The prevalence of head louse infestation among urban and rural children in Korea

The prevalence of head louse (Pediculus hamanus var. capitis) infestation in preschool and school children in 9 urban and 8 rural areas of Korea, was investigated. Of 11,865 children who were examined for head lice and nits, 2,900(24.4%) were found infested. The over-all infestation rate of rural children, 58.9%, was higher than that of urban children, 14.4%. There also existed significant differences in the infestation rate among various regions of urban as well as rural areas. Females were more infested than males. But there was no differences in infestation rate in either sex of preschool age. The infestation rate increased gradually from the age of 6, reached a plateau between 9-12 years of age and thereafter slowly decreased. The infestation rate of an orphanage children was higher than that of general childhood population. Health education and mass-delousing attempt are urgently required to lower such a high prevalence of head louse infestation in Korea.     

Infestation status of head louse and treatment with lindane shampoo in children of primary school and kindergarten in Chinju-shi, Kyongsangnam-do, Korea

The infestation status of head louse among children attending primary schools and kindergartens in Chinju-shi, Kyongsangnam-do, Korea, was investigated between June and July 1999. Out of 2,288 children examined, 3.9% of boys (48/1,242) and 23.5% of girls (246/1,046) were infested with nits or adult/nymphs of lice. The effectiveness of lindane shampoo (1% gamma benzene hexachloride solution) was evaluated after one or two time applications to all the children infested. The negative conversion rate of pediculosis was 93.5%. Effective control measures are needed to control and prevent such ectoparasite infestation amongst children.     

Head louse infestation among girls in an orphanage and women in a mental hospital and mass-delousing with bioallethrin (PARA aerosol)]

After evaluation of presence of nits and/or lice, PARA aerosol(bioallethrin with piperonyl butoxide) was applied to 97 women and 43 girls, regardless of the results of their infestation, living at 2 separate institutions. Twelve days after the first treatment the second treatment was carried out and the presence of head lice was examined for the evaluation of treatment effect. Among total 140 subjects, 98(70.0%) were nit positive and 85(60.7%) were louse positive. The infestation rates of girls by nit(86.0%) and louse(86.0%) were higher than those of women, nit 62.9% and louse 49.5% (p less than 0.01). Also the detection rate of lice among nit positive subjects was higher in girls(100%) than in women(78.7%). On the second evaluation 12 days after treatment, 36(97.3%) out of 37 girls and 46(95.8%) out of 48 women were found louse-free. There was no difference in the treatment efficacy between the women and girls.     

Treatment of head louse infestation with 4% dimeticone lotion: randomised controlled equivalence trial

Objective To evaluate the efficacy and safety of 4% dimeticone lotion for treatment of head louse infestation.Design Randomised controlled equivalence trial.Setting Community, with home visits.Participants 214 young people aged 4 to 18 years and 39 adults with active head louse infestation.Interventions Two applications seven days apart of either 4.0% dimeticone lotion, applied for eight hours or overnight, or 0.5% phenothrin liquid, applied for 12 hours or overnight.Outcome measures Cure of infestation (no evidence of head lice after second treatment) or reinfestation after cure.Results Cure or reinfestation after cure occurred in 89 of 127 (70%) participants treated with dimeticone and 94 of 125 (75%) treated with phenothrin (difference -5%, 95% confidence interval -16% to 6%). Per protocol analysis showed that 84 of 121 (69%) participants were cured with dimeticone and 90 of 116 (78%) were cured with phenothrin. Irritant reactions occurred significantly less with dimeticone (3/127, 2%) than with phenothrin (11/125, 9%; difference -6%, -12% to -1%). Per protocol this was 3 of 121 (3%) participants treated with dimeticone and 10 of 116 (9%) treated with phenothrin (difference -6%, -12% to -0.3%).Conclusion Dimeticone lotion cures head louse infestation. Dimeticone seems less irritant than existing treatments and has a physical action on lice that should not be affected by resistance to neurotoxic insecticides.     

