Prevalence and Associated Factors of Head Lice (Pediculosis capitis) Among Primary School Students in Varzaqan Villages, Northwest of Iran

Human head lice (Pediculus humanus capitis) is one of the important lice species that only infects the human scalp (1). Head lice contamination is spread abroad parasitic contamination that causes serious health problems in many communities, particularly among school children (2). Pediculosis is a significant health problem in countries with fewer health standards (3). These human ectoparasites are transmitted mainly through direct head-to-head contact and indirect contact by sharing personal objects such as hats, combs, brushes, and scarves (4, 5). The primary sign of head lice infestation is severe itching because of lice feeding on the host scalp and neck area, subsequently leading to secondary bacterial infection (3, 6). It may lead to psychological and social problems and academic failure in children (7). Various head lice prevalence rates have been reported in children around the world, such as 67.5% in Ethiopia (8), 26.6% in Jordan (9), and 23.2% in Thailand (10).

Several studies from different areas of Iran have reported various rates of head lice infestation. For example, a systematic review by Moosazadeh et al. reported a prevalence of 7.4% in primary school students (11). Other studies have shown different rates, including 10.5% in Khuzestan (12), 29.35% in Qom (13), 3.2% in Kormanj, North Khorasan (3), 5.7% in Galugah, Mazandaran province (14), and 4.8% in Khaje, East Azerbaijan province (15). Also, Ziaoddini et al. showed an annual prevalence of head lice in East Azerbaijan province from 1.12% in 2014 to 6.70% in 2018 (16). In addition, some studies showed significant risk factors including prior infestation, number of combs per day, frequency of bathing, presence of a health teacher, sharing personal objects, knowledge of pediculosis, and the distance between children in each class (14), as well low parental literacy, long hair, number of family members, mother’s job (housewife), father’s job (worker/unemployed), using a common comb, lack of bathrooms at home, and low frequency of showering (11). Its prevalence also depends on the season, detection method, founding of head lice infestation or existence of nits, and the effectiveness of pediculicides (17).

Due to the prevalence of head lice infestation in different areas, we need to improve the community's health and help regional policymakers and health providers. Therefore, the present study was conducted to determine the prevalence of P. h. capitis and related factors in primary school children in the villages of Varzaqan city in the Northwest of Iran.

This primary school-based, cross-sectional study was conducted in Varzaqan villages in the northwest of Iran from December 2019 to January 2020. The study was conducted among 400 boys and girls between 7 and 12 years old from 26 primary schools selected through convenience sampling in rural regions. The sample size was calculated using Cochran's formula of n = ${\displaystyle \frac{z^{2}pq}{d^2}}$ in which z = 1.96 (3), P = 0.5, and d = 0.05. The consent of students and their parents to participate in the study and being a primary school student were the study's inclusion criteria. Students from other grades were excluded. The information was collected in two parts: demographic data and health examination results. A family doctor examined the participants' scalps and hair individually under the flashlight for all life cycle stages of head lice (such as nites/eggs, nymph, or adult lice). Also, a demographic checklist (with 13 questions) recorded the data on age, gender, school grade, parents’ jobs, parents’ literacy, number of combs per day, previous lice infestation, frequency of bathing per week, bathroom at home, family income, and presence of a health educator in school. The data analysis was performed using descriptive (frequency and percentage) and analytical methods, including chi-square and t-tests (SPSS software, version 16). A P-value of less than 0.05 was considered significant.

The Ethics Committee of Tabriz University of Medical Sciences approved the present investigation (Permit No. IR.TBZMED.REC.1398.863). However, written consent was obtained from all participants' legal guardians after being thoroughly informed of the study.

Overall, 400 primary school students from 26 elementary schools (with 949 students) of 11 villages were included in this study. Most participants were boys (52.8%), and all of them lived in rural areas. The overall head lice infestation rate was 10.3% (n = 41), including 14.8% (n = 28) in girls and 6.2% (n = 13) in boys. There was a significant relationship between the pediculosis prevalence and gender of students (P < 0.05). The prevalence of head lice infestation was higher in children who had mothers with low educational levels (P = 0.001). On the other hand, the father's job had a significant relationship with pediculosis (P = 0.001). Also, pediculosis had significant relationships with factors such as a history of infestation (P = 0.001), the presence of a bathroom at home (P = 0.002), household income (P = 0.001) (Table 1), bathing per week (P = 0.001), and the number of combs per day (P = 0.001) (Table 2). Unfortunately, none of the schools in the study had a health teacher.

Despite advances in health and medical science, head lice continues to be a public health problem in poor and developing countries (13). In the present study, the total prevalence of P. capitis among primary school children in the rural regions of Varzaqan city was 10.3%. As known, P. capitis is an infestation that often affects children. Depending on the socioeconomic status, these infestations may affect a large portion of a population (12). Previous epidemiological studies have shown various rates of head lice infestation in different countries, such as 3.3% in France (18), 5.3% in Australia (19), 87% in Pakistan (20), 23.2% in Thailand (10), 16.7% in Egypt (21), 4.1% in Korea (22), 13.5% (23) and 13.1% in Turkey (17). Various studies from different regions of Iran have shown different prevalence rates, from 0.47% in Isfahan in 2003 to 23.9% in Hormozgan in 2007 and 27% in Sistan and Baluchestan (1). According to previous studies, the prevalence of infestation is usually higher in rural areas (12, 13, 24), which could be due to better social, economic, and educational status in urban areas (24). It may also be related to better hygiene because there is often a health teacher in urban schools (12).

Similar to previous studies in Iran and other parts of the world (9, 11-14, 17), the findings of this study showed that the prevalence of pediculosis was more than two folds higher in schoolgirls than in schoolboys. This significant difference could be related to different behavioral patterns between boys and girls, such as long hair in girls that need better care and combing; besides, female hair is probably a suitable place for head lice because of covering with a scarf (12, 13). In the present study, socioeconomic factors such as mother’s education level, father’s job, and family income had a significant association with head lice infestation. On the other hand, the infestation was related to personal health habits like a history of infestation, low frequency of bathing, and combing hair. Several studies have shown relationships between socioeconomic status and head lice (11-14).

Our findings suggested a lower infestation rate in students with educated mothers, which may be due to the knowledge of pediculosis. Besides, educated mothers may have a more positive attitude and knowledge about hygiene. In general, higher education levels of parents can lead to more appropriate health behaviors in the family, which is supported by other studies (14, 24).

According to a third Turkish school survey, the rate of pediculosis was more common among students with a prior personal and family infestation. However, the frequency of bathing and using a common comb did not affect the prevalence of head lice (17). Another study conducted in Turkey showed that female gender, living with three or more siblings, and low parental literacy levels were risk factors of infestation (25). According to a cross-sectional study in Jordan in 2012, pediculosis was significantly related to sex, living in rural areas, a history of infestation, low income, long hair, lack of a bathroom, low frequency of bathing, and hair washing (9). A cross-sectional study in Mexico showed low income and low frequency of hair washing as risk factors for head lice infestation (26), which is consistent with the present study. This study showed that pediculosis is still a significant health problem in low socioeconomic regions.

This research had some limitations. It was conducted in a limited area and used a convenience sampling method that may have affected the generalizability of the results.