[Susceptibility and insecticide resistance mechanisms in Anopheles albimanus from the southern Yucatan Peninsula, Mexico].
OBJECTIVE
To diagnose susceptibility levels and insecticide resistance mechanisms in Anopheles albimanus from the southern Yucatan Peninsula (YP), Mexico.


METHODS
F1 generation of An. albimanus females, collected from November to December 2005 in six villages in the Othon P. Blanco municipality in Quintana Roo and the Calakmul municipality in Campeche, were exposed to deltamethrin, DDT, pirimiphos-methyl and bendiocarb in susceptibility tests, as well as to biochemical assays in order to calculate the enzyme levels related to insecticide resistance.


RESULTS
High levels of DDT and deltamethrin resistance were found in An. albimanus collected from the six villages, and a high resistance to pirimiphos-methyl was found in those from La Union, Quintana Roo. Biochemical assays showed high levels of glutathione S-transferase (GST), cytochrome P450 and esterases (with pNPA substrate) in all villages. The frequency of An. albimanus with altered acetylcholinesterase (AChE) was high in La Union (33%).


CONCLUSIONS
The An. albimanus populations collected in the south of the YP are resistant to DDT and deltamethrin, whereas resistance to pirimiphos-methyl was significant only in those collected from La Union. The mechanisms explaining this resistance are based on high concentrations of GST, cytochrome P450 and esterasas, the former being responsible for DDT metabolism and the others for pyrethroid metabolism. The altered AChE was the mechanism correlated to pirimiphos-methyl resistance in La Union. The results of the present study have important practical consequences for the chemical control of An. albimanus in the south of the YP.
Dzul
Felipe A
FA
Centro de Investigación de Paludismo, Instituto Nacional de Salud Pública, Tapachula, Chiapas, Mexico.
Patricia Penilla
R
R
Rodríguez
Américo D
AD
D000110:Acetylcholinesterase / Q000032:analysis; D000818:Animals; D000852:Anopheles / Q000201:enzymology; D003577:Cytochrome P-450 Enzyme System / Q000032:analysis; D003634:DDT; D003627:Data Interpretation, Statistical; D004950:Esterases / Q000032:analysis; D005260:Female; D005982:Glutathione Transferase / Q000032:analysis; D007305:Insecticide Resistance / Q000187:drug effects; D007306:Insecticides; D008800:Mexico; D009032:Mosquito Control; D009570:Nitriles; D009946:Organothiophosphorus Compounds; D011722:Pyrethrins; D012621:Seasons
D007306:Insecticides; D009570:Nitriles; D009946:Organothiophosphorus Compounds; D011722:Pyrethrins; C014153:pirimiphos methyl; C017180:decamethrin; D003577:Cytochrome P-450 Enzyme System; D003634:DDT; D005982:Glutathione Transferase; D004950:Esterases; D000110:Acetylcholinesterase