Skip to main content
Research article - Peer-reviewed, 2006

Vertical transmission of American foulbrood (Paenibacillus larvae) in honey bees (Apis mellifera)

Fries I, Lindstrom A, Korpela S


The mode of transmission between hosts (horizontal versus vertical) of disease agents is important for determination of the evolution of virulence in pathogens. For disease management, it is imperative that the epidemiology of the disease is understood and pathogen transmission rates between hosts is a key factor for this understanding. Surprisingly little is known about transmission rates in honey bee pathology. We have studied the rate of vertical transmission of Paenibacillus larvae, the causative agent of American foulbrood (AFB) in honey bee colonies, as colonies reproduce by colony fission (swarming), by culturing for the spores from repetitive samples of adult bees. The results demonstrate vertical pathogen transmission to daughter swarms. The spore density declines over time in both mother colonies and daughter swarms if mother colonies do not exhibit clinical disease symptoms. Occasional positive samples more than a year post swarming, also in daughter swarms, indicate production of infectious spores from diseased larvae, without clinical disease observable by beekeepers, and/or maintenance of infective spores in the hive environment, allowing both horizontal and vertical transmission to be maintained. The results suggest that the virulence of AFB, being lethal at colony level in contrast to other bee diseases shaped by evolution, could be dependent on apicultural practices and that the pathogen probably would be maintained without causing frequent colony mortality in a natural system. (c) 2006 Elsevier B.V. All rights reserved

Published in

Veterinary Microbiology
2006, volume: 114, number: 3-4, pages: 269-274

Authors' information

Fries, Ingemar
Swedish University of Agricultural Sciences, Department of Entomology
Lindström, Anders
Swedish University of Agricultural Sciences, Department of Entomology
Korpela, Seppo

UKÄ Subject classification

Veterinary Science
Environmental Sciences related to Agriculture and Land-use
Animal and Dairy Science

Publication Identifiers


URI (permanent link to this page)