Prevalence, Risk Factors, and Phylogenetic Characterization of Pediculus humanus capitis Among Primary Schoolchildren in Algeria.

INTRODUCTION

Pediculus humanus capitis is a cosmopolitan ectoparasite that causes scalp pruritus, particularly among children in low- and middle-income countries. Transmission occurs mainly through direct head-to-head contact, and various risk factors have been implicated in increasing susceptibility to infestation. Nevertheless, epidemiological and molecular data on head lice infestation in Algeria remain limited.

MATERIALS AND

METHODS

This cross-sectional epidemiological study aimed to estimate the prevalence of pediculosis capitis and to identify associated risk factors among Algerian primary schoolchildren across 21 provinces over a 10-year period (2015-2024). A total of 34,152 children aged 8 to 11 years from 124 schools were screened for infestation. Data were collected on infestation status, demographic variables, and hair characteristics. In addition, mitochondrial cytochrome b gene sequencing was performed on representative specimens to investigate phylogenetic diversity and lineage distribution.

RESULTS

The overall prevalence of head lice infestation was 3.5%, with a mean intensity of 7.8 lice per infested individual and a mean abundance of 0.23 lice per child. Significant regional and annual variations in prevalence were observed. Infestation was nearly four times higher in girls than in boys (5.18% vs. 1.58%; OR = 3.53, p < 0.001). Additional risk factors included long, straight hair and poor scalp hygiene. Phylogenetic analysis revealed the co-circulation of two mitochondrial clades (A and B), with a slight predominance of clade A, indicating underlying genetic diversity and regional heterogeneity in lineage distribution.

CONCLUSION

This first large-scale national survey integrating epidemiological and phylogenetic approaches provides a comprehensive overview of head lice infestation in Algeria. The findings support the implementation of targeted school-based prevention programs and highlight the importance of molecular surveillance to better understand lice population structure and to inform sustainable control strategies.