Could a warmer climate increase the risk of mosquito-borne viruses in Sweden?

Olivia Wesula Lwande is a researcher at the Department of Clinical Microbiology at Umeå University.

ImageMattias Pettersson

We asked Olivia Wesula Lwande, who has just been appointed as a senior lecturer at Lund University, five questions about this buzzing new research.

Congratulations on the grant! What does receiving nearly 9 million SEK for the WARNS-Sweden project mean to you and your research?

“I am truly grateful for this support. It gives us an important opportunity to address an emerging public health concern in Sweden and generate the evidence needed to better understand and anticipate these infections.”

The project focuses on West Nile and Usutu viruses. What are these viruses, and why do we need to keep an eye on them in Sweden?

“Both are mosquito-borne viruses that circulate mainly between mosquitoes and birds but can also infect humans. West Nile virus can cause severe neurological disease, while Usutu virus has also been associated with neurological complications, although severe human disease is less commonly reported. As their potential impact in Sweden remains insufficiently understood, we need to strengthen our preparedness, particularly to protect vulnerable individuals.”

Climate change is an important part of the project. How could a warmer climate affect the risk of these types of infections in Sweden?

“Warmer temperatures could create more favourable conditions for mosquito activity and virus transmission, potentially extending the transmission season. However, the actual risk depends on several factors. Our project will investigate how Swedish mosquitoes respond to projected climate scenarios to help us better understand how these risks may evolve.”

What do you personally find most exciting about the project and are looking forward to finding out?

I am particularly excited about bringing together mosquito experiments, studies of people at increased risk of severe disease, and climate-based risk modelling. Understanding whether Swedish mosquitoes can transmit these viruses under future climate conditions, alongside investigating previous exposure in vulnerable populations, will help us build a clearer picture of the potential risks.

What do you hope WARNS-Sweden will ultimately lead to once the project is completed?

“I hope the project will contribute to a sustainable national surveillance system, clearer clinical testing guidance and a climate-informed early warning system. Ultimately, the goal is to support earlier detection, better-informed public health decisions and improved protection for those most at risk.”

Olivia Wesula Lwande is excited that the new project combines mosquito experiments, studies of people at increased risk of severe disease, and climate-based risk modelling.

ImageMattias Pettersson