I don’t think animals should be tested to develop new medicine. My reasons are: animal abuse, animals infecting others, and humans and animals have different DNA.
My first reason is animal abuse. We should not test on animals because it is abusive. They can get seriously hurt or die. Animal abuse is not right. The more an animal is abused, the more it doesn’t trust humans. If the animal is abused, it should be a criminal offense, no matter what the cause is.