In anti-
malaria operations the use of
DDT for indoor residual spraying has declined substantially over the past 30years, but this
insecticide is still considered valuable for
malaria control, mainly because of its low cost relative to alternative
insecticides. Despite the development of resistance to
DDT in some populations of
malaria vector Anopheles mosquitoes (Diptera: Culicidae),
DDT remains generally effective when used for house-spraying against most species of Anopheles, due to excitorepellency as well as insecticidal effects. A 1990 cost comparison by the World Health Organization (WHO) found
DDT to be considerably less expensive than other
insecticides, which cost 2 to 23 times more on the basis of cost per house per 6 months of control. To determine whether such a cost advantage still prevails for
DDT, this paper compares recent price quotes from manufacturers and WHO suppliers for
DDT and appropriate formulations of nine other
insecticides (two
carbamates, two
organophosphates and five
pyrethroids) commonly used for residual house-spraying in
malaria control programmes. Based on these 'global' price quotes, detailed calculations show that
DDT is still the least expensive
insecticide on a cost per house basis, although the price appears to be rising as
DDT production declines. At the same time, the prices of
pyrethroids are declining, making some only slightly more expensive than
DDT at low application dosages. Other costs, including operations (labour), transportation and human safety may also increase the price advantages of
DDT and some
pyrethroids vs.
organophosphates and
carbamates, although possible environmental impacts from
DDT remain a concern. However, a global cost comparison may not realistically reflect local costs or effective application dosages at the country level. Recent data on
insecticide prices paid by the health ministries of individual countries showed that prices of particular
insecticides can vary substantially in the open market. Therefore, the most cost-effective
insecticide in any given country or region must be determined on a case-by-case basis. Regional coordination of procurement of public health
insecticides could improve access to affordable products.