it wasn't man-made as such, it was seen in south america, where it caused the odd lump, but the rabbits there (cottontails) had become fairly resistant to it... However, in the european rabbit, it is fatal... it was introduced to Australia and Europe etc. as a control method...
It's a virus that is passed from rabbit to rabbit via an insect vector eg. mozzie, rabbit flea or another biting vector eg. mites...
there seems to be a cycle where resistance to the disease provokes higher virulence of the virus - it's pretty quick to evolve :?