Traces of nickel and lead found in the blood samples of patients were primarily established to be the root cause of the undiagnosed disease in Eluru, Andhra Pradesh, a release from Chief Minister YS Jaganmohan Reddy’s office said on Tuesday, reported PTI. The source of these particles, however, remains unknown.

The disease has so far claimed one life and left over 500 people ill. People suddenly fell unconscious after suffering fits and nausea from the night of December 5. The symptoms included a bout of epilepsy, memory loss for a few minutes, anxiety, vomiting, headache and back pain.

A team of experts from Delhi’s All India Institute of Medical Sciences, who conducted a preliminary examination of blood samples, made out that lead and nickel particulate matter could be the root cause of the mysterious disease. The preliminary findings were presented to the chief minister on Tuesday.

“We have tentatively identified the primary cause of this strange phenomenon, but it is not yet clear what its source is and how and why it has happened,” state Health Commissioner Katamaneni Bhaskar told the Hindustan Times. “For instance, the chemicals were found in the bodies of the patients but not in either water or any other food substance.”

Reddy told the authorities to conduct a detailed study and submit a report. “The chief minister directed the authorities to conduct a thorough investigation on the heavy metal content in the patients’ bodies and constantly monitor the treatment process,” the CMO release added.

However, a comprehensive report on the causative agents that triggered the disease outbreak could come out only in about a week, even as different agencies and institutions went about collecting samples of water, food and blood for a detailed analysis.

Another team from AIIMS, New Delhi, is now trying to find out how the heavy metals crept in, by examining the water and food samples, according to PTI. Hyderabad-based Centre for Cellular and Molecular Biology has sought stool and bile samples of the patients for a viral and bacteriological analysis.

Vegetable samples collected from Eluru were sent to the National Institute of Nutrition in Hyderabad, while blood serum samples were sent to the Indian Institute of Chemical Technology for chemical analysis. “These results are awaited,” the official report said.

This handout photo released by Public Relation Department, Andhra Pradesh government, on December 6, 2020, shows state Health minister Alla Nani (centre) visiting patients that are receiving medical care for an undiagnosed illness at a government hospital in Eluru. (Credit: Public Relation Department, Government of Andhra Pradesh/ AFP PHOTO)

A team comprising scientists and officials of the Eluru Municipal Corporation, health department and revenue department was formed to track the source of contamination of drinking water, if there was any, according to The Indian Express.

Deputy Chief Minister (Health) AKK Srinivas said that water comes to Eluru through two canals. Officials will trace the route to find out if there is contamination at any point, he said. “As the canals pass through agriculture fields, we are looking at the possibility of contamination due to pesticides,” an unidentified official told the newspaper.

Meanwhile, Dr PR Srinivas, the resident medical officer in charge at the Eluru Government Hospital, told The Indian Express that at least six people were readmitted there on Tuesday after they suffered seizures and vomiting. The doctor said the readmitted patients were earlier brought in on Sunday and Monday with similar complaints. There were discharged following treatment. “As of now, the patients are under observation,” Srinivas said.

He also said that the number of cases has reduced. “From Tuesday evening till Wednesday morning, in a period of 12 hours, we have received just four cases, of which two suffered seizures while two complained of giddiness,” he said. “About 40 people are undergoing treatment.”

Earlier in the day, Andhra Pradesh health authorities said that out of the 561 people infected, over 450 had recovered and another 81 were being treated in the hospital. Another 29 people were sent for better care to government hospitals in Vijayawada and Guntur, and of these, 20 had recovered.

The deputy chief minister said the affected people were recovering well and there was no need to panic. “Full details as to what triggered the mysterious disease will be known only after the central agencies submit their reports.” he added. “Primarily, lead has been found to be the cause of the outbreak.”

Apart from a two-member expert team deployed by the World Health Organisation, a three-member team drafted by the Union Ministry of Health and Family Welfare arrived in Eluru on Tuesday and went around the affected areas to collect samples.

A special sanitation drive was undertaken in Eluru city, its adjoining rural pockets and Denduluru from where the cases have been reported.