Larvacides Provide Cost-Effective Mosquito Control, Disease Prevention

RESEARCH TRIANGLE PARK, N.C. -- Larvacides, chemicals applied to prevent mosquito breeding in various environments, provide a cost-effective solution to reduce the spread of malaria and other vector-borne diseases worldwide, according to a new study by RTI International and funded by the U.S. Agency for International Development.

The study evaluated the cost of using larvacides in three different African settings -- a coastal metropolitan area of Dar es Salaam in Tanzania, a densely populated Kenyan highland area (Vihiga District), and a lakeside district in rural Kenya (Mbita Division).

The annual cost per person protected in those settings using larvacides, according to the study, ranged from $0.94 to $2.50.

"Our analysis demonstrated that larvacides are a viable and cost-effective tool that can complement existing malaria control methods in many settings across Africa," said Gene Brantly, malaria prevention program director at RTI International. "Larvacides are comparable in cost to other proven interventions and can enhance the overall effectiveness of integrated vector management programs."

To date, the majority of malaria control programs in sub-Saharan Africa have focused on residential and clinical interventions, such as insecticide-treated bed nets, indoor residual spraying and medicines to treat those infected.

Costs per person per year for larvacide protection ranged from $0.94 in the coastal metropolitan area in Tanzania, to between $0.79 and $1.50 in the densely populated district of Kenya, to between $1.94 and $2.50 in the lakeside district in rural Kenya.

The findings showed that the cost effectiveness of larval control depends mainly on the type of area treated and the population density.

"Malaria control managers and other decision makers should consider using larvacides as part of integrated vector management strategies to complement indoor residual spraying and insecticide-treated nets," Brantly said. "By providing preventive treatments to citizens as well as targeting the breeding grounds of the insect that carries these diseases, we can make a greater impact at reducing and eliminating many of these debilitating diseases."

Indoor residual spraying activities are applied to interior walls to eliminate mosquitoes in living spaces, and insecticide-treated nets are placed in the homes over bedding to protect against mosquitoes.

This project extends work RTI has been doing for more than ten years to prevent and control vector-borne diseases and complements a mass drug distribution program RTI launched earlier this year with support from USAID to control or eliminate five neglected tropical diseases in much of the world, particularly Africa.

Two microbial larvacide products from Valent BioSciences Corporation were used as the basis for cost analysis in the study. The products target mosquitoes and related flies without affecting non-target insect populations.

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