New study on insecticide resistance in lice

A recently-published study has found high occurrance of a genetic mutation in a lice sample which correlates with resistance to permethrin and malathion treatments.

The study by Bouvresse et al., published in the December 2012 edition of Journal of the American Academy of Dermatology collected lice samples from a survey of 74 elementary schools in Paris and conducted ex vivo assays and subsequent gene sequencing.

They found that no lice used in the assays survived after a 1 hour treatment with malathion. Only a small porportion of lice (~15%) survived after similar treatment with permethrin / piperonyl butoxide.

Of all the lice with workable DNA sequences (670 lice), greater than 98% showed the presence of the homozygous kdr mutation which has been often correlated with insecticide resistance.

The authors conclude that the resistance-conferring mutation is widespread among their sample, but caution that this is not predictive of treatment failure with these insecticides.