A Pilot Study of the Use of Oral Ivermectinto Treat Head Lice in Primary School

Students in Australia

Marian J. Currie, Ph.D.,*,� Graham J. Reynolds, M.H.P.,*,� Nicholas J. Glasgow, M.D.,*

and Francis J. Bowden, M.D.*,�

*Australian National University Medical School, Canberra Hospital, WODEN ACT, Australia, �Academic Unit ofInternal Medicine, Canberra Hospital, WODEN ACT, Australia

Abstract: Head lice are a common, costly public health problemworldwide. We aimed to determine the feasibility of an ivermectin interven-tion program. Consenting students in two schools were screened for headlice. Infested students and siblings at one school were offered a head licefact sheet and two doses of oral ivermectin, 7 days apart. Parents of infestedstudents in the other school were given the same fact sheet and asked totreat the child and siblings using their preferred topical treatment. Sevenhundred two of 754 (93.1%) students enrolled in the two schools werescreened; 40 (5.3%; 95% CI 3.7–6.9) had head lice; 31 (9.4%; 95% CI 6.1–12.2)in the intervention school and nine (2.5%; 95% CI 1.1–3.8) in the controlschool. Subsequently 93.6% of children in the intervention school weretreated with oral ivermectin. No adverse events were reported. At 6 monthsthe reduction in the head lice infestation rates for the intervention and con-trol schools were 87% and 56%, respectively. This pilot study suggests thatschool wide screening for head lice and the administration of oral ivermectinis feasible and acceptable. A randomized controlled trial at 20 schools isplanned.

Infestation with Pediculus humanus capitis (head lice)occurs in every human population and crosses all eco-nomic and social boundaries. Worldwide prevalenceestimates range between 0.7% in boys in an Iranian ele-mentary school (1) and 84% in rural India (2). In theUnited States, an estimated 6 to 12 million head lice

infestations occur each year (3), and the economic costsattributable to lost productivity when parents stay homewith their children is estimated to be US $4 to $8 billionannually (4).

Topical treatments such as shampoos containingpyrethroids, malathion, or carbaryl are effective, but

Address correspondence to Marian J. Currie, Ph.D., AcademicUnit of Internal Medicine, Australian National University MedicalSchool, Building 4 Level 2, Canberra Hospital, P.O. Box 11,WODEN ACT 2606, Australia, or e-mail: marian.currie@act.gov.au.

DOI: 10.1111/j.1525-1470.2010.01317.x

� 2010 Wiley Periodicals, Inc. 595

CLINICAL AND LABORATORY INVESTIGATIONS

Pediatric Dermatology Vol. 27 No. 6 595–599, 2010

concerns exist about their toxicity, and resistance to thesepediculicides is well established (5,6).

The treatment of ectoparasitic diseases suffers fromthe perception that they represent a nuisancemore than aserious threat to health; however, in some disadvantagedgroups (e.g., the Australian Indigenous population), ithas been observed that ectoparasitic disease can predis-pose children toGroupAStreptococcal infectionand thepostinfectious complications that include glomerulone-phritis and rheumatic fever. The itching associated withhead lice can cause significant sleep disturbance, and theinappropriate use of home insecticides for treatment hasbeen reported (7).

A paucity of clinical trials of head lice treatment exists(8), and a need for novel population health approachessubsists. The antihelminthic agent, ivermectin, has beenrecommended for the treatment of head lice whereresistance to pediculicides has developed. Laboratorystudies have shown that topical application of the drug iseffective in killing head lice in vitro (9), and recentlypublished studies demonstrate the efficacy of oral iver-mectin for hard to treat head lice in theUnitedKingdom,Ireland, Israel, and France (10) and in impoverishedcommunities in India and Brazil (2,11). Oral ivermectinhas been used safely in children formore than 20 years inpopulation-based programs for the treatment of oncho-cerciasis under the supervision of the World HealthOrganization (12–14). An oral dose of ivermectin pro-duces blood levels, which are toxic to the louse. Becausethe live eggs that have been laid on the hair shafts takearound 7 days to hatch, a second dose of ivermectin hasbeen suggested 7 to 10 days after the first to affect a cure(15). The Therapeutic Goods Administration in Aus-tralia has approved ivermectin for human use as atreatment for strongyloidiasis as well as onchocerciasis,and ‘‘off-label’’ use of this product has been suggested forhead lice and scabies in humans. However, it is rarelyused in practice, and its value has not been tested in anAustralian primary school setting.

