Elephants are among the most intelligent non-humans, arguably on par with chimpanzees, and both African and Asian elephants are endangered.
In 1995, 16-month old Kumari, the first Asian elephant born at the National Zoo in Washington, DC, died of a mysterious illness. In 1999, Gary Hayward of Johns Hopkins University and collaborators published their results identifying a novel herpesvirus, EEHV1 as the cause of Kumari's sudden death. They now show that severe cases like this one are caused by viruses that normally infect the species, rather than by viruses that have jumped from African elephants, which was their original hypothesis.