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PubMedDate not supplied

Drugs used in the treatment of pediculosis.

Pediculosis is the result of infestation by one of two families of sucking lice. The Pediculidae include the agents of head and body lice. Pubic lice belong to the family Pthiridae. Pediculus humanus capitis (the head louse) and Pediculus humanus humanus (the body louse) look identical. The two differ by the slightly larger size of the average body louse, as well as where they reside and deposit their eggs. Head lice live in the scalp hair and deposit their ova on hair shafts. Body lice live in the seams of clothing and deposit their ova on fabric fibers, usually in the seams of the clothing. Although body lice are common vectors of disease, head lice have not been proven to act as disease vectors. This having been said, the two are so closely related that it is naive to believe that head lice will never be shown to spread disease.

Humans↗

PubMed1983

Epidemiology and control of human head louse in Malaysia.

A survey of 4.112 primary school children living in and around Kuala Lumpur, Malaysia, revealed that 12.9% of the children were infested with Pediculus humanus capitis. Indians (28.3%) and Malays (18.9%) have a higher prevalence than Chinese (4.6%). The higher prevalence among Indians and Malays correlates well with their lower socio-economic status in the community; long hair also contributes to the higher rates of pediculosis among them. The prevalence rate was found to be related to socio-economic status, length of hair, family size, age, crowding and personal hygiene. Treatment with 0.2% and 0.5% malathion in coconut oil gave cure rates of 93% and 100%. Treatment with gammexane and actellic at 0.5% concentration gave a cure rate of 100% against adults and nymphs of Pediculus humanus capitis.

Age Factors↗

PubMed1994

[Phylogeny of lice (Insecta: Anoplura) of the Old World Monkey (Catarrhina)].

The genera Pediculus and Pthirus were studied cladistically, although the genus Pedicinus was also taken into account. Morphological characters from the literature, and some established through direct study were analyzed. Using five methods of cladistic analysis, one most parsimonious tree with a c.i. = 0.84 and a length of 38 was obtained ((Pedicinus)+(Paenipediculus+(Parapediculus+(Pedicu lus humanus capitis+Pediculus humanus humanus). A novelty of this study is the inclusion of the subgenus.

Animals↗

PubMedDate not supplied

The prevalence of ectoparasites in Ethiopian immigrants.

Newly arrived Ethiopian immigrants in Israel were screened for ectoparasitic insects and mites. Of 304 individuals examined 65.1% were infested with the head louse (Pediculus humanus capitis). The infestation rate among children varied between 65 and 100%. Children aged 6-11 years were the most infested group and no differences between girls and boys were found. The infestation rate in children was significantly higher than that found in adults. Approximately 39% of those examined were infested with the body louse (Pediculus humanus humanus). The rate of infestation with this parasite was higher in adults than in children and higher in females than males. Ten percent of the immigrants examined were infested with the scabies mite (Sarcoptes scabiei) and 4.3% with the human flea (Pulex irritans).

Adolescent↗

PubMed2002

Comparative in vitro pediculicidal efficacy of treatments in a resistant head lice population in the United States.

OBJECTIVE: To compare the pediculicidal activity of 5 head lice products available in the United States on head lice from south Florida. DESIGN: In vitro pediculicidal product comparison. SETTING: Lice Source Services, Inc, located in Plantation, Fla, a clinic for the treatment and grooming of individuals with pediculosis capitis. PARTICIPANTS: Head lice were collected from healthy clients with Pediculus capitis that came to Lice Source Services, Inc, to seek their services. INTERVENTIONS: Within 2 to 6 hours of capture, lice were placed in continuous direct contact with the pediculicide products and observed at regular intervals. Results were compared with findings of a recent study of a treatment-sensitive population of head lice conducted in Panama. MAIN OUTCOME MEASURE: Percentage of lice dead at regular observation intervals between 5 minutes and 3 hours of continuous exposure to the pediculicides. RESULTS: Two prescription products, Ovide lotion (0.5% malathion) and 1% lindane shampoo, were ranked in the same order as in 2 previous studies (first and last, respectively). The order of effectiveness from most to least effective was as follows: Ovide lotion, A-200 shampoo (a natural pyrethrin product synergized with piperonyl butoxide), undiluted Nix (1% permethrin), diluted Nix, RID (a natural pyrethrin product synergized with piperonyl butoxide), and 1% lindane shampoo. CONCLUSIONS: There were statistically significant differences in the efficacy of all the products when compared with the results found in the recent study in Panama, except for Ovide lotion. Of those tested, Ovide was the only pediculicide in the United States that had not become less effective. The difference in efficacy of 1% lindane, Nix, and pyrethrins between the Panama and Florida studies supports the argument that some head lice in the United States have become resistant to these treatments.

