KOLKATA (AFP) - Scores of fly-infested mentally disabled patients have been found naked and filthy at a government-run hospital in India, prompting an outcry, a charity worker said on Thursday (Aug 18).

Photos of the thin patients living in what appear to be appalling conditions at the health facility in West Bengal state were posted on social media this week, making national headlines.

Anjali Mental Health Rights founder Ratnaboli Ray said her workers discovered the patients naked and sleeping on the floor because of outbreaks of bugs, during a visit to the hospital this week.

"The pictures cannot describe the reality. The stench was unbearable and it was simply subhuman," Ms Ray told AFP from Kolkata, the capital of West Bengal.

"There were at least 20 women naked in one ward and they had to sleep on the floor because their bedding had bugs," she said, adding that most of the patients living at the hospital were from impoverished families.

She said she had repeatedly alerted officials to the deplorable conditions at the Berhampore Mental Hospital, housing about 400 adults with various mental illnesses.

But she said she was repeatedly ignored, prompting her charity to post the pictures on Twitter.

"We have many times informed the higher officials about the maltreatment that inmates face but nothing happened," she said.

Only a tiny fraction of India's huge numbers of mentally ill receive adequate treatment, according to studies published in The Lancet and other medical journals this year.

They suffer discrimination and abuse and often languish in facilities, in a country where families often regard disability as punishment for misdeeds in a past life.

West Bengal health services director B R Sathapathy said he would take unspecified action to help the patients after seeing the frontpage newspaper reports.

"We will send a team to assess the situation in the hospital and take necessary steps," he told AFP of the hospital in Baharampur, 50km from Kolkata.

Ms Ray said her workers discovered unbathed patients with flies living in their hair and beards. One of the pictures shows three men crouching naked on the floor of a corridor.

Ms Ray said the patients themselves have complained of a lack of basic amenities at the hospital including clean drinking water, functioning bathrooms and proper food.

Some 1.5 million people suffer intellectual disabilities such as Down's Syndrome in India. But experts say the figures are strikingly low for the world's second most populous country where many health issues go undiagnosed.