The first human-to-human transmission of the H5N1 bird flu virus in Pakistan has been confirmed by the World Health Organization.
The case late last year involved members of a family in northwest Pakistan. A poultry worker became infected and survived, but three of his brothers were infected and two died, BBC News reported.
Genetic-sequencing tests on bird flu virus samples collected from three of the four brothers confirmed human-to-human transmission of the H5N1 virus.
While there was human-to-human transmission between the brothers, the "outbreak did not extend into the community, and appropriate steps were taken to reduce future risks of human infections," the WHO said.
The northwestern region of Pakistan has 85 percent of the country's poultry farms, BBC News reported. It was one of the regions hit by bird flu last year, and thousands of birds were killed to prevent the spread of the disease.