Initial hypotheses were wildly different, including environmental change-related stresses, malnutrition, pathogens (i.e., disease including Israel acute paralysis virus), mites, or the class of pesticides known as neonicotinoids, which include imidacloprid, clothianidin, and thiamethoxam. Most new research suggests the neonicotinoid hypothesis was incorrect, however, and that pesticides play little role in CCD compared to "Varroa" and "Nosema" infestations. Other theories included radiation from cellular phones or other man-made devices and genetically modified crops with pest-control characteristics. In 2010, U.S. researchers announced they had identified a co-infection of invertebrate iridescent virus type 6 (IIV-6) and "N. ceranae" in all CCD colonies sampled.