(CNN) India has put more than 300 people under surveillance after a 23-year-old man was diagnosed with the Nipah virus, a rare and often deadly disease.

Authorities in the southern Indian state of Kerala said Wednesday that they had identified 311 people who may have come in contact with the man and four other people displaying symptoms of the disease. All of them are under observation and have been told not to leave their homes.

"No risks are being taken with respect to this and hence we are observing people who came into contact with the patient for even a short period of time," said Dr. V. Meenakshi, a senior state health official.

More than 230 people were tested during that outbreak, which caused widespread panic in the Northern Kerala region. The disease has resurfaced a year after an outbreak killed 17 people.More than 230 people were tested during that outbreak, which caused widespread panic in the Northern Kerala region.

However, this time state officials said they have quickly swung into action to isolate, observe and treat anyone who may have come into contact with the virus.

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