Resting behavior of malaria vectors in Mannar District of Sri Lanka with reference to zooprophylaxis
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Date
2013
Journal Title
Journal ISSN
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Publisher
University of Kelaniya
Abstract
Background:
The most important factors for effective zooprophylaxis in reducing malaria transmission are the presence of predominate populations of a strongly zoophilic mosquitoes and domestic animals for their blood-meal.
Methods:
Resting behavior of anopheline mosquitoes was evaluated using indoor and outdoor mosquito collection techniques. Mosquitoes were captured using 389 outdoor cattle-baited traps and indoor hand catches in 5672 houses at 12 possible malaria sensitive areas situated 12 km apart; Pesali, Keeri, Erukkallampeddi, Moor, Vankalai, Narawallikulam, Vanchiyankulam, Arvanum, Arrippu, Kokkupadayan, Koolankulam and Pandaraveilli for 12 months (June 2012 to June 2013) on a weekly basis. These areas had mostly homogenous characteristics in vegetations and house type. All collected mosquitoes were identified using standard taxonomic keys. A hypothesis test was conducted to determine whether there is a difference between indoor and outdoor collections.
Results:
A total of 3986 anopheline mosquitoes were collected from both indoor (n= 3122) and outdoor (n= 864) collection techniques. Anopheles subpictus was found to account for over 97.5% (n= 3887) of Anopheles species collected in the study areas. Other species were; 1.4% An. peditaeniatus (n= 57), 0.6% An. varuna (n= 22), 0.3% An. pallidus (n= 10), 0.2% An. nigerrimus (n= 7), 0.05% An. tessellatus (n= 2), and 0.03% An. aconitus (n= 1). Only 3 species namely, An. subpictus (n= 485), An. tessellatus (n= 2) and An. aconitus (n= 1) were recorded from indoor
hand catches. In experimental cattle-baited hut trials, An. subpictus (n= 3026) was found to have
the highest exophilic tendency (96.9%) compared to other anophelines encountered. The
hypothesis test suggests that there was a significant difference of An. subpictus attracted to
cattle-baited traps and human dwellings (P = 0.008). Although the main vector An. culicifacies
was absent, the presence of the secondary vector An. subpictus was observed in high numbers in
the District.
Conclusion:
Exophilic and zoophilic tendencies of An. subpictus are conducive for zooprophylaxis. The study
further indicates that zooprophylaxis may be a potential strategy for malaria control. It is
recommended that in areas with a predominant An. subpictus population, cattle could be kept
close to human dwellings to maximize the effects of zooprophylaxis.
Description
Annual Research Symposium Abstracts, FGS, University of Kelaniya, 28-29 November, 2013, Kelaniya
Keywords
Citation
Proceedings of the Annual Research Symposium, Faculty of Graduate Studies, University of Kelaniya. 2013; 14: 132-133.