Free access
Volume 32, Number 3, May-June 2001
Page(s) 199 - 214
DOI: 10.1051/apido:2001122

Apidologie 32 (2001) 199-214

Implications of horizontal and vertical pathogen transmission for honey bee epidemiology

Ingemar Friesa and Scott Camazineb

a  Department of Entomology, Swedish University of Agricultural Sciences, Box 7044, 750 07 Uppsala, Sweden
b  Department of Entomology, Penn State University, 539 ASI Building, University Park, PA 16802, USA

(Received 15 January 2001; accepted 8 March 2001)

The degree to which a disease evolves to be virulent depends, in part, on whether the pathogen is transmitted horizontally or vertically. Eusocial insect colonies present a special case since the fitness of the pathogen depends not only on the ability to infect and spread between individuals within a colony, but also on the ability to spread to new individuals in other colonies. In honey bees, intercolony transmission of pathogens occurs horizontally (by drifting or robbing) and vertically (through swarming). Vertical transmission is likely the most important route of pathogen infection of new colonies. Theory predicts that this should generally select for benign host-parasite relationships. Indeed, most honey bee diseases exhibit low virulence. The only major exception is American foulbrood (AFB). In light of current ideas in evolutionary epidemiology, we discuss the implications of horizontal and vertical pathogen transmission for virulence of AFB and other honey bee diseases.

Key words: honeybee / epidemiology / pathogen transmission / horizontal transmission / vertical transmission

Correspondence and reprints: Ingemar Fries

© INRA, EDP Sciences, DIB, AGIB 2001

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access.

An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

  • If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
  • You can define your own OpenURL resolver with your EDPS Account.
    In this case your choice will be given priority over that of your library.
  • You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see You should disable this module if you wish to use the OpenURL server that you or your library have defined.