By PP Singh BBC reporter in Guwahati

The authorities in India's north-eastern state of Assam say at least 100 people - mostly children - have died from a strain of Japanese encephalitis.

The disease has hit six districts in the state during the last month.

Mosquitos transmit the disease to humans

It is endemic amongst pigs and is transmitted to human beings by mosquitoes.

The state Health Minister, Dr Bhumidhar Barman, told the BBC that the disease thrives in dirty environments and mostly affects poor farmers and tribal peoples.

The minister acknowledged that although the number of deaths was increasing every year, there were no separate funds to counter this disease.

He said intensive spraying was being carried out in areas prone to the disease.

Doctors say the symptoms of the disease include high fever, stiffness of the neck, headache and drowsiness leading to coma.

Death toll rising

Dr Nandita Choudhury, Principal of Assam Medical College in Dibrugarh, said nearly 300 patients had been admitted since the end of June.

The death rate amongst children was over 40%, and that so far 98 people have died so far .

She said the death toll is likely to rise still further.

Health officials in Dibrugarh district say two more patients have recently died in different nursing homes taking the total number of deaths to 100.

Dr Chowdhury said the disease is now spreading in other areas of the Brahmaputra Valley and if immediate measures are not taken it will not be long before the virus spreads to other areas of the state also.

An official of a leading international non governmental organisation, Medicins Sans Frontieres - William Claus - told the BBC that the state government should take effective measures to check the disease.

He also said a better system should be put in place to effectively monitor its spread.

The number of deaths in the state caused by the disease has been on the increase in the past few years.

In 1997, the death toll was 26, whereas it went up to 113 last year.