Common house mosquito (Culex pipiens)

BIOZ – Environmentally friendly control of West Nile virus transmitting mosquitoes

The BIOZ project aims to identify environmentally friendly alternatives to control mosquitoes that transmit West Nile virus. The focus is on public education and networking among the agencies involved. Central to the project will be a dialogue between the scientific community, the public, and the authorities on future prevention measures to control the West Nile virus (WNV).

Research approach

The Institute of Occupational, Social and Environmental Medicine  (Goethe University) is responsible for the overall project, which includes citizen science, ecological experiments, and surveys. The focus is on an overarching dialog between science, the public, and authorities.

Together with citizens, the application practice and acceptance of a so-called multi-biocide are tested in the area around Halle (Saale) and Leipzig. The application involves three clove oils that allotment gardeners put in rain barrels. The four-week application is accompanied by questionnaire surveys on the acceptance and application practice of the oils. In a further step, possibilities for the biological control of WNV vectors will be examined. For this purpose, different predators of mosquito larvae will be investigated with regard to their effectiveness. In individual rain barrels, the larvae are inserted together with three potential predators (diving beetles, copepods, backswimmers) and two potentially toxic green algae (Oocystis, Scenedesmus).

ISOE is responsible for the monitoring of the social science activities as well as the stakeholder involvement. As an example, relevant stakeholders for the prevention and control of WNV will be identified in Saxony-Anhalt. In interviews with experts, options and barriers for the implementation of WNV prevention and control measures will be identified. All measures aim to improve existing communication structures between the relevant authorities. The results will be presented and discussed in an overarching dialogue between science and society. Here, the main focus will be on identifying future strategies for the control of WNV-transmitting mosquitoes.

Background

West Nile virus is a widespread so-called arthropod-borne virus that is transmitted by mosquitoes (vectors) to hosts (birds) or mis-hosts (humans and horses). In Germany, the West Nile virus was detected for the first time in 2018. While these were still confirmed infections in horses and birds, the number of detected infections increased in 2019 and included five local infections in humans. West Nile fever caused by WNV usually heals without complications, although late sequelae are not uncommon with certain pre-existing conditions. There is no specific antiviral therapy against WNV and it is treated symptomatically.

Currently, so-called Bti preparations (Bacillus thuringiensis israelensis) and S-methoprene (an insect hormone) are the only larvicides against mosquitoes approved for use by the public in Germany. Therefore, there is an urgent need for other larvicides that are efficient, easy to use, sustainable, and widely accepted by the public. Sources of alternative larvicides may include biological counterparts of mosquito larvae. For example, backswimmers, swimming beetles, and copepods can be used as predators of mosquito larvae. The presence of algae of the genera Oocystis and Scenedesmus increases the mortality of mosquito larvae. Clove essential oil, in turn, impedes egg laying and is a larvicide. Additional studies are needed to expand the range of larvicides that can be used, to assess user acceptance of alternative mosquito control under environmental conditions, provide balanced public information regarding larvicide intervention strategies, and to identify and link up key stakeholders for an environmentally friendly control of WNV-transmitting mosquitoes.

Research and project partners

Goethe University Frankfurt, Institute of Occupational, Social and Environmental Medicine

Funding

The project “WNV prevention through biocide interventions against the common WNV vector culex pipiens: experiments, citizen science and cross-cutting dialogue” is funded by the German Federal Ministry of Health (BMG).

Duration

2021/01 – 2022/12