SCREENING OF HAEMATOBIA-IRRITANS IRRITANS (DIPTERA, MUSCIDAE) POPULATIONS FOR PYRETHROID RESISTANCE-ASSOCIATED SODIUM-CHANNEL GENE-MUTATIONS BY USING A POLYMERASE-CHAIN-REACTION ASSAY
Fd. Guerrero et al., SCREENING OF HAEMATOBIA-IRRITANS IRRITANS (DIPTERA, MUSCIDAE) POPULATIONS FOR PYRETHROID RESISTANCE-ASSOCIATED SODIUM-CHANNEL GENE-MUTATIONS BY USING A POLYMERASE-CHAIN-REACTION ASSAY, Journal of medical entomology, 35(5), 1998, pp. 710-715
A polymerase chain reaction (PCR)-based rapid screening procedure was
developed to test individual horn flies, Haematobia irritans irritans
(L.), for the presence of a specific nucleotide substitution in the so
dium channel gene sequence that has been associated with pyrethroid re
sistance. By a systematic optimization of reaction conditions and judi
cious choice of FCR primers differing in DNA sequence by a single nucl
eotide, we identified pyrethroid-susceptible or resistant sodium chann
el alleles in individual flies. Laboratory and field populations were
examined by both the PCR assay and conventional filter paper bioassays
with the pyrethroid cyhalothrin to verify that populations containing
greater proportions of individuals with the resistant sodium channel
allele DNA sequence also had higher bioassay LC50 values. The PCR assa
y far resistance alleles gave definitive information on the genotype o
f an individual fly and detected the presence of heterozygous individu
als that might serve as reservoirs of resistance genes in field popula
tions.