Prevention and treatment of head lice in children

Pediculosis humanus capitis in 6-7 years old schoolchildren in Valencia, Spain

OBJECTIVES

Pediculosis humanus capitis is a worldwide public health concern that affects mostly school-aged children. The aim of this study is to determine the rate of pediculosis and to determine possible risk factors in a group of primary school children in Valencia, Spain; 227 children, 6-7 years old, were selected from 7 schools.

METHODS

A self-reported questionnaire completed by the parents/guardians about the presence of pediculosis in their children and their knowledge about pediculosis. The results recorded in the questionnaire were analysed by SPSS® software.

RESULTS

30.4% of the children had pediculosis. The results showed significant variation (p < 0.05) in prevalence depending on the following factors: sex, hair length, level of parental education, family size, presence of affected family member in the home, and frequency of hair washing. Less than half of parents/guardians showed an appropriate level of knowledge on pediculosis. Pediculosis remains a health problem in Valencian schoolchildren. The family size and existence of another member with pediculosis were shown to be the main potentiating factors.

CONCLUSIONS

Parents are not sufficiently informed about pediculosis and adopt inappropriate practices. There is a need to promote studies with the objective of determining risk factors for pediculosis as well as the need for actions to increase the knowledge of parents and healthcare professionals on this parasitosis to prevent outbreaks in the community, assure correct treatment and maintain effective epidemiological surveillance.

Head louse infestations before and during the COVID-19 epidemic in Israel

Head louse infestations caused by Pediculus humanus capitis (Phthiraptera: Pediculidae) are a public health problem in developing and developed countries worldwide. Head to head contact is by far the most common mode of lice transmission. In March 2020, WHO declared the COVID-19 outbreak as a pandemic. Starting from March 2020, the Israeli government established mandatory isolation for extensive periods including closure of school systems for very long time. The aim of the project was to compare the pediculicide sale numbers before the COVID-19 epidemic with those starting of the epidemic in 2020, as a possible marker for changing epidemiology of head lice during the COVID pandemic. Data were collected from a large pharmacy chain in Israel, which provided the actual sales of pediculicides during the years 2010-2020. During the period 2010-2019 a significant increase of pediculicide sales from 281,986 - 498,107 was observed, the highest number being from 2019. In 2020, this number dropped to 294,477, a significant drop compared to previous years and to 2019. The results of this study suggest that head louse infestations are increasing in the last years, while the extended isolation of children due to COVID-19 influenced significantly the infestation rate of children with head lice.

Impact of a health educational interventional program on reducing the head lice infestation among pupils in an elementary school of a sub-tropical region: a quasi-experimental study

BACKGROUND

Pediculosis is an important social challenge that can be caused by human head louse, Pediculus humanus capitis. This infestation is cosmopolitan, especially in countries with low hygiene and sanitation. Regular health education classes for students and their parents are required to reduce this infestation in schools and families. This study aimed to evaluate the impact of a health education intervention program on reducing head lice among pupils of an elementary school.

METHODS

In a quasi-experimental study, a total of 880 elementary school girls were screened for pediculosis in (2017-2018). The prevalence of pediculosis follow-up continued monthly until the end of the school year after a two months educational intervention course. Visual inspection was applied for initial diagnosis of infection. The suspected cases were confirmed by wood lamp and potassium hydroxide (KOH) microscopic examination. Also eight questions about diagnostic, epidemiology, treatment and prevention were answered in a questionnaire by 50 volunteer parents before and after the training intervention course, to evaluate their general knowledge and measure the effectiveness of learning. All data were statistically analyzed using SPSS software (version 20.0, SPSS, Inc., Chicago, IL, USA). McNemar's test was also applied to investigate the prevalence rate before and after the intervention. A p -value of less than 0.05 was considered as statistically significant.

RESULTS

At the beginning of study, pre-intervention prevalence of pediculosis among pupils was 8.4% (49/594). The mean age in all pupils was 9.86 ± 1.83 years old and the most infestation was shown in fourth-grade students with 10 years old. Analysis of statistics demonstrated a significant difference between having infestation and the number of members in the families. Post-intervention phase led to a decreased prevalence of pediculosis in pupils to 3% (8/594) (p-value < 0.05). Based on statistical analysis of questions before and after the training in the questionnaire, a significant increase of parental knowledge was observed on the prevention program of pediculosis (p-value < 0.001).

CONCLUSION

The prevalence of pediculosis was significantly reduced following the educational interventions in the school. The applied interventions may be implemented in other residual centers to get rid of this important infestation.