Prevalence of pediculosis and scabies in preschool nursery children of Afyon, Turkey

Scabies and pediculosis are ubiquitous, contagious, and debilitating parasitic dermatoses. The tendency of high prevalence of pediculosis and scabies among school and preschool age children has prompted us to conduct a head louse and scabies prevalence survey among preschool nursery children in our district. A school-based, crosssectional study was performed, with 1,134 children chosen for evaluation. All cases were evaluated by physical examination and a detailed, structured questionnaire. The infestation was found in 14 (1.2%) of 1,134 children; 9 (0.8%) with pediculosis capitis and 5 (0.4%) with scabies. We found that infestations were more frequent in children with mothers whose education levels were low. This indicates the necessity of an improvement in the economic and sociocultural status of the community and the promotion of hygiene concepts and practices in order to improve health of preschool age children.     

Epidemiological aspects of head lice in children attending day care centres,urban and rural schools in Uberlândia,central Brazil

From November 1996 to March 2000, a total of 884 children between 0 and 15 years, from 11 institutions including day care centres, public urban and public rural schools in Uberlandia, State of Minas Gerais, central Brazil, were examined for head louse infestation. Children's sex, race, age and some hairs characteristics were shown to be associated to parasite infestation. A prevalence rate of 35% was found and the highest rates were observed in black, female children, with long, dark, wavy hairs. Hairs density and thickness did not seem to influence significantly the distribution of this pediculosis in Uberlandia's schoolchildren. Differences observed between the prevalence rates of head lice in children from the urban institutions suggest there is a greater epidemiological heterogeneity in this group when compared to the rural schoolchildren.     

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 re‐infestations 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.     

Negligible Egg Positive Rate of Enterobius vermicularis and No Detection of Head Lice among Orphanage Children in Busan and Ulsan,Korea (2014)

To determine whether pinworm infections and head lice infestations spread among children in orphanages, 117 children from 4 orphanages in Busan-si and Ulsan-si, Korea, were examined for enterobiasis and head lice infestation between January and February 2014. The overall rate of Enterobius vermicularis egg positivity was 0.85%, whereas none of the children had head lice infestations. The rate of pinworm infection was much lower among the orphanage children compared to the rates observed in previous studies among kindergarten and primary school students. Moreover, the risk factors for enterobiasis were less frequent among these subjects than previously reported. The personal hygiene and health of the orphanage children were supervised by a regular, employed nurse through a health education program. In conclusion, pinworm infection was efficiently controlled among the children in orphanages, and this might be related to good personal hygiene practices in Korea.     

Risk factors associated with head louse infestation in Korea

Head louse infestation (HLI) is one of the most frequently occurring parasitic diseases in children. This study was conducted to investigate the socioeconomic and personal factors influencing HLI in the Republic of Korea. A total of 2,210 questionnaires about various factors related to HLI were obtained from children in 17 primary schools throughout the country. The rate of HLI was significantly lower in children who lived together with mother or in a family where both parents worked. In addition, HLI was lower in children whose fathers or mothers were public officers or teachers. However, HLI was higher in children who had small families and washed their hair less often. Education levels of parents and the number of children in family were not significant. Improvement of socioeconomic factors and personal hygiene will be helpful for reducing HLI.     

“Eczema” of the nape: A marker of pthiriasis capitis

Pthirus pubis usually infests the pubis, inguinal folds, buttocks and perianal region. In hairy males or when the infestation is longstanding, this louse can also occur on the thighs, abdomen, chest, axillae and beard. Eyelashes may be involved in children. The involvement of the scalp is very rare. We describe four girls with P. pubis infestation located exclusively on the scalp which was characterized by a rash on the nape that can suggest a head and neck form of atopic dermatitis.     

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.     

