Regional Distribution of <I>Paenibacillus larvae</I> subspecies <I>larvae</I>, the Causative Organism of American Foulbrood, in Honey Bee Colonies of the Western United States

Abstract

We examined honey bee, Apis mellifera L., colonies pollinating almonds in California during February 2003 for Paenibacillus larvae subsp. Larvae, the causative organism of the virulent brood disease American foulbrood. Colonies originating from the Rocky Mountain area and California had significantly higher numbers (P < 0.05) of bacterial colony-forming units (CFUs) (408 and 324 per 30 adult bees, respectively) than colonies from the upper Midwest (1.28). Colonies from the northwestern, central, and southwestern United States had intermediate CFU or bacterial colony levels. Operations positive for P. larvae larvae were relatively uniform at approximately 70-80%, and no regional significant differences were found. Percentages of colonies with high CFUs (> or = 400 per 30 bees) differed significantly, with those from the Rocky Mountain region having 8.73% compared with those of the upper Midwest with 0%. The significance of CFU levels was evaluated by inoculating healthy colonies with diseased immatures and sampling adult bees. The number of CFUs detected per diseased immature was conservatively estimated to be approximately 399 CFUs per 30 adult bees. We defined this spore level as 1 disease equivalent. Based on this, 3.86% colonies in our survey had 1 or more disease equivalent number of P. larvae larvae CFUs. Operations with high P. larvae larvae spore levels in their colonies will likely observe American foulbrood if prophylaxis is not practiced diligently.

A historical review of managed honey bee populations in Europe and the United States and the factors that may affect them

“…Of all diseases of the honey bee, AFB has had the greatest impact on the industry. In 2000, annual economic loss attributed to AFB infection in the US was estimated at US$5 million (Eischen et al, 2005). This estimate is likely only a fraction of the cost to the industry prior to the mid-1900s.…”

Honey Bees (Apis mellifera L.) and Pollination Issues: Current status, impacts and potential drivers of decline

“…AFB has had the greatest impact on the apiary industry. In 2000, the annual economic loss attributed to AFB infection in the US was $5 million (Eischen, Graham & Cox, 2005). It is considered to be more virulent than European foulbrood.…”

In vitroevaluation of the effects of some plant essential oils onPaenibacillus larvae, the causative agent of American foulbrood

“…In the year of 2000, AFB infection in the United States resulted in an annual economic loss of approximately 5 million USD. [4] AFB is a transmissible destructive disease that affects the larval and pupal stages of honey bees. The disease is spread by the exchange of materials between honey bee colonies, the presence of numerous hives in a confined area and the trade of bee packages and bee products.…”