Ovicidal efficacy of high concentration dimeticone: A new era of head lice treatment

Heukelbach, Jörg; Sonnberg, Susanne; Becher, Heiko; Melo, Iana L. Araujo de; Speare, Rick; Oliveira, Francisco Artur Forte

doi:10.1016/j.jaad.2010.04.003

Cited by 25 publications

(18 citation statements)

References 5 publications

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“…However, as Sonnberg et al pointed out, the age of the eggs on the head at time of the test are not known and rearing conditions are not standardized [6]. It will be interesting to see whether or not the ovicidal efficacy differs between tests where the eggs are treated on the scalp [our study, 3,4,5,7 & 8] compared to tests where the eggs were grown ex vivo off the scalp by the continuous feeding method (ie in a Plexiglas receptacle attached to the wrist of volunteers) [6,9]. "League tables" of clinical efficacy for each country/region might be generated by these approaches.…”

Section: Discussionmentioning

confidence: 99%

An ex vivo, assessor blind, randomised, parallel group, comparative efficacy trial of the ovicidal activity of three pediculicides after a single application - melaleuca oil and lavender oil, eucalyptus oil and lemon tea tree oil, and a "suffocation" pediculicide

Barker

Altman²

2011

BMC Dermatol

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BackgroundThere are two components to the clinical efficacy of pediculicides: (i) efficacy against the crawling-stages (lousicidal efficacy); and (ii) efficacy against the eggs (ovicidal efficacy). Lousicidal efficacy and ovicidal efficacy are confounded in clinical trials. Here we report on a trial that was specially designed to rank the clinical ovicidal efficacy of pediculicides. Eggs were collected, pre-treatment and post-treatment, from subjects with different types of hair, different coloured hair and hair of different length.MethodSubjects with at least 20 live eggs of Pediculus capitis (head lice) were randomised to one of three treatment-groups: a melaleuca oil (commonly called tea tree oil) and lavender oil pediculicide (TTO/LO); a eucalyptus oil and lemon tea tree oil pediculicide (EO/LTTO); or a "suffocation" pediculicide. Pre-treatment: 10 to 22 live eggs were taken from the head by cutting the single hair with the live egg attached, before the treatment (total of 1,062 eggs). Treatment: The subjects then received a single treatment of one of the three pediculicides, according to the manufacturers' instructions. Post-treatment: 10 to 41 treated live eggs were taken from the head by cutting the single hair with the egg attached (total of 1,183 eggs). Eggs were incubated for 14 days. The proportion of eggs that had hatched after 14 days in the pre-treatment group was compared with the proportion of eggs that hatched in the post-treatment group. The primary outcome measure was % ovicidal efficacy for each of the three pediculicides.Results722 subjects were examined for the presence of eggs of head lice. 92 of these subjects were recruited and randomly assigned to: the "suffocation" pediculicide (n = 31); the melaleuca oil and lavender oil pediculicide (n = 31); and the eucalyptus oil and lemon tea tree oil pediculicide (n = 30 subjects). The group treated with eucalyptus oil and lemon tea tree oil had an ovicidal efficacy of 3.3% (SD 16%) whereas the group treated with melaleuca oil and lavender oil had an ovicidal efficacy of 44.4% (SD 23%) and the group treated with the "suffocation" pediculicide had an ovicidal efficacy of 68.3% (SD 38%).ConclusionOvicidal efficacy varied substantially among treatments, from 3.3% to 68.3%. The "suffocation" pediculicide and the melaleuca oil and lavender oil pediculicide (TTO/LO) were significantly more ovicidal than eucalyptus oil and lemon tea tree oil pediculicide (EO/LTTO) (P < 0.0001). Ranking: 1. "Suffocation" pediculicide (68.3% efficacy against eggs); 2. Melaleuca oil and lavender oil (44.4%) pediculicide; 3. Eucalyptus oil and lemon tea tree oil (3.3%) pediculicide. The "suffocation" pediculicide and TTO/LO are also highly efficacious against the crawling-stages. Thus, the "suffocation" pediculicide and TTO/LO should be recommended as first line treatments.Trial RegistrationThe study was listed at the Australian/New Zealand Clinical Trial Registry (ANZCTR): reg. no. 12609000884202.

