The deformed wing virus (DWV), known to be ubiquitous in honey bees, has now been detected in bumblebees. In addition, the neogregarine Apicystis bombi has been discovered to be more prevalent than previously thought. Here, we assess for the first time the lethal and sublethal effects of these parasites during single and mixed infections of worker bumblebees (Bombus terrestris). Overall, we find that A. bombi exhibits both lethal and sublethal effects. DWV causes lethal effect and may reduce the sub lethal effects imposed by A. bombi. The results show that both parasites have significant, negative effects on bumblebee health, making them potentially of conservation concern
A. bombi from Argentina and Europe share a common, relatively recent origin. The absence of genetic structure across space and host species suggests that A. bombi may be acting as an emergent infectious disease across bee taxa and continents.