Rare rodent-borne virus killed Shankar, lone African Elephant at Delhi Zoo: ‘First such case in India’

“It was positive for EMCV. It is a very rare disease. It is an acute disease with no visible symptoms,” Delhi Zoo director Dr Sanjeet Kumar told The Indian Express. “There have been some cases previously found in European zoos and other zoos globally. Generally, it infects pigs, but a wide variety of zoo animals can be affected including big cats and several lesser-known species,” he said.

A source in the Delhi zoo said that rodent menace is among the biggest issues yet to be fully tackled, which has been raised over the recent years. Studies suggest that African elephants are particularly susceptible to the virus, with outbreaks reported worldwide in captivity and in the wild. The virus can be transmitted by food or water contamination caused from feces or urine of a rodent species.

According to zoo authorities, Shankar had shown mild symptoms on the morning of September 17, when he was found eating fewer leaves and grasses and passing loose stools, though he continued to consume fruits, vegetables and concentrate normally.

“Treatment was given by the veterinary team and the animal was under observation of the animal keeping staff,” the official statement by the zoo had read.

Around 7.25 pm, Shankar collapsed inside his enclosure and, despite emergency treatment, succumbed by 8 pm. “There was no report of sickness or abnormal behaviour till September 16,” Dr Kumar had said earlier.

The post-mortem was conducted by experts from the IVRI, Bareilly, the zoo’s health advisory committee and a representative of the Union Ministry of Environment, Forest and Climate Change.

Dr Kumar said that while EMCV is transmitted through rodents, controlling them in open enclosures remains a challenge. “Generally, rodents are there, roaming here and there, and it is difficult to control them. There is no accumulated food in the elephant enclosure — rodents only go where there is meat or feed left for two or three hours at night. The elephant only gets leaves or grasses, and only in the afternoon it gets concentrate,” he explained.

“Herbivores generally get dry grams, which they finish fast. But surely, since the enclosure is open, rodents can go here and there. Rodents are one of the carriers; even squirrels can be carriers,” he added.

A senior scientist at IVRI said the animal’s autopsy report revealed lesions in the heart and some haemorrhages, which are typically seen in foot-and-mouth disease or certain viral infections. “After three to four trials, heart disease, tuberculosis, FMD and anthrax were ruled out,” the scientist said.

“The circumstantial evidence showed that it was a sudden death or peracute death. The zoo veterinarian tried to feed glucose after having noticed it stopped eating. But, they didn’t report the sickness then…only death was reported,” the scientist said.

Sources in the zoo said there had been “multiple recommendations to get Shankar a mate” over the years, but the animal remained solitary.

In 2012, after reaching adolescence, Shankar was separated from his Asian counterparts and kept in a solitary enclosure, in a decision that later drew appeals from conservationists for his release.

Dr Kumar said that there is currently no vaccine for EMCV and no visible symptoms before sudden death, making it extremely difficult to detect or prevent.

The zoo has remained closed since August 30 due to an avian influenza outbreak.