Projets
JapoRisk
Monitoring of Aedes japonicus in Belgium and assessment of its vector competence for West Nile, Usutu and Japanese encephalitis virus to evaluate the potential risk for human health
Aedes japonicus is an invasive mosquito originating from East Asia. It has spread worldwide via the international trade of used tyres, with further establishment in countries with a temperate climate. In Belgium, Ae. japonicus was first detected in 2002 in Natoye (Namur province). Since then, two other populations have been detected, in Maasmechelen (Limburg province) and in Eupen (Liège province). In 2024, through citizen surveillance of exotic mosquitoes, 13 specimens (confirmed via DNA-barcoding) were reported at 11 locations in the provinces of Limburg, Liège and Luxemburg, indicating that the actual extent of spread remains unknown as well as the origin of the specimens. An increasing abundance and spread of Ae. japonicus could have an important impact on public health. With its opportunistic feeding behaviour - targeting mammals (incl. humans) and birds - the species has the potential to act as a bridge vector for zoonotic diseases. Laboratory studies showed that Ae. japonicus is a competent vector for West Nile virus (WNV) and Usutu virus (USUV) under specific conditions. However, the competence of Belgian Ae. japonicus populations for these viruses remains unknown. Also, as a consequence of climate change, the species might further spread and establish, and become an efficient vector of these viruses under increased mean annual temperatures.
Therefore, this project aims to assess the potential public health risk of Ae. japonicus in Belgium by studying the occurrence and spread of the species, its vector competence under current and changing climate conditions, and the origin and modes of spread of the species. The outcomes will provide essential insights for the development of targeted public health strategies and vector control measures.
The project includes 6 Work Packages (WP).
WP1 consists of monitoring the occurrence and assessing the spread of Ae. japonicus, between 2026 and 2029. The first year, monitoring will start in two municipalities where Ae. japonicus has been reported by citizens. During the mosquito season, larval sampling will be carried out at breeding sites which are preferred by Ae. japonicus, such as cemeteries and allotment gardens. When the presence of the species is confirmed, oviposition traps will be installed to collect eggs. Based on the results, the monitoring area will be expanded throughout the season and in subsequent years in order to evaluate the extent of the spread. Thiswill allow us to better understand and assess the invasive status of Ae. japonicus as well as to collect information on its genetic diversity and population structure (cf WP3).
WP2 will evaluate the ability of the Belgian Ae. japonicus population(s) to acquire, maintain, and transmit WNV and USUV under laboratory conditions. Eggs will be collected in Belgium (cf WP1), hatched under controlled laboratory conditions, and the resulting adults will undergo vector competence experiments. This will first be tested at constant 25°C, a temperature often used in vector competence studies. If competence at 25°C is confirmed, subsequent studies will investigate how temperature variations affect transmission dynamics. This research is essential to understand how climate change may alter arbovirus transmission in Belgium and its potential public health implications.
In WP3, through a 2-step approach (viz. use of available microsatellite markers followed by whole-genome sequencing on a subset of samples), we will investigate the population genetic diversity and structure of the collected Ae. japonicus mosquitoes in Belgium (cf WP1) and compare our results with established populations from neighbouring European countries, hypothesising active dispersal of the species. This will allow us to determine the possible origin of the Belgian
specimens.
WP4 to WP6 cover general project management aspects such as the coordination, the reporting, the valorisation and exploitation of the results, and the data management
Investigateur principal:
Dates:
2026 2029Collaborateurs:
Partenaires externes:
SciensanoBopCo - RBINS