Head lice were also affected by COVID-19: a decrease on Pediculosis infestation during lockdown in Buenos Aires

Pediculosis is a worldwide disease affecting school-aged children produced by the presence of the head louse, Pediculus humanus capitis De Geer, an obligate ectoparasite on the human scalp feeding exclusively on blood. Transmission occurs primarily through direct physical head-to-head contact. In March 2020, the World Health Organization (WHO) declared the COVID-19 outbreak as a pandemic. COVID-19 is caused by SARS-CoV-2, a variant of the coronavirus. Therefore, on March 18, 2020, the Argentinean government established mandatory isolation for an indefinite period. This obligatory isolation interrupted regular classes avoiding direct contact between children, thus affecting the dispersal route of individuals and the evolution of head louse populations. In this study, we evaluated through an online survey how confinement affected the prevalence of lice during lockdown compared to the situation prior to confinement. The survey allowed to discriminate the different control strategies, the number of treatments, and the amount of insects recorded by parents. Data of 1118 children obtained from 627 surveys were analyzed. As the main result, it was observed that prevalence of lice decreased significantly from before (69.6%) to during (43.9%) COVID-19 lockdown. Moreover, head lice infestation was more effectively controlled in households with up to 2 children in comparison to households with 3 or more children. This is the first study that analyzed the prevalence of head lice during COVID-19 pandemic. In addition, this work demonstrated the impact of social distance in the population dynamics of head lice and how it could affect the control strategies in the future.

Comparative efficacy of permethrin 1%, lindane 1%, and dimeticone 4% for the treatment of head louse infestation in Iran

Pediculosis capitis occurs worldwide. Children in the age group of 5-13 years are the ordinary victims. Population-based studies show that the prevalence of pediculosis is 1.6-13.4% in various regions of Iran. In this observer-blinded trial, we conducted a study to evaluate the comparative efficacy and safety of permethrin 1% and lindane 1% shampoos and dimeticone 4% lotion to cure head lice infestation in children aged 7-13 years in female primary schools in Ahvaz City, Iran. Children with head lice were randomized to receive each treatment. Two applications of permethrin 1% or dimeticone 4% were done, 1 week apart. However, lindane 1% was used just once for treatment cases. Data analysis was done using SPSS software. Recovery differences between the groups were tested using the chi-squared test. Four hundred forty-four louse-infested schoolgirls were randomly treated with them. Permethrin, lindane, dimeticone, and placebo produced the recovery rates 56.8, 31.5, 51.4, and 10.8% on day 2 post-treatment, respectively. Cure rates were in the permethrin group on days 8 and 15, respectively, 69.4 and 90.1%. The success rates were in the lindane group on days 8 and 15, respectively, 73 and 86.5%. The success rates were in the dimeticone group on days 8 and 15, respectively, 60.4 and 94.6%. It is recommended dimeticone lotion (4%) as a very effective and safe pediculicide for pediculosis control. With proper application, dimethicone can rapidly cure head lice infestation with minimal reinfestation.

International recommendations for an effective control of head louse infestations

Head louse infestations continue to be a concern of public health in most countries, including the most developed ones. The present recommendations are intended to inform and stress the role and impact of the different authorities, institutions, industry, and the public in the control of head lice in order to reduce the prevalence of this parasite. We encourage health authorities to pursue more effective methods to correctly identify such infestations, and evaluate existing and new pediculicides, medical devices, louse repellents, and louse- and nit-removal remedies. Pediculicides and medical devices must have verifiable claims in the instructions for use and should be tested periodically to document current levels of resistance by lice to the active ingredients and to the formulated products. Where the prevalence of lice is claimed to be epidemic, children should be periodically evaluated objectively to document the actual level of prevalence. Continuing education for health providers and the general population promises to correct misinformation regarding the biology, prevention, and management of lice. Parents should regularly inspect their children for head lice and treat as necessary. Health authorities are encouraged to eliminate policies and practices that rely upon school exclusion as a means to reduce incidence and prevalence, e.g., the 'no-nit' policy which lacks scientific justification, and are counterproductive to the health and welfare of children.

