By Ashfaq Yusufzai, Peshawar
Pakistan culled thousands of birds last year to stop bird flu spreading
The first case of human-to-human transmission of avian flu in Pakistan has been confirmed.
Tests carried out by the World Health Organisation (WHO) show that bird flu killed some members of a family in north-west Pakistan late last year.
The WHO says steps were taken to prevent future fatalities in the area.
Pakistan's north-west and southern regions were hit by bird flu last year. Thousands of birds were culled to control the spread of the disease.
The confirmation of people dying from bird flu came on Thursday, after samples collected from a family in the north-western city of Peshawar tested positive.
Dr Mukhtiar Zaman Afridi, head of the isolation ward for avian flu patients at Khyber Teaching Hospital in Peshawar, told the BBC that a poultry worker in Peshawar apparently passed the disease on to members of his family.
The worker, whose name is being withheld on the request of the WHO, was brought to the hospital with avian flu symptoms on 29 October 2007, he says.
He has fully recovered since then.
But on 12 November, the elder brother of the poultry worker was brought in with similar symptoms. He died a week later.
On 21 November, two more brothers of the same worker came down with bird flu.
One of them died on 28 November, while the other has recovered, Dr Afridi said.
Apart from the poultry worker, none of the others was found to have had any direct contact with sick or dead poultry.
Genetic sequencing tests performed by WHO laboratories in Egypt and the US on samples collected from three of the four brothers established human-to-human transmission.
Serum taken from all three was found to have been infected by the H5N1 avian influenza virus.
A WHO report says the tests suggest "limited human-to-human transmission."
It adds, however, that this "outbreak did not extend into the community, and appropriate steps were taken to reduce future risks of human infections."
Pakistan's north-western region is home to 85% of the country's poultry farms.