Excessive amounts of lead and nickel were found in the blood samples of patients who had fallen sick due to a “mysterious disease” in India.

Excessive amounts of lead and nickel were found in the blood samples of patients who had fallen sick due to a “mysterious disease” in the southern India state of Andhra Pradesh, a medical official has told Al Jazeera.

More than 500 people in Andhra Pradesh’s Eluru town fell ill, reporting nausea, seizures and fainting on Saturday. At least one person died due to the illness on Sunday.

The preliminary findings by medical experts, according to a statement by the local government, suggest that lead and nickel poisoning could be responsible for the illness.

“Till now the results we have received from the experts from AIIMS (All India Institute of Medical Science) shows lead and nickel in excess quantities in the blood of the patients,” Dr AVR Mohan, medical superintendent of District Hospital Vijayawada, told Al Jazeera over the phone.

“Initially, we had sent samples of 10 patients and yesterday (Tuesday) we have sent 30 more samples whose results are likely to come today.”

Dr Mohan, who is also the district coordinator of health services for Vijayawada, said that none of the patients was found to have COVID-19. “We have conducted COVID-19 tests for each of the patients but none of them came positive.”

He said 72 patients suffering from the mysterious disease were admitted to the hospital.

“We have already discharges more than 400 patients from the hospital,” he said.

The health official said at least six patients who had recovered from the illness suffered a second seizure attack and were readmitted to the hospital. “They were later discharged from the hospital,” Dr Mohan told Al Jazeera.

Officials have also collected vegetable samples and milk from the districts involved for testing.

“More tests are being conducted by [the] Indian Institute of Chemical Technology and other institutes and the results are expected soon,” a statement from the Andhra Pradesh chief minister’s office said.

Initially it was suspected that water contamination could have been the cause of the illness but health experts did not find lead or nickel in the water samples tested.

On Tuesday, Indian authorities said they were investigating if organochlorines which are used as pesticides or in mosquito control had caused the outbreak.

Federal legislator GVL Narasimha Rao, who is from the state, said on Twitter that he had spoken with government medical experts and that the “most likely cause is poisonous organochlorine substances”.

“It is one of the possibilities,” said Geeta Prasadini, a public health director in Andhra Pradesh state, adding they were awaiting test reports to determine the cause.

Originally published at msn