Molecular Markers of Pesticide Resistance and Pathogens in Human Head Lice (Phthiraptera: Pediculidae) From Rural Georgia, USA

Although the head louse, Pediculus humanus capitis De Geer, and body louse, Pediculus humanus humanus L., both have a worldwide distribution, the occurrence of head louse pediculosis appears to be more prevalent in modern societies despite systematic use of various pediculicides. This study tested head lice collected in rural Georgia and body lice collected in Russia for the prevalence of a kdr-biomarker that is associated with permethrin resistance. This study also screened lice for the presence of DNA from Bartonella quintana and Acinetobacter species. The kdr-permethrin resistance biomarker for the T917I mutation was detected by RFLP and PCR in 99.9% of head lice tested from Georgia, whereas only 2.9% of body lice from Russia tested positive for this kdr biomarker. DNA of B. quintana was detected in 10.3% of head lice from Georgia, whereas 84.8% of body lice from Russia tested positive. Acinetobacter DNA was detected in 80.8% (95% CI, 68-89%) of head lice from Georgia and all body lice from Russia tested.

Treatment of human head lice infestations in a single application with a new galenic lotion

To evaluate the efficiency and safety of a new galenic meta-emulsion for the treatment of human head lice (Pediculus capitis) in a single application. A controlled clinical study was conducted comparing lice infestation and nit hatching observed before and after a treatment in a single application. Eighty-two of the 87 children included completed the study. An infestation control was performed on 36 and 46 children, 8 and 24 h respectively after application. Five days later, a meticulous hair examination was carried out to check that the lice infestation was completely cured. After a single application of the lotion being tested, an examination of the scalp with a head lice detection comb, as well as an examination of the rinsing water and the towel used for drying after washing, showed that out of the total 1285 lice, there were no live lice. The percentage of nits hatching before treatment was close to 70%. In comparison, after an 8-h treatment (t(+8)), the percentage of nits hatching was 2.1%, with only 0.35% of living nymphs. After a 24-h treatment (t(+24)), 1.9% hatched with 0.38% living nymphs. Nymphs were revealed to be non-viable. After 5 days (t(+120)), no living adult or immature lice were found on the subjects tested. Moreover, observation of tolerance levels to this treatment at days 1, 5 and 12 showed no side effects. The specific galenic lotion completely cured head lice infestation in the population studied in a single application. The lotion, a patented meta-emulsion, has a mechanical action that asphyxiates lice and nits. Considering the advantages of the single application, the possibility of complete concomitant therapeutics for a whole school population within only 1 day and the high level of tolerance to this treatment, this approach seems simple and promising.

Influence of the formulations in removing eggs of Pediculus humanus capitis (Phthiraptera: Pediculidae)

Head lice lay eggs in human head hairs in order to reproduce. There is a difficulty associated to the process of detaching these eggs: they are tightly gripped to the hair by a secretion produced by female head lice. The physical removal of eggs has become an important part of treatment of louse infestations. The finding of new products to loosen the eggs is necessary to avoid mistaken diagnosis or reinfestations. This work aimed to compare different kinds of pediculicide formulations in order to find if their presentations represented differences in the egg remover effect. We also wanted to present a new device to test the efficacy of the egg remover formulations. Products with creamy presentations (Bio infant lice and egg remover and hair conditioner) and one containing dimethicone (Nyda) showed the lower mean forces compared with the control (lower mean forces represented best removal activity). Whereas, the Biferdil egg remover (gel) and Nopucid Tribit (hydroalcoholic lotion) had no egg removal effect, presenting the highest mean forces (177.82 and 189.99 mN, respectively) compared with the control. Additionally, we proposed a removal index (RI) to compare the efficacy of different products on the egg removal activity (RI > 0, good performance). The higher index values were for Bio infant lice and egg remover (0.72) and Biferdil hair conditioner (0.58). The lowest index values were for Biferdil egg remover (-0.26) and Nopucid Tribit (-0.35).The formulation of over the counter pediculicides in the egg remover effect was discussed.

How long do louse eggs take to hatch? A possible answer to an age-old riddle

There are no rigorous data on how long eggs of the head louse, Pediculus capitis (Phthiraptera: Pediculidae), take to hatch. Pediculicide users often report reinfestations after apparently successful treatments in the absence of infective contacts. This study aimed to resolve the question of whether some louse eggs hatch after the completion of treatment, thereby giving rise to a new infestation. Data were extracted from the records of lice collected after treatments in 20 clinical intervention trials. All datasets were eliminated except those in which only newly hatched louse nymphs were found prior to the final assessment. This excluded the possibility that new eggs were laid after the first treatment and thus any young lice found must have originated from eggs laid before the start of treatment. This identified 23 of 1895 (1.2%) records with evidence of louse nymphs emerging at 13 days or more after the first treatment, 3–6 days longer than previous estimates. Current treatment regimens for pediculicides of two applications 7–10 days apart appear inadequate, which may explain continuing infestation in the community. Therefore, it is suggested that a revised approach using three treatments applied at intervals of 1 week should prevent the survival of any nymphs and their development into a new generation of adults.

