Japanese encephalitis

Caused by Flaviviridae virus Carried by pigs and wading birds Transmitted to humans by female mosquitoes Symptoms: Flu with headache, fever and weakness Can lead to inflammation of the brain

Nepal is gripped by an outbreak of Japanese encephalitis.

Officials say about 100 people have died in Uttar Pradesh and more than 400 people have been admitted to hospital.

But the actual number of people suffering and dying of encephalitis may be much more.

Many of the affected districts are very poor with agriculture as the main source of income.

Rivers originating from Nepal bring floods almost every year.

The waterlogged areas, including farmlands, work as breeding grounds for mosquitoes.

Mosquitoes

Health officials say the disease was first reported in this region 22 years ago.

So far about 7,000 people have died of the disease.

Female mosquitoes transmit the virus

Doctors say the disease Japanese Encephalitis is caused by the Flaviviridae virus and is carried by pigs and wading birds.

The virus is transmitted to humans by female mosquitoes.

Children up to 15 years age are the worst hit by this disease.

It begins with flu with headache, fever, weakness and vomiting.

In some cases the illness progresses to inflammation of brain.

The state's director general of health services, Dr Harishchandra Vaishya, says that in March each year, the government implements a plan to control the disease.

"This includes fogging to kill mosquitoes and (a) public awareness drive," he told the BBC.

Vaccine shortage

However, newspaper reports suggest that the drives do not have much impact, mainly because the health department does not have adequate infrastructure at the level of the villages.

Paddy fields are breeding ground for mosquitoes

Some experts suggest that pigs in the area should be killed as a permanent solution.

But health officials say that this may not be possible due to political reasons.

The state administration has also stopped supplying the Japanese encephalitis vaccine for the past three years.

A director in the health department, Dr JS Chawala, says "there are administrative problems in vaccination. The Central Institute, Kasauli, is not able to supply enough vaccines."

Health officials add that the government has no money to import the vaccine from Japan.

A senior doctor in the Gorakhpur Medical College, Dr YK Singh, complains that the administration does not give priority to local health problems.

He suggests that the vaccine could be made available in private stores so that people could buy it.

He also says his hospital has not been provided with essential machines and equipment to provide emergency care to serious patients.