The zoo said the elephant, Dottie, died Monday during the third trimester of her first pregnancy, WSB-TV in Atlanta reported Tuesday.
Zoo officials said veterinarians first noticed irregularities with the protein levels in the elephant's blood Oct. 10 and she then lost nearly 800 pounds in only 11 days. The officials said zookeepers tried to treat the unknown infection with antibiotics but Dottie died five days after starting her treatment.
The official cause of death will be determined via necropsy performed by the zoo's veterinary team along with the Department of Pathology in the College of Veterinary Medicine at the University of Georgia.
"We are saddened by the sudden loss of Dottie. I know our veterinary and animal management team worked diligently to ensure she received the best care and treatment possible. This is especially sad for us because Dottie was pregnant with her first calf," said Dennis Kelly, president and chief executive of the zoo. "We will miss her here at Zoo Atlanta."