India GardenKeymaster@india-gardenAugust 9, 2016 at 7:48 am #12754
Honey Bee Diseases
American Foulbrood is a highly lethal and contagious disease of honey bees, caused by the spore-forming bacteria Bacillus larvae. The disease causes larvae to die after cells are capped. Worker bees have difficulty trying to remove the dead larvae, and often contaminate the hive with additional spores. As the colony weakens and dies out, bees from other colonies (sometimes from several miles away) will be apt to rob out the remaining honey. As they travel through the hive, they become contaminated as well, and introduce the bacterial spores to their colony as well. Antibiotics do not kill this bacteria or prevent the disease, but merely hold it off temporarily. Colonies known to be infected with American Foulbrood must be destroyed by burning to prevent the disease from spreading to a other hives and other nearby apiaries. Beekeepers who suspect that a hive may contain AFB should contact their state apiary inspectors immediately. Failure to do so could put all of their hives at risk, as well as those of others in the vicinity. AFB is not harmful to humans or any other creature besides honey bees.
European Foulbrood is another bacterial disease, although slightly less contagious that AFB. If diagnosed at an early stage, a colony can recover from a mild infection of EFB. Beekeepers are advised to consult and follow the advice of their state apiary inspectors.
Nosema is a condition caused by the microsporidia Nosema apis or Nosema cerana. This microbe attacks the cells in the wall of a honey bee’s stomach, where it reproduces and attacks repeatedly, eventually destroying the stomach lining. This cycle of infection takes some time to build up, during which the bee is increasingly unable to digest food. As a result, the bees become weaker and their hind-guts fill with fecal material. Nosema disease has traditionally been associated with long-lived overwintering bees, confined in the hive for extended periods of time. If unable to take periodic cleansing flights (due to cold weather), severe dysentery symptoms may become apparent in the hive and around the entrance. Housecleaning activities of healthy bees often cause them to ingest spores, initiating their infection. Typically the disease disappears once spring weather allows for regular cleansing flights and spring pollen plants induce increased brood rearing. However, new strains appear to be more virulent, and may attack a colony during any time of year, especially if the colony health has been compromised by pesticide exposure or other factors. Treatment for nosema includes feeding colonies syrup medicated with Fumigillin.
Chalkbrood is a brood disease caused by the fungus Ascophaera apis. Beekeepers typically notice the condition in early spring when workers remove and discard infected larvae near the entrance of the hive. There is no medical cure for chalkbrood disease, but it is rarely serious to the colony. As spring brood rearing increases, a colony typically out-grows the condition. If it persists year after year in the same colonies, beekeepers should discard the combs and sterilize woodenware before installing new foundation.
Sacbrood Virus affects only the honey bee larvae, and is mildly contagious within the hive. Typically, the disease can be stopped by requeening a colony. The break in the brood cycle allows worker bees to remove all infected larvae during an interval when no additional larvae of a susceptible age are present. There is no medical treatment for sacbrood.
Other Honey Bee Viruses are commonplace today. There are many viruses that negatively affect honey bees (around 30 currently known). Some, such as Deformed Wing Virus produce visible symptoms, but most do not. Viruses are mainly vectored between bees and colonies by parasitic mites. There is currently no medical treatment for bee viruses. But effectively managing mite populations can greatly reduce the impact of bee viruses.
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