# Prevalence and Molecular Characterization of Parasitic Lice in Tibetan Yaks, Pigs and Sheep

## TL;DR

This study examines lice infestations in Tibetan yaks, pigs, and sheep, finding high prevalence and identifying species through molecular analysis to aid in disease control.

## Contribution

The study provides the first molecular characterization of lice in plateau livestock, revealing species identities and prevalence rates.

## Key findings

- Lice prevalence was 51.3% in yaks, Tibetan sheep, and Tibetan pigs, with regional variation from 7.7% to 67.5%.
- Female lice were significantly larger than males across all three species, with specific morphometric differences.
- Molecular analysis identified lice species as Linognathus vituli, Linognathus africanus, and Haematopinus apri with high genetic similarity to known isolates.

## Abstract

The infestation of ectoparasites poses a severe problem in animal breeding, severely affecting animal health and causing substantial economic losses. However, limited information is available regarding lice infestations in plateau livestock. To address this, we collected and examined lice samples from Tibetan yaks, pigs and sheep, amplifying the rrnS and cox1 genes for evolutionary analysis. The results revealed that the prevalence of lice was 51.3% (95% CI: 44.0–58.6%) in yaks, Tibetan sheep and Tibetan pigs, with regional prevalence ranging from 7.7% to 67.5%. Morphometric analysis showed that female lice were bigger than male lice. In Tibetan pigs, females exhibited a prominent longer body length (p < 0.05), belly length (p < 0.01) and body length to body width ratio (p < 0.05). In yaks, females had longer body length (p < 0.01) and body width (p < 0.05). For Tibetan sheep, female lice had larger body length (p < 0.001), body width (p < 0.001), head length (p < 0.05) and belly length (p < 0.05). Additionally, molecular identification revealed that lice infesting wild and domestic yaks were Linognathus vituli with 96.59–98.78% (wild yaks) and 96.33–98.71% (yaks) similarity to the OL677823.1 isolate. Lice infesting Tibetan sheep were identified as Linognathus africanus, showing 99.02–99.76% similarity to the OP948898.1 isolate. Lice from Tibetan pigs were identified as Haematopinus apri, with 96.38–98.31% similarity to the ON000922.1 isolate. Moreover, cox1 gene analysis of lice from Tibetan pigs showed 96.97–97.72% similarity to the KC814616.1 isolate. It is concluded that these findings could provide valuable insights into the prevention and control of lice-related diseases in plateau animals, enhancing animal health and mitigating economic losses.