Released January 21, 2009
AUBURN UNIVERSITY, Ala. -- The recent death of a 27-year-old Chinese women from avian flu is a reminder of the suffering this disease has inflicted on almost 200 people across Asia and Africa who died from it, but it and two similar Chinese cases does not mean that humanity has moved any closer to a worldwide pandemic, according to one expert
He says the likelihood of such a mass outbreak, despite these recent tragic deaths, is no greater than a two years ago when the disease dominated national and international headlines.
The recent outbreaks are what Robert Norton would describe as spatially diverse, meaning that the three outbreaks were not concentrated in a single region but occurred throughout the country at roughly the same time.
Moreover, Norton, an Auburn University veterinary bacteriologist who works with the Alabama Cooperative Extension System to educate Alabamians about avian flu and other biosecurity issues, says these isolated cases appear to be entirely that — isolated cases that likely occurred through direct human contact with infected poultry.
“These seem to be isolated cases that don’t appear to be spreading to anyone else, Norton says, adding that Chinese officials are currently trying to determine the sources of the three outbreaks, all of which likely stemmed from exposure to sick birds.
“That’s one of the criteria that they [medical investigators] look for — consuming sick poultry or being exposed to it in some other way,” Norton says, adding that the other three cases are likely to be linked to the same type of exposure.
As a rule, health authorities in China and throughout much of Asia assess any human outbreak of avian flu to determine the source of infection. Detection of human-to-human transmission of the flu could be a sign that the H5N1 virus — the strain of bird flu causing health authorities the most concern — had mutated into a form that could be spread among large numbers of people.
However, medical investigators are now certain that one of the victims, a 16-year-old male from Huaihua City in Hunan, contacted the disease from exposure to sick or dead poultry.
Norton says officials have not uncovered any evidence revealing that the other outbreaks occurred from any factor other than exposure to diseased poultry. “There is no indication at this point that they are anything other than ordinary cases stemming from direct exposure to infected birds,” Norton says.
“While I would never want to discount the tragedy of these cases, these are the sorts of things that we’re going to see occur from time to time,” Norton says. The good news is that so long as avian flu outbreaks occur intermittently and only from direct exposure to birds, the disease will not become a worldwide pandemic. Moreover, Norton says a growing number of researchers and investigators suspects that H5N1 lacks the propensity mutate into a virus that could threaten humans on a large scale.
“We see this with a lot of viruses besides H5N1 in which changes in a genome occur, but it’s kind of a dead-end street in terms of its threat to humans,” Norton says.
Nevertheless, he says the recent outbreaks and similar cases that may follow impose an immense strain on Chinese health officials and other developing countries throughout Asia and Africa — a fact addressed recently by China’s health minister, Chen Zu, who says his country faces a grim situation in preventing and controlling human flu outbreaks.
“It’s an extraordinarily expensive undertaking, not only for China but also for any country faced with these occasional outbreaks,” Norton says.
“You’re talking about an investment of hundreds of thousands of dollars of treatment therapy for each infected patient, not to mention the exacting footwork involved in tracking down the source of the outbreak as well as the people who may have come in contact with the infected individual.”
The costs for lower-tier nations, such as Malaysia or Vietnam, are even more imposing, Norton says.
In many countries, particularly in Southeast Asia, poultry farming remains a subsistence-level lifestyle, characterized by the close human-to-animal contact common to U.S. farming in the 19th century. Experience has shown time and again that this close contact increases exposure to flu strains and, ultimately, the likelihood that these strains could mutate into forms that could be spread among humans.
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http://www.aces.edu/department/extcomm/npa/newsline/archives/003851.php
