At least one person has died and 227 have been hospitalized from an unidentified disease in the southern Indian state of Andhra Pradesh. Patients had a wide range of symptoms from nausea to unconscious decline, doctors said.

Officials are investigating the cause of the illness, which swept the city of Eluru over the weekend. This comes as India continues to struggle with the second wave of coronavirus.

Andhra Pradesh has been one of the most affected states - with more than 800,000 infected people and is the third city with the highest number of cases in the country. But Covid-19 does not appear to be the cause of hospitalizations over the weekend. The country's health minister, Alla Kali Krishna Srinivas, said all patients had tested negative for coronavirus.

"People who got sick, especially children, suddenly started vomiting after complaining of eye burns. Some of them fainted or had seizures," a medical worker at Eluru Government Hospital told the Indian Express newspaper.

Srinivas said the patients' blood samples did not reveal any evidence of a viral infection.

"We ruled out water pollution or air pollution as the cause after officials visited areas where people got sick," he said. "It is a mysterious disease and only laboratory analysis will reveal what it is."

70 people have been discharged from the hospital, while 157 others are still being treated, officials said.

The Prime Minister of the state, Jaganmohan Reddy, said that special medical teams are being sent to Eluru to investigate the cause of the disease. Reddy is also expected to visit the city to meet with patients and their families.

However, the opposition party Telugu Desam has called for an investigation into the incident, insisting the pollution was the cause of the mysterious disease.

Adapted from BBC