Epidemiology and prevalence patterns of head lice infestation in Isfahan Province, central Iran based on a surveillance study (2017–2024)

Abstract

This study aimed to describe the demographic, temporal, spatial, and treatment-related epidemiology of head lice ( Pediculosis capitis ) infestation in Isfahan Province, central Iran, using population-based surveillance data. A retrospective population-based analysis was conducted using routine pediculosis surveillance data recorded between 2017 and 2024. All confirmed cases registered in the national surveillance system were included. Information on age group, sex, nationality, residential area, reporting date, and prescribed treatment was analyzed. Prevalence rates were calculated as the number of reported cases per 1,000 population using annual county- and subgroup-specific population denominators. Temporal trends, seasonal variation, and subgroup differences were assessed using descriptive statistics and inferential tests, and spatial patterns were examined using geographic information system (GIS) mapping. A total of 226,466 infestation episodes were reported during the study period. Prevalence was substantially higher in females than in males, and the greatest burden was observed among children aged 6–12 years. A clear seasonal pattern was identified, with peaks in autumn corresponding to the school calendar. Reported prevalence declined markedly in 2020, likely reflecting disruption of school-based screening, healthcare access, and surveillance during the COVID-19 pandemic, and increased again thereafter. Spatial analysis showed marked heterogeneity across counties, with Natanz consistently representing the highest-burden area. Overall reported prevalence was 6 per 1,000 population, with county-level rates ranging from 1 to 7 per 1,000. Permethrin shampoo accounted for more than 90% of prescribed treatments. Head lice infestation remains a notable public health issue in Isfahan Province, with a disproportionate burden among females and school-aged children, clear seasonal peaks, and marked geographic heterogeneity. Population-standardized prevalence estimates identified persistent high-burden areas, particularly Natanz County, highlighting the need for targeted local interventions. Strengthening school-based control programs, monitoring treatment effectiveness, and maintaining resilient surveillance systems during public health disruptions may improve long-term control. However, the findings should be interpreted considering the limitations of surveillance-based data, including potential underreporting and lack of socioeconomic information.