Recommendation to standardize pediculicidal and ovicidal testing for head lice (Anoplura: Pediculidae)

Pediculosis capitis is a prevalent and highly communicable condition infesting millions of elementary school students annually. Topical insecticides are the present standard treatment for this condition. Because resistance of head lice to insecticides is a growing concern, assessment of efficacy of pediculicidal and ovicidal activity of the various agents is needed for public health interests. Given the number of anecdotal and market-driven reported studies, assessment of topical lice therapies requires standardized testing. Evaluations based on adaptations of World Health Organization guidelines are not ideal, whereas a protocol reflecting clinical exposure to insecticides is preferable.

Eradication of lice in cattle

The purpose of this field study was to develop and evaluate eradication as a strategy to control lice in cattle. Thirty-three herds of cattle were selected and observed during a period of two and a half years. Before eradication, biting lice (Damalinia bovis) were present in 94% of the herds and 27% of the animals. Sucking lice (Linognathus vituli) were present in 42% of the herds and 5% of the animals. These levels were very similar to those reported from other countries in Northern Europe. The eradication strategy was successful in 28 of 33 herds, but lice were still present in 5 herds 3 to 6 months after treatment. Biting lice were present in all these 5 herds, sucking lice were present in 3 herds. During the next 12 months, nine of the 28 herds were reinfected with lice. Six herds were reinfected with just biting lice, 2 herds with just sucking lice and one herd was reinfected with both. There was no significant difference between the 2 louse species regarding the risk of unsuccessful eradication or reinfection. The only significant risk factor for reinfection was either purchase of livestock or use of common pasture, combined with failure in pre-treatment of newly introduced animals.

[Pediculosis in rural schools of Lublin Province]

The aim of the work was to study the prevalence of pediculosis capitis among schoolchildren in rural areas of Lublin Province in Eastern Poland and to examine its correlation with socio-economic conditions. A group of 42759 schoolchildren aged between 6 and 15 years from 52 rural primary schools were examined. The level of unemployment, number of physicians and number of nurses per 10000 inhabitants were examined in the area of experiment. We achieved the following results: a total of 682 children were found to be infested with Pediculus humanus capitis, mean prevalence was 1.6%. The girls were more frequently infected than boys (75% for girls and 24% for boys). The children most frequently affected were those aged 6 (1.6%) and 8 to 12 years (1.6-2.1%). The children least affected were those aged 13 to 14 years (0.8-1.1%). The infestation rate was strictly correlated with the number of nurses per 10000 inhabitants. There was no relationship between the level of unemployment or the number of physicians and the infestation rate on experimental area. Our investigations seems to confirme that the prevalence of P. h. capitis is influenced by the level of primary health care, particulary quality of school nurses' work.

[The importance of different pig diseases in the Netherlands]

As part of the project 'Clean pigs', IPG Institute for Pig Genetics BV made an inventory of the impact of different diseases on the Dutch pig industry. An expert panel assessed the importance of the different diseases with regard to public health, farm economy, the pig sector and export sales. The possibilities for the diagnosis of the different pathogens were listed and the goal for the next years, was set. Diseases were classified into three categories, according to their importance for the Dutch pig industry (Table 2). The diseases that can be eradicated are Salmonella (only specific strains), Pasteurella multocida DNT + PAR), Actinobacillus pleuropneumoniae, Haematopinus suis (lice) and Sarcoptes scabei (var. suis) (mange). National introduction of list A en most list B diseases of the OIE classification must be prevented.

Evaluation of the in-vitro pediculicidal action of four known insecticides and three medicinal plant extracts

Human lice is an increasing community health problem worldwide. This is particularly true among school children who spend most of their daytime in crowded areas. Four commercially known insecticides and three medicinal plant extracts were studied to evaluate their pediculicidal activities in-vitro. The best result with insecticides was achieved with malathion (Lt5o 10.396 and slope function 1.183). The best result with medicinal plant extracts was achieved with neem oil (A. indica) (Lt5o 85.27 and slope function 1.480). Although, neem oil extract was less active than malathion, yet it is more safe for human usage.