Adult↗

PubMed1988

Pyrethrins combined with piperonyl butoxide (RID) vs 1% permethrin (NIX) in the treatment of head lice.

In a randomized controlled trial, 58 subjects were treated for Pediculus humanus var capitis with either pyrethrins combined with piperonyl butoxide (RID, Pfizer Inc, New York) or 1% permethrin (NIX, Burroughs Wellcome Co, Research Triangle Park, NC); 31 subjects received RID and 27 subjects received NIX. Both products were applied according to manufacturer's directions so that NIX was applied only on the first visit and RID was applied on the first visit and again seven days later. After each treatment with a pediculicide, the comb supplied by the manufacturer was used to remove nits. Seven days after the initial visit, NIX was determined to be significantly better than RID for eradicating the lice infestation. Of the 27 subjects receiving NIX, 26 were live free vs 14 of the 31 RID-treated subjects. At day 14, there was no statistically significant difference in the treatments (27 of 27 NIX-treated vs 29 of 31 RID-treated subjects were lice free). The RID comb was superior to the NIX comb for nit removal. Both treatments were effective and well tolerated, and no subject experienced adverse reactions.

Adolescent↗

PubMed2006

In vitro pediculicidal and ovicidal activity of an extract and oil from fruits of Melia azedarach L.

BACKGROUND: Head louse infestation is difficult to control because of increasing lice resistance to synthetic pediculicidal drugs. OBJECTIVE: To test the activity of extract and oil obtained from fruits of Melia azedarach L. against the head louse Pediculus humanus capitis. METHODS: A filter paper diffusion bioassay was carried out in order to determine the pediculicidal and ovicidal activity of extract and oil from M azedarach L. fruits. RESULTS: Both vegetable products, tested either individually or in combinations, showed high levels of mortality on adult lice, with values ranging between 62.9% and 96.5%. The highest mortality rate was obtained with a combination of 20% ripe fruit extract with 10% ripe fruit oil. A formulation made with both extract and oil at 10% plus the addition of emulsifier and preserving agents showed 92.3% pediculicidal activity. The products were also successful in delaying or inhibiting nymph emergence, with the formulation being the most effective, with a complete inhibition of emergence. LIMITATIONS: Because adult lice are sensitive to starvation and therefore control mortalities are often higher than 20% in tests with field specimens, the results may not reflect the direct effect of the extract. CONCLUSIONS: These results demonstrate the possibility of using Melia products for controlling head lice, which are difficult to control because of their resistance to the currently used anti-louse agents.

Animals↗

PubMed2000

Resistance and the control of lice on humans and production animals.

Phthiraptera (lice) are specialised insects adapted to parasitise many warm-blooded vertebrates, including domestic animals and humans. Often, attempts by the host to alleviate the irritation created by lice, causes derangement of the hair/fur coat. Unless treated, this derangement may cause economic losses due to hide damage and/or downgrading of wool/hair/fur. In 1981, application of aqueous insecticide solutions (dipping) for the control of sheep body lice (Bovicola ovis) was largely superseded by off-shears pyrethroid "pour-on" treatments. By 1985, several field failures with these products were found to be due to low-level (20x) insecticide resistance. In 1990, high-level (640x) resistance was diagnosed in a New South Wales population. However, despite 30+years use, organophosphate-based products are still usually effective. Until recently, cattle lice caused little concern. Treatments were applied mainly for aesthetic reasons when cattle were to be presented for sale, and also to prevent damage to fences by rubbing cattle. However, the introduction of quality-management programmes have raised awareness of the economic losses due to hide damage associated with lice infestations. Emerging industries such as emu and alpaca farming have raised the pest status of other louse species, and necessitated insecticidal intervention. In humans, attempts to control head lice, Pediculus humanus capitis, infestations have repeatedly failed around the world.

