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By Stephanie Nebehay
GENEVA, Dec 18 (Reuters) - The eight suspect human bird flu cases in Pakistan are likely a combination of infections from poultry and limited person to person transmission due to close contact, a top World Health Organisation expert said on Tuesday. Keiji Fukuda, coordinator of WHO’s global influenza programme, said while unconfirmed, any human to human spread seemed similar to previous outbreaks in Thailand and Indonesia — affecting close family members caring for sick loved ones.
There was no immediate cause for alarm and the United Nations agency was not raising its level of pandemic alert for the time being, he said, adding it was very reassuring that "we are not seeing large increases in the number of cases".
"Right now it doesn’t look like pure human to human transmission. It looks like the veterinarian, who was the index case, and a number of other suspect cases had poultry exposure," Fukuda told Reuters in an interview.
"It is definitely possible that we have a mixed scenario where we have poultry to human infection and possible human to human transmission within a family, which is not yet verified."
But human to human transmission "would not be particularly surprising or unprecedented," he added.
Eight people have tested positive for the H5N1 bird flu virus in North West Frontier Province since late October, and one of the confirmed cases has died. A brother of the dead man also died, but was never tested, so is not counted among them.
H5N1 is mainly an animal disease, but experts fear it could mutate into a form that could spread easily between people, causing a pandemic which could kill millions of people. In Thailand, a mother was killed by the virus in 2004 after cradling her dying infected daughter all night. The largest known cluster of human bird flu cases worldwide occurred in May 2006 in Indonesia’s North Sumatra province, where as many as seven people in an extended family died.
Three WHO experts, led by Hassan El-Bushra of its regional Cairo office, is in Pakistan helping investigate the outbreak.
The "index" case, who recovered, is a veterinarian who helped with culling operations and it is his two brothers who died after taking care of the ill man, according to Fukuda.
"This type of close contact we know can result in human to human transmission sometimes," he said.
"Right now, based on the information we have, the investigation going on and the feedback from the field team, we don’t have anything pointing to push the alarm bells or increase the (pandemic alert) phase," he added.
The WHO uses a series of six phases of pandemic alert to gauge the level of threat. The world is currently in phase 3, a new influenza virus subtype is causing disease in humans, but is not yet spreading efficiently and sustainably among humans.
"In terms of public health implications, we are looking for human to human transmission where casual contact can lead to infections and allow big outbreaks in communities," Fukuda said.
A team from the U.S. Naval Medical Research Unit NAMRU-3 laboratory in Cairo was expected in Pakistan on Wednesday to carry out further tests on the samples from the suspect cases. (Editing by Sami Aboudi)