Cost-effectiveness of annual targeted larviciding campaigns in Cambodia against the dengue vector Aedes aegypti

OBJECTIVE To assess the cost-effectiveness (CE) of annual targeted larviciding campaigns from 2001 to 2005 against the dengue vector Aedes aegypti in two urban areas of Cambodia with a population of 2.9 million people. METHODS The intervention under analysis consisted of annual larviciding campaigns targeting medium to large water storage containers in households and other premises. The CE compared the intervention against the hypothetical alternative of no intervention. The CE was calculated as the ratio of disability adjusted life years (DALYs) saved to the net cost of the intervention (in 2005 US dollars) by year. A sensitivity analysis explored the range of study parameters. RESULTS The intervention reduced the number of dengue cases and deaths by 53%. It averted an annual average of 2980 dengue hospitalizations, 11 921 dengue ambulatory cases and 23 dengue deaths, resulting in a saving of 997 DALYs per year. The gross cost of the intervention was US$ 567 800 per year, or US$ 0.20 per person covered. As the intervention averted considerable medical care, the annual net cost of the intervention was US$ 312 214 (US$ 0.11 per person covered) from a public sector perspective and US$ 37 137 (US$ 0.01 per person covered) from a societal perspective. The resulting CE ratios were: US$ 313/DALY gained from the public perspective and US$ 37/DALY gained from the societal perspective. Even under the most conservative assumption, the intervention remained cost effective from both perspectives. CONCLUSIONS Annual, targeted larviciding campaigns appear to have been effective and cost-effective medium-term interventions to reduce the epidemiologic and economic burden of dengue in urban areas of Cambodia.