For the most part, whole herd infection is caused by human intervention. By eliminating the carnivores that prey on the herds, you allow the infections to spread through out the whole herd. Here on the main land, the Wolf and wild cat are almost extinct. The remaining HG's today are loosing the knowledge of being able to read the signs of infection in their kills. In the past, they were very adept at it, and it wasn't that much of a problem. One of the most changed places by man, has to be Hawaii. It started with Capt. Cook and the rats that came ashore then, and ended up with very little original flora and fauna left today. Very lovely as far as tourist traps go. It's no wonder there's no instinctos there. There's nothing to be instincto about! ` [log in to unmask]