An unidentified illness in India has left hundreds hospitalized and at least one person dead.

The illness in the southern Indian state of Andhra Pradesh, as detailed in an Associated Press report early Monday, was first detected on Saturday in the city of Eluru. On Sunday night, a 45-year-old man who had been hospitalized with symptoms described as being similar to epilepsy and nausea died.

Symptoms among affected patients have also included loss of consciousness and anxiety. Hundreds have been hospitalized, with current estimates—including in this CBS News report—showing that more than 300 people in the region have sought care in connection with the unidentified illness.

A team of government-appointed experts had arrived in the city for a thorough investigation as of Monday. Prior to their reported arrival, officials in the region had taken water samples from affected areas, with results showing no signs of contamination. Furthermore, there have been confirmations of people treated for the unexplained illness who had no known link to the municipal water supply. Patients, whose ages vary, have thus far tested negative for COVID-19 and other diseases.

Dr. Suhasini, DM&HO, Krishna told the Times of India on Monday he had "never seen" cases like those who have fallen ill by this unidentified cause.

"We are watching the health condition of patients who fell sick at Eluru," Dr. Suhasini said. "Two kids admitted at the old government hospital in Vijayawada are doing well. We are waiting for test reports. In my 25 years of service, I have never seen such cases."

This year has also seen Andhra Pradesh report the country's third-highest count of confirmed COVID-19 cases. India at large, meanwhile, has the second-highest number of total cases behind the United States.