Indianapolis Zoo President Rob Shumaker delivered an emotional announcement that the second elephant in their care had died within a week.

8-year-old African elephant “Kalina” died suddenly on Tuesday morning, just days after 6-year-old “Nyah” was lost after “a short illness.” Both elephants were killed by elephant endotheliotropic herpesvirus, or EEHV, which can cause a fatal hemorrhagic disease.

“It is one of the most deadly viral infections in elephants worldwide but is most commonly found in Asian elephants,” the zoo said in a press release posted on Facebook. “It occurs in elephants in the wild as well as those in human care such as in sanctuaries and zoos. EEHV can strike without warning.”

“We’ve had a really difficult day. We’ve lost two of our youngest African elephants within a week of each other,” Shumaker said at a Tuesday press conference. “Our zoo family is devastated.”

No other elephants at the zoo have tested positive for the “very aggressive” disease, which is not preventable and has no vaccine. Fortunately, the disease is restricted to elephants alone. While they “do not know what caused this to become active in Nyah and Kalina so suddenly,” Shumaker confirmed that “it poses no risks to humans or any other animals.”