This study was undertaken to evaluate the effectiveness of four complementary and combined strategies to minimize the presence of the invasive mosquito Aedes albopictus, firmly established in Sant Cugat del Vallès, Catalonia, Spain. A quasi-experimental design including six neighbourhoods was performed in 2008-2009. The abundance of mosquitoes was monitored through ovitraps. The multiple intervention strategy consisted of four actions: source reduction; larvicide treatments (Bacillus thuringiensis israelensis and diflubenzuron); adulticide treatments (alfacipermetrin); and cleaning up uncontrolled landfills. The results showed the number of eggs significantly reduced in the areas with intervention. In 2008, the accumulate median of eggs was 175 and 272 in the intervention and control areas, respectively. In 2009, these medians were 884 and 1668 eggs. In total, 3104 households were visited and 683 people were interviewed. During inspections inside the houses, the cooperation of citizens in 2009 was 16% higher than that in 2008 (95% CI 13-19%). These findings suggest that the strategy was effective in reducing the number of eggs. Citizen cooperation, an essential factor for success, was observed through a high level of collaboration by the home owners, who allowed entry into their private dwellings. This study could be a model for controlling the populations of Ae. albopictus in the Mediterranean region.

Solid waste, scuppers and vegetable gardens were found to be important factors characterizing premises with larval habitats. People claimed to know about this insect and they considered it to be an important issue that diminished their quality of life.