Rapid action to implement control measures stemmed the spread of three invasive mosquito species – at least for the time being – after routine surveillance inspections revealed their presence at five locations in the Netherlands in July 2010.
A team with the Dutch government’s Center for Vector Management (CVM) was conducting inspections of companies that import used tires when it discovered the invasive mosquitoes. The species included two known disease vectors – the yellow fever mosquito (Aedes aegypti) and the Asian tiger mosquito (Aedes albopictus) – as well as the American rock-pool mosquito (Aedes atropalpus).
This is the first time Ae. aegypti has been found in the Netherlands, according to Ernst-Jan Scholte of the CVM. Scholte and six coauthors wrote an article about the introduction and control efforts, published in Rapid Communications in November 2010. Scholte and his colleagues also reported the first discovery of Ae. albopictus in the outdoor environment in the Netherlands.
The Dutch government initiated continuous surveillance for invasive mosquito species in 2006, following the discovery of Ae. albopictus related to companies that imported Lucky bamboo. In a gradual expansion of national surveillance, used-tire importers were added to the list of sites in 2009.
Control Measures and Conclusions
The CVM team initiated control measures within a week after the first finding in late July. Infested locations were sprayed with VectoBac® (Bti) or VectoMax® (Bti/Bsph) biological insecticides against larvae, and/or deltamethrin against adult mosquitoes. French mosquito control specialists of EID Rhône Alps did the first treatment, as well as the training of the local applicators. This mosquito abatement district established VectoBac® WDG space spray techniques and VectoMax® CG applications, in cooperation with Valent BioSciences Corporation, for their Ae. albopictus control program.
Larval control within a surrounding 500-meter perimeter included removal of potential larval habitats for container-breeding Aedes spp. when possible; or treatment with VectoBac® space sprays or VectoMax® granules.
Larvicidal treatments were made once every two to three weeks until the first week of November. The last specimen of the invasive species was collected in an adult trap on October 5.
In the report, Scholte and his colleagues said that available data for the 2010 season suggest that the implemented control measures had been effective, though it was too early to assess whether eradication had been achieved.
The report concluded: “Having witnessed these introductions of exotic invasive mosquito species that pose a potential threat to public health in Europe, international collaboration and action by medical entomologists, public health experts, policy makers and the tire-business industry is critical to address this.”