Pediculosis in a school population

This nonexperimental, retrospective study of elementary, middle school, and high school children (a) determined the prevalence of pediculosis, (b) identified populations susceptible to head lice infestation, and (c) examined the role of the school nurse in pediculosis management. The findings showed the highest prevalence of pediculosis was among younger school-age children, and girls were 3 times more likely to be infested than boys. Hispanic children had the highest rate of infestation, followed by Caucasian children. African American children showed a 15% infestation rate, a finding not supported by other studies. The role of the school nurse in pediculosis management was restricted by time and budgetary constraints. Findings of this study support the need for a standardized data collection system for pediculosis in all school districts.

The methodology and operation of a pilot randomized control trial of the effectiveness of the Bug Busting method against a single application insecticide product for head louse treatment

A Department of Health leaflet suggests two treatment methods for head lice: mechanical removal by wet combing; and insecticide lotion/rinses. However, there are no reports in the literature comparing the effectiveness of these two treatment methods and well controlled clinical trials of insecticide treatments are sparse. A pilot randomized control trial of the effectiveness of a specific method of wet combing, 'Bug Busting', against a single application of a proprietary insecticide product is reported. The difficulties of designing a trial are discussed and modifications that would allow a definitive trial to take place are suggested. The pilot study included enzyme analysis of lice for insecticide resistance status assessment.

Head lice for A & E nurses

Accident and emergency nurses are in an excellent position to offer skill and advice on the treatment of head lice, from health education to diagnosis and cure to contact tracing. This paper offers guidance on how to detect lice and how to treat infestation. There are a number of treatment options available, including pharmacological and physical treatments. Choosing the most appropriate option can be difficult due to reports of 'Super Nits' resistant to insecticides and lack of data to support the use of alternative methods such as 'wet combing' and aromatherapy treatments. However, nurses do need to be aware of how lice move between people, so they can take an active role in health education and make sure that patients affected by head lice are managed properly.

Increased control of the sheep biting louse Bovicola (Damalinia) ovis with deltamethrin formulated in a fractionated wool grease carrier

The synthetic pyrethroid deltamethrin (DM) containing a trace of [(14)C]-DM was formulated with non-oxidised sterol and wax ester fractions (F1) of wool grease and as the commercial preparation 'Clout-S'. These were applied as a 'backline' strip to sheep immediately after shearing and the concentration of [(14)C]-DM at meridians adjacent to the application strip and at 1/4 and 3/4 of the dorsal-ventral distance was determined. The F1 formulation resulted in significantly greater lateral spread of DM with less remaining at the application site (66+/-8% of dose) 98 days after treatment compared to 'Clout-S' (94+/-3% dose). Autoradiographic examination of treated wool demonstrated that there was more DM in the lower half of the wool staple when formulated in F1 compared to 'Clout-S'. Greater mortality occurred when sheep biting lice Bovicola (Damalinia) ovis were exposed in vitro to wool containing DM from F1 compared to 'Clout-S' treated sheep. In field trials there was increased efficacy against synthetic pyrethroid resistant B. ovis with F1 formulation than with 'Clout-S'. The study has demonstrated that synthetic pyrethroid availability, and therefore efficacy, can be significantly increased when the insecticide is formulated in a 'carrier' with the physicochemical characteristics of wool grease.

Scabies and pediculosis

Scabies and pediculosis are ubiquitous, contagious, and debilitating parasitic dermatoses. They have been known since antiquity and are distributed worldwide. Clusters of infestation occur-for example, scabies affecting immunocompromised individuals or patients and staff in hospitals and nursing homes for the elderly, and pediculosis affecting schoolchildren or homeless people. Associations with other disorders are common: infections with human T-cell leukaemia/lymphoma virus I (HTLV-I) and HIV are associated with scabies, and trench fever and exanthematous typhus with pediculosis. Specific forms of scabies, including bullous scabies or localised crusted scabies, may be misdiagnosed. Moreover, definitive parasitic diagnosis can be difficult to obtain, and the value of new techniques remains to be confirmed. Difficulties in management have returned scabies and pediculosis to the limelight.

