Switzerland reports first local cases of mosquito-borne Chikungunya virus

Chikungunya, a tropical disease transmitted by mosquitoes, has been reported in Switzerland for the first time without prior travel to high-risk areas.

First locally acquired cases detected in Ticino

Four people in Ticino have tested positive for Chikungunya fever, according to Blick, and were found not to have previously travelled to an area deemed to be high risk (typically tropical countries in Asia, South America and Africa).

Ticino Department of Health and Social Affairs confirmed the cases in a press release, noting that the infections were traced to the Piano di Magadino area. Officials explained that all four patients are suffering from “mild joint problems” but are “otherwise [doing] well.”

Chikungunya symptoms and Asian tiger mosquito risk in Switzerland

According to the Federal Office of Public Health (FOPH), the chikungunya virus is spread by infected mosquitoes, primarily the Asian tiger mosquito (Aedes albopictus).

Symptoms can develop between three and seven days after a bite and can range from a high fever and joint or muscle pain to headaches and occasionally a skin rash.

Typically, the “disease is not generally dangerous”, but in rare instances “can lead to long-lasting fatigue and debilitating joint pain,” adds the FOPH. Treatment focuses on relieving symptoms.

A preventative vaccine, Vimkunya, was authorised for use in Switzerland earlier this year for people aged 12 and above, although it is primarily targeted at those travelling to high-risk areas.

While Asian tiger mosquitoes have spread to several cantons in Switzerland, local transmission usually happens only when someone infected abroad returns and is then bitten by a tiger mosquito, which spreads it to others. The cases in Ticino mark the first recorded instances of local transmission in Switzerland.

The Ticino Department of Health and Social Affairs emphasised that the cases were “not unexpected” as tiger mosquitoes are “now permanently present in Ticino.” The risk of further spread is “considered negligible” due to the time of year, although residents are urged to follow general guidance on mosquito bites.