West Nile virus (WNV) and Usutu virus (USUV) have been present in Germany for many years. Both viruses are transmitted by mosquitoes and circulate mainly between birds as the main hosts. However, as so-called zoonotic pathogens, both viruses can also infect humans. Infection with WNV in particular can lead to severe courses. Due to the close relationship of the two viruses, there is a risk of co-infection in humans and animals, but also in mosquitoes. Previous studies have shown that simultaneous infection of German mosquito species with WNV and USUV influences the transmission of both viruses.

The subproject E.1.2 Molecular mechanisms in coinfections and new detection methods will investigate potential interactions between the two viruses during a sequential co-infection in native mosquitoes. The aim is to investigate whether the transmission of both viruses is influenced by sequential co-infection and whether simultaneous transmission of WNV and USUV to humans or animals is possible after such co-infection.  For this purpose, mosquitoes are infected with WNV or USUV under laboratory conditions and a few days later with the respective other virus. The infections are carried out via virus-containing blood to mimic natural transmission. During the infection trials, the mosquitoes' excrement is also collected and examined, as this can provide valuable information about the course of the infection. At the end of the infection trials, saliva will be collected from the mosquitoes and examined for viral RNA or infectious virus particles, just like the mosquitoes themselves. The results from these experiments will be integrated into future surveillance and control strategies in Germany.

Partners and affiliated entities

• BNITM (Bernhard-Nocht-Institut für Tropenmedizin) Hamburg
• FLI (Friedrich-Loeffler-Institut) Greifswald-Insel Riems
• CvO (Carl-von-Ossietzky-Universität) Oldenburg
• ZALF (Leibniz-Zentrum für Agrarlandschaftsforschung) Müncheberg
• GFS e.V (Gesellschaft zur Förderung der Stechmückenbekämpfung) Speyer
• IZI (Fraunhofer Institut für Zelltherapie und Immunologie) Leipzig

Involved IMED Scientists

Prof. Dr. Cornelia Silaghi
PD Dr. Helge Kampen
Dr. Mandy Schäfer
Dr. Birke A. Tews