Prevalence of Pediculus capitis infestation among school children of Chinese refugees residing in mountainous areas of northern Thailand, CK Fan, CW Liao, MS Wu, NY Hu, KE Su

Tags: northern Thailand, Pediculus capitis infestation, Chiang-Rai Province, Taipei Medical University, head lice, infestation, MOUNTAINOUS AREAS, Chinese refugees, National Yang-Ming University, Pediculus capitis, aboriginal children, prevalence rate, primary school, National Taiwan University, head lice infestation, Akka, Department of Health, Stanczak J. Occurrence, Kaohsiung J Med Sci, Chinese Association for Relief and Ensuing Services, Ministry of Hygiene of Thailand, Pediculosis capitis, aboriginal village, Thailand Figure, Kaohsiung J Med Sci 1999;15, Parasitology, College of Medicine, Ministry of Foreign Affairs, Tronic B. Images, Markell and Voge's Medical Parasitology, Kua-Eyre Su4 Department of Parasitology, College of Medicine
Content: Pediculus capitis infestation in Thailand PREVALENCE OF PEDICULUS CAPITIS INFESTATION AMONG SCHOOL CHILDREN OF CHINESE REFUGEES RESIDING IN MOUNTAINOUS AREAS OF NORTHERN THAILAND Chia-Kwung Fan, Chien-Wei Liao,1 Ming-Shuan Wu,2 Neng-Yeou Hu,3 and Kua-Eyre Su4 Department of Parasitology, College of Medicine, and 2Department of Internal Medicine, Wan-Fang Hospital, Taipei Medical University; 1Institute of Parasitology, College of Medicine, National Yang-Ming University; 3Clinical Laboratory, Chu-Tung Hospital, Department of Health, Hsin-Chu; 4Department of Parasitology, College of Medicine, National Taiwan University, Taipei, Taiwan. An epidemiologic survey of Pediculus capitis infestation among Akka aboriginal and Han children of Chinese refugees living in mountainous areas at elevations of 1,100 to 1,400 m in Chiang-Rai Province of northern Thailand was conducted during January 2003. Of the 303 children examined, 43 (14.2%) had P. capitis infestation. The overall infestation rate for P. capitis in Akka children (29.3%, 12/41) was significantly higher than that in Han children (11.8%, 31/262; 2 = 8.161, p = 0.002). The prevalence in Akka (52.2%, 12/23) and Han girls (19.7%, 31/157) was higher than that in Akka (0%) and Han boys (0%), respectively (p < 0.001), and the prevalence was higher in Akka girls than in Han girls (2 = 10.978, p = 0.001). The high prevalence of P. capitis infestation among these girls was possibly due to poor environmental hygiene and unavailability of sufficient water. Key Words: Pediculus capitis, school children, refugees, Chiang-Rai Province, Thailand (Kaohsiung J Med Sci 2004;20:183­7)
Pediculus capitis (head louse) is a cosmopolitan parasite that is especially prevalent in temperate and cold regions wherever personal or general hygiene is low [1]. Lice will chiefly infest the human scalp, and female lice will deposit their eggs on the hair, where they become firmly attached. The eggs or nits are quite small, glistening white, and may be seen with the naked eye. About 10 days after deposition, they hatch into nymphs, which are quite similar structurally to the adults, and they mature in about 2 weeks. Both larvae and adults feed on blood obtained by their piercing mouth-
Received: November 3, 2003
Accepted: January 16, 2004
Address correspondence and reprint requests to: Dr. Chia-Kwung
Fan, Department of Parasitology, College of Medicine, Taipei
Medical University, 250 Wu-Hsin Street, Taipei 110, Taiwan.
E-mail: [email protected]
parts. Reportedly, 6­12 million individuals are infested with head lice yearly in the USA, 72% of whom are children who usually acquire the infestation from schoolmates [2]. Luis and Wawi refugee villages are located in mountainous areas at elevations of 1,100 to 1,400 m in Chiang-Rai Province, northern Thailand. Chinese refugees live in these villages, and include several different aboriginal populations and Han peoples who migrated from southern China between 1949 and 1952. The Akka population living in Luis village is the largest of the aboriginal populations, while most Han people live in Wawi village. Aboriginal and Han people differ in their traditional culture. Medical services are provided by Taipei Medical University, Taiwan, and, to improve the health status of school children, a survey of and treatment for P. capitis infestation among Han and Akka school children was conducted during January 2003.
