An Assessment of the Effects of Insecticide-Treated Livestock Protective Fences (LPF) for Protecting Humans from Anthropophilic Mosquitoes and Malaria Transmission in a Suburb of Kumasi in the Forest Zone of Ghana
A. Abonuusum *
Department of Ecological Agriculture, School of Applied Science and Art, Bolgatanga Polytechnic, Box 767, Bolgatanga, Ghana.
K. Owusu-Daaku
Department of Theoretical and Applied Biology (TAB), Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana.
A. Benjamin
Department of Statistics, School of Applied Science and Art, Bolgatanga Polytechnic, Box 767, Bolgatanga, Ghana.
B. Bauer
Institute for Parasitology and Tropical Veterinary Medicine, Free University of Berlin, Robert-Von-Ostertagstr. 7-13, 14163 Berlin, Germany.
R. Garms
Bernhard Nocht Institute for Tropical Medicine (BNITM), Bernhard Nocht Str. 74, 20359 Hamburg, Germany.
T. Kruppa
Department of Molecular Parasitology, Bernhard Nocht Institute for Tropical Medicine (BNITM) Bernhard Nocht Str. 74, Germany.
*Author to whom correspondence should be addressed.
Abstract
Aim: The study investigated whether a 100 cm high livestock protective fence (LPF), effectively protects humans against anthropophilic mosquitoes and hence malaria.
Study Design: Four experimental segregated, half-roofed shelters with concrete floors, each measuring 6m x 7m, separated from each other by 500m, fenced by 100cm high chicken wire, one of them enclosed by an LPF, were used.
Place and Duration of Study: Work was done on Boadi Cattle Farm by Kumasi Centre for Collaborative Research in Tropical Medicine, Kwame Nkrumah University of Science and Technology, Ghana, for four weeks.
Methodology: Human landing catches of mosquitoes were conducted twice a week. Two groups of two mosquito collectors worked at each of the four shelters during the same night; one group collected from 1800h to midnight, the second group from midnight to 0600h. One collector collected inside as the other collected outside at a distance of about 20m.
Results: Altogether 6118 mosquitoes were collected, of which 773 Anopheles gambiae, 11 A. funestus, 874 A. ziemanni and 4460 Culicinae. There were insignificant (P = 0.30) and significant (P = 0.0003) decreases in numbers of A. ziemanni and culicines entering the shelters with LPF respectively. However, significantly more A. gambiae entered the LPF fenced shelters than in unfenced shelters (P = 0.0008). A variation of hourly biting activities of A. gambiae with a peak between 0100 and 0400 at Boadi and between 1100 and 0300 at two sites at Anwomaso, was observed. Plasmodium falciparum infections were detected in only 1% of A. gambiae but not in A. ziemanni. All 47 A. gambiae s.l. randomly selected and tested using Polymerase Chain Reaction were identified as A. gambiae s.s.
Conclusion: LPF protects humans against some mosquitoes but not the malaria vector, A. gambiae.
Keywords: Mosquitoes, Anopheles gambiae, Plasmodium falciparum, malaria, shelters