April 11, 2005. Copyright 2005, Graphic News. All rights reserved

Bird Flu -- potential risks and consequences
By Mark Rutter

LONDON, April 11, Graphic News:  There were three large-scale global outbreaks of influenza during the 20th century, the most serious of which occurred in 1918, when an estimated 20-40 million died worldwide. As a 10-year-old Vietnamese girl became the 50th victim of Asian bird flu in March, scientists and healthcare authorities around the world are gearing up to prevent another pandemic.

Influenza or flu pandemics occur when a new strain of the flu virus emerges to which people have little or no immunity. There is some evidence to suggest that previous pandemic flu viruses originated in birds. Scientists have recently characterised the virus responsible for the 1918 pandemic, known as ÒSpanish FluÓ, by isolating it from the bodies of victims exhumed from frozen Arctic tundra. H5N1 -- the strain currently causing concern -- is principally an avian disease, prevalent in birds in a number of Asian countries. Domestic poultry flocks are especially vulnerable. The first human cases infected with this strain occurred in Hong Kong in 1997, where six of the 18 people infected died. A bigger outbreak was averted by implementing measures to stop further spread, including culling around 1.5 million chickens.

Since 2003, human deaths from this strain have occurred in Vietnam, Thailand and Cambodia. Although millions of poultry have been destroyed, at vast expense, many farms where chickens come into contact with wild geese and ducks still pose risks. Humans catch the disease through close contact with live infected birds. Unlike normal flu, which is easily passed from person to person through the air or through touching, human to human spread of the H5N1 strain remains rare. But, as flu viruses are renowned for their ability to mutate by altering their genetic material, the fear is that a highly virulent strain capable of easy transmission between people could emerge, leading to a new pandemic.

Once it breaks out, it is unlikely that the global spread of a pandemic flu virus could be prevented. The symptoms of pandemic flu are similar to ordinary flu, but much more severe, with infection not confined to the winter. Everybody would be at risk of infection, although certain groups such as the very young and old would be more vulnerable to death. It would cause extensive disruption to everyday life, with the possible closure of schools and businesses, and restrictions on travel and movement. Most developed countries have contingency plans in place. As a viral disease, influenza cannot be treated with antibiotics. Some anti-viral drugs are available but their effectiveness is uncertain.

Vaccination offers some hope. Many countries are engaged in developing bird flu vaccines, with the first human trials against the H5N1 strain planned in the U.S. soon. Although mutations in the flu virus could render such vaccines ineffective, it is hoped that the vaccine would at least work partially -- enough to make the difference between life and death. If public health authorities waited for the emergence of such a strain before formulating a vaccine, millions could die before sufficient quantities of the vaccine were able to be manufactured.
/ENDS