Last modified: Saturday, January 27, 2007
avian flu booklet
BLOOMINGTON, Ind. -- Avian flu is not yet a large-scale threat to humans, but it wouldn't take much to change that. The virus that causes the disease, H5N1, may be only one or a few mutations away from easy human-to-human transmission. Many experts believe it is not a matter of whether such a mutation will occur, but when.
According to the federal Centers for Disease Control and Prevention, the spread of H5N1 virus from one person to another has been rare and has not continued beyond one person. No evidence for genetic reassortment between human and avian flu virus genes has yet been found, which is one of the requirements for a pandemic to occur.
A 45-page pamphlet is now available to the public identifying the main threats from avian flu and other forms of influenza and explaining how people can best protect themselves and their families from these threats.
The pamphlet, titled "Influenza and Its Growing Importance: An Investigative Compilation," can be viewed at http://www.indiana.edu/~pirt/flu/flufull6.htm. It resulted from a public health class at Indiana University Bloomington in which students examined the existing information about avian flu and similar diseases such as SARS. The purpose of the IU pamphlet is to alert and inform people about influenza, including symptoms, prevention and treatment.
A person with avian flu may have no respiratory symptoms at all. Yet infection by H5N1 can cause respiratory failure in as few as three to five days. If human-to-human transmission does arise, this combination of long incubation and lethal effect will make avian flu extremely volatile and difficult to control.
For an avian flu virus to be able to jump the species barrier between animals and humans, it must go through a recombination event that changes its surface proteins to make it more adept at entering and destroying human cells. For this to happen, two different forms of flu virus must be present in the same animal so genetic material can be exchanged. This could happen in pigs, for example, which are highly susceptible to infection from many types of pathogenic avian strains as well as human strains of flu. Inside a pig, a virulent strand of avian flu could recombine with human flu that has the proteins necessary to enter human cells.
People most at risk for developing new forms of flu are those who are in close association with animals such as poultry, waterfowl and swine. To most effectively prevent the human-to-human transmission that is characteristic of the world's greatest flu pandemics, recombination events must be prevented from occurring in the animals in which they are most likely to occur. This requires that people who deal with these animals have an overall habit of cleanliness.
The major factors contributing to the spread of the avian flu virus are poor hygienic practices. If public health systems in the United States and the rest of the world are adequately prepared, they can help prevent pandemics and control outbreaks.