Prevalence of head lice infestation and its associated factors in primary school students in Shiraz City, Fars Province, Iran

Pediculus humanus capitis is an obligate ectoparasite transmitted mainly through direct head-to-head contact, affecting millions of school-aged children worldwide. This study aimed to determine the prevalence of head lice infestation and identify associated risk factors among primary school pupils in Shiraz City, Fars Province, Iran. A cross-sectional study was conducted from September 2023 to March 2024 among 367(228 boys and 129 girls, grades 7–12) students selected by multistage cluster sampling. Screening was performed by trained staff using inspection and systematic combing. Data were analyzed using SPSS version 24, Microsoft Excel, and Python (Google Colab). Chi-square tests were applied, with p < 0.05 considered significant. The prevalence of infestation was 18.25%. Girls were more affected than boys (34.8% and 9.6%, p < 0.001), and the highest prevalence occurred at age 10-year-old students (45.46%). Significant associations were found with family size trend (p = 0.053), hair length, comb use frequency, and itching, especially in the postauricular and occipital regions (p < 0.001). No significant relationships were observed with parental education, nationality, housing type, hair washing frequency, or sharing of personal items. Head lice infestation remains a relevant public health issue among schoolchildren in Shiraz. The findings highlight gender, hair length, and family size as significant risk factors, while regular hygiene practices show a protective effect. Preventive programs focusing on health education for families and schools are recommended to reduce infestation rates.