Activity of tea tree oil and nerolidol alone or in combination against Pediculus capitis (head lice) and its eggs

Head lice infestation is an emerging social problem in undeveloped and developed countries. Because of louse resistance increasing, several long-used insecticidal compounds have lost their efficacy, and alternatives, such as essential oils, have been proposed to treat this parasitic infestation. The present study investigated the efficacy of two natural substances: tea tree (Melaleuca alternifolia) oil and nerolidol (3,7,11-trimethyl-1,6,10-dodecatrien-3-ol) against lice and its eggs. Products were used alone and in combination (ratio 1:1 and 1:2) from 8 % dilution. The in vitro effect of natural substances at different concentrations were evaluated against 69 head lice (adults and nymphs) and 187 louse eggs collected from school children in Chieti-Pescara (Central Italy) over a 6-month period. The lice mortality was evaluated for 24 h by a stereo light microscope. The ovicidal activity was monitored by microscopic inspections for 15 days. Tea tree oil was more effective than nerolidol against head lice with 100 % mortality at 30 min and 1 % concentration. On the contrary, nerolidol expressed a more pronounced ovicidal activity inducing the failure of 50 % of the eggs to hatch at 1 % concentration after 4 days; the same effect was achieved by using a twice concentration of tea tree oil. The association of the two substances both in ratios 1:1 and 1:2 combined efficaciously their insecticidal and ovicidal effect; in particular, the ratio 1:2 (tea tree oil 0.5 % plus nerolidol 1 %) acted producing both the death of all head lice at 30 min and the abortive effect of louse eggs after 5 days. These results offer new potential application of natural compounds and display a promising scenario in the treatment of pediculosis resistant cases. The development of novel pediculicides containing essential oils could be, in fact, an important tool to control the parasitic infestation.

Assessment of the efficacy and safety of a new treatment for head lice

Infestation with head lice is a widespread, persistent, and recurring issue leading to serious health problems if untreated. We are facing resistance phenomena to usual pediculicides and questions about their direct or cumulative toxicity. The aim of this trial was to assess the efficacy of a new product, free of chemical insecticides but with a physical effect. This product contains components whose antilice efficacy has already been demonstrated, as well as Andiroba oil which asphyxiates the lice and Quassia vinegar which dissolves the chitin of the nits (they are then inactivated). 30 patients with head lice infestation, aged 3–39 years, applied the treatment one to three times, 5 days apart. Cure was defined as the absence of live lice after 5, 10, or 14 days, and symptoms are usually associated with infestation. Easiness and safety of the treatment were assessed by the patients and/or their parents. Overall cure rates were 20% on D5 after one treatment, 37% on D10 after two treatments, and 90% on D14 after three treatments. Symptoms such as itch, scalp dryness, redness, and flakiness rapidly diminished. This treatment seems to be a beneficial addition or a valuable alternative to existing treatments, considering the total absence of chemical insecticides, the absence of drug-resistance induction in head lice, the absence of major toxicological risks compared with usual pediculicides, and the favourable patient use instructions.

Contact and fumigant toxicity of hexane flower bud extract of Syzygium aromaticum and its compounds against Pediculus humanus capitis (Phthiraptera: Pediculidae)

