Rdl gene polymorphism and sequence analysis and relation to in vivo fipronil susceptibility in strains of the cat flea.

The gamma-amino butyric acid (GABA)-gated chloride ion channel in the insect central nervous system is the target of cyclodiene and phenylpyrazole insecticides. Resistance to dieldrin has been reported in several insect species and was associated with a point mutation (Ala285 to Ser substitution) in the M2 transmembrane domain of the GABA-gated chloride ion channel (the resistant to dieldrin [Rdl] gene). A partial Rdl gene sequence was reported previously in specimens of the cat flea, Ctenocephalides felis (Bouché).