Bees encounter viral, bacterial, and fungal pathogens that can have serious impacts on colony health and survival. Some of these pathogens are highly contagious on their own, and others can also be spread by the Varroa mite.
Beekeepers maintain constant vigilance and routines to combat pathogens, including administering preventative varroacides and other treatments as needed.
Some infections are more worrisome than others. The spore-forming bacteria that causes American foulbrood (AFB) is so persistent that destroying the colony completely is recommended to prevent the spread of this disease.
Because of diseases like AFB, each state has an apiary inspection program to help beekeepers deal with pathogens, and prevent the spread of disease. This is also why many beekeepers manage bees within a colony that has removable frames. Getting an up-close look and sample of the honey bee brood is essential to monitoring colony health.
Nosema disease is widespread, and caused by a single-celled parasite that infects the gut-lining of the bee, causing dysentery and other colony health impacts.
As problematic as bacterial and fungal infections are for honey bees, viruses are incredibly wide-spread, due to the prevalence of the Varroa mite.
Deformed Wing Virus (DWV)
(Chart Image here-2021 Prevalence of DWV-A)This chart from the Bee Informed Partnership shows the Prevalence of Deformed wing virus (DWV). DWV is closely linked to Vvarroa mite infection. On average DWV is found in roughly 80% of bee colonies sampled across the United States. Bees with twisted, deformed wings are a sure sign of DWV infection (and Varroa mite infestation). The bees, unable to fly, can be seen crawling in front of the colony. Explore the Bee Informed Partnership database here.