Here, we report the findings of a pilot study designedto determine the feasibility of an ivermectin interventionprogram and the effect of the program on the prevalenceof head lice in primary school in the Australian CapitalTerritory (ACT), Australia, 6 months after treatment.

MATERIALS AND METHODS

This study was approved by the ACT Health HumanResearch Ethics Committee and was registered with theTherapeutic Goods Administration (Australia’s regula-tory agency for medical drugs and devices) under theClinical TrialNotification Scheme.Children at twoACTprimary schools (kindergarten to year six) took part in

the pilot study. The two schools were located in the samesuburb with the intervention school being a fee-payingschool and the control school a government school. Asthis was a feasibility study, allocation to intervention andcontrol groups was made arbitrarily.

Advertisements for the study were posted throughoutthe two schools, and a letter containing a synopsis of thestudy and a consent form was mailed to each family inthe school communities. Students, whose parents con-sented to their participation in the school-wide screeningprogram, were checked by trained staff for head lice ornits, or both. All head hair was combed at least twice,for approximately 5 minutes per child for short hair and10 minutes for long hair, as this method has been foundto be superior to direct visual examination for thedetection of head lice (12). Students were classified asinfested if screening staff located at least one live louseand confirmed the presence of lice with another staffmember. If a live louse was found, students were furthervisually screened until the presence or absence of 15head lice was determined to enable classification ofstudents as more heavily infested. All screened studentsreceived the nit comb used for their screen (labeled withtheir name) and a drink bottle and pencil embossed withthe study logo. Children at the intervention schoolfound to have live head lice were reviewed by a medicalofficer who confirmed the diagnosis, took a generalmedical history, and obtained written consent for par-ticipation in the study and the administration of oralivermectin from the child’s parent or guardian. Infestedstudents and their siblings in the intervention schoolwere given oral ivermectin (200 l ⁄kg) as a single dose onboth day 1 and day 7—the most commonly recom-mended dose (15,16), and it is possible that use of thehigher dose used by Chosidow et al in the managementof hard-to-treat head lice may limit the application ofivermectin to the general community of children. Themanagement of infested students in the control schoolwas left to the parents to decide (usual care) after theywere provided with the local health authority fact sheeton the diagnosis and management of head lice. Educa-tion department policy requires all infested students tobe treated before they can return to school. Infestedstudents were followed up 14 days, 3 and 6 months aftertreatment using the previously described hair combingtechnique. To determine any adverse events, parents oftreated children were asked to contact the researchers atany time between days 1 and 7 if they thought their childwas exhibiting side effects and were telephoned on days7 and 14 and asked directly about any side effects. Theentire population of both schools were rescreened6 months after the initial intervention, and a question-naire was sent to all families to elicit data concerning

596 Pediatric Dermatology Vol. 27 No. 6 November ⁄December 2010

infestations and their management subsequent to theinitial screening.

RESULTS

Seven hundred and two out of 754 (93.1%) studentsenrolled at the two primary schools at the time of theinitial screen, and 4- to 12-year-olds participated in thescreening program; 339 ⁄353 (96.0%) from the interven-tion school and 363 ⁄401 (90.5%) from the controlschool. Fourteen parents opted out of the screeningprogram, two in the intervention school and 12 in thecontrol school. Thirty-eight students were absent fromthe two schools during the initial screening program; 12(3.4%) and 26 (6.5%) students from the intervention andcontrol schools, respectively. Age and sex characteristicsof screened participants did not significantly differ be-tween the two schools (p = 0.9).

