RHD2, or rabbit hemorrhagic disease variant 2, is a viral disease that mutated from a more common disease called RHD. Sometimes rabbits with the disease will just drop dead. In other cases, an infected rabbit will become depressed and lethargic and bleed from the nose and mouth. There is no treatment for RHD or RHD2, but sometimes rabbits with unusually strong immune systems will survive the infection. The only thing you can do is to isolate infected rabbits from healthy rabbits to stop the transmission of the virus.