Bird Flu Alarm

Understanding Avian Influenza

Avian Influenza in Humans

While avian influenza spreads rapidly among birds, it does not infect humans easily, and there is no confirmed evidence of human-to-human transmission. Of the 15 subtypes known, only subtypes H5 and H7 are known to be capable of crossing the species barrier.

The symptoms of avian influenza in humans are akin to those of human influenza, ie. fever, sore throat, cough and in severe cases pneumonia. Human deaths from avian influenza were unknown until 1997, when six people in Hong Kong died from the particularly virulent H5N1 strain.

In January 2004, a major new outbreak of H5N1 avian influenza surfaced again in Vietnam and Thailand's poultry industry, and within weeks spread to ten countries and regions in Asia, including Indonesia, South Korea, Japan and China. Intensive efforts were undertaken to slaughter chickens, ducks and geese (over 40 million chickens alone were slaughtered in high-infection areas), and the outbreak was contained by March, but the total human death toll in Vietnam and Thailand was 23 people.

It is feared that if the avian influenza virus undergoes antigenic shift with a human influenza virus, the new subtype created could be both highly contagious and highly lethal in humans. Such a subtype could cause a global influenza pandemic, similar to the Spanish Flu that killed over 20 million people in 1918. In February 2004, avian influenza virus was detected in pigs in Vietnam, increasing fears of the emergence of new variant strains.

Fresh outbreaks in poultry were confirmed in Ayutthaya and Pathumthani provinces of Thailand, and Chaohu city in Anhui, China, in July 2004.

In North America, the presence of avian influenza was confirmed at several poultry farms in British Columbia in February 2004. As of April 2004, 18 farms have been quarantined to halt the spread of the virus. Two cases of humans with avian influenza have been confirmed in that region.

In August 2004 Avian Flu was confirmed in Kampung Pasir, Kelantan, Malaysia. Two chickens were confirmed to be carrying H5N1. As a result Singapore has imposed a ban on the importation of chickens and poultry products. Similarly the EU has slapped a ban on Malaysian poultry products. A cull of all poultry has been ordered by the government within a 10KM radius of the location of this outbreak

Understanding Avian Influenza