Resistant strain of head lice prevalent in North America

Resistant strain of head lice prevalent in north america

(HealthDay)—Widespread use of pyrethrins- or pyrethroid-based products appears to have resulted in selection pressure for a highly-resistant strain of human head lice in North America, according to research published in the March issue of the Journal of Medical Entomology.

Kyong Sup Yoon, of the University of Massachusetts in Amherst, and colleagues performed genotyping on DNA extracted from samples of human collected from 32 locations in the United States and Canada.

The researchers found that the frequency of a knockdown-type resistance allele T917I (TI) was high in North American lice (88.4 percent). In U.S. lice, TI frequency overall was 84.4 percent from 1999 to 2009 and increased to 99.6 percent from 2007 to 2009. In Canadian lice, TI frequency was 97.1 percent in 2008. The of the TI mutation in human head lice in North America may be the result of selection pressure caused by the widespread use of pyrethrins- or pyrethroid-based pediculicides for many years.

"The frequencies of TI in North American head louse populations were found to be uniformly high, which…is likely a main cause of increased pediculosis and failure of pyrethrins- or permethrin-based products in Canada and the United States," the authors write. "Alternative approaches to treatment of head lice infestations are critically needed."

Head louse collections were provided by Nycomed Canada and Topaz Pharmaceuticals.

More information: Abstract
Full Text (subscription or payment may be required)

add to favorites email to friend print save as pdf

Related Stories

Head lice beginning to show permethrin resistance

Jun 05, 2012

(HealthDay) -- Although live head lice obtained from school-aged children in Paris remain susceptible to the insecticide malathion, approximately 14 percent have been found to be resistant to permethrin, suggesting ...

Louse genetics offer clues on human migrations

Feb 27, 2013

A new genetic analysis of human lice from across the world sheds light on the global spread of these parasites, their potential for disease transmission and insecticide resistance. The results are published February 27 in ...

Recommended for you

Study: Americans endure unwanted care near death

2 hours ago

Americans suffer needless discomfort and undergo unwanted and costly care as they die, in part because of a medical system ruled by "perverse incentives" for aggressive care and not enough conversation about what people want, ...

Failed Medicare payments law remains relevant

2 hours ago

In a new commentary in the journal JAMA Surgery, Dr. Eli Adashi recounts what he and other advocates saw as merits of the originally bipartisan Sustainable Growth Rate Repeal and Medicare Provider Paymen ...

User comments