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American Public Health Association
133rd Annual Meeting & Exposition
December 10-14, 2005
Philadelphia, PA
APHA 2005
4236.0: Tuesday, December 13, 2005 - Table 2

Abstract #111741

Evaluating the welfare implications of the first round of indoor residual spraying in Bioko Island, Equatorial Guinea

Christopher Schwabe, Dr1, Luis E. Benavente, MD, MSc1, Miguel Torrez, MD, MSc1, Abebe Gedamu, BS1, Immo Kleinschmidt, Dr2, and Brian Sharp, Dr2. (1) International Division, Medical Care Development Inc, 104 Bradford Road, Keene, NH 03431, (603)357-2228, chris@schwabe.us, (2) Medical Research Council, 491 Ridge Road, 40 91 Overport PO BOx 70380, Durban, South Africa

Introduction: Indoor residual spraying (IRS) and improved case management are being introduced on Bioko Island, Equatorial Guinea (EG), with financing from Marathon Oil in partnership with the government of EG to reduce malaria transmission. A first round of IRS was completed in 2004 and its impact on the welfare of the inhabitants of Bioko assessed.

Purpose: To assess the welfare implications of the 1st round of IRS on the population of Bioko Island.

Methods: A household expenditure and retrospective health care demand survey was conducted in February 2004 on 575 households residing in 17 sentinel site areas throughout the island. Urban houses were selected from satellite images using an algorithm to generate random coordinates. Rural houses were selected through systematic random sampling based on hand-drawn maps of housing areas. Annual per capita household income was used to measure living standards and a food-energy intake methodology was employed to estimate the incidence of poverty. Two measures of the economic burden of malaria were derived: the direct and indirect cost-of-illness, and the willingness-to-pay to avoid an episode of malaria. The impact of the 1st round of IRS on the probability of clinical malaria requiring treatment was evaluated from data on pre and post spraying Entomological Inoculation Rates and estimates of the resultant change in the incidence of new infections.

Results: 12% of the 3528 individuals enumerated reportedly suffered an illness event during the preceding 4 weeks. 65% of these were malaria with 45% reportedly confirmed by microscopy. Reported malaria incidence is highest among households below the relative poverty line. The economic burden is borne disproportionately by the poorest households, and is catastrophic for those living below the poverty line. The 1st round of IRS is estimated to have reduced annual malaria cases requiring treatment to roughly 1/3rd of pre-spray levels, yielding a net benefit to the population of 2.6% to 3.6% of Island's estimated total annual income. The benefit incidence is pro-poor.

Implications: IRS not only had an appreciable impact on reducing malaria transmission but contributed substantially to reducing the economic burden from malaria and achieving poverty alleviation objectives.

Learning Objectives:

Keywords: Economic Analysis, Infectious Diseases

Presenting author's disclosure statement:

I wish to disclose that I have NO financial interests or other relationship with the manufactures of commercial products, suppliers of commercial services or commertial supporters WITH THE EXCEPTION OF grant from Marathon Oil Company.

Learning from Prevention Interventions and Evaluation Measures to Improve Health

The 133rd Annual Meeting & Exposition (December 10-14, 2005) of APHA