Efficacy of two praziquantel treatments among primary school children in an area of high Schistosoma mansoni endemicity, Nile Delta, Egypt

Praziquantel is the cornerstone of schistosomiasis control. A number of reports from endemic areas suggest that resistance or tolerance to praziquantel might exist in Schistosoma mansoni. Several explanations were postulated. The present work was designed to test the hypothesis that a low praziquantel (pzq) cure rate in Egypt is due to survival and maturation of immature stages that escaped pzq, which is effective against mature S. mansoni worms only. The study sample included 1351 children attending El Rouse primary school located in El Rouse village, Nile Delta, Egypt. All children received 2 pzq doses (40 mg/kg) 4 weeks apart. Diagnosis of S. mansoni infection and cure assessment were based on examination of 2 Kato slides prepared from a single stool sample collected before and 4 weeks after the first and second treatments. The cure rate was 78·8% after the first treatment and increased significantly to 90·8% after the second treatment. Egg reduction rates were 71·2% and 77·2% after 1 and 2 treatments respectively. Pre-treatment intensity of infection has a great influence on cure and egg reduction rates. Our results confirmed that low praziquantel cure rate, in Egypt, might be attributed, even partially, to survival and maturation of the immature S. mansoni stages that escaped pzq that is effective against mature worms only.     

Randomised, controlled, assessor blind trial comparing 4% dimeticone lotion with 0.5% malathion liquid for head louse infestation

Background

Malathion 0.5% has been the most prescribed pediculicide in the United Kingdom for around 10 years, and is widely used in Europe and North America. Anecdotal reports suggest malathion treatments are less effective than formerly, but this has not been confirmed clinically. This study was designed to determine whether malathion is still effective and if 4% dimeticone lotion is a more effective treatment for head louse infestation.

Methodology/Principal Findings

We designed this study as an assessor blinded, randomised, controlled, parallel group trial involving 58 children and 15 adults with active head louse infestation. Each participant received two applications 7 days apart of either 4% dimeticone lotion, applied for 8 hours or overnight, or 0.5% malathion liquid applied for 12 hours or overnight. All treatment and check-up visits were conducted in participants'' homes. Cure of infestation was defined as no evidence of head lice after the second treatment. Some people were found free from lice but later reinfested. Worst case, intention to treat, analysis found dimeticone was significantly more effective than malathion, with 30/43 (69.8%) participants cured using dimeticone compared with 10/30 (33.3%) using malathion (p<0.01, difference 36.4%, 95% confidence interval 14.7% to 58.2%). Per protocol analysis showed cure rates of 30/39 (76.9%) and 10/29 (34.5%) respectively. Irritant reactions were observed in only two participants, both treated with malathion.

Conclusions/Significance

We concluded that, although malathion liquid is still effective for some people, dimeticone lotion offers a significantly more effective alternative treatment for most people.

Trial Registration

Controlled-Trials.com ISRCTN47755726     

Intestinal parasites infestation and anemia in primary school children in Gaza Governorates--Palestine

A comparative study was carried out to identify the prevalence of anemia, nutritional indices and intestinal parasitic infestation in primary school children. The target population included 209 pupils aged 6-11 years, attending schools in two areas, Rimal area (urban) and Jabalia village (rural), in Gaza Governorates. Prevalence of intestinal parasites was high in Jabalia village (more than 53%) in comparison to Rimal area (33%). The main intestinal parasites were Entamoeba histolytica, Giardia intestinalis and Ascaris lumbricoides. Polyparasitism frequency is higher especially in rural area. In both areas anemia showed a high prevalence in children due to malnutrition and intestinal parasitic diseases. There was no association between intestinal parasitic infestation and children growth, but there was association between anemia and intestinal parasitic infestation in children, particularly in rural area. The correlation between anemia and mixed infestation reaches a highly significant level.     

Evolutionary relationships of "Candidatus Riesia spp.," endosymbiotic enterobacteriaceae living within hematophagous primate lice

