Genetic diversity, microbiome composition and socio-sanitary predictors of head lice (Pediculus humanus capitis) among disadvantaged children in Klang Valley, Malaysia.

Pediculosis capitis remains a neglected public health issue in Malaysia, particularly among disadvantaged children. While the genetic diversity of head lice is well studied, their associated microbiome and links to socio-sanitary conditions remain unclear. This study examined 266 children from ten children's establishments in Klang Valley and Greater Kuala Lumpur, of whom 89 (33.46%) were positive for pediculosis capitis. Cytochrome c oxidase subunit I (COI) barcoding identified two clades: A (36%) and C (64%). 16S rRNA metagenomic profiling of pooled samples revealed higher microbial diversity in Clade C compared to Clade A, with opportunistic bacteria, including Propionibacterium acnes, Streptococcus spp., Bacteroides fragilis, and Staphylococcus aureus being detected. Logistic regression identified age, head lice awareness, and eating with hands as significant predictors of infection. These findings demonstrate that head lice not only cluster genetically but also may harbour clade-dependent microbiomes, with potential health implications. The integration of genetic diversity, microbial variation, and socio-sanitary data highlights the multifactorial risks of pediculosis capitis in vulnerable populations, underscoring the importance of combined ectoparasite control and hygiene interventions.