Biology and transmission potential of malaria vector mosquitoes in Elabered sub-zone, Eritrea
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Date
2001-11
Authors
Okbaldet, Yohannes Bein
Journal Title
Journal ISSN
Volume Title
Publisher
University of the Free State
Abstract
This study was intended to assess the biology and transmission potential of the
malaria vector mosquitoes in Elabered sub-zone, Eritrea. Field collected
Anopheles mosquitoes sampled during the malaria transmission season, from
September to November 2000, were identified morphologically in the field.
Morphological identification revealed that members of the An. gambiae complex
were the most abundant and the only malaria vector species present during the
study period. All the members of the An. gambiae complex were subjected to
polymerase chain reaction (peR) assay and results showed An. arabiensis was the
only member of the An. gambiae complex found in this area.
Blood meal ELISA tests showed that 16.9% and 66.9% of 266 An. arabiensis
were human and bovine fed, respectively. The percentage of mixed feeds, on both
on human and bovine was only 3.8%. A total of 12.4% of the samples failed to
react either to human or bovine anti-sera. None of the non-vector anophelines
tested positive for human blood. Anopheles arabiensis in this particular area
preferred to feed and rest outdoors rather than indoors, and biting was more
intensive in the first half than in the second half of the night. Plasmodium falciparum infection was also determined using ELISA for 589 An.
arabiensis specimens. There was no apparent monthly variation in infection rate,
0.5%, 0.8% and 0.7% for September, October and November, respectively. Based
on the entomological inoculation rate derived from the hourly night bait catches carried out, during the whole transmission season, a villager could be exposed to
0.08 infective bites/night.
Anopheles arabiensis in this particular area is susceptible to deltamethrin, lambdacyhalothrin,
propoxur and DOT. However, permethrin resistant strains might be
present and more tests at field level are required to verify the result and monitor
the situation.
Description
Keywords
Malaria, Anopheles gambiae, Anopheles arabiensis, Plasmodium falciparum, Vector biology, Transmission, Infection rate, Entomological inoculation rate,, Polymerase chain reaction,, Enzyme linked irnmuno-sorbent assay,, Insecticide susceptibility,, Eritrea, Insects as carriers of disease, Mosquitoes as carriers of disease, Dissertation (M.Sc. (Zoology and Entomology))--University of the Free State, 2002