Blood film samples were taken of 30 percent of the population in the Commune of Arcahaie, Haiti, to determine the effect on malaria transmission produced by the periodic treatment of homes with the dichlorvos residual fumigant. Prior to insecticidal treatment, infants 0–12 months showed a positivity index of 6.5 percent in 2,489 smears. At 1 and at 2 years after treatment, samples in the same age group had positivity indices of 7.0 and 2.2 percent, respectively. Plasmodium falciparum was the principal parasite but infections of P. vivax and P. malariae also occurred. Despite reduction in infection levels in infants and in children over 1 year of age interruption of malaria transmission was not apparent.
Pan American Health Organization; formerly Co-director of National Malaria Eradication Service, Port-au-Prince, Haiti.
Government of Haiti; formerly Co-director of National Malaria Eradication Service, Port-au-Prince, Haiti. Present address: Director General, CAMEP, Port-au-Prince, Haiti.