The head lice, Pediculus humanus capitis De Geer is an obligate ectoparasite of humans that causes pediculosis capitis, a nuisance for millions of people worldwide, with high prevalence in children. P. humanus capitis has been treated by methods that include the physical remotion of lice, various domestic treatments, and conventional insecticides. None of these methods render complete protection, and there is clear evidence for the evolution of resistance and cross-resistance to conventional insecticides. Non-toxic alternative options are hence needed for head lice treatment and/or prevention, and natural products from plants are good candidates for safer control agents that may provide good anti-lice activity. The plant extracts are good and safe alternatives due to their low toxicity to mammals and easy biodegradability. The present study carried out the pediculocidal activity using the hexane flower bud extract of Syzygium aromaticum (Myrtaceae) against P. humanus capitis examined by direct contact and fumigant toxicity (closed- and open-container methods) bioassay. The chemical composition of S. aromaticum flower bud hexane extract was analyzed by gas chromatography-mass spectrometry. The major chemical constituent (58.79%) of flower bud hexane extract S. aromaticum was identified as chavibetol (5-allyl-2-methoxyphenol) by comparison of mass spectral data and retention times. The hexane extract of S. aromaticum was subjected to gas chromatography analysis, and totally 47 compounds were detected, of which chavibetol was predominantly present. The other major constituents present in the hexane extract were eugenol acetate (phenol,2-methoxy-4-(2-propenyl)-,acetate (15.09%), caryophyllene-(I1) (2,6,10,10-tetramethyl bicyclo [7.2.0] undeca-1,6-diene (13.75%), caryophyllene oxide (3.04%), 2,6,6,9-tetramethyl-1,4,8-cycloundecatriene (1.67%), and copaene (1.33%). The filter paper contact bioassay study showed pronounced pediculicidal activity in the flower bud hexane extract of S. aromaticum. The toxic effect was determined for every five in an 80-min treatment. The result showed percent mortality of 40, 82, and 100 at 5, 10, and 20 min, and the median lethal time (LT(50)) value was 5.83 (0.5 mg/cm(2)); 28, 82, and 100 at 5, 10, and 30 min. (LT(50) = 6.54; 0.25 mg/cm(2)); and 13, 22, 42, 80, and 100 at 5, 10, 20, 40, and 80 min (LT(50) = 18.68; 0.125 mg/cm(2)), respectively. The vapor phase toxicity was tested at 0.25 mg/cm(2). There was a significant difference in pediculicidal activity of S. aromaticum extract against P. humanus capitis between closed- and open-container methods. Adult mortalities were determined for every five in 60 min (closed method) and for every ten in 180 min (open method). The closed method showed the percent mortality was 45, 88, and 100 at 5, 10, and 15 min (LT(50) = 5.39), respectively. In the open-container method, the percent mortality was observed 5, 20, 47, 84, and 100 at 10, 20, 60, 120, and 180 min (LT(50) = 47.91), respectively. The mortality was more effective in the closed containers than in open ones, indicating that the effect of hexane extract was largely a result of action in the vapor phase exhibited fumigant toxicity. Studies of anti-lice activity of extract provide the basis for preliminary conclusions of structure activity relationships; although no clear patterns can yet be drawn. We here attempt to provide a concise compilation of the available information on anti-lice activity of plant extracts and plant-derived compounds.

A randomized, assessor-blind, parallel-group, multicentre, phase IV comparative trial of a suffocant compared with malathion in the treatment of head lice in children

BACKGROUND/OBJECTIVES

There are concerns about the effectiveness of head lice treatments because of increasing resistance and safety. This trial compared the safety and efficacy of a suffocant-based head lice treatment to malathion in children.

METHODS

The trial used strict entry criteria, standardized treatment and assessment regimens, sibling treatment where appropriate and a primary efficacy end-point defined as the absence of live head lice.

RESULTS

A total of 216 children were enrolled. One hundred and sixty-nine were per-protocol. The suffocant was significantly more effective than malathion for the intention-to-treat population (53.9% vs 40.4% louse-free, unadjusted P = 0.052; adjusted P = 0.024), as well as for the per-protocol population (57.8% vs 43.0% louse-free, unadjusted P = 0.054; adjusted P = 0.045). Adverse events were limited to itching or stinging and there were no serious or systemic adverse events. Repeat insult patch testing with the suffocant resulted in no adverse reactions. In vitro tests confirmed that the suffocant is a potent ovicide and pediculicide with 100% mortality of eggs and lice following a 20-min contact time.

CONCLUSIONS

The suffocant is shown to be significantly more effective in eliminating head lice than malathion in children, while being associated with a low incidence of mild, transient adverse events.

[Metal microchanelled fine-toothed comb use in the diagnosis of pediculosis]

BACKGROUND

Methods for the diagnosis of Pediculus humanus var. capitis are controversial and most studies are based on direct visual exam.

OBJECTIVE

The objective of this study was to compare the diagnosis efficacy of both direct visual exam and the use of a metal microchanelled fine-toothed comb.

METHODS

946 children and teenagers 4 to 19 years of age were examined. Each individual's hair was examined twice to determine whether there was infestation by lice or nits, through direct visual exam and the use of a metal microchanelled fine-toothed comb.

RESULTS

The visual diagnosis detected infestation in 30.7% of the cases, while the metal comb detected infestation in 51.5%. Females were the most affected. The forms of parasites detected through direct visual exam were: only lice (adults and/or nymphs) 1.4%, only live nits 64.8% and live nits and lice, 33.8%; with the metal comb the percentages were 6.4%, 23.6% and 70%, respectively. The average time to find a louse was 57 seconds with the fine-toothed comb and 116.4 seconds through the direct visual exam.

