Presentation Title

Molecular Markers of Pesticide Resistance and Pathogens in Head Lice

Location

Atrium

Session Format

Poster Presentation

Research Area Topic:

Natural & Physical Sciences - Environmental Sciences & Sustainability

Co-Presenters, Co- Authors, Co-Researchers, Mentors, or Faculty Advisors

S. E. Braswell, L. A. Durden, S. Zohdy, N. K. Tokarevich, M. E. Eremeeva

Abstract

Background:

Human head lice (Pediculus humanus capitis) are obligate blood-sucking external parasites that live at the base of hair shafts near the scalp. An estimated 6-12 million head louse infestations (HLI) occur each year among children 3 to 11 years of age. Resistance to insecticides is considered to be a major factor in the increasing number of HLI. We evaluated geographically distant lice for the occurrence and prevalence of biomarkers of resistance to permethrin, the most commonly used over-the-counter (OTC) pediculicide. Lice were also tested for carriage of Bartonella quintana, the etiological agent of trench fever.

Methods:

Human lice were collected in the U.S., Russia, and Madagascar in 2004 - 2014. DNA was extracted and a 332-bp fragment of the louse house-keeping gene encoding the alpha-subunit of the sodium channel was amplified by PCR. Permethrin resistance mutation L932F was detected by restriction fragment length polymorphism analysis. Detection of B. quintana was performed using a TaqMan assay.

Results:

DNA was isolated from 502 lice, including: 213 head lice from Georgia, USA, 163 body lice from Russia, and 116 head lice from Madagascar. The L932F mutation was detected in 98% of head lice from the U.S, 1.41% of body lice from Russia, and 20% of head lice from Madagascar. DNA from B. quintana was detected in 64% (n=161) of body lice from Russia and 10.% of head lice from the U.S. (n=213).

Conclusions:

Evidence for the presence of B. quintana in head lice from Georgia, USA was obtained for the first time, which suggests frequent exposure to this pathogen may occur in the state. The rate of L932F mutation varied in lice from distantly separated regions and was most prevalent in lice from Georgia, USA. It is possible that current OTC permethrin based head louse treatments are widely ineffective in the USA.

Keywords

Head lice, Bartonella quintana, qPCR, Pesticide resistance, kdr, Point mutation

Presentation Type and Release Option

Presentation (Open Access)

Start Date

4-24-2015 2:45 PM

End Date

4-24-2015 4:00 PM

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Apr 24th, 2:45 PM Apr 24th, 4:00 PM

Molecular Markers of Pesticide Resistance and Pathogens in Head Lice

Atrium

Background:

Human head lice (Pediculus humanus capitis) are obligate blood-sucking external parasites that live at the base of hair shafts near the scalp. An estimated 6-12 million head louse infestations (HLI) occur each year among children 3 to 11 years of age. Resistance to insecticides is considered to be a major factor in the increasing number of HLI. We evaluated geographically distant lice for the occurrence and prevalence of biomarkers of resistance to permethrin, the most commonly used over-the-counter (OTC) pediculicide. Lice were also tested for carriage of Bartonella quintana, the etiological agent of trench fever.

Methods:

Human lice were collected in the U.S., Russia, and Madagascar in 2004 - 2014. DNA was extracted and a 332-bp fragment of the louse house-keeping gene encoding the alpha-subunit of the sodium channel was amplified by PCR. Permethrin resistance mutation L932F was detected by restriction fragment length polymorphism analysis. Detection of B. quintana was performed using a TaqMan assay.

Results:

DNA was isolated from 502 lice, including: 213 head lice from Georgia, USA, 163 body lice from Russia, and 116 head lice from Madagascar. The L932F mutation was detected in 98% of head lice from the U.S, 1.41% of body lice from Russia, and 20% of head lice from Madagascar. DNA from B. quintana was detected in 64% (n=161) of body lice from Russia and 10.% of head lice from the U.S. (n=213).

Conclusions:

Evidence for the presence of B. quintana in head lice from Georgia, USA was obtained for the first time, which suggests frequent exposure to this pathogen may occur in the state. The rate of L932F mutation varied in lice from distantly separated regions and was most prevalent in lice from Georgia, USA. It is possible that current OTC permethrin based head louse treatments are widely ineffective in the USA.