Do Long Lasting Insecticidal Treated Nets Alone and Long Lasting Insecticidal Treated Nets plus Indoor Residual Spraying combination have an effects on Anopheles arabiensis Patton (Diptera: Culicidae) population densities, biting cycle, biting places and biting rate; A randomised Control Trial in central and eastern, Sudan.

A cluster randomized controlled trial, with two interventions (study arms) ) Long Lasting InsecticidalTreated Nets (LLIN) alone and a combination of Long Lasting Insecticidal Treated Nets plus Indoor Residual Spraying (LLIN + IRS) was carried out with an objective to identify the species composition, abundance, densities, biting cycle, biting places and human biting rate of Anopheles arabiensis in 30 clusters from four areas Ahoosh, Alhagabdalla, Galabat and New Halfa in central and eastern Sudan.Mosquito samples were collected indoor and outdoor from human dwellings using CDC light trap collection method.Species identifications showed that 94.7 % specimens were Anopheles arabinoses Patton.Mean density was found 1.5 ± 0.5 and 1.1 ± 0.3 for LLIN and LLIN+IRS respectively.The overall density was 1.4 ± 0.3 Anopheles / room / day.65.7% of Anopheles arabiensis population was fed indoor "Endophagic".The pooled ratios between indoor and outdoor for study arm LLIN alone was 1.7:1 and 1.5: 1 for LLIN+ IRS.No significant difference between biting places of Anopheles arabiensis indoor and outdoor in the study arm LLIN alone and LLIN+ IRS in four study areas.The biting activity of Anopheles arabiensis was found to extend throughout the night with the peak commencing in the early of the night).Indoor Man Biting Rate IMBR was significantly higher compared to outdoor (1.52 and 1.03 bites / person /night) for LLIN study arm, while the Outdoor Man Biting Rate (OMBR) was (0.8 and 0.6 bites / person /night) for LLIN+IRS study arm respectively.The overall mean man biting rate indoor was (1.4 ± 0.34 bites / person /night) , while the mean man biting rate outdoor was (0.7 ± 0.15 bites / person /night).There was a significant difference between indoor and outdoor human biting rate (P < 0.05).The study revealed that Anopheles arabiensis is the dominant malaria vector in Sudan, was fed throughout the night with the peak commencing in the early of the night, bites indoor (Endophagic) and there was no difference in biting places, biting time and man biting rates between combining LLIN with IRS relative to use LLIN alone.