The primary endosymbiotic bacteria from three species of parasitic primate lice were characterized molecularly. We have confirmed the characterization of the primary endosymbiont (P-endosymbiont) of the human head/body louse Pediculus humanus and provide new characterizations of the P-endosymbionts from Pediculus schaeffi from chimpanzees and Pthirus pubis, the pubic louse of humans. The endosymbionts show an average percent sequence divergence of 11 to 15% from the most closely related known bacterium "Candidatus Arsenophonus insecticola." We propose that two additional species be added to the genus "Candidatus Riesia." The new species proposed within "Candidatus Riesia" have sequence divergences of 3.4% and 10 to 12% based on uncorrected pairwise differences. Our Bayesian analysis shows that the branching pattern for the primary endosymbionts was the same as that for their louse hosts, suggesting a long coevolutionary history between primate lice and their primary endosymbionts. We used a calibration of 5.6 million years to date the divergence between endosymbionts from human and chimpanzee lice and estimated an evolutionary rate of nucleotide substitution of 0.67% per million years, which is 15 to 30 times faster than previous estimates calculated for Buchnera, the primary endosymbiont in aphids. Given the evidence for cospeciation with primate lice and the evidence for fast evolutionary rates, this lineage of endosymbiotic bacteria can be evaluated as a fast-evolving marker of both louse and primate evolutionary histories.     

Prevalence, risk factors and economic importance of infestations with Sarcoptes scabiei and Haematopinus suis in sows of pig breeding farms in Hesse, Germany

A cross-sectional survey was performed in 110 randomly selected pig-breeding farms of southern Hesse, Germany to estimate the prevalence of ectoparasite infestations and to find possible risk factors. Ear scrapings of, if available, 10 sows per farm were examined for Sarcoptes scabiei var. suis (De Geer) (Acaridida: Sarcoptidae) by the potassium hydroxide digestion method, and a total of 2754 sows was inspected for skin lesions and infestations with Haematopinus suis (L.) (Anoplurida: Haematopinidae). Data on farm profiles and sows were collected by a questionnaire. In total, 19.1% and 2.5% of the sows were found to be infested with S. scabiei or H. suis, respectively. The percentage of mite or louse infestation was significantly higher in sows showing pruritus than in those without skin lesions. Both ectoparasite infestations were related neither to the age of sows nor their reproduction status, nor to the time interval to last ectoparasite treatment. Using farms as the unit of analysis, the estimated prevalence of mange mite and louse infestations was 45.4% and 14.5%, respectively. There was no significant association between the presence of S. scabiei and H. suis in the farms. Risk factors for S. scabiei infestation were mixed housing of dry and nursing sows in the same unit (vs. separate housing) and straw bedding (vs. strawless). For louse infestation, only mechanical cleaning of stable units (vs. additional use of disinfection methods) and pasturing of gilts and dry sows were identified as risk factors. The economic loss by S. scabiei infestation in the study population was assessed at euro 4200 per affected farm and year on average.     

Nasal bots and lice from white-tailed deer in southern Alberta, Canada

Heads of 64 white-tailed deer (Odocoileus virginianus) fawns, harvested in the vicinity of Magrath, Alberta, Canada, (49 degrees 24'782'N, 112 degrees 52'113'W) were examined for the presence of nasal bots and lice. The deer were collected between 8-30 January 2004 as part of a government-approved herd reduction protocol. The entire surface of each head was scanned visually for the presence of lice. Each head was split longitudinally, and the nasal passages, sinuses, and ethmoid region were washed for recovery of nasal bots. First instar Cephenemyia spp. were recovered from 17 heads (27%). Intensity of infestation ranged from 1-18 larvae (mean intensity 4.8). Among fawns, there were no significant differences in prevalence or mean intensity between the sexes. Two species of nasal bots were identified. Smaller larvae, tentatively identified as C. jellisoni, were present in 16 of 17 infested deer while larger specimens, tentatively identified as C. phobifera, were found in four deer; and in three of the four it co-occurred with C. jellisoni. The presence of C. phobifera in Alberta would represent a range extension for this species, which has not been known to occur west of North Dakota. Thirty-one fawns (48%) were infested with the sucking louse Solenopotes ferrisi. One infested fawn also had one specimen of the chewing louse, Tricholiopeurus lipeuroides.     

Enterobius vermicularis egg positive rate in a primary school in Chungchongnam-do (province) in Korea

The egg positive rate of Enterobius vermicularis was investigated among students of a primary school and a kindergarten located in the rural area of Tangjin-gun, Chungchongnam-do in December, 1998. Of the 189 examinees, 28 (14.8%) were found to be infected with E. vermicularis by the adhesive cellotape anal swab method. The infection rates ranged from 4.2% to 26.1% among school children, and the highest rate was observed in children attending kindergarten. Three months after treatment with albendazole, four (14.3%) out of 28 infected children still remained infected with E. vermicularis. Through this survey, we were able to determine that E. vermicularis infection is still prevalent among children in rural areas of Korea.     

