Rising global temperatures favor the spread into Swiss regions of arthropod vectors that were once confined to tropical countries. Furthermore, the large number of people traveling abroad to areas where diseases such as dengue, chikungunya, and Zika fever are endemic could contribute to the emergence of locally transmitted cases in our country, due to the presence of competent vectors such as the tiger mosquito (Aedes albopictus).

Although the risk of autochthonous cases of these diseases in Switzerland is currently low (thanks in part to a well-established arthropod surveillance and control system), the FOPH and the FSVO consider strategic to be prepared for these possible future events. Furthermore, other vector-borne diseases, such as West Nile virus disease, are relatively common in neighboring countries. In Switzerland, the West Nile virus was detected in native mosquitoes for the first time in 2022, and the first case of locally acquired transmission in humans was confirmed in Ticino in 2025. This clearly shows that while the risk of the disease emerging in our country is low, local transmission is still possible.

To further reduce the risk of new cases of West Nile virus and protect people and animals (particularly horses), the FOPH, the FSVO, the Institute of Microbiology at SUPSI, and the Ticino health authorities will jointly develop an integrated regional monitoring program for West Nile virus, focusing on human, animal, and environmental health (One Health approach), which could serve as a blueprint that could be then implemented at the national level.

FOPH Director Anne Lévy emphasized the importance of this work for public health: “Although we currently only have had to confirm one locally transmitted case, it is crucial to take action at an early stage in order to protect our population effectively. SUPSI is carrying out essential groundwork in this area for the whole of Switzerland”.

The strategic location of Canton Ticino as the “door” for the rest of Switzerland, makes it an ideal location where to implement this project.

The visit held at the SUPSI Campus in Mendrisio served to lay the groundwork for this renewed collaboration. The FOPH delegation, led by Director Anne Lévy, visited the laboratories of the SUPSI Institute of Microbiology, directed by Prof. Francesco Origgi, to learn more about the activities carried out in collaboration with the cantonal health authorities, represented by the Director of the Department of Health and Social Affairs of the Canton of Ticino, State Councilor Raffaele De Rosa, the Cantonal Chief Medical Officer, Giorgio Merlani, and the Cantonal Veterinarian, Luca Bacciarini.

Over the years, the cantonal mandate and service activities of the SUPSI Institute of Microbiology have enabled the institution to expand its expertise and knowledge in the monitoring and control of arthropod vectors (mosquitoes) and vector-borne infectious agents. The close collaboration with federal agencies will facilitate the development of an integrated regional program for monitoring West Nile virus.

Thanks to its many years of experience in this field and its recognition throughout Switzerland as a model when it comes to vector and vector-borne pathogen monitoring and control, the SUPSI Institute of Microbiology is ready to serve as a vector-borne pathogen preparedness competence center for the whole country. 

Measures at national level 
In collaboration with the Federal Food Safety and Veterinary Office (FSVO), the Federal Office for the Environment (FOEN) and other partners from the fields of human and veterinary medicine, environmental authorities and research, the Federal Office of Public Health has drawn up national action plans for dengue, chikungunya and Zika, as well as for West Nile fever. These serve as a basis for the cantons to draw up their own cantonal strategies and plans. The action plans promote a coordinated approach across Switzerland, covering coordination, diagnosis, surveillance, prevention, communication, case management and vector control.

Other key areas include raising awareness among travellers at Zurich, Geneva and Basel airports, as well as collaboration with reference laboratories and research institutions.