title: Colony collapse disorder: a descriptive study.
abstract: BACKGROUND
  Over the last two winters, there have been large-scale, unexplained losses of managed honey bee (Apis mellifera L.) colonies in the United States. In the absence of a known cause, this syndrome was named Colony Collapse Disorder (CCD) because the main trait was a rapid loss of adult worker bees. We initiated a descriptive epizootiological study in order to better characterize CCD and compare risk factor exposure between populations afflicted by and not afflicted by CCD.
  
  
  RESULTS
  Of 61 quantified variables (including adult bee physiology, pathogen loads, and pesticide levels), no single measure emerged as a most-likely cause of CCD. Bees in CCD colonies had higher pathogen loads and were co-infected with a greater number of pathogens than control populations, suggesting either an increased exposure to pathogens or a reduced resistance of bees toward pathogens. Levels of the synthetic acaricide coumaphos (used by beekeepers to control the parasitic mite Varroa destructor) were higher in control colonies than CCD-affected colonies.
  
  
  CONCLUSIONS
  This is the first comprehensive survey of CCD-affected bee populations that suggests CCD involves an interaction between pathogens and other stress factors. We present evidence that this condition is contagious or the result of exposure to a common risk factor. Potentially important areas for future hypothesis-driven research, including the possible legacy effect of mite parasitism and the role of honey bee resistance to pesticides, are highlighted.
authors: Pennsylvania Department of Agriculture, Harrisburg, PA, USA.
authors: Dennis
authors: D
authors: Vanengelsdorp
authors: Jay D
authors: JD
authors: Evans
authors: Claude
authors: C
authors: Saegerman
authors: Chris
authors: C
authors: Mullin
authors: Eric
authors: E
authors: Haubruge
authors: Bach Kim
authors: BK
authors: Nguyen
authors: Maryann
authors: M
authors: Frazier
authors: Jim
authors: J
authors: Frazier
authors: Diana
authors: D
authors: Cox-Foster
authors: Yanping
authors: Y
authors: Chen
authors: Robyn
authors: R
authors: Underwood
authors: David R
authors: DR
authors: Tarpy
authors: Jeffery S
authors: JS
authors: Pettis
mesh_terms: D000818:Animals; D001516:Bees / Q000254:growth & development / Q000502:physiology; D011156:Population Density; D014481:United States