Role of some environmental factors on the breeding activity of Anopheles arabiensis in New Halfa town, eastern Sudan

Anopheles arabiensis breeding was studied during March 1999-June 2000 in New Halfa town. Of 3642 anopheline larvae collected, 3633 [99.75%] were A. arabiensis: 82.49%, 11.56%, 3.08% and 2.88% of the larvae were collected from shallow sunlit pools resulting from pipes leakages, rain pools, irrigation canals and man-made pools respectively. The overall mean density was 24.34 larvae/10 dips: 40.73 during the rainy season, 30.45 during irrigation and 13.10 in the dry season. Water for crop cultivation increased the relative humidity [P = 0.013] and both factors enhanced A. arabiensis breeding [P < 0.005]. There was no significant difference between the rainy and irrigation seasons. A. arabiensis breeding in this area has become perennial as a result of crop irrigation

Climatic variables and transmission of falciparum malaria in New Halfa, eastern Sudan

The study investigated the role of climatic variables and irrigated agricultural on the seasonality of malaria transmission in New Halfa, eastern Sudan. A time-series analysis was performed using monthly climatic variables, monthly water available for irrigation of crops and monthly slide positive rate of malaria during the period 1986-2002. Cases of malaria were reported every month of the year with a mean of 13.0/100 persons/month [95% CI: 11.9-14.2], and bimodal annual pattern in autumn and winter seasons. Rainfall was the significant climatic variable in the transmission of the disease, whereas heavy rainfall was found to initiate epidemics. Temperature, relative humidity and irrigation water were not significant factors