Epidemiology of malaria in New Halfa, an irrigated area in eastern Sudan

A prospective study investigated the epidemiology of malaria in an agricultural area in eastern Sudan from November 1999 to June 2000 [1 irrigation and 1 dry season]. In monthly parasite surveys, 99/ 1539 blood films from 190 individuals were positive for malaria: 95% for Plasmodium falciparum, 3% P. vivax and 2% P. ovale. The slide positive rate [SPR] of malaria episodes ranged from 3.7% to 12.8% in different months of the survey, with a peak in January. There was no significant difference in SPR between irrigation and dry seasons [7.2% versus 5.1%]. SPR differed significantly by age group and was highest in under 5-year-olds. However, there was no significant difference in SPR between males and females. Transmission and intensity of malaria in this area is perennial and moderate rather than low

Anopheles arabiensis: abundance and insecticide resistance in an irrigated area of eastern Sudan

The abundance of Anopheles arabiensis and its susceptibility to insecticides was studied in New Halfa, eastern Sudan, from March 1999 to June 2000. Of 4854 females anophelines collected, 4847 [99.9%] were An. arabiensis and 7 [0.1%] An. pharoensis. Female An. arabiensis were breeding throughout the year, with 2 peak densities, during the rainy [158.4 females/room/day and 84.7 larvae/10 dips] and irrigated seasons [136.8 females/room/day and 44.8 larvae/10 dips]. The mean biting activity was 28.8 bites/person/ night, found throughout the night, mainly outdoors. Susceptibility of An. arabiensis to insecticides dichloro-diphenyl-trichloroethane [DDT], malathion and fenitrothion was 97.8%, 96.3% and 100% respectively. An. arabiensis is the sole malaria vector in the area and is perennial rather than seasonal