Household-Level Expenditure on Protective Measures Against Mosquitoes on the Island of La Réunion, France

Background: For decades La Réunion has experienced a number of epidemics that have resulted in efforts to control the density of Aedes species on this Island. This study was conducted to assess household-level expenditure on protective measures against mosquito nuisance on the Island of La Réunion in 2012. Methodology/Principal Findings: Data was collected during a cross-sectional survey of 1024 households and used to determine the relationship between the use of chemically-based protective measures and subjective and objective indicators of the density of Aedes albopictus. The average household expenditure in July 2012 was USD 9.86 and the total household-level expenditure over a one-year period was extrapolated to USD 28.05million (range: USD 25.58 million to USD 30.76 million). Much of this money was spent on measures thought to be relatively ineffective against Aedes mosquitoes. Expenditure on protective measures was not influenced by the level of knowledge on mosquitoes or by the visual nuisance they generated at home, but rather by the perception of risk related to a future epidemic of chikungunya and socioeconomic factors. Most importantly, household spending on protective measures was found to be influenced by a measure of zone-level mosquito density (the Breteau index), but not by objective indicators of the presence of mosquitoes within or around the house. Conclusions/Significance: Household-level expenditure on chemically-based protective measures is high when compared to the investment made by public entities to achieve vector control, and it is differentially influenced by subjective and objective measures of mosquito density. The current situation could be improved, firstly by ensuring that the public is well-informed about mosquitoes and the effectiveness of various protective measures, and secondly by implementing interventions that could either complement current vector-control strategies and improve their effectiveness on a country-level, or that would steer the population toward the appropriate behaviours. Author Summary: The French Ministry of Health has, for decades, dedicated numerous resources to control mosquito density on the Island of La Réunion. These efforts were strengthened following an outbreak of chikungunya, a virus transmitted by Aedes mosquitoes, in 2005–2006. In order to understand how public perception and behaviour is affected by this vector, a study was undertaken in 2012. Public behaviour was assessed using estimates of household expenditure on protective measures against mosquitoes. Information was gathered using a survey administered to 1024 households on the Island. Knowledge about mosquitoes was found to be poor across the sample, while perceptions of a risk from epidemics were high. The threat of a chikungunya epidemic was found to be associated with increased expenditure on protective measures, as was a zone-level measure of mosquito density, the Breateau Index. The most important finding is that overall household expenditure due to mosquitoes over a one-year period is USD 28.05 million, rather high when compared to the public service investment. Future vector-control in La Réunion needs to ensure that public health messages are understood by the population and that interventions are implemented that promote appropriate behaviours and reduce current spending at the household-level on protective measures.