Daily number of bee louse (Braula coeca) in honey bee (Apis mellifera carnica and A. m. syriaca) colonies maintained under semi‐arid conditions

Experimental work was conducted at two apiaries located in Irbid district and in Shuna North, Jordan, during the years 2004–2006. The aims of these investigations were to estimate the seasonal changes in the infestation rates of the bee louse (Braula sp.) and to develop an easy and rapid method of estimating the infestation rate on workers with bee Braula. Two major honey bee subspecies are reared in Jordan; Apis mellifera carnica and Apis mellifera syriaca were used in this study. The results showed that the infestation rate began to increase rapidly in May, reaching the season's maximum rate of 16.2%, 15.8% and 17.4% for A. m. carnica and 22.6%, 23.9% and 22.9% for A. m. syriaca in December of 2004, 2005 and 2006, respectively. The maximum adult numbers of bees were found in April and June, whereas the minimum for the year was in January in both honey bee subspecies colonies during the study period. The actual population of the bee louse could be estimated by counting the daily dropped lice and multiplying by a factor of 158. This factor is valid for the experimental colonies of both subspecies kept for 3 years under semi‐arid Mediterranean conditions.     

Heritability of resistance to infestation with the body louse, Bovicola ovis, in Romney sheep bred for differences in resistance or resilience to gastro-intestinal nematode parasites

The inheritance of resistance to louse infestation and the related allergic skin disease, cockle, was examined in Romney lambs. The lambs used in the study were the 2001- and 2004-born progeny of four experimental breeding lines (“Resistant”, “Susceptible”, “Resilient” and “Control”) developed as part of a long-term study of the genetics of host resistance (maintenance of low faecal egg count (FEC) under nematode challenge) or resilience (maintenance of health and productivity under nematode challenge irrespective of FEC) to nematode parasites in sheep. Between 13 and 22 progeny (equally distributed between males and females, where possible) from each of five sires in each line were selected each year for this trial. All lambs (n = 701) were examined for lice (Bovicola ovis) before artificial infestation; in 2001 the lambs were free of natural infestation, whilst in 2004 naturally acquired infestation was evident. In November 2001 and May 2002, approximately 60 B. ovis were transferred to each lamb, followed by monitoring at approximately 2-monthly intervals until August 2002. Similar procedures, but with fewer monitoring times, were repeated on the 2004 lambs. Overall, lambs in the Control line were significantly more susceptible to louse infestation and cockle compared with those in the other three lines (P < 0.001). Least squares-means (SEM) of log-transformed louse score for the control, resistant, susceptible and resilient lines, respectively, were 2.178 (0.045), 1.499 (0.050), 1.618 (0.050) and 1.587 (0.044), and for cockle score were 1.36 (0.05), 0.76 (0.05), 0.95 (0.05) and 0.78 (0.05). From all progeny together, the heritability of log-transformed louse score was 0.22 (Standard Error (SE) 0.06) in autumn and 0.34 (SE 0.08) in winter, with a value of 0.44 (SE 0.09) when these data were combined. These estimates were similar to those obtained for resistance to gastro-intestinal nematodes in these breeding lines, using log-transformed FECs. Heritability estimates for cockle score in autumn, winter and when combined were 0.06 (SE 0.04), 0.45 (SE 0.09) and 0.40 (SE 0.09), respectively. The genetic correlations of mean log-transformed louse score with mean cockle score and levels of two different louse antigens in wool were, respectively, 0.97 (SE 0.04), 0.96 (SE 0.08) and 0.95 (SE 0.09). However, there was no significant genetic correlation between louse scores and FEC. These results suggest that selective breeding would be effective in reducing louse infestation and cockle in sheep, but that differences in louse burdens were not related to differences in nematode burdens as indicated by FECs.