Titer your dog for immunity to parvo. Aside from concrete there's not much you can do to kill the virus in your lawn, bleach if it's hard surface but one lawn it can live for 6 months.
I"m sad for the puppy. Also for your friend for not knowing better.
Parvovirus | ASPCA
Venus of Crooked Creek 1/26/13
Otto von Hena-C 05/23/08
Morgan Donnermond 08/04/01 to 9/28/12 Long Live the Queen!
I have duct tape and I am not afraid to use it.