Quantification of the efficiency of treatment of Anopheles gambiae breeding sites with petroleum products by local communities in areas of insecticide resistance in the Republic of Benin.
BACKGROUND
The emergence of Anopheles populations capable of withstanding lethal doses of insecticides has weakened the efficacy of most insecticide based strategies of vector control and, has highlighted the need for developing new insecticidal molecules or, improving the efficacy of existing insecticides or abandoning those to which resistance has emerged. The use of petroleum products (PP) against mosquito larvae had an immense success during early programmes of malaria control, but these compounds were abandoned and replaced in the 1950s by synthetic insecticides probably because of the high performances given by these new products. In the current context of vector resistance, it is important to elucidate the empirical use of PP by quantifying their efficiencies on resistant strains of Anopheles.


METHODS
Larvae of Anopheles Ladji a local resistant strain were exposed to increasing concentrations of various PP (kerosene, petrol and engine oils) for 24 hours and the lethal activities recorded. The highest concentration (HiC) having no lethal activity (also referred as the NOEL or no effect level) and the lowest concentration (LoC100) yielding 100% mortality were rated for each PP on the Ladji strain. Prior to laboratory analysis, KAP studies were conducted in three traditional communities were insecticide resistance is clearly established to confirm the use of PP against mosquitoes.


RESULTS
Laboratory analysis of petrol, kerosene and engine oils, clearly established their lethal activities on resistant strains of Anopheles larvae. Contrary to existing references, this research revealed that exposed larvae of Anopheles were mostly killed by direct contact toxicity and not by suffocation as indicated in some earlier reports.


CONCLUSIONS
This research could serve as scientific basis to backup the empirical utilisation of PP on mosquito larvae and to envisage possibilities of using PP in some traditional settings where Anopheles have developed resistance to currently used insecticides.
Djouaka
Rousseau F
RF
Centre de Recherche Entomologique de Cotonou, 06 BP 2604, Republic of Benin. rousseaudj@yahoo.com
Bakare
Adekunle A
AA
Bankole
Honore S
HS
Doannio
Julien M C M C
JM
Kossou
Hortense
H
Akogbeto
Martin C
MC
D000818:Animals; D000852:Anopheles / Q000187:drug effects / Q000502:physiology; D001541:Benin; D001947:Breeding; D005742:Gasoline / Q000633:toxicity; D007305:Insecticide Resistance; D007306:Insecticides; D007648:Kerosene / Q000633:toxicity; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D009032:Mosquito Control / Q000379:methods*; D010578:Petroleum / Q000633:toxicity; D011722:Pyrethrins
D005742:Gasoline; D007306:Insecticides; D007648:Kerosene; D010578:Petroleum; D011722:Pyrethrins