Four chikungunya patients in Ticino live in the same neighbourhood

Four chikungunya patients live on the same street in Ticino, putting a close cluster of infections under scrutiny by cantonal authorities. The patients live in the same neighbourhood in the southern Swiss canton, according to information published on November 5, 2026.

Ticino’s cantonal medical officer, Giorgio Merlani, said two of the four people may have been infected by the same mosquito. The other patients were most likely bitten by related mosquitoes. The suspected links focus attention on the area where the patients live and on the tiger mosquitoes that can transmit the virus.

The canton has acted locally, working with the Ticino University of Applied Sciences, known as SUPSI, to spray a substance aimed at killing adult tiger mosquitoes. That response targets the insect population in the neighbourhood at the centre of the cases.

The four infections may be connected through mosquitoes in the same neighbourhood. Merlani said two patients could have been bitten by one mosquito, while the others were most likely bitten by mosquitoes related to it.

That account points to a tightly local pattern: the patients live on the same street, and officials suspect a link among the insects involved. The explanation remains a probability, rather than a confirmed account of how each person became infected.

For Ticino, the proximity has shaped the response. Authorities and SUPSI focused mosquito control on the patients’ neighbourhood, where officials believe related insects may have been active. The cluster brings together the human cases and the local mosquito population in one area, giving the canton a defined place to target its intervention.

Ticino worked with SUPSI to spray a substance that kills adult tiger mosquitoes. The treatment was applied into the air in the neighbourhood where the four patients live, Merlani said.

The operation was designed to affect adult mosquitoes in the immediate area. Merlani described the approach as very effective, citing how little ground a tiger mosquito covers over its lifetime. The insects fly barely more than 100 metres, he said, a range that makes neighbourhood-level treatment relevant to the cluster.

The intervention reflects a targeted response by cantonal authorities and the local university of applied sciences. It links the suspected mosquito connections to a practical step taken where the patients live, while focusing specifically on adult tiger mosquitoes.

A tiger mosquito’s short flight range helps explain the local focus of the spraying. Merlani said the insect flies barely more than 100 metres during its lifetime. The four patients’ shared neighbourhood therefore became the focus of the canton’s mosquito-control measure.

The response brings together Ticino’s cantonal medical officer and SUPSI, with the aim of killing adult tiger mosquitoes in the area. Officials have linked some infections to the same or related mosquitoes, while describing those links as likely rather than certain.

For residents of the neighbourhood, the reported cases have prompted a targeted intervention on their street. The episode also shows how a cluster of patients can lead authorities to act at a local scale when they suspect a connection to nearby mosquitoes.