Phylogenetic analysis and pyrethroid resistance mutation profiling of Haematopinus tuberculatus in buffaloes from Naqadeh, Iran

Haematopinus tuberculatus is a major ectoparasite of water buffaloes, causing substantial economic losses. Widespread pyrethroid use has driven the emergence of resistance in H. tuberculatus populations, highlighting the need for a deeper understanding of the underlying genetic mechanisms. This study examined the genetic diversity and resistance mechanisms of H. tuberculatus from Naqadeh, Iran, analyzing 372 lice samples collected from 71 buffaloes across 10 farms. Molecular identification, based on mitochondrial cox1 partial sequence amplification and sequencing, confirmed all samples as H. tuberculatus and revealed close genetic relatedness to populations from China. Phylogenetic analysis of cox1 demonstrated its utility as a genetic marker for intra-specific differentiation. Furthermore, sequencing of the voltage-gated sodium channel (VGSC) gene revealed four key amino acid substitutions: T917I, I920F, V929R, and L930M. Notably, the T917I and I920F mutations have been previously linked to pyrethroid resistance in Pediculus humanus capitis, as well as in Bovicola and Haematopinus species. This suggests a similar potential for pyrethroid resistance in the H. tuberculatus populations examined in this study. These findings highlight the urgent need to implement integrated pest management (IPM) strategies that reduce reliance on pyrethroids and emphasize alternative control measures to safeguard buffalo health and productivity.