** Latest update: 22/07/2005.**
Many experts say that the world is now closer to a flu pandemic than it has been at any time since 1968. The key pre-requisites for a flu pandemic are: a novel virus of animal origin which jumps the species barrier and is able to replicate in the human body and be easily transmitted from human-to-human.
The current avian flu virus, H5N1 fails just the final test.
Avian Flu human cases
In September 2004, a possible human-to-human transmission of the Avian Flu was reported in Thailand. In July 2005, two other cases had been reported, without confirmation from the WHO which is still investigating them.
A World Health Organisation team of expert consultants were invited in April 2005 to assess the situation in Northern Vietnam: their conclusion highlighted that the H5N1 Avian Flu strain has undergone significant genetic changes in the region and may therefore spark off an Influenza Pandemic .
Scientists and experts from the WHO have expressed their concerns about the increasing number of case clusters in the north of Vietnam, the expanding age range of cases and the wider period of infection.
By the end of June 2005, 54 of the 108 identified human cases in Asia had died. The main victims have been young, healthy adults which puzzles the scientific experts.
Paradoxically, experts raise the alarm bell because they have monitored a lower rate of infections that result in deaths. The WHO specialists predict that the avian influenza virus would probably lose pathogenicity when it acquires the improved transmissibility needed to ignite a pandemic.
Mr Klaus Stöhr - Head of the WHO Global Influenza Programme - estimates that an influenza pandemic could hit 20% of the world population, leading to 2 to 7.4 million deaths globally.
Avian Flu features : the "Avian Plague"
Avian influenza, or "bird flu", is a contagious disease of animals caused by viruses that normally infect only birds. One of the forms of the illess, known as ?highly pathogenic avian influenza?, is extremely contagious in birds and rapidly fatal, with a mortality approaching 100%. Birds can die on the same day that symptoms first appear.
The H5N1 virus is now endemic among poultry in many south-Asian countries (Vietnam, Thailand, Indonesia, China, North Korea, Malaysia, Cambodia, Philippines, Laos) and has been reported in Japan as well. Therefore, the objective is no longer eradication but rather containment.
Although first identified in 1997, since 2004 the avian flu virus has become more pathogenic, has survived several days longer, has been found in mammals and can be asymptomatic - 1/3 of domestic ducks in Thailand are reportedly infected without developing any obvious signs. Wild birds, which were thought of not being hit by the virus, have been found dead and highly pathogenic.
It has already caused the culling of more than 125 million birds and major economic disrupts, estimated at 8-12 billion Euros, as well as the death of more than 50 people.
Read more:
Related EPHA article on preparedness planning
Related EPHA article on EU action on Avian Flu
Related Briefing note on Influenza
WHO Inter-country consultation Influenza A/H5N1 in Humans in Asia
WHO report: ?Avian Flu: assessing the pandemic threat?
