Abnormal Pathogen Levels Characterize Colony Collapse Disorder

VanEngelsdorp, D., Evans, J. D., Saegerman, C., Mullin, C., Haubruge, E., Nguyen, B. K., Frazier, M., Frazier, J., Cox-Foster, D., Chen, Y., Underwood, R., Tarpy, D. R., Pettis, J. S.  2009.  Colony Collapse Disorder: A Descriptive Study.  Public Library of Science ONE 4(8):  1-17.

http://www.ncbi.nlm.nih.gov/pubmed/?term=colony+collapse+disorder%3A++a+descriptive+study

                Colony Collapse Disorder (CCD) is a recently discovered phenomenon associated with three major qualities.  Colonies will have a sharp decline in the numbers of adult honey bee workers.  Contrary to expectations, there will be a lack of dead worker bees in and around the hive.  Also, there is a sharp influx of pest invasion by wax worms as well as kleptoparasitism from healthier hives.  CCD is a communicative disease that typically affects hives during the winter months. In order to gain a more complete understanding of the disease, extensive studies on colonies and their susceptibility are necessitated.

VanEngelsdorp et al. performed studies on CCD colonies in order to characterize the disease, assess risk factors, and gain further insight into the extent and severity.  They monitored commercial hives (healthy, weak, and CCD hives) in 13 apiaries in Florida and California for sixty days in January and February 2007.  91 colonies were observed over the course of the study, and quantitative data were collected regarding the status of each colony.  In a standard commercial colony, honeycomb is expected to cover 90% or more of the hive containment.  Based on this statistic, VanEngelsdorp et al. assumed that 60% coverage characterized a week colony susceptible to CCD infection.  The three identifiable symptoms of CCD discussed previously were used to officially diagnose a colony.  VanEngelsdorp et al. hypothesized that bee colonies deemed to have ongoing CCD will share common risk factors such as pathogen exposure or stress factors.  Risk factors that were measured include several macro-parasites, seven viruses, bacteria, and pesticide susceptibility.  These factors were quantified over the course of the study on CCD hives and tested for correlation to CCD infection.

VanEngelsdorp et al. were able to confirm their hypotheses and ascertain that CCD infection is contagious among hives based on exposure to certain risk factors.  The study was not able to pinpoint an exact causation for CCD.  CCD, however correlated with several factors: pesticide resistance, European Foul Brood (EFB), Kashmir Bee Virus (KBV), and multiple other factors.  With this information, bee farmers can be more aware of the risk factors associated with a disease capable of decimating honey bee populations.  Because bees provide both financial benefits for farmers directly as well as essential pollinator roles for flowering plant species within their ecosystem, it is essential that diseases such as CCD are understood and controlled.  Farmers may utilize additives to bee hives to protect their colonies; the threat of CCD could be eradicated or minimally more properly managed.