number of visits to emergency departments of all ages for reasons of gastroenteritis was increasing. The number of passages was 70 in S02 versus 59 in S01, an increase of 19%. The number of hospitalizations remained stable with 7 hospitalizations in S02 compared to 8 in S01.
In children under 5 years old, the number of visits to the emergency room for gastroenteritis remained stable with 27 visits in S02 versus 24 visits in S01. The number of hospitalizations after a visit to the emergency room remained stable with 3 hospitalizations as in S01.
In S02, the share of emergency activity among children under 5 years old for gastroenteritis increased compared to the previous week (5.5% in S02 vs 4.3% in S01).
Chikungunya, Health, Gastro, Flu
