Twenty-eight of Bihar's 32 districts are infected with kala azar, the deadly black fever, as poverty, unhygienic lifestyle and government apathy make the disease endemic to the region.
Experts running kala azar research centres in collaboration with the World Health Organisation (WHO) and working to develop affordable drugs said the entire Gangetic plains of the state are infected with kala azar.
"It's affecting the poor people in villages who can't afford treatment. The geographic location, poverty, bad hygiene and lack of a definite plan by the government are contributing heavily to the growth of the disease," said T.K. Jha, medical director of one of the two kala azar research centres here.
Kala azar - medically known as Visceral Leishmaniasis - is a vector-born disease and is characterised by fever, weight loss, swelling of spleen and liver and anaemia that could lead to cardiovascular complications.
The parasite attacks bone marrow and weakens the immune system leading to increased vulnerability to infections and diseases. Black fever is also the second-largest parasitic killer in the world after malaria.
The sand flies multiply in cow-dung that villagers use as fuel or to plaster their shanties with. The flies survive on the sap in banana groves, bamboo stands and decomposed cow-dung and thrive in thatches used to make tiny houses.
Flies that have bitten infected humans also transmit the disease when they bite another person.
Jha, who is the principal investigator of a United Nations Development Programme-WHO project on kala azar, said in the pre-independence era, the parasite came to the state from Assam via West Bengal.
"But things have changed and Bihar is now the source of all kala azar cases. People migrate from here to Delhi or West Bengal and spread the disease there, too," he added.
He said the disease came to Bihar in late 1930s and was there till 1950 and later disappeared from the state due to malaria eradication efforts. "But it came back in 1970 and the mortality rate was 30 percent."
"Now the disease is spreading from west Bihar to east Uttar Pradesh, east Bihar to north of Bengal and north Bihar to Nepal," Jha added.
Kala azar currently occurs in 62 countries, primarily in the developing world. Around 90 percent of world cases are found in India, Bangladesh, Nepal, Sudan and northeast Brazil. Experts say over 60 percent of the cases in the five states are found in Bihar alone.
Treatment of the disease currently costs over Rs.12,000.
"When our income is less than Rs.1,500 a month, how can we afford treatment that costs us over Rs.12,000. Since it is affecting hundreds of thousands of people in the state, the government must give free treatment," said Sevati Devi, a resident of Bishonpur, a village around 15 km from this rural town.
Like Sevati, there are thousands who seek government intervention to fight the disease.
"For the last two months, I have been suffering but the district healthcare service providers could not diagnose the problem. They neither have the expertise nor infrastructure to cure patients," said Mohammad Idris from Motihari district.
"The socio-economic status of these villagers does not allow them treatment. Here the government needs to step in. At least the government must club the intervention programme with the revised tuberculosis programme in the state," said Shyam Sunder, who runs a kala azar research centre and a clinic in Muzaffarpur.
However, he was optimistic about a new drug developed by the Institute of One World Health, a non-profit pharmaceutical company in the US.
"The drug has already got a nod from the WHO and the Drug Controller General of India (DCGI). The clinical trials are over and a Hyderabad-based company will produce the oral pills in India," he said.
"Since the cost will be around $15 (about Rs.700), the villagers can now afford treatment," he added.
Sunder, also a professor of medicine at the Banaras Hindu University, said: "The state government had set up a committee to suggest ways to deal with the health menace. We had given them a number of suggestions, including spraying of DDT at least twice a year.
"As experts we can only suggest ways, but the government seems to lag in implementation."
He said the Bihar government had provided free medicine to medical colleges but "how many villagers go to medical colleges? Free and efficient treatment must be given at primary healthcare centres"