[Multiple insecticide resistances and mutation of in north-central Anhui Province].

OBJECTIVE

To understand the status of resistance to multiple insecticides and the frequencies of mutations in from north-central Anhui Province.

METHODS

From July to September, 2014, the mosquito larvae were collected in Huaibei, Bengbu and Chuzhou cities of the north-central Anhui Province and reared to adults. The female adult mosquitoes at 3-5 days post emergence were tested for susceptibility to the four insecticides, namely 0.05% deltamethrin, 5% malathion, 0.1% bendiocarb and 4% DDT, by using the standard WHO resistance tube bioassay. The detection of the point mutations of the gene at codon 1014 was conducted by PCR and DNA sequencing in the deltamethrin-resistant and -susceptible mosquitoes.

RESULTS

High levels of resistance to all the four insecticides were found in all the three tested populations, although mosquito mortality varied among populations and test insecticides. Among the test insecticides, DDT showed lowest mortality with no significant difference ( = 1.027, > 0.05) in all test populations, whereas significantly different mortalities were observed among populations for the remained three insecticides tested (deltamethrin, malathion, and bendiocarb) ( = 23.823, 33.955, 128.841; all < 0.01). Two types of non-synonymous mutation at codon position 1014 (L1014F and L1014S) were observed. A positive correlation between L1014F mutation frequencies and deltamethrin resistance levels were detected in the three mosquito populations ( = 0.718, < 0.01).

CONCLUSIONS

The observed high levels of resistance to multiple-insecticides coupled with the occurrence of medium to high frequencies in populations of could profoundly affect the mosquito vector control programme in China. The local health departments need to strengthen vector dynamic monitoring and implement rational resistance management strategies.