Sad, very sad... But very true, which is even more sad...
They die of flu and die of bus,
Die of hardpad, die of scabies,
Foreign ones can die of rabies,
But usually they die of us.
Terry Pratchett
And they also die of war (which is just another us). Not only pets but animals in general, domesticated and wildlife. Damn unjust, because animals do not wage wars. Humans do. Animals are the most innocent victims of war.
They die of us...