This study, conducted by a team of researchers from various institutions in the United States, aimed to better understand Colony Collapse Disorder (CCD), a phenomenon characterized by the rapid loss of adult worker bees from managed honey bee colonies. The researchers collected and analyzed data from 91 colonies, both affected by CCD and healthy, to identify potential risk factors and causes of CCD. Key findings include: 1. **No Single Cause Identified**: Among 61 quantified variables, no single measure emerged as the primary cause of CCD. 2. **Higher Pathogen Loads**: Bees in CCD colonies had higher levels of pathogens and were co-infected with more pathogens compared to control colonies, suggesting either increased exposure or reduced resistance. 3. **Lower levels of Coumaphos**: CCD colonies had lower levels of coumaphos, a synthetic acaricide used to control Varroa mites, compared to control colonies. 4. **CCD as a Contagious Condition**: The distribution of dead and weak colonies in CCD apiaries was not random, indicating that CCD may be contagious or result from exposure to a common risk factor. 5. **Genetic Analysis**: Mitochondrial DNA analysis revealed that most colonies were of Eastern European origin, with only one Western European colony identified. 6. **Pesticide Exposure**: No significant differences were found in the prevalence or load of pesticides between CCD and control colonies, although higher levels of coumaphos were detected in control colonies. The study suggests that CCD involves an interaction between pathogens and other stress factors, and highlights areas for future research, such as the legacy effect of mite parasitism and the role of honey bee resistance to pesticides.This study, conducted by a team of researchers from various institutions in the United States, aimed to better understand Colony Collapse Disorder (CCD), a phenomenon characterized by the rapid loss of adult worker bees from managed honey bee colonies. The researchers collected and analyzed data from 91 colonies, both affected by CCD and healthy, to identify potential risk factors and causes of CCD. Key findings include: 1. **No Single Cause Identified**: Among 61 quantified variables, no single measure emerged as the primary cause of CCD. 2. **Higher Pathogen Loads**: Bees in CCD colonies had higher levels of pathogens and were co-infected with more pathogens compared to control colonies, suggesting either increased exposure or reduced resistance. 3. **Lower levels of Coumaphos**: CCD colonies had lower levels of coumaphos, a synthetic acaricide used to control Varroa mites, compared to control colonies. 4. **CCD as a Contagious Condition**: The distribution of dead and weak colonies in CCD apiaries was not random, indicating that CCD may be contagious or result from exposure to a common risk factor. 5. **Genetic Analysis**: Mitochondrial DNA analysis revealed that most colonies were of Eastern European origin, with only one Western European colony identified. 6. **Pesticide Exposure**: No significant differences were found in the prevalence or load of pesticides between CCD and control colonies, although higher levels of coumaphos were detected in control colonies. The study suggests that CCD involves an interaction between pathogens and other stress factors, and highlights areas for future research, such as the legacy effect of mite parasitism and the role of honey bee resistance to pesticides.