Animals↗

PubMed2004

Pediculosis capitis among schoolchildren in urban and rural areas of eastern Poland.

The objective of this study was to compare the prevalence of head pediculosis in the rural and urban environments of Lublin Province (eastern Poland) in 1996-2000 and to examine socioeconomic factors influencing distribution among schoolchildren. A total of 95,153 schoolchildren living in urban and rural areas were examined twice yearly by school nurses. The overall rate of head pediculosis differs significantly between rural (1.59%) and urban (0.48%) schools in eastern Poland. Children between 8 and 12 years old were most frequently infested. Pediculosis was observed most frequently in girls both in the urban (63.5%) and rural (75.3%) schools and this was related with hairstyles. The prevalence of pediculosis decreased with increasing life standards, i.e. with high income, accessibility and consumption of water and better health care systems. Our findings showed that prevalence of pediculosis capitis depends on the age and sex of the schoolchildren and their living conditions. Hygienic controls of schoolchildren by nurses are important in the elimination of Pediculus humanus capitis. Our results confirmed pediculosis capitis is still a problem in different environments, particularly with lower life standards and poorer economic conditions of health care.

Adolescent↗

PubMed1997

Head louse infestations: epidemiologic survey and treatment evaluation in Argentinian schoolchildren.

BACKGROUND: Our aim was to demonstrate that the treatment of individual cases is effective, but not sufficient, to control endemic Pediculus capitis, and that eradication of the epidemiologic school focus may lower significantly the prevalence of infestation. Statistical data on the degree of infestation relating to socio-economic and cultural variables were also updated. Therapeutic effects and educational impact were evaluated. METHODS: An educational and motivational program was designed for pupils, parents, and teachers: 326 children and 15 adults were subjected to clinical and parasitologic evaluation. The recorded parameters included the age, sex, hair style and length, presence of other dermatologic diseases, degree of infestation, clinical remission, parasitologic remission, dwelling type and features, need to share a bed with co-dwellers, availability of home tap water supply, level of family income, and periodic medical controls. The entire population received treatment with neutral shampoo and rinsing cream containing 1% permethrin. Exclusion criteria were the presence of acute scalp inflammation and a history of pyrethrin and/or pyrethroid sensitivity. Statistical analysis was performed as required on data expressed as frequencies, percentages, means, and standard deviations by chi-square and Fisher exact tests. RESULTS: The overall infestation prevalence rate was 81.5%, the highest values corresponding to children from 6 to 11 years of age, with a slight predominance in males (55.4% vs. 44.6%). A significantly greater rate of clinical remission was observed in subjects enjoying home tap water supplies (p < 0.01). CONCLUSIONS: The model of research plus action adopted allows the following conclusions to be drawn: (i) individual and isolated treatments for pediculosis are useful, but will not by themselves allow for the epidemiologic control of this parasitosis; (ii) massive, complete, and simultaneous treatments lead to a significant decrease in infestation prevalence; (iii) educational measures tending to foster collective awareness enable greater epidemiologic surveillance to be achieved; (iv) careful inspection of the entire scalp is essential with the use of a powerful light source and lenses with high magnification, as the parasite has no predilection for any given area; (iv) socio-economic and cultural conditions are not relevant for infestation, although a good home tap water supply is essential for treatment.

Adolescent↗

PubMed2000

Pediculosis capitis in northern Jordan.

BACKGROUND: Little is known about the prevalence of pediculosis among school students in northern Jordan. OBJECTIVE: To study the incidence of pediculosis among school students of different socio-economic levels in northern Jordan. METHOD: A total of 2519 school students of both sexes enrolled in eight elementary governmental schools were examined for the presence of Pediculus capitis. Schools were grouped into four socio-economic classes: very low (VL), low (L), medium (M), and high (H). The chi-squared test was performed to analyze the results. RESULTS: Overall, 338 students (13.4%) were infested with nits, immature or adult P. capitis. Girls showed a higher prevalence (14.5%) than boys (11.1%). Statistical analysis for socio-economic classes and infestation rates yielded a significant effect of the four classes on infestation. This conclusion was evident among schoolgirls, where infestation rates were 28.8%, 18.9%, 6.1%, and 0.2% in VL, L, M, and H socio-economic classes, respectively. Schoolchildren in the age group 8-9 years exhibited higher prevalence rates (16% in boys and 22.1% in girls), while prevalences declined to 10.2% and 6.6% among boys and girls aged 10-12 years, respectively. CONCLUSIONS: This study reveals that socio-economic status is a major factor influencing the occurrence of pediculosis among school students of both sexes in Jordan. A national campaign should be implemented to enhance public awareness.

