An unexpected number of tiger mosquitoes found by citizens in Belgium

Published on: 
Monday, December 12, 2022
Last updated on 12-12-2022 by Marinka Vangenck

The mosquito season is officially over. From May till the end of October, Sciensano and the Institute of Tropical Medicine, Antwerp (ITM) found the Asian tiger mosquito at 12 locations in Belgium. As many as 9 of these 12 locations, mostly gardens, were reported by citizens on the website MuggenSurveillance.be/SurveillanceMoustique.be. The, unexpected, numerous findings highlight the importance of the monitoring of exotic mosquitoes across Belgium, and the key role of citizen participation.

Sciensano and the Institute of Tropical Medicine, Antwerp (ITM) are closely monitoring the presence of exotic mosquitoes in Belgium through the MEMO+ project. The project actively monitors several highway parkings, so called ‘points of entry’, where tiger mosquitoes potentially enter the country through traffic. Complementary, in May 2022, Sciensano and the ITM launched a participation platform MuggenSurveillance/SurveillanceMoustiques where citizens can upload photos of a tiger mosquito. As a result, the tiger mosquito was detected at 12 different locations in Belgium; 9 through citizen participation and 3 through active monitoring. This is many more than what was expected. 

Javiera Rebolledo, epidemiologist and project leader at Sciensano: “Between May and October 2022, we received about 300 notifications from citizens. In 9 cases, the picture that we received was clearly a tiger mosquito. These positive notifications led, in 6 cases, to field inspections where we found extra tiger mosquitoes at 4 locations. It is quite unexpected and worrying that the tiger mosquito was detected at so many different places. It is clear that the contribution of citizens in the monitoring of tiger mosquitoes is of great value and complements the active monitoring at points of entry.”

At several locations, we could observe eggs and larvae, meaning that the tiger mosquito was locally reproducing. Moreover in 2 locations the tiger mosquito was also spreading in the area and causing nuisance in private gardens. This means that the tiger mosquito was present in high numbers which increases the possibility of overwintering of eggs and thus the chance of establishment in Belgium”, adds Isra Deblauwe, entomologist at ITM.

The mosquito causes a lot of nuisance during the day because of its aggressive biting behaviour. Moereover, after biting an infected person, the tiger mosquito can transmit viruses such as dengue, chikungunya and Zika. It is therefore important to get a good view of the introduction and presence of this mosquito species in our country. Over the past few years, the number of findings of tiger mosquitoes increased and this trend is expected to continue in the coming years. It is therefore important to create more awareness around the tiger mosquito. Furthermore, the researchers hope that the high number of findings last summer will be a signal to scale up the monitoring of the tiger mosquito and also further develop prevention and control. Now we are still in time to take all these measures to delay the establishment of the tiger mosquito in Belgium for as long as possible.    

The map below shows the locations where the tiger mosquito was detected during the 2022 mosquito season. 

Map results tiger mosquito monitoring 2022 We would already like to invite everyone to join our search for tiger mosquitoes next year as well, at the start of the mosquito season around mid-April 2023.

The project is a collaboration between Sciensano, the Institute of Tropical Medicine (ITM) and the Barcoding Facility for Organisms and Tissues of Policy Concern (BopCo) for the molecular identification of collected exotic mosquitoes. This project is funded by the Federal and Federated Entities for Environment and Health through the National Environment and Health Action Plan (NEHAP).

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