CONCLUSIONS

Diagnosis with the microchanelled fine-toothed comb is twice as fast and 3.6 times more efficient than through direct visual exam.The direct visual exam detects non-active, past infestations, and underestimates active ones.

In vitro screening of anti-lice activity of Pongamia pinnata leaves

Growing patterns of pediculocidal drug resistance towards head louse laid the foundation for research in exploring novel anti-lice agents from medicinal plants. In the present study, various extracts of Pongamia pinnata leaves were tested against the head louse Pediculus humanus capitis. A filter paper diffusion method was conducted for determining the potential pediculocidal and ovicidal activity of chloroform, petroleum ether, methanol, and water extracts of P. pinnata leaves. The findings revealed that petroleum ether extracts possess excellent anti-lice activity with values ranging between 50.3% and 100% where as chloroform and methanol extracts showed moderate pediculocidal effects. The chloroform and methanol extracts were also successful in inhibiting nymph emergence and the petroleum ether extract was the most effective with a complete inhibition of emergence. Water extract was devoid of both pediculocidal and ovicidal activities. All the results were well comparable with benzoyl benzoate (25% w/v). These results showed the prospect of using P. pinnata leave extracts against P. humanus capitis in difficult situations of emergence of resistance to synthetic anti-lice agents.

Epidemiological aspects of Pediculosis capitis and treatment evaluation in primary-school children in Iran

This study was undertaken to assess the prevalence of and epidemiological factors associated with, head lice infections in Iranian primary schools in 2006 and evaluate data on the therapeutic efficacy of lindane shampoo. A total of 40586 children (19774 boys (48.72%) and 20812 girls (51.28%)] from 198 Governmentprimary schools in Kerman, were screened for head lice between March and June 2006. The diagnosis of head lice infestation was confirmed by clinical inspection of scalp and hair for the presence of adult lice nymphal stage, or eggs (nit) by line-toothed head lice comb. All children infested with lice were treated with lindane shampoo (1% gamma benzene hexachloride). The overall prevalence of head lice infestation was 1.8%. The prevalence of infestation was significantly higher in girls (2.9%) than in boys (0.6%) (p = 0.000). The infestation rate was greater among pupils who were living in rural areas (4.6%) than in urban areas (1.5%). Of the 721 children with a positive examination result, 424 pupils (58.8%) were reported as having been infested with head lice in the previous 6 months. Mother's education level was a significant risk factor in this model (p < 0.05). At 2 weeks after the primary treatment, the success rates of treatment were 49%. Comprehensive survey in our work showed the better future of the disease and related factors. Education campaigns by health care officials, physicians and teachers are expected to be helpful for head lice control. It is essential that governments should be supported form cooperation between the school authorities and public health centers to successful control head lice infestation in primary school. Also there is an urgent need to identify safe, novel insecticides for proved efficacy.

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.

Itch and scratch: scabies and pediculosis

Scabies and lice infestations are almost an everyday diagnosis in the dermatology clinics. Along with the unbearable itch, resistance to medication, secondary infection, and the high risk for spreading the parasite to their close contacts, the patients have also to battle with many myths, prejudice, and shames connected to those infestations.

Head louse infestations: the "no nit" policy and its consequences

Health authorities in the USA, Canada and Australia recommend a "no nit" policy, i.e. the immediate dismissal of all children who have head lice, eggs and/or nits on their hair from school, camp or child-care settings. These children would be readmitted to the institution only when all head lice, eggs and nits have been removed. The "no nit" policy assumes that all nits seen when examining the scalp are viable and therefore the infested individual should be treated for lice, and all nits must be removed from the scalp. However, it has been repeatedly shown that only a small number of children who have nits on their scalp are also infested with living lice. Accordingly, in the USA alone 4-8 million children are treated unnecessarily for head lice annually, which amounts to 64% of all lice treatments. In addition, 12-24 million school days are lost annually. The annual economic loss owing to missed workdays by parents who have to stay home with their children adds US$4-8 billion to the country's economy. The policy also results in serious psychological problems for children and their parents. Therefore, the "no nit" policy should be abandoned and alternative ways of examination and treatment for head lice should be found.

