Four local chikungunya cases confirmed in Ticino, first transmission in Switzerland

Four cases in the Magadino plain

On Wednesday, 4 November 2026, Ticino's health department announced four cases of chikungunya fever, the first local transmission of the virus in Switzerland. None of the four had travelled recently to regions where the virus circulates. All four live in the same neighbourhood of the Magadino plain. The cantonal doctor, Giorgio Merlani, told Keystone-SDA on request that two of the infections may come from the same mosquito, while the other two were most likely caused by a descendant of the first mosquito. The patients have persistent joint pain, but the canton describes their clinical course as favourable and says they otherwise feel well.

Spraying and investigations

After the virus was found in the patients' blood, a substance that kills adult tiger mosquitoes was sprayed into the air over their neighbourhood. The spraying was carried out with the SUPSI university of applied sciences in Ticino. Merlani said the method is highly effective because a tiger mosquito rarely flies more than 100 metres in its lifetime. Epidemiological investigations and mosquito control measures have been launched in the affected zones under the direction of the cantonal doctor, with support from municipal authorities and federal offices.

Risk assessment

The cantonal doctor rates the current risk to the population as very low, bordering on negligible. Two reasons are given: the small number of cases and the imminent end of the mosquito season. The canton sees no need for special measures for the wider public. Investigations in the affected zones are still under way, and the figures reported so far are the four confirmed cases.

How chikungunya spreads

Chikungunya is an RNA virus passed on through bites from infected mosquitoes, mainly the Asian tiger mosquito and the yellow fever mosquito. It does not spread directly from person to person, and native Swiss mosquito species cannot carry it. Symptoms usually appear seven to nine days after a bite and include fever and joint pain that can last a long time, along with muscle pain, headaches and rashes. Serious cases are rare. The Asian tiger mosquito was first detected in Ticino in 2003, and a locally breeding population was found near Chiasso in 2007. The insect has since spread widely across the canton, and individual specimens keep turning up north of the Alps.

Outbreaks abroad and travel advice

The World Health Organization warned in July 2026 about the worldwide spread of chikungunya. Large outbreaks are under way in countries around the Indian Ocean and in Africa, including India and Mauritius, and an estimated third of La Réunion's population had already been infected. Many travellers return with the infection, mostly to France. Switzerland records about 10 to 40 chikungunya cases a year. People returning from tropical countries with fever, joint pain or a rash are advised to see a doctor and to protect themselves against mosquito bites for 14 days after returning, to prevent local transmission. According to the Federal Office of Public Health, a June 2026 recommendation from the Swiss expert committee on travel medicine advises vaccination for trips to areas with a chikungunya epidemic. For longer or repeated stays in higher-risk regions, vaccination can be considered after an individual risk assessment.