In the two schools, 40 students (28 females and 12males aged 5 to 11 years) from 29 families were infestedwith head lice; a 5.3% (95%CI 3.7–6.9) infestation rate.In the intervention school, 31 students (9.1%; 95% CI6.1–12.2) from 22 families had live lice detected. Thenumber of students infested per family at the time of theinitial screening ranged from one to three. Among these,uptake of ivermectin tablets was 93.6% (29 ⁄31). Tenuninfested and two reportedly infested siblings (aged 5 to14 years) also received ivermectin treatment. Two stu-dents did not receive ivermectin treatment; in one case,consent was given by one parent but not the other, andthe parents of the other child preferred to use a non-pharmaceutical treatment (hair conditioner and a licecomb). Parents of all treated children reported adminis-tering the seconddose of ivermectin at 7 days; no adverseevents were reported. Six children in the interventionschool were taking medications; two had an adrenalininjector for anaphylaxis caused by peanuts, and one ofthese was also taking an antihistamine (Loratidine); twoothers were taking a bronchodilator (Salbutamol) forasthma, and one of these two was also taking an antiin-flammatory asthma medication (Fluticasone with

salmeterol), one child was on an antihistamine (deslor-atidine) and one child was taking an anticonvulsant(Ethosuximide).

In the control school, nine (2.5%; 95% CI 1.1–3.8)students from seven families were found to have livehead lice. Two of three children in one family were in-fested. Control school students and their siblings weretreated by their parents; four families used hair condi-tioner and wet combing, and three families used topicalpediculicides; two families used KP24 medicated foam(Maldison), and the other family used Banlice mousse(Pyrethrins 1.65mg ⁄g and Piperonyl Butoxide16.5mg ⁄g).

Seventeen or 42.5% of all infested students from 13families were found to have 15 or more live heads lice;41.9% (13) and 44.4% (4) of infested students in theintervention and control school, respectively. Parents of31 ⁄40 (77.5%) infested students in the two schools re-ported at least one previous head lice infestation (rangeone to >20 times). All these students had been exposedto multiple pharmaceutical or nonpharmaceutical treat-ments, or both.

Rates of infestation detected at 14 days, 3, and6 months are reported in Table 1. None of the 12 moreheavily infested children at the intervention school hadany head lice detected at the 14-day and 3-month follow-up screening, but two had 15 live lice or more at6 months.One of the four heavily infested children at thecontrol school was similarly infested at all three follow-upvisits.The rateof infestation in the intervention schoolat 6 months was 1.2% (95% CI 0.2–2.2), which repre-sented a statistically significant decrease in point preva-lence (Fishers exact Chi square p £ 0.0001). Only one ofthe students infested at 6 months had been classified asinfested during the initial screening. No significantchange in the rate of infestation occurred in the controlschool at 6 months. Four of the six students found to beinfested at 6 months had not been infested at the initialscreening. The other two children, from the same family,had more than 15 live lice detected at all four study-timepoints (Table 1).

TABLE 1. Screening and Head Lice Infection Rates by Study Allocation

Screentime

Intervention school Control school

Screened Infested Screened Infested

No. % (95% CI) No. % (95% CI) No. % (95% CI) No. % (95% CI)

Initial 339 ⁄ 353 96.0 (94.3–97.7) 31 ⁄ 339 9.1 (6.1–12.2) 363 ⁄ 401 90.5 (87.4–93.4) 9 ⁄ 363 2.5 (0.9–4.1)14 days 31 ⁄ 31 100.0 (88.8–100) 0 ⁄ 31 0 (0–11.2) 9 ⁄ 9 100 (66.4–100) 0 ⁄ 9 0 (0–33.6)3 mos 31 ⁄ 31 100.0 (88.8–100) 0 ⁄ 31 0 (0–11.2) 8 ⁄ 9 88.9 (51.7–99.7) 2 ⁄ 9 22.2 (2.8–60)6 mos 326 ⁄ 369 88.5 (85.1–91.6) 4 ⁄ 326 1.2 (0.03–2.4) 368 ⁄ 419 87.8 (84.3–90.8) 6 ⁄ 368 1.6 (0.3–2.9)

