More than a century after kala azar first struck Bihar in an epidemic form, the disease not only persists but also appears to be discriminating against the poorest of the poor - the Dalits.

Apparently 90 percent of the victims belong to the socially marginalized section. Also known as leishmaniasis, the disease is estimated to have killed over 200 Dalits, including children, in the last two years.

The chronic and potentially fatal parasitic kala azar is transmitted by sand flies and is characterised by irregular bouts of fever, weight loss, swelling of the spleen, liver and anaemia.

It used to earlier affect the backward caste Yadav community and the Bhumihars, a powerful landed upper caste. But the situation seems to have changed.

According to research, the disease is most visible in the Musahar and Paswan community due to their poor living conditions. "Kala azar is killing poor Dalits, mostly from the Musahar and Paswan community, more than others in the state," said C.P. Thakur, an expert on the disease and a former central health minister.

According to a study by him, the disease breaks out in virulent form every 15 years. It had taken a big toll of human lives in Vaishali, Muzaffarpur, Sitamarhi and Samastipur districts in 1977 and hit again with the same ferocity in 1991-92.

The disease may thus strike the state in a big way between 2005 and 07, he warned.

Action Aid International India, in a survey last year, found that kala azar had affected the Musahar settlement in the flood-prone Darbhanga district.

Dalit activist Misri Manjhi said that out of 250 houses in Musahari Tola (a Dalit settlement) in Goanpura village under Phulwarisharif, 90 were in the grip of kala azar.

"Over two dozen people have died due to the disease in the last two years (in the area)," Manjhi said. Kala azar has also hit children in this Dalit settlement. "Around 20 children are suffering from the disease," he said.

According to one estimate, over 2,400 people have died of kala azar in the last nine years in Bihar. However, the incidence has fallen from 75,523 cases and 1,417 deaths in 1992 to 12,909 cases and 130 deaths in 2000.

State government officials speak of preventive measures like free distribution of medicines, the spraying of pesticides like DDT and doctors visiting affected settlements. But facts speak differently.

In Phulwarisharif's Musahari Tola, Dalits suffering from kala azar were not given medicines by the government and no pesticides were sprayed either, people complain.

The Patna High Court in April had taken serious note of the fact that the state government had not initiated measures to provide proper medical care to kala azar patients or to fight the disease.

In Bihar, Kala azar dates back to 1882 when a disease called 'kala dukh', or black sorrow, was recorded in Purnea district. The disease took an epidemic form in 1891, 1917 and 1933 claiming thousands of lives.

The central government hopes to eradicate kala azar by 2007.