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.

Parasitic infections and maternal awareness of preschool children in Karmouz district, Alexandria

Intestinal parasitic infections are widespread especially among preschool children living in poor areas. Also pediculosis has been perceived as a public health nuisance for decades. A cross-sectional study was conducted on 256 children and their mothers in a poor urban district to assess mothers' knowledge and practices as regards parasitic infections and infestations that may be present in her preschool child, and to correlate the presence of these infections with her awareness. A pre-designed questionnaire that included socio-demographic data, items to assess mothers' knowledge of sources and preventive measures of parasitic infections and infestations and her practices was completed. A stool sample was collected from children and examined using formol-ether technique and Sellotape technique was used to detect Enterobius vermicularis. Pediculus capitis was diagnosed by inspection of the scalp and was found to be the most prevalent parasite found in 58.9% of those children followed by Enterobius vermicularis in 46%. A strong positive association between pediculosis and enterobiasis was detected (phi coefficient = 0.956, p < 0.001). Socioeconomic level affected both knowledge and practices scores where one point change in knowledge score or socioeconomic score caused an increase in practice score of 0.279 and 0.071, respectively. Also higher risk of pediculosis was found to be significantly associated with female sex and low socioeconomic level. An increase of one point in practice score showed a decrease in the log likelihood ratio of enterobiasis of 14.3%. The majority of mothers (77.3%) were found to be aware that their children had a parasitic infection, which was significantly associated with results of stool analysis. This indicates that awareness building is not enough to be of practical benefit. Appropriate and detailed control methods of parasitic infections and pediculosis must be taught and applied by parents and community. Socio-economic development, organized health programs and motivation should be undertaken to help today's children.

The persistent efficacy of doramectin pour-on against biting and sucking louse infestations of cattle

A repeated-exposure challenge model was used to evaluate the pour-on formulation of doramectin in preventing the establishment of louse infestations in cattle. Twenty calves cleared of preexisting biting and sucking louse infestations were randomly and equally allocated to either a doramectin-treated or untreated control group, with five replicates per group. Doramectin pour-on was administered topically at a dose rate of 500 microg/kg body weight. Every 14 days, from a pool of seeder calves with infestations of at least 50 biting and 50 sucking lice each, 10 calves were selected and 1 was placed in each replicate pen. Every week during the 112-day study, 9 predilection sites on the doramectin-treated and untreated calves were examined to estimate the louse population density. A calf met the infestation criterion for a louse species when two or more live lice were counted on two or more body regions for two consecutive count days. Because only 4 of 10 untreated calves acquired Solenopotes capillatus infestations, the persistent efficacy of doramectin against S. capillatus was not evaluated. Bovicola bovis and Linognathus vituli infestations in the untreated calves developed shortly after exposure to infested seeder calves. The acquisition of B. bovis and L. vituli infestations in the doramectin-treated group was delayed for 77 days and 105 days, respectively.

[Knowledge and practice concerning pediculosis in a health district]

Pediculosis is an endemics that has recently intensified world wide and also in Cuba as of 1970. A study was performed in the schools located in the health area of the Vedado Polyclinics in the City of Havana to find out the level of knowledge acquired and the practices followed that may have an effect on the control of this disease. Two qualitative techniques i.e. group analysis and non-participatory observation allowed to gather information. Wrong pieces of knowledge and ill practices were detected such as the belief that nits can fly, the use of a drug called Lindano 1% to treat children as a preventive method while they are in class, application of products in a wrong way, use of harmful products and no taking out of nits in a systematic way. These mistaken concepts and practices affect the analysis of cases and thus, they should be taken into consideration to increase the efficiency of the control program.

