Bluetongue virus (BTV) causes a vector-borne disease of considerable veterinary and economic importance. The virus is spread by biting midges (family Ceratopogonidae). BTV exposure has been reported in a wide range of ecological settings, but evidence from very high-altitude areas remains limited. To our knowledge, this is the first report of serological evidence of BTV exposure of domestic ruminants at extremely high altitudes (>4500 m) in Ali Prefecture, western Tibetan Plateau, China. Testing with a competitive enzyme-linked immunosorbent assay revealed that 31.1% of 633 blood samples collected from sheep, goats, yaks, cattle, and yak–cattle hybrids in Ali Prefecture in 2023 were positive for BTV-specific antibodies, with seroprevalence varying from 90.7% in goats to only 0.4% in yaks, confirming significant geographical and interspecies differences ( p < 0.001). BTV-specific antibodies were detected in animals from locations above 4500 m, indicating previous exposure at elevations where evidence remains scarce. These findings provide baseline seroepidemiological data relevant to livestock health in alpine ecosystems, and support the need for strengthened entomological surveillance in high-altitude regions.
Song et al. (Wed,) studied this question.