Islamabad - Health officials on Friday were investigating a possible human-to-human transmission of bird flu among four brothers in north-west Pakistan, two of whom later died. Khushnood Akhtar, secretary in Pakistan's Ministry of Health, said the bird flu cases occurred last month in Manshera, North-West Frontier Province, when a man contracted the H5N1 virus while working on a poultry farm and helping to cull sick birds.
Human-to-human transmissions are extremely rare, with only 3 previous cases in Indonesia, Cambodia and Vietnam.
The Pakistani man, who has not been identified, survived the virus, but may have infected three of his brothers, none of whom had ever been to the farm or were believed to have been in contact with sick birds, Akhtar told Deutsche Presse-Agentur dpa.
Two of the brothers died from pneumonia-like symptoms but were buried by family members before health officials could take blood samples to test for the virus.
A third brother who lives in the United States but was visiting Manshera at the time also tested positive for bird flu, but survived and has since returned to the US, Akhtar told dpa.
"The two brothers died and we suspect that they might have died because of the human transmission of the H5N1 virus," he said. "We have requested the World Health Organization (WHO) send a team to the area so we can find out exactly what happened there."
WHO officials in Islamabad could not be reached for comment.
Globally, bird flu has killed at least 208 people worldwide out of 339 cases since 2003. Most human cases of H5N1 are linked to contact with infected birds, but experts fear the virus might mutate into a form that spreads easily among humans, potentially sparking a pandemic that could kill millions of people.
The two Pakistani brothers who survived are the first confirmed people in Pakistan to contract the virus, while health officials are not sure whether they will be able to confirm that the two who died succumbed to bird flu.
There have been outbreaks of bird flu within the country's commercial poultry population, prompting culls of around 50,000 birds.
The latest reports contradict earlier claims by a health official at a hospital in Peshawar, the capital of North-West Frontier Province, who erroneously said the two victims had worked on a poultry farm and died earlier this month. He also did not have any information about the two brothers who survived.