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Section: Discussionmentioning

confidence: 99%

An ex vivo, assessor blind, randomised, parallel group, comparative efficacy trial of the ovicidal activity of three pediculicides after a single application - melaleuca oil and lavender oil, eucalyptus oil and lemon tea tree oil, and a "suffocation" pediculicide

Barker

Altman²

2011

BMC Dermatol

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“…The significantly lower hatch rates obtained after intermittent feeding of head lice adults may reflect the need of head lice to feed repeated times in order to mate and lay eggs. In addition, there is the advantage of known age and therefore the possibility to evaluate differences in pediculicide susceptibility according to the age of eggs [9]. The continuous feeding method is simple to establish and cheap to conduct.…”

Section: Discussionmentioning

confidence: 99%

“…The continuous feeding method is simple to establish and cheap to conduct. We have previously used this method and have convincingly shown that high concentration dimeticone products have a high ovicidal efficacy, as compared to low concentration dimeticone, permethrin and pyrethrum [9]. Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Consequently, health professionals and consumers often cannot determine if effectiveness is due to adulticidal and ovicidal properties of the product, or a result of mechanical removal of adults and eggs by adjunctive combing. Thus, there is a clear need for adequately designed and standardized adulticidal and ovicidal ex vivo assays [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

“…Reliable data on ovicidal efficacy requires testing of fertile eggs with high hatch rates at different stages of development, as susceptibility to insecticides may vary according to the development of the embryo [9]. This can be achieved in an environment that closely mimics the natural habitat of head lice, which means that head lice would feed on human hosts, either by intermittent or continuous feeding.…”

Section: Introductionmentioning

confidence: 99%

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Ex Vivo Development of Eggs from Head Lice (Pediculus humanus capitis)

Sonnberg¹,

Oliveira²,

Melo³

et al. 2010

TODJ

Self Cite

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Abstract:Background: Data on ovicidal activity of pediculicides are essential to determine the efficacy of commercial products, and to define application schemes. We present an adaptation of historical methods for rearing head lice, and describe their development ex vivo.Methods: Adult head lice were collected and fed on volunteers to obtain fertile eggs of known age. Two methods of feeding were applied: interval feeding (performed every 8-12 hours), and continuous feeding (placing lice in a round Plexiglas receptacle, closed with gauze attached to the skin). Eggs were incubated at 25-28,6°C and 51,8% -69,3% relative humidity. The following outcome measures were used: appearance of eye spot; presence of embryonic structures; presence of embryonic movements; and hatching. A total of 340 eggs were obtained by continuous feeding. Of these, 205 were examined daily. The remaining 135 eggs and those obtained by interval feeding (n=159) were observed once, to confirm hatching status.Results: Eye spots of the embryos started to appear 6 days after oviposition (median = 7 days), and embryonic movements were first seen 9 days after oviposition (median =11 days). Interval feeding of head lice revealed a hatch rate of 10,7% (17/159), as compared to a hatch rate of 80,9% (275/340) achieved with continuous feeding. Hatching started 9 days after oviposition (median = 12 days). Skin irritation (papular rash; moderate to severe itching) appeared after continuous feeding of adult lice on volunteers.Conclusions: Continuous feeding of head lice on a human host is a suitable approach to obtain head lice eggs for ovicidal testing. The method is simple and cheap, offers conditions similar to the natural habitat, and hatch rates are high. However, side effects on volunteers are considerable.

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Pediculosis and Cimicosis

Dhar

Srinivas

2019

Harper's Textbook of Pediatric Dermatology

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Ovicidal efficacy of high concentration dimeticone: A new era of head lice treatment

Cited by 25 publications

References 5 publications

An ex vivo, assessor blind, randomised, parallel group, comparative efficacy trial of the ovicidal activity of three pediculicides after a single application - melaleuca oil and lavender oil, eucalyptus oil and lemon tea tree oil, and a "suffocation" pediculicide

An ex vivo, assessor blind, randomised, parallel group, comparative efficacy trial of the ovicidal activity of three pediculicides after a single application - melaleuca oil and lavender oil, eucalyptus oil and lemon tea tree oil, and a "suffocation" pediculicide

Ex Vivo Development of Eggs from Head Lice (Pediculus humanus capitis)

Pediculosis and Cimicosis

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