The death of a sambar deer at the city zoo from rabies has prompted the authorities to initiate precautionary steps, including vaccinating the animals and their handlers.

A team, led by zoo veterinary surgeon Nikesh Kiran, began administering emergency anti-rabies vaccine to the animals in the sambar deer enclosure on Tuesday. Seven of the 73 sambar deer were vaccinated by darting, Dr. Nikesh said.

No sambar deer were showing any symptoms of rabies at present, he said.

Seventeen zookeepers who handled the sambar deer were given post-exposure anti-rabies vaccine. It is intradermal and requires five doses.

Other animal handlers will be given a single-dose prophylactic vaccine later.

The female sambar deer died at the zoo on Sunday evening. The zookeepers had reported that the animal was displaying strange behaviour, hitting its head and trying to bite the handlers and the other deer. Instructions were given to isolate it immediately in a nearby elephant enclosure. However, the animal jumped into the drain there, and despite attempts by the zookeepers to bring it out, the deer died of aspiration.

The necropsy of the deer was conducted at the zoo. Since it had been behaving strangely, the head of the animal was sent to the State Institute for Animal Diseases, Palode, for a detailed examination. As a lateral flow test came back positive for rabies, the zoo authorities has been asked to initiate precautionary measures. The results of a fluorescent assay test held to confirm the diagnosis is awaited.

Not all animals to be jabbed

Vaccinations were started as it is difficult to know if the other sambar deer were bitten, Dr. Nikesh Kiran said.

The other herd animals such as spotted dear or black buck would not be given anti-rabies vaccine as it was not included in their routine. There were also practical issues involved such as difficulty in determining which of them had been darted or not.

As sambar deer do not move as swiftly, they are easier to dart. They are also sprayed with paint quickly to sort them from the unvaccinated ones.

The other zoo animals would also be vaccinated as a preventive measure.

The source of the disease was difficult to pinpoint, Dr. Nikesh said. Rabies could spread from mammals, but palm civet, mongoose, dogs, and cats were the ones likely to bite the zoo animals and spread the disease. In this instance, palm civets or mongoose were suspected to be the source.

As the zoo is a biosecurity zone, the Corporation on Tuesday captured and vaccinated 12-odd stray dogs within the zoo and museum compound.

The last time a rabies case was reported in the zoo was back in 2012 when a dog entered through the broken grates of a drain and went around some enclosures before ending up in that of lion-tailed macaques where it was darted and captured. It was taken to the Pettah veterinary hospital and died the next day. As rabies was confirmed in the dog, all those who handled it and the zoo animals were vaccinated.