International health experts have been dispatched to Pakistan to help investigate the cause of South Asia's first outbreak of bird flu in people and determine if the virus could have been transmitted through human contact, officials said Sunday.
Four brothers — two of whom died — and two cousins from Abbotabad, a small city about 30 miles north of Islamabad, were suspected of being infected by the H5N1 virus, said WHO spokesman Gregory Hartl in Geneva. A man and his niece from the same area who had slaughtered chickens were also suspected of having the virus.
Another person in a separate case who slaughtered poultry in nearby Mansehra, 15 miles away, also tested positive for the disease, he said.
Details surrounding the cases remained confusing, with Pakistan's Health Ministry issuing a statement Saturday saying six people had initially tested positive for the virus last month, while the WHO said eight had been reported. Hartl said the discrepancy was likely linked to a technicality since six patients had tested positive using an internationally recommended method while a less reliable test was used on the others.
Specimens were never collected from one of the brothers who died, and many of those who tested positive experienced only mild symptoms and were not hospitalized, Hartl said.
He added a team of WHO experts have been sent to Pakistan to help determine the cause. He said all four brothers were believed to have worked on a farm and poultry outbreaks had earlier been reported in the area. But one brothers, Mohammed Tariq, said only one sibling worked on the farm.
Hartl said WHO has not ruled out limited human-to-human transmission.
"We can't answer that yet," he said. "It's possible."
The H5N1 virus has killed at least 208 people worldwide, mostly in Southeast Asia and China, since it began ravaging Asian poultry stocks in late 2003. So far, most human cases have been linked to contact with sick birds.
A team from the U.S. Naval Medical Research Unit in Cairo was being dispatched to Pakistan to help with the investigation, said Dave Daigle, a spokesman for the U.S. Centers for Disease Control and Prevention in Atlanta.
Khalif Bile, WHO representative in Pakistan, told The Associated Press on Saturday that preliminary tests had been carried out. He said the WHO was encouraging the government to carry out confirmation tests in the same government laboratory and the results should be available by Tuesday.
People who came into contact with those infected in Pakistan are being monitored, the WHO said.
A brother of the two men who died in Pakistan said Saturday he had been hospitalized with flu-like symptoms. Mohammed Ishtiaq said he fell ill last month after slaughtering chickens suspected of carrying bird flu at a farm near Abbottabad.
"I was not aware that this was such a dangerous disease," said Ishtiaq, a veterinary doctor who works for a government-funded livestock program. He said he wore no protective clothing.
His two brothers did not accompany him to the farm, but visited him in a hospital, Ishtiaq told Associated Press Television News in the village of Sukur.
He identified his brothers as Mohammed Ilyas and Mohammed Idrees and said they were both studying at an agriculture college in the northwestern city of Peshawar.
It was unclear if they had other contact with poultry or another potential sources of infection.
Muqarab Khan, director general of livestock and animal husbandry in the province, said animal surveillance was under way across the province.
Poultry vaccine campaigns also have been started and all farms in the surrounding area have been closed.
Pakistan has grappled with outbreaks of bird flu in poultry for the past two years, but had previously not confirmed cases in humans.