Key Points

Chikungunya, Dengue, and Zika

• Since May 1, 2026, 110 imported cases of dengue, 31 imported cases of chikungunya, and 1 imported case of Zika have been identified and investigated in the Île-de-France region. These figures remained significantly lower than those observed in 2025.
• The first outbreak of locally transmitted chikungunya was identified in Nogent-sur-Marne in Val-de-Marne (94), with 6 cases identified to date. The onset dates of symptoms for these five cases range from August 16 to August 29.

West Nile Virus Infections

• As of September 28, 206, 23 locally acquired human cases of West Nile virus (WNV) infection had been identified in Île-de-France, including 13 neuroinvasive cases and 3 deaths.
• In 2026, avian and equine cases of WNV infection were also identified in the region. As a reminder, the summer of 2025 was marked by the emergence of West Nile virus in Île-de-France.

COVID-19

• In Île-de-France during S39, an increase in the use of emergency room services and SOS Médecins for suspected COVID-19 was observed. The circulation of SARS-CoV-2 in wastewater continued an upward trend.

Typhoid Fever

• Since the beginning of 2026, the number of typhoid fever cases among travelers returning from Senegal has risen sharply in the Île-de-France region, with 41 cases reported. Between 2022 and 2025, between 9 and 18 cases were reported annually.
• Given this trend, vaccination against typhoid fever should be considered for people traveling to Senegal, particularly in light of the 7th edition of the Youth Olympic Games being held in Dakar, from October 31, 2026, to November 13, 2026.