Albendazole: single or combination therapy with permethrin against pediculosis capitis

Pediculosis capitis is a worldwide problem and a growing concern because of resistance to pediculicides. In the present study, we investigated whether albendazole could be used in the treatment of pediculosis capitis in combination with 1% permethrin or alone. A total of 150 children were randomly divided to five groups of 30 each. Group 1 got albendazole in a single dose (400 mg), group 2 got albendazole at 400 mg for 3 days, group 3 was given 1% permethrin, group 4 took 1% permethrin and albendazole in a single dose (400 mg), and group 5 got 1% permethrin and albendazole in a dose of 400 mg for 3 days. Groups given albendazole were also given another 400 mg dose of albendazole after 1 week. The success rate of treatment at the 2-week follow-up for all groups was 61.5%, 66.6%, 80.0%, 84.6%, and 82.1%, respectively. No statistically significant difference was found between the groups. The results of this study suggest that albendazole is effective against pediculosis capitis and there is no synergistic effect between albendazole and 1% permethrin.

Pediculosis capitis

Pediculosis capitis is a worldwide public health concern. Infestation occurs most commonly in children, with a peak incidence between 5 to 11 years of age. The condition is more common in girls and less common in Black children. Direct head-to-head contact is the most common mode of transmission. Pruritus is the most common symptom of infestation. The gold standard for diagnosing pediculosis capitis is finding a live louse or nymph in the scalp or viable egg in the scalp hair. Pediculicides are the most effective treatment. All household members and close contacts should be examined and treated concurrently if infested. The child should be allowed to return to school or to a child care facility after proper treatment. The child should be discouraged from close, direct head contact with others or from sharing items that have come in contact with the hair.

Milben, Läuse und Flöhe

Ectoparasitoses or epizoonoses are skin disorders caused by animal parasites living on the body surface. Worldwide they are among the most frequent dermatoses, particularly in infancy and childhood. Distinguishing between conditions caused by permanent and temporary ectoparasites is important for the course and the required therapy. Permanent ectoparasites, such as scabies mite and head louse, spend all their life in or on the skin and have to be killed on the patient with suitable acaricides or pediculicides. In contrast, temporary ectoparasites, as animal mites or fleas, attack humans only for feeding. Symptomatic topical therapy is usually sufficient, eventually in combination with decontamination measures in the environment. This article summarizes skin conditions caused by mites, lice and fleas with special emphasis on distinctive features in children.

Pediculus capitis infestation according to sex and social factors in Argentina

OBJECTIVE

To determine the intensity of Pediculus capitis infestation (abundance) among Argentinean schoolchildren. Children's sex and social stratum were analyzed as modifiers of the general prevalence and degree of parasitism.

METHODS

The study included 1,370 schoolchildren (692 girls, 678 boys) from 26 schools of the province of La Rioja (21 public schools, five private schools). Classic prevalence was obtained as the percentage of children with nits and/or lice. Moreover, five degrees of parasitism were classified: 0) children with no signs of pediculosis; 0+) children with evidence of past infestation; 1) children with a recent infestation and low probability of active parasitism; 2) children with a recent infestation and high probability of active parasitism; 3) children with mobile lice (active pediculosis).

RESULTS

The general prevalence was 61.4% (girls: 79%; boys: 44%, p<0.001). Private schools showed lower prevalence than public schools (p=0.02), especially due to the low prevalence in boys. Fifty percent of children were classified in classes 0 and 0+, 22% in class 1; and 28% in grades 2 and 3. The proportion of children in grade 3 was higher in public schools than in private schools. There were significant sexual differences in the intensity of parasitism for grades 2 and 3, where girls' rates exceeded twice those of boys'.

CONCLUSIONS

Sex and social stratum are important modifiers of P. capitis general prevalence and degree of infestation. The classification of children by intensity of infestation allowed a more precise delimitation of this condition, which is especially important for disease surveillance and application of control measures.

Ectoparasitic sexually transmitted diseases: Scabies and pediculosis

Scabies and pediculosis are diagnosed on an almost daily basis in many dermatology offices. Whether the patient seeks medical attention because of the often unbearable itch of scabies or because of the fear of lice infestations, the physician should be on the lookout for these ectoparasitic infestations. Secondary bacterial infection, resistance to medication, and the risk of spread of the infestations to family members and other close contacts may complicate the problem. Patients frequently have to battle the myths, prejudices, and even shame that are associated with such infestations.

Treatment of pediculosis capitis with thiabendazole: a pilot study

BACKGROUND

Despite the improvement of health standards, head lice infestation remains a problem worldwide. In addition, there is increasing evidence that head lice are becoming resistant to common pediculocides.

AIM

To test the potential effectiveness of thiabendazole, a potent and broad-spectrum antiparasitic and scabicidal agent, for the treatment of pediculosis capitis.

METHODS

Twenty-three female patients, aged 7-12 years, who had active head lice infestation, were treated with oral thiabendazole, 20 mg/kg twice daily for 1 day, with repeat treatment after 10 days.

