title: Use of Bacillus thuringiensis var israelensis as a viable option in an Integrated Malaria Vector Control Programme in the Kumasi Metropolis, Ghana.
abstract: BACKGROUND
  Integrated Vector Control (IVC) remains the approach for managing the malaria-causing vector. The study investigated the contribution of Bacillus thuringiensis israelensis (Bti) in the control of malaria by targeting the larvae and also mapped and documented major breeding sites in the Kumasi metropolis, Ghana.
  
  
  METHODS
  Using a hand held GPS receiver unit, major breeding sites within the metropolis were mapped out during the larval survey. Mosquito larvae were then collected from the breeding sites and reared in an insectary to obtain an F1 generation for laboratory bioassays. The minimum effective dosage of Bti Water Dispersible Granular (WDG) formulation was determined by a series of bioassays. Based on the results obtained in the laboratory, the optimum effective dosage of Bti formulations against naturally occurring larvae of the indigenous mosquito species was determined through open field trials.
  
  
  RESULTS
  A total of 33 breeding sites were identified and geo-referenced during the larval surveys with the majority of the breeding sites located in the Asokwa sub-metropolis, Kumasi, Ghana. A Bti (3,000 International Toxic Unit (ITU)/mg) concentration of 0.026 mg/l resulted in 50% mortality whilst a concentration of 0.136 mg/l resulted in 95% mortality. Results from the open field trials with Bti showed that a dosage of 0.2 kg/ha is as effective as 0.4 kg/ha in suppressing late instars and resulting pupae.
  
  
  CONCLUSIONS
  This study reveals that Bti at a very low dosage of 0.2 kg/ha is highly effective against Anopheles larvae and therefore offers viable options for the management of vector mosquitoes. Further research is needed to extend this to the field in order to determine its ability to reduce malaria incidence.
authors.forename: Rita
authors.initials: R
authors.lastname: Nartey
authors.forename: Ellis
authors.initials: E
authors.lastname: Owusu-Dabo
authors.forename: Thomas
authors.initials: T
authors.lastname: Kruppa
authors.forename: Sandra
authors.initials: S
authors.lastname: Baffour-Awuah
authors.forename: Augustina
authors.initials: A
authors.lastname: Annan
authors.forename: Samuel
authors.initials: S
authors.lastname: Oppong
authors.forename: Norbert
authors.initials: N
authors.lastname: Becker
authors.forename: Kwasi
authors.initials: K
authors.lastname: Obiri-Danso
mesh_terms: D000818:Animals; D000852:Anopheles / Q000382:microbiology* / Q000469:parasitology; D001413:Bacillus thuringiensis / Q000502:physiology*; D001681:Biological Assay; D005260:Female; D005869:Ghana / Q000453:epidemiology; D006801:Humans; D007303:Insect Vectors / Q000382:microbiology* / Q000469:parasitology; D007814:Larva; D008288:Malaria / Q000517:prevention & control* / Q000635:transmission; D010572:Pest Control, Biological / Q000379:methods*; D010961:Plasmodium / Q000502:physiology*