Insecticide-Treated Curtains No Substitute for Routine Control Efforts to Fight Dengue Fever

Newswise — The first-known study comparing costs of routine Aedes aegypti mosquito control programs (RACP) and insecticide-treated curtains (ITC) reveals that the cost of RACP is substantially lower than that of ITC implementation for dengue control and prevention. The study, conducted among others, by the Institute of Tropical Medicine “Pedro Kouri,” appears in the May issue of the American Journal of Tropical Medicine and Hygiene.

The study found that costs of RACP per household in Venezuela and Thailand were $2.14 and $1.89 (USD), respectively. ITC implementation costs were $1.90 per curtain in Venezuela and $1.96 in Thailand. The average number of curtains distributed per household was approximately four, making the yearly cost of ITC implementation over three times higher than the cost of RACP.

According to the manufacturer, the residual insecticidal efficacy of ITC is currently estimated at two years. However, the only published field evidence shows excellent results through the first 12 months; then ITC uptake rapidly declines over time. Assuming that ITC alone were as effective as RACP, they would have to last at least three years to make them equally cost-effective.

“It’s clear from our research that insecticide-treated curtains are an expensive tool in the fight against dengue,” said Alberto Baly, MA Economics, PhD, Institute of Tropical Medicine “Pedro Kouri.” “The increased costs along with the lack of hard evidence from different ecological settings on their effectiveness alone, or in combination with other control efforts, reiterates the fact that we need further studies to evaluate effectiveness. In the meantime, countries should continue to invest in strengthening RACPs as cost-effective baseline measure.”

Dengue is a vector-borne disease mainly transmitted by the Aedes aegypti mosquito. Approximately 2.5 billion people in more than 100 countries are at risk of dengue infection, which affects 50 million people and causes 24,000 unnecessary deaths, yearly. There is currently no vaccine for dengue, therefore the only approach to preventing and controlling the disease is through control programs that reduce mosquito populations and prevent mosquito-human contact.

“There are limited resources to address tropical diseases that afflict millions of people across the world, including dengue,” said Peter J. Hotez, MD, PhD, President, American Society of Tropical Medicine and Hygiene. “These economic studies help us understand what control efforts work and are most cost-effective.”

Researchers evaluated the costs of supplies and materials, insecticides, insecticide-control curtains, personnel, transportation operations and utilities. The main cost driver for ITC is the cost of the curtain itself. A substantial reduction in manufacturer costs would be required to reduce overall implementation costs.

About ASTMHAmerican Society of Tropical Medicine and Hygiene, founded in 1903, is a worldwide organization of scientists, clinicians and program professionals whose mission is to promote global health through the prevention and control of infectious and other diseases that disproportionately afflict the global poor.