West Nile virus: what we know and what we still need to learn about a growing summer threat

What is it about?

West Nile virus is spread by mosquitoes and circulates mainly between birds, while humans and horses are occasional, 'dead-end' hosts. Warmer summers, changing rainfall and expanding mosquito populations have made it a recurring seasonal threat in Europe, including Italy, where two viral lineages now co-circulate. Most infected people have no symptoms or a mild flu-like illness, but a minority, especially older and immunocompromised people, develop neuroinvasive disease such as meningitis, encephalitis or paralysis, with high mortality and long-term disability. In this review, written by Italian infectious diseases specialists and ecologists, we summarize the epidemiology, how the virus causes disease, the clinical picture, the pitfalls of laboratory diagnosis, available and experimental treatments, prevention strategies including blood and organ donor screening, and vaccine prospects.

Featured Image

Photo by National Institute of Allergy and Infectious Diseases on Unsplash

Photo by National Institute of Allergy and Infectious Diseases on Unsplash

Why is it important?

There is still no specific antiviral treatment and no human vaccine for West Nile virus, while climate change keeps extending its geographic range and transmission season. By bringing together clinical, diagnostic and ecological knowledge and highlighting the main research gaps, this review offers clinicians and public health professionals an up-to-date reference for recognizing, managing and preventing infections, and points to the priorities for future studies.

Perspectives