RESULTS

On the 11th day, meticulous hair examination showed that 21 patients had responded to treatment [91%; 95% confidence interval (CI), 71-98%], with 14 showing complete responsiveness (61%; 95% CI, 40-78%). The only adverse reactions observed were nausea and mild dizziness, which occurred in four patients, three of whom took the drug on an empty stomach.

CONCLUSIONS

Thiabendazole may be a promising treatment for head lice infestation. The primary action of this drug seems to be the inhibition of parasite microtubule polymerization by binding to beta-tubulin. In addition, thiabendazole may interfere with the synaptic transmission of lice through its probable cholinergic effect. As pediculosis capitis is a very communicable disease, the unresponsiveness to thiabendazole could largely be attributed to new infestations during the drug-free interval. Therefore, massive and simultaneous rather than individual and isolated treatments should be used to achieve the epidemiologic control of this ectoparasitosis. As this is a preliminary study, the performance of double-blind, randomized controlled trials on this subject is warranted. Thiabendazole, either alone or in combination with other agents, may prove to be of particular use in areas in which head lice show resistance to common pediculocides.

A survey on head lice infestation in Korea (2001) and the therapeutic efficacy of oral trimethoprim/sulfamethoxazole adding to lindane shampoo

Total of 7,495 children including 3,908 boys and 3,587 girls from a kindergarten and 15 primary schools were examined for head lice infestation (HLI). The overall prevalence of HLI in this study was found to be 5.8%. Head lice were much more commonly detected in girls than in boys with prevalence of 11.2% and 0.9%, respectively. Sixty-nine children with HLI were treated with 1% lindane shampoo alone (group 1), and 45 children with HLI were treated with 1% lindane shampoo and oral trimethoprim/sulfamethoxazole (group 2), and follow-up visits were conducted 2 and 4 weeks later. The children who still had HLI 2 weeks after the primary treatment were treated again. At the 2-week follow-up visit, the treatment success rates of groups 1 and 2 were 76.8% and 86.7%, respectively, and at the 4-week follow-up visit, the rates were 91.3% and 97.8%, respectively. No statistically significant synergistic effect was observed for the combination of a 1% lindane shampoo and oral trimethoprim/sulfamethoxazole.

Levamisole: a safe and economical weapon against pediculosis

Twenty-eight patients with pediculosis capitis, defined as the presence of pruritus, living eggs, and/or lice in the hair, were enrolled in an uncontrolled open pilot study. The subjects were school-age girls (7-12 years old), apparently free of other diseases, and not treated for pediculosis for 4 weeks prior to this study. Family contacts were not treated for pediculosis. The mothers of the patients, who had given informed consent, were asked not to use any topical pediculocide on the girls during the drug trial. Other than the drug administered in the study, the subjects did not take any oral medicine, including cotrimoxazole and ivermectin, during the trial. Treatment consisted of 3.5 mg/kg once daily oral administration of levamisole for 10 successive days, which was given to the subjects in their school by health personnel. A 10-day course was chosen because the subjects lived in unhygienic and overcrowded conditions in a poor village where head lice infestation was hyperendemic. Therefore, two treatment courses spaced 10 days apart could not preclude new infestations from other affected persons and fomites and might have led to a false deduction of drug ineffectiveness. Substituting "N" for the grade of living nits and "L" for adult lice, three forms of response based on the meticulous examination of the entire scalp with the use of a lens with high magnification and a powerful light source were considered: (i) total responsiveness, defined as N2 = 0 and L2 = 0; (ii) partial responsiveness, defined as 0 not equal N2 < N1 and 0 not equal L2 < L1; and (iii) complete unresponsiveness, defined as N2 > or = N1 or L2 > or = L1. The detection of unhatched nits which were operculated and generally located within one-quarter of an inch of the scalp was used to indicate the presence of lice infestation and also to judge the clinical response. For those small nits whose opercula were difficult to see with a hand lens, a low power microscopic study was performed to determine whether the nits were unhatched or not. Of the 28 girls enrolled in the study, one patient refused to take the drug after 2 days of treatment. No adverse reactions were noted in any of the 28 subjects. On the 11th day, meticulous hair examination showed that 23 patients had responded to treatment (85%; 95% confidence interval (CI): 66-94%). Of these, 18 showed complete responsiveness (67%; 95% CI: 48-82%). More complete information is given in Table 1. Confidence intervals were calculated using the likelihood method. This study suggests that levamisole is effective against pediculosis with a dose of 3.5 mg/kg administered for 10 days.