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DISCUSSION

This pilot study showed that the whole-of-school headlice screening approach was feasible. Screening teamswere made welcome in both schools, and no complaintswere made by staff, students, or parents at either school.The high uptake of the study medication among inter-vention school parents suggests that use of oral iver-mectin was acceptable to parents. It became clear in thecourse of the trial that the parents of children with headlice had unsuccessfully tried most of the available topicaltreatments, were frustrated with their lack of efficacy,concerned about their toxicity and preferred to use hairconditioner.We found that only two parents objected tothe use of ivermectin. The ivermectin was well tolerated,and parents reported that they were very happy with theease of its administration compared to topical treat-ments. This is in keeping with other Australian research,which found that parents rated the time spent in man-aging head lice as a significant problem (17).

The 5.3% head lice infestation rate found in thispopulation is lower than the rates reported in otherAustralian (18–20) and overseas primary schools (21–23); however, the disparity in the rates between the twoACT schools is consistent with the literature from Aus-tralia and other market economies (24) and does not, webelieve, result from any socioeconomic differences be-tween the schools. In fact, the higher infestation rate wasfound in the fee-paying school.

It is possible that compliance with head lice treatmentmay have been higher among students from the inter-vention school because the medication was supplied tothe parents by a doctor on the day of lice detection andsupplied free of charge; however, the aim of the pro-posed randomized trial is to compare ivermectinadministration with current practice in primary schools,however imperfect that may be. During the conduct ofthe pilot study, several parents complained to us thatalthough they treat their infested children, they find thatother parents do not. Should the proposed randomizedtrial demonstrate that ivermectin is effective in reducingthe prevalence of head lice in local schools and isacceptable to the school communities, we will recom-mend that universal screening and ivermectin treatmentfor infested students is implemented as an ongoing,funded program in local schools. Moreover, we believethat the ease of administration of two doses of an oralmedication with proven efficacy in managing hard-to-treat head lice versus messy topical, sometimes ineffec-tive treatments and time consuming head combingmakesuch a program very appealing to parents who may wellbe willing to make a financial contribution to itsimplementation.

Concerns about the safety of ivermectin in children(25) may be unfounded. Ivermectin is an extremely safedrug, demonstrated by the low number of adverse eventsreported during the administration, since 1987, of over530 million doses in sub-Saharan African children totreat onchocerciasis (14,26).

It has been suggested that head lice screening pro-grams do not reduce the incidence of head lice and arenot cost effective (25). We agree with this conclusion iftreatment is based on the use of topical pediculicides;however, we hypothesize that if whole of school screen-ing is combined with an effective treatment (i.e., iver-mectin) then the program is likely to work.

Our nonrandomized pilot study was not designed todemonstrate any differences in the efficacy of the twoapproaches to control, but it is interesting to note the87% reduction in head lice in the intervention school at6 months follow-up. We further hypothesize that chil-dren infested with a high number of lice act as ‘‘super-spreaders’’ of head lice, and that topical treatments areunlikely to successfully treat this group because ofresistance. Administration of ivermectin may be thecrucial step in breaking the cycle of transmission in therelatively closed environment of primary schools. Thispilot forms the first part of a larger project; a cluster-randomized trial of ivermectin versus usual treatment forhead lice in 20 primary schools and a parasitologicaltesting substudy. Sucha studywill address the limitationsof this pilot study including the difference in infestationrates, the rate of resistance among the lice in our popu-lation, and the use of self report measures of compliancewith treatment in both the intervention and controlschools.

ACKNOWLEDGMENTS

We would like to thank the staff, students, and par-ents from the two schools for taking part in the pilotstudy. We would also like to acknowledge the con-tribution of the ACT Department of Education andthe Catholic Education Office and the 12 head licescreeners. Thank you also to the anonymous reviewersof this paper.

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