Excessive amounts of heavy metals such as lead and nickel were found in the blood samples of patients suffering from the mysterious disease in Eluru town of West Godavari district in Andhra Pradesh in southern India. 

"We found lead and nickel in the blood samples in excess amount. This can be one of the causes. We are sending more samples to the All India Institute of Medical Sciences (AIIMS) in New Delhi," Himanshu Shukla, joint collector, West Godavari district told IANS.

He said scientists were suspecting these heavy metals were causing the mysterious ailment that has already affected hundreds. Eluru, 58 km northeast of Vijayawada, headquarters of West Godavari district, is paddy cultivation and aquaculture heavyweight.

"We are working backward in trying to find out the sources from which this nickel and lead would have come," he said.

Shukla said water and milk have already been tested for these metals and their absence in them has ruled them out to be a cause.

"So definitely it is not water and milk. It can be other things. Already we have covered vegetables if they could be a source and there are multiple other sources like sweets," said the Indian Administrative Service officer.

Officials and medical experts have adopted the elimination method, ruling one possibility after the other as the malady is of elusive nature and yet to be confirmed with authority.

Last night, vegetable samples were shipped to the National Institute of Nutrition (NIN) in Hyderabad for testing. Other samples have also been flown to Delhi, whose results could be expected in the next 12 hours.

Meanwhile, cases of the illness rose to 551, out of which 174 are active while 350 have been discharged.

(IANS)