Interventions for treating headlice

BACKGROUND

Infection with head lice is a widespread condition in developed and developing countries. Infection occurs most commonly in children, but also affects adults. If left untreated the condition can become intensely irritating and skin infections may occur if the bites are scratched.

OBJECTIVES

The aim of this review was to assess the effects of interventions for head lice.

SEARCH STRATEGY

Trials register of The Cochrane Infectious Diseases Group; Medline; Embase; Science Citation Index; Biosis and Toxline; reference lists of relevant articles; pharmaceutical companies producing pediculicides (published and unpublished trials); UK and US Regulatory Authorities.

SELECTION CRITERIA

Randomised trials (published and unpublished) or trials using alternate allocation were sought which compared pediculicides with the same and different formulations of other pediculicides, and pediculicides with physical methods.

DATA COLLECTION AND ANALYSIS

Of the 70 identified studies, only three met the inclusion criteria and one is awaiting assessment. Two reviewers independently assessed trial quality. One reviewer extracted the data.

MAIN RESULTS

We found no evidence that any one pediculicide has greater effect than another. The two studies comparing malathion and permethrin with their respective vehicles showed a higher cure rate for the active ingredient than the vehicle. The third study comparing synergised pyrethrins with permethrin showed their effects to be equivalent. Adverse effects were reported in a number of trials and were all minor, although reporting quality varied between trials.

REVIEWER'S CONCLUSIONS

Permethrin, synergised pyrethrin and malathion were effective in the treatment of head lice. However, the emergence of drug resistance since these trials were conducted means there is no direct contemporary evidence of the comparative effectiveness of these products. The 'best' choice will now depend on local resistance patterns. There is currently no evidence from trials to indicate the effectiveness of physical methods, such as combing/'BugBusting' or other chemical control methods such as the use of herbal treatments, when used in the curative treatment of head lice. Future trials should take into account the methodological recommendations that arise from this review.

Prevention and treatment of head lice in children

Head louse infestations (pediculosis) are prevalent worldwide. In developed countries, the infestation rate of 4- to 13-year-old children remains high despite preventive efforts. This is due to the existence of numerous ineffective pediculicides, the incorrect use of the effective agents, toxicological concerns and the development of louse strains resistant to insecticides. One of the most effective tools for the prevention and control of lice is the louse comb, which should be used regularly for the detection of living lice at an early stage of infestation, and as an accessory to any treatment method to remove living and dead lice. The louse comb can also be used systematically for the treatment of infestations, for confirmation that treatment with pediculicides has been successful, and for the removal of nits (dead eggs or egg shells). Most pediculicides are only partially ovicidal. Therefore, 10 days after beginning treatment with any antilouse product, the scalp of the child should be examined. If no living lice are found, the treatment should be discontinued. If living lice are still present, treatment should be continued with a product containing a different active ingredient. Suffocating agents such as olive, soya, sunflower and corn oils, hair gels and mayonnaise are able to kill a significant number of lice only if they are applied in liberal quantities for more than 12 hours. However, they lubricate the hair and therefore may facilitate combing and removing lice and eggs from the scalp. Nits may remain glued on the hair for at least 6 months, even after a successful treatment, and lead to a false positive diagnosis of louse infestation. If nits are seen on the hair, the child should be examined, but treatment should be initiated only if living lice are found. Formulations containing 5% acetic acid or 8% formic acid, as well as acid shampoos (pH 4.5 to 5.5) and conditioners, in combination with a louse comb, can be helpful for removing nits. There is no conclusive evidence that using essential oils to repel lice is effective. Regular examination of the child's head using a louse comb is the best measure to detect re-infestation at an early stage. Educating caregivers, nurses and teachers about louse biology, epidemiology, prevention and control is of paramount importance. The psychological effect of an infestation with lice is significant and often associated with anxiety and fear. The child should not be made to feel responsible for having lice, or be punished or reprimanded.