The threat of honey bee RNA viruses to yellow-legged hornets: Insights from cross-species transmission events.

Viral diseases are a significant challenge in beekeeping, and recent studies have unveiled a potential link between these diseases and the yellow-legged hornets (Vespa velutina), notorious predators of honey bees. However, it remains unclear whether virus diseases are commonly shared between honey bees and hornets or are merely sporadic cross-species transmission events. To address this knowledge gap, we conducted a study utilizing hornet-keeping practices in Yunnan, Southwest China. Our findings demonstrate that deformed wing virus (DWV-A) and Israeli acute paralysis virus (IAPV) can be transmitted from honey bees to yellow-legged hornets. We detected virus replication in various hornet stages, including pupae with IAPV infections, indicating the similarities between infected hornet and honey bee stages. Furthermore, we observed signs and infection intensities of DWV-A and IAPV comparable to those in honey bees. While different polymorphisms were found in the virus isolates from yellow-legged hornets, the sequences remain similar to honey bee counterparts. While our findings suggest that DWV-A and IAPV behave like common diseases, we observed a natural elimination of the viruses in hornet colonies, with minimal alterations in viral sequences. Consequently, these events appear to be cross-species transmission from honey bees, with yellow-legged hornets acting as potential incidental hosts. Further investigations of virus monitoring in hornets promise valuable insights into the disease ecology of bee-infecting viruses.