This is true for about 90% of viruses, but only in terms of actually causing symptomatic illnesses. They may actually INFECT one species, but other species can be carriers. Bacterial infections aren't as selective. As long as the conditions in the host organism are right, they'll flourish, regardless of the species. Again, they may not cause symptoms, but that's a function of the host's immune system.
Sent from my HTCEVOV4G using Tapatalk