Embryonic development of human lice: rearing conditions and susceptibility to spinosad

Cueto, G. Mougabure; Zerba, Eduardo; Picollo, María Inés

doi:10.1590/s0074-02762006000300005

Cited by 29 publications

(31 citation statements)

References 19 publications

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“…First, testing of ovicidal efficacy of pediculicides can be conducted on head lice eggs collected from infested individuals. Hatch rates using this approach range between 90% and 95% [21][22][23][24][25] but there are only indirect markers to determine the eggs' age, such as their color [19]. Therefore, pediculicide testing according to age or developmental stage is limited.…”

Section: Discussionmentioning

confidence: 99%

“…We matched external features of development to the age of head lice eggs. Mougabure Cueto et al [19] used developmental criteria to classify head lice eggs into three developmental stages; early, medium and late embryos. The features described by Mougabure Cueto et al were also observed in our experiment, but age of head lice eggs in that study was not known, because the eggs had been collected from infested individuals.…”

Section: Discussionmentioning

confidence: 99%

“…Incubation of head lice eggs, either obtained by interval feeding or continuous feeding, was performed within ideal conditions of temperature (25-28,6°C) and relative humidity (51,8% -69,3%), as described recently by Mougabure Cueto et al [19]. Eggs were kept in Petri dishes on Whatman filter paper exposed to a 12h day-night rhythm for a minimum of 14 days.…”

Section: Incubation Of Eggsmentioning

confidence: 99%

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

Sonnberg¹,

Oliveira²,

Melo³

et al. 2010

TODJ

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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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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Incubation Of Eggsmentioning

confidence: 99%

See 1 more Smart Citation

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

Sonnberg¹,

Oliveira²,

Melo³

et al. 2010

TODJ

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“…Compared to other insecticides, spinosad has a unique mechanism of action in which it alters nicotinic and gamma-aminobutyric acid receptor function. 26,27 This leads to neuronal excitation, involuntary muscle contraction, and periods of hyperexcitation, which ultimately causes paralysis and death of the lice. 25,28 One of the challenges with insecticides that affect the nervous system is that they are not active against larvae early in development.…”

Section: Clinical Pharmacologymentioning

confidence: 99%

“…One of the proposed advantages of spinosad is that it is not significantly metabolized and may be present longer to act against larvae once their nervous systems do develop. 26,27 This could potentially decrease the need for multiple treatments.…”

Section: Clinical Pharmacologymentioning

confidence: 99%

Recent New Drug Approvals. Part 1: Drugs with Pediatric Indications

Shelton

Chhim

Christensen

2012

The Journal of Pediatric Pharmacology and Therapeutics

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This two-part review provides information about drugs that have been recently approved by the Food and Drug Administration and focuses on drugs approved with pediatric indications or approved in adults with active pediatric studies. Information was obtained from the product labeling and selected published studies. Part 1 reviews recently approved drugs with labeled pediatric indications, and Part 2 will review recent drug approvals in adults that have potential use in pediatrics and have active studies.

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Pediculus humanus capitis (head lice) and Pediculus humanus humanus (body lice): response to laboratory temperature and humidity and susceptibility to monoterpenoids

2009

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Human pediculosis is produced by Pediculus humanus humanus (Linnaeus 1758) and Pediculus humanus capitis (De Geer 1767). Laboratory-reared body lice, susceptible to insecticides, were used as reference in toxicological studies on head lice. In this work, we evaluated the survival of both subspecies at different temperatures and relative humidities and we propose the optimal conditions for comparative bioassays. Moreover, we used these conditions to test the activity of three monoterpenoids against both lice. The results showed differential response to changes in temperature and humidity between both organisms. The survival of body lice ranged between 83% and 100% and was not affected for the tested conditions. The survival of head lice depended on temperature, humidity, and exposure time. The optimal conditions for head lice were 18 masculineC and 97% relative humidity at 18 h of exposition. The insecticidal activity of three monoterpenoids (pulegone, linalool, and 1,8-cineole), evaluated according the selected conditions by topical application, showed no significant differences between males of body and head lice. To conclude, as head lice required more special laboratory conditions than body lice, the optimal head lice conditions should be used in both organisms in comparative bioassays. Body louse is an appropriate organism for testing products against of head louse.

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Embryonic development of human lice: rearing conditions and susceptibility to spinosad

Cited by 29 publications

References 19 publications

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

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

Recent New Drug Approvals. Part 1: Drugs with Pediatric Indications

Pediculus humanus capitis (head lice) and Pediculus humanus humanus (body lice): response to laboratory temperature and humidity and susceptibility to monoterpenoids

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