According to sources, at least one person has died and 200 others are in hospital due to an unexplained illness in India's Andhra Pradesh province.

In Eluru, an ancient city famous for its hand-woven items, the disease was identified on Saturday evening. Patients have since reported symptoms ranging from nausea and anxiety, doctors said to loss of consciousness.

The Press Trust of India news agency announced that a 45-year-old man who was in the hospital with symptoms close to epilepsy and nausea died on Sunday evening.

Officials are attempting to ascertain the cause of the illness. So far no signs of pollution have been shown in water samples from affected areas and patients have tested negative for Covid-19.

State Secretary YS Jagan Mohan Reddy visited a government hospital and spoke with sick patients. Opposition leader N Chandrababu Naidu requested an "impartial, full-fledged investigation into the incident" on Twitter.

With more than 800,000 cases detected, Andhra Pradesh state is among those hardest affected by Covid-19. Like the rest of India, the state's health system has been frayed by the virus.