In vitro detection and quantification of botulinum neurotoxin type e activity in avian blood

Appl Environ Microbiol. 2011 Nov;77(21):7815-22. doi: 10.1128/AEM.06165-11. Epub 2011 Sep 9.


Botulinum neurotoxin serotype E (BoNT/E) outbreaks in the Great Lakes region cause large annual avian mortality events, with an estimated 17,000 bird deaths reported in 2007 alone. During an outbreak investigation, blood collected from bird carcasses is tested for the presence of BoNT/E using the mouse lethality assay. While sensitive, this method is labor-intensive and low throughput and can take up to 7 days to complete. We developed a rapid and sensitive in vitro assay, the BoTest Matrix E assay, that combines immunoprecipitation with high-affinity endopeptidase activity detection by Förster resonance energy transfer (FRET) to rapidly quantify BoNT/E activity in avian blood with detection limits comparable to those of the mouse lethality assay. On the basis of the analysis of archived blood samples (n = 87) collected from bird carcasses during avian mortality investigations, BoTest Matrix E detected picomolar quantities of BoNT/E following a 2-h incubation and femtomolar quantities of BoNT/E following extended incubation (24 h) with 100% diagnostic specificity and 91% diagnostic sensitivity.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Bird Diseases / diagnosis*
  • Birds
  • Blood Chemical Analysis / methods*
  • Botulinum Toxins / blood*
  • Botulism / diagnosis
  • Botulism / veterinary*
  • Chemistry Techniques, Analytical / methods*
  • Fluorescence Resonance Energy Transfer / methods
  • Great Lakes Region
  • Immunoprecipitation / methods
  • Sensitivity and Specificity
  • Time Factors


  • Botulinum Toxins
  • botulinum toxin type E