Though anthrax has been ruled out as the cause of death, officials said they were yet to ascertain what led to the male rhino's death in April.
As the reports from Indian Veterinary Research Institute, Bareilly, the National Institute for Communicable Diseases and a private vet lab here established that anthrax was not the cause, officials said they have eased the precautionary measures taken at the zoo after the rhino's death.
Now, the animal enclosure has been opened for public view.
The four-year-old male Indian rhinoceros, Junior Raja, listed as an endangered species, was found dead on April 29 at its enclosure at the zoo.
Suspecting the symptoms to be those of anthrax during the post mortem, the dead rhinoceros' blood and food samples were sent for testing to the Indian Veterinary Research Institute, Bareilly, the National Institute for Communicable Diseases and a private vet lab here.
"All three results have come out and are negative," Delhi zoo curator Riaz Khan told PTI.
On what was the real reason that caused the animal's death, Khan said, "We are still finding out what the reason is, but it definitely isn't anthrax as the results clearly show".
