Muscovy duck parvovirus
Muscovy duck parvovirus (MDPV) causes what's known as “three-week disease” in China. It is the least pathogenic of the two main parvovirus infections which affect waterfowl.
Transmission: MDPV is spread through direct and indirect contact, usually associated with contamination of the environment with feces from infected hosts. It is also transmitted vertically. In older birds that become subclinically infected, a latent infection may become established. These birds may then act as carriers of the disease and transmit the virus through their eggs to their offspring.