A CSIC project monitors the pathogen in mosquitoes.
Scientists from the Doñana Biological Station (EBD-CSIC) led by Jordi Figuerola can detect whether a mosquito is a carrier of the West Nile virus up to a month before the first cases of infection in humans occur. This advantage gives the administrations room to notify the population of nearby towns to take measures such as the use of mosquito nets or insecticides.
“In most cases, the infection does not produce major symptoms. 80% of human infections are asymptomatic, and 19% may have a slight fever. In just under 1% it can cause a serious illness, known as West Nile virus fever, with encephalitis, and sometimes even death”, declares Jordi Figuerola.
The virus has been circulating in Spain since 2003, with few cases registered until 2016. In 2020, the disease reached a peak of 77 serious cases and 8 deaths, the majority in Andalusia. Since then, surveillance and investigation have been intensified.
Figuerola and his team take mosquito samples every week to check if they have the virus. They determine to which species they belong, and relate the circulation of the pathogen with meteorological parameters such as average temperature and rainfall, as well as with infectivity in humans. With this they hope to be able to forecast whether, depending on the weather conditions and the circulating mosquito strains, there is more or less risk.
“We also study the feeding behavior of mosquitoes, especially in areas of Huelva, Cádiz and Seville, to find out what determines why they feed more than humans. We want to predict at least a month in advance if it will be a good mosquito season, or a season with a lot of viruses”, Figuerola explains. This information will later be reflected in a web page with distribution maps so that the town halls and local authorities can establish surveillance and control programs. Isabel Troytino