Animals↗

PubMed2003

The prevalence of pediculosis capitis in schoolchildren in Mersin, Turkey.

BACKGROUND: Pediculosis capitis is an endemic parasitosis affecting many countries of the world. The aim of this study was to investigate the incidence of head lice infestation in Mersin, Turkey. METHODS: A total of 5318 elementary schoolchildren, aged 8-16 years, were examined for the presence of Pediculus capitis. If any evidence of head lice was detected, such as live or dead eggs, or nits, the child was considered to be infected. The following details were recorded for each child: age, sex, family size, monthly income, number of siblings, parents' education, presence or absence of social security of the family, pet (cat or dog) ownership, and frequency of hair washing (per week). The chi-squared test and logistic regression analysis were performed to analyze the results. RESULTS: Pediculosis capitis was detected in 360 (6.8%) children. The prevalence of infestation was significantly higher in girls (13.3%) than in boys (1.1%) (chi2 = 313.2, d.f. = 1, P = 0.000). Children aged 8-9 years exhibited a significantly lower prevalence rate than those aged 10-11 years and those aged 12 years and above. The following variables were found to be statistically significantly related to pediculosis capitis: sex, age, father's education level, and pet ownership (cat or dog). CONCLUSIONS: Our results show that the prevalence of pediculosis capitis is not very high in Mersin, Turkey, and is observed in all schools regardless of the socio-economic and personal hygiene status of the children.

Adolescent↗

PubMed1993

Patterns of erythrocyte digestion by bloodsucking insects: constraints on vector competence.

Two general patterns of erythrocyte digestion were observed in representative species from four insect orders. Ingested erythrocytes were hemolyzed rapidly, and blood meals remained liquefied within body lice, Pediculus humanus L. and the fleas Ctenocephalides felis (Bouché) and Xenopyslla cheopis (Rothschild). Peritrophic membrane was absent. In contrast, there was a lag time of 6-18 h before substantial degradation of erythrocytes within the blood meals of bed bugs, Cimex lectularius L.; the sand fly Phlebotomus papatasi Scopoli; and the mosquitoes Anopheles stephensi Liston and Culex pipiens L. Blood meals of sand flies and mosquitoes were clotted and surrounded by peritrophic membrane at 18-24 h after feeding. Clotting and peritrophic membrane were less pronounced in bed bugs. It is proposed that acquisition and maintenance of pathogen types (i.e., prokaryotic versus eukaryotic) within insects are constrained by the general pattern of bloodmeal processing.

Animals↗

PubMed2005

Identification of sodium channel mutations in human head louse (Anoplura: Pediculidae) from Denmark.

The presence of the two mutations T9291-L932F in the voltage-sensitive sodium channel gene associated with permethrin resistance (kdr-like) was shown in head louse, Pediculus humanus capitis De Geer, populations in Denmark. The existence of one susceptible and one T929I-L932F haplotype based on the limited single nucleotide polymorphism (SNP) of these sequences was established. One louse had an SNP causing a G943A substitution in the trans-membrane segment five of domain II on the sodium channel, which has not been identified in other insect species. A polymerase chain reaction-restriction endonuclease method using genomic DNA to discriminate between resistant and susceptible alleles in head lice was developed and implemented. The SNP that results in the T9291 substitution also creates a cutting site for the restriction endonuclease SspI, and the presence of one or two SspI cutting sites in head lice is diagnostic for the T9291-L932F haplotype.

Amino Acid Sequence↗

PubMed2007

Host-symbiont interactions of the primary endosymbiont of human head and body lice.

