Multiple viral infections in insect vectors with synergistic effects are common in nature, but the underlying mechanism remains elusive. A new study, published in Science China Life Sciences and led by Dr. Taiyun Wei (Institute of Vector-borne Virus Research Center, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University), looked more closely at a mosaic virus and its transmission by leafhoppers.