Guwahati, Jan. 22: From the wilds of Kaziranga to the safe sanctuary of the zoo, rhinos are falling prey to unseen predators.

The Assam State Zoo in Guwahati today reported a rhino’s death from suspected anthrax, a fatal infectious disease that can spread rapidly and even infect humans.

Guards spotted the 30-year-old male rhino, Jon, collapsing around 5.30am with blood oozing from its anus. Death came in an instant.

Zoo pathologist B.K. Gogoi said preliminary microbiological tests indicated the animal died of anthrax. Detailed tests were ordered to confirm it, though no post-mortem was done because it is prohibited in case of death from suspected anthrax.

“Jon seemed perfectly okay till last evening. His death was sudden,” divisional forest officer Narayan Mahanta said.

Jon is the third one-horned rhino to die in as many days. On Saturday, poachers shot and gouged out an adult female’s horn near Kaziranga National Park. They also killed her calf and drilled its head in search of a horn that hadn’t formed.

The incident at the zoo has caused even more alarm than the Kaziranga killings because of the threat of an anthrax epidemic looming large on the horizon.

As many as 14 Kaziranga rhinos died of anthrax in 1974.

A committee headed by the principal chief conservator of forests, M.C Malakar, has been constituted to oversee a prevention campaign. Mahanta said animals in all the enclosures would be vaccinated along with cattle within a 2-km radius of the sprawling zoo.

Wildlife expert Kushal Konwar Sarma, who also teaches at the College of Veterinary Sciences in Khanapara, said precautionary steps must be taken fast to prevent anthrax from spreading. “This is a serious case,” he added.

Caused by a spore-forming bacterium, Bacillus anthracis, anthrax is difficult to control because the spores remain active under the soil for many years. John’s carcass was “buried deep” in the evening in accordance with the Central Zoo Authority’s guidelines.

Forest minister Rockybul Hussain and senior officials of the forest department visited the zoo earlier in the day to enquire about the anthrax scare.

Jon’s death has left the zoo with only five rhinos. The 30-year-old male had been brought to the zoo on August 23, 1980, from Pobitora Wildlife Sanctuary.

In Kaziranga, three persons were arrested and remanded in judicial custody for their involvement in Saturday’s poaching incident. The trio — Sumu Mura, Ranjit Kurmi and Budhan Bhuyan — spent a night in detention.

The Asom Jatiyatibadi Yuva Chatra Parishad took out a procession and staged a protest at Kohora Chariali in Kaziranga in protest against poaching.