Veterinarians at Springfield's Dickerson Park Zoo are studying the death of Nisha, she's the 16-month old elephant that died yesterday morning at the zoo.

Officials say she was treated for a herpes virus that usually kills elephants in just five days. Zoo officials say Nisha received aggressive treatment and good care, but now one California-based animal group called In Defense of Animals, is calling for the zoo to stop breeding. The group claims that the facility is contaminated.