Document Type : Original Article
Authors
1
Laboratory of Veterinary Parasitology, School of Animal Science and Technology, Foshan University
2
Laboratory of Veterinary Parasitology, school of Animal science and Technology, Foshan University
3
Institute of Animal science, Xizang Academy of Agricultural and Animal Husbandry Sciences, Lhasa, china
4
Institute of Animal Science, Xizang Academy of Agricultural and Animal Husbandry Sciences, Lhasa, china
5
Institute of Animal Science, Xizang Academy of Agricultural and Animal Husbandry Sciences, Lhasa, China
6
Agriculture and Rural Bureau of Dazi District, Lhasa, China
7
Animal Disease Prevention and control Center of Shigatse, China
8
Nyainrong County Agricultural Science and Technology Service Station, Nagqu, china
9
Nyainrong County Agricultural Science and Technology Service Station, Nagqu, China
10.30466/vrf.2026.2076665.4977
Abstract
Hypoderma sinense larvae, as tissue-invasive parasites, migrate through host tissues for months before completing their development in the subdermal tissue of the back. This migratory behavior induces lesions in surrounding tissues, compromising meat quality and economic value. To quantify the tissue damage and characterize the associated microbial communities, this study collected second- and third-stage larvae along with diseased tissues from infected yak skin.
A systematic analysis correlated these larval stages with parasite abundance and tissue damage extent. Histopathological examination evaluated structural changes in affected tissues, while bacterial isolates from lesion sites were obtained through culture-based methods. Bacterial species were identified by sequencing the 16S rDNA gene and conducting phylogenetic analysis.
Third-stage larvae caused significantly greater tissue damage in yaks than second-stage larvae. Histopathological analysis using hematoxylin-eosin and Masson staining revealed multi-layered lesions along the migration paths of third-instar larvae, extending from the epidermis to muscular layers. Key pathological features included: (i) infiltration of inflammatory cells, primarily neutrophils and macrophages; (ii) granuloma formation with fibrous encapsulation; and (iii) scar tissue deposition in perilesional areas.
Microbial analysis identified four bacterial genera—Escherichia, Enterococcus, Staphylococcus, and Bacillus—representing at least five distinct species, with a minimum of four being conditional pathogens. These bacteria vary in their involvement in lesion progression and may contribute to risks of secondary infection and disease transmission.
This study characterized the histopathological features and bacterial profiles of lesions associated with Hypoderma sinense third-stage larval infections, providing insights for clinical diagnosis and management of the disease and its associated microbial pathogens.
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