Dead bees looking old; may appear as high death numbers in front of colony or sudden colony collapse. Signs are highly variable and not well characterized. Only possible to confirm under molecular examination.
Kashmir bee virus (KBV) is apparently widespread and considered the most virulent of honey bee viruses, at least under laboratory test conditions. Adult bees die within three days when injected with KBV. At moderate infection levels, KBV can kill colonies when found with varroa mites present (supposedly virus is transmitted by mites). Typically they exhibit no apparent signs, though sometimes bees tremble and are otherwise seemingly unable to move. Dead bees may look dark, “old,” and hairless.
Other viruses such as acute bee paralysis virus, chronic bee paralysis virus, Israeli acute paralysis virus
Moore PA, Wilson ME, and Skinner JA. 2019 update. Honey Bee Viruses, the Deadly Varroa Mite Associates. Bee Health. Accessed 2023. https://bee-health.extension.org/honey-bee-viruses-the-deadly-varroa-mite-associates/
Chen Y, et al. 2004. Transmission of Kashmir bee virus by the ectoparasitic mite Varroa destructor. Apidologie 35(4): 441-448. https://www.apidologie.org/articles/apido/pdf/2004/04/M4021.pdf
Grozinger C, Underwood R, and Lόpez-Uribe M. 2020. Viruses in Honey Bees. PennState Extension. Accessed 2023. https://extension.psu.edu/viruses-in-honey-bees