The first mycetome was discovered more than 340 yr ago in the human louse. Despite the remarkable biology and medical and social importance of human lice, its primary endosymbiont has eluded identification and characterization. Here, we report the host-symbiont interaction of the mycetomic bacterium of the head louse Pediculus humanus capitis and the body louse P. h. humanus. The endosymbiont represents a new bacterial lineage in the gamma-Proteobacteria. Its closest sequenced relative is Arsenophonus nasoniae, from which it differs by more than 10%. A. nasoniae is a male-killing endosymbiont of jewel wasps. Using microdissection and multiphoton confocal microscopy, we show the remarkable interaction of this bacterium with its host. This endosymbiont is unique because it occupies sequentially four different mycetomes during the development of its host, undergoes three cycles of proliferation, changes in length from 2-4 microm to more than 100 microm, and has two extracellular migrations, during one of which the endosymbionts have to outrun its host's immune cells. The host and its symbiont have evolved one of the most complex interactions: two provisional or transitory mycetomes, a main mycetome and a paired filial mycetome. Despite the close relatedness of body and head lice, differences are present in the mycetomic provisioning and the immunological response.

Animals↗

PubMed2000

Overdiagnosis and consequent mismanagement of head louse infestations in North America.

BACKGROUND: Lay personnel and many health care workers in the United States believe that head louse infestations caused by Pediculus capitis are exceedingly transmissible and that infested children readily infest others. Schoolchildren therefore frequently become ostracized and remain so until no signs of their presumed infestations are evident. Repeated applications of pediculicidal product and chronic school absenteeism frequently result. METHODS: To determine how frequently louse-related exclusions from schools and applications of pediculicidal therapeutic regimens might be inappropriate, we invited health care providers as well as nonspecialized personnel to submit specimens to us that were associated with a diagnosis of pediculiasis. Each submission was then characterized microscopically. RESULTS: Health care professionals as well as nonspecialists frequently overdiagnose pediculiasis capitis and generally fail to distinguish active from extinct infestations. Noninfested children thereby become quarantined at least as often as infested children. Traditional anti-louse formulations are overapplied as frequently as are "alternative" formulations. Pediculicidal treatments are more frequently applied to non-infested children than to children who bear active infestations. CONCLUSIONS: Pediculicidal treatments should be applied solely after living nymphal or adult lice or apparently viable eggs have been observed. Because health care providers as well as lay personnel generally misdiagnose pediculiasis, and because few symptoms and no direct infectious processes are known to result, we suggest that the practice of excluding presumably infested children from school may be more burdensome than the infestations themselves.

Administration, Topical↗

PubMed2004

Infestation of people with lice in Kathmandu and Pokhara, Nepal.

The prevalence of infestation with head lice and body lice, Pediculus spp. (Phthiraptera: Pediculidae) and pubic (crab) lice Pthirus pubis (L.) (Phthiraptera: Pthiridae), was recorded from 484 people in Nepal. The prevalence of head lice varied from 16% in a sample of people aged 10-39 years of age, to 59% in street children. Simultaneous infestations with head and body lice (double infestations) varied from 18% in slum children to 59% in street children.

Adolescent↗

PubMedDate not supplied

Efficacy of a reduced application time of Ovide lotion (0.5% malathion) compared to Nix creme rinse (1% permethrin) for the treatment of head lice.

Our objective was to conduct a randomized, investigator-blinded evaluation of the pediculicidal and ovicidal activity of a reduced application time (20 minutes) of Ovide (0.5% malathion) compared to Nix (1% permethrin) in a south Florida population infested with Pediculus humanus capitis. Either Ovide or Nix was applied according to the label instructions. However, Ovide application time was reduced to 20 minutes. At day 8, subjects with live lice were re-treated with the same product and procedure as on day 1. Ovicidal and pediculicidal efficacy were evaluated at days 8 and 15. A subject free of lice and viable eggs at day 15 was considered to be a treatment success. Percent efficacy was calculated using the number of subjects free of lice and viable eggs per total number of subjects treated. We found that a 20-minute application of Ovide was significantly more pediculicidal and ovicidal (98%) compared to Nix (55%) at day 15 (p < 0.0001). The percentage of Ovide subjects who required treatment at day 8 was half that of the Nix group. The reinfestation rate was 0% with Ovide and 33% with Nix. In conclusion, a 20-minute treatment with Ovide, instead of the approved 8- to 12-hour application, cured 40 of 41 subjects (98%), demonstrating superior efficacy to Nix. The poor efficacy of Nix confirms the resistance of head lice to permethrin in south Florida.

Adolescent↗