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© 2004 Elsevier. All rights reserved.
C.K. Fan, C.W. Liao, M.S. Wu, et al
MATERIALS AND METHODS Luis and Wawi villages are located near the borders of Laos and Myanmar in the mountainous areas of Chiang-Rai Province, northern Thailand (Figure), an area of approximately 10,000 km2. These villages have approximately 20,000 Han and 4,000 aboriginal inhabitants. The study areas are located at about latitude 20°N and longitude 100°E, with mean daily temperatures of 10°C to 35°C, and relative humidity varying between 25% and 50%. This study included Akka school children from Luis village and Han school children from Wawi village. The hair of each child was examined visually (gross examination), paying special attention to the back of the head, which is a preferred nesting area for lice. After the examination, each infested child was given two packages of pediculicides, permethrin 1% (Nix Cream; Wellcome Co, Burlington, NC, USA), to kill the lice by washing their hair once a week within a 2-week treatment period as instructed by our physician. statistical significance was tested using the Chisquared test. RESULTS In total, 303 children, including 41 Akka children (18 boys and 23 girls) and 262 Han children (105 boys and 157 girls) were examined. The mean age was similar for both genders and ranged from 8 to 14 years in both populations. Of the 303 children examined, 43 (14.2%; 43/303) had P. capitis infestation. The overall P. capitis infestation rate was 29.3% (12/41) for Akka children and 11.8% (31/262) for Han children. The prevalence was 52.2% (12/23) in Akka girls, 0% in Akka boys, 19.7% (31/157) in Han girls and 0% in Han boys (Table). Overall, the prevalence in Akka children was higher than that in Han children (2 = 8.161, p = 0.002); the prevalence in Akka girls was also higher than that in Han girls (2 = 10.978, p = 0.001).
prevalence of P. capitis infestation in Akka aboriginal children in northern Thailand was not low (29.3%). In Poland, head lice infestation was found in 3.2% of 27,800 primary school children [5]. In Turkey, it was reported that 4.1% of 4,365 school children were infested with head lice [6]. In Australia, of 456 children examined, 33.7% had evidence of head lice infestation [7]. Infestation was found in 3.7% of 6,882 school children in Nigeria [8], and the prevalence was extremely high in Argentinian children (81.5%) [9]. In Asia, 37.2% of 912 primary school children in Korea were infested [10], and in Taiwan, 12.8% of 2,725 aboriginal children had evidence of head lice infestation [1]. It is noteworthy that the prevalence of P. capitis infestation in Akka girls was extremely high (52.2%). To our knowledge, Akka girls wash their hair infrequently (once per month) due to insufficient water in the remote mountainous areas, which may be an important factor contributing to the high prevalence. None of the Akka and Han boys examined were infested by head lice, possibly because almost all had their hair cut short, providing little area for the lice to live on. Many reports indicate that head lice are more prevalent in girls than boys [1,7,11]. In Korea, the prevalence rate in girls is reported to be 19 times higher than that in boys [12]. Not surprisingly, since northern Thailand is situated in the tropics, temperature and humidity are high throughout the year, making infestation with head lice very probable. Although the infested children were treated weekly with permethrin during a 2-week period, which reportedly has cure rates of 98% and 96% on days 7 and 14 post-treatment, respectively [13], these children might reacquire the infestation due to poor knowledge and environmental hygiene. Although public health education may be a feasible measure in the prevention of P. capitis, intensive chemotherapy for infested Chinese children resident in mountainous areas of northern Thailand is more important due to their parents' poor economic conditions. Providing more medical services is necessary in the future.
DISCUSSION
ACKNOWLEDGMENTS
Head lice are transferred from one person to the next by direct contact or by contact with clothing, hats, or hair from "lousy" individuals. Not only do head lice infestations pose a hazard to the health of children because they suck blood and cause allergic scalp dermatoses [3], but they may also play a role as vectors of Rickettsia prowazekii, the etiological agent of louseborne epidemic typhus [4]. In the present study, the overall
The authors are grateful to the Military Ministry, Ministry of Foreign Affairs, and Ministry of Hygiene of Thailand. The authors also wish to thank the Ministry of Foreign Affairs, Department of Health, Chinese Association for Relief and Ensuing Services, and Taipei Medical University, Taiwan, for their support of this investigation. Dr. Chamberlain helped with the revision of this paper.
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Figure. Map of Chiang-Rai Province, northern Thailand, showing selected study areas. x = Akka aboriginal village; s = Han village.
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Table. Prevalence of Pediculus capitis infestation among Akka and Han school children in mountainous areas of Chiang-Rai Province, northern Thailand
No. examined No. positive Positive rate (%)
Akka children
Boys
18
Girls
23
Total
41
0
0.0
12
52.2*
12
29.3
Han children
Boys
105
0
0.0
Girls Total
157
31
19.7*
262
31
11.8
*p < 0.001; p < 0.01.
REFERENCES 1. Fan PC, Chung WC, Fan CK, et al. Prevalence and treatment of Pediculus capitis infestation among aboriginal school children in northern Taiwan. Kaohsiung J Med Sci 1999;15: 209­17. 2. Markell EK, John DT, Krotoski WA. Markell and Voge's Medical Parasitology. Pennsylvania: WB Saunders, 1999. 3. Driscoll DM, Tronic B. Images in clinical medicine. Pediculosis capitis. N Engl J Med 1996;335:790. 4. Robinson D, Leo N, Prociv P, Barker SC. Potential role of head
lice, Pediculus humanus capitis, as vectors of Rickettsia prowazekii. Parasitol Res 2003;90:209­11. 5. Wegner Z, Racewicz M, Stanczak J. Occurrence of pediculosis capitis in a population of children from Gdansk, Sopot, Gdynia and the vicinities. Appl Parasitol 1994;35:219­25. 6. Ilhan F, Budak S, Guruz AY. The prevalence of Pediculus humanus capitis among the students of a secondary and three elementary schools in Karsiyaka-Izmir, Turkey. J Egypt Soc Parasitol 1997;27:157­61. 7. Speare R, Buettner PG. Head lice in pupils of a primary school in Australia and implications for control. Int J Dermatol 1999; 38:285­90. 8. Ebomoyi EW. Pediculosis capitis among urban school children in Ilorin, Nigeria. J Nat Med Assoc 1994;86:861­4. 9. Chouela E, Abeldano A, Cirigliano M, et al. Head louse infestations: epidemiologic survey and treatment evaluation in Argentinian schoolchildren. Int J Dermatol 1997;36:819­25. 10. Huh S, Pai KS, Lee SJ, et al. Prevalence of head louse infestation in primary school children in Kangwon-do, Korea. Korean J Parasitol 1993;31:67­9. 11. Fan PC, Chung WC, Fan CK. Studies of Pediculus capitis infestation among school children in Taiwan and offshore islands with a special emphasis on evaluation of pediculosis control program in the past years. Chin J Parasitol 1999;12: 71­87. 12. Hong HK, Kim CM, Lee JS, et al. Infestation rate of head lice in primary school children in Inchon, Korea. Korean J Parasitol 1995;33:243­4. 13. DiNapoli JB, Austin RD, Englender SJ, et al. Eradication of head lice with a single treatment. Am J Public Health 1988;78: 978­80.
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CK Fan, CW Liao, MS Wu, NY Hu, KE Su

File: prevalence-of-pediculus-capitis-infestation-among-school-children.pdf
Title: Prevalence of Pediculus Capitis Infestation Among School Children of Chinese Refugees Residing in Mountainous Areas of Northern Thailand
Author: CK Fan, CW Liao, MS Wu, NY Hu, KE Su
Author: Chia-Kwung Fan; Chien-Wei Liao; Ming-Shuan Wu; Neng-Yeou Hu; Kua-Eyre Su
Keywords: Pediculus capitis; school children; refugees; Chiang-Rai Province; Thailand
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