Bird Flu: A Historical Perspective
Recent outbreaks have put avian influenza, commonly known as bird flu disease, at the center stage of the global health community. From relative anonymity, the disease acquired notoriety for itself when it claimed more than fifty human lives. The deaths from bird flu disease are relatively small when compared to the number of deaths from other diseases. However, the possibility of a global pandemic is serious enough that deaths caused by bird flu warrant a closer examination and alarm.
Another pandemic waiting to happen
Officials at the World Health Organization (WHO) has said that the world is ripe for another influenza pandemic. An influenza pandemic occurs roughly every 30-40 years. The last influenza pandemic, which originated in Hong Kong in 1969, claimed 34,000 lives in the United States and even more in the Asian region. Although the viral subtype of the disease is still in circulation, the human body has already developed antibodies for it.
Historical precedence is not enough of a basis towards setting off global alarm bells. However, the patterns seen in the outbreaks point to the possibility of another influenza pandemic. There are an increasing number of cases wherein humans have been infected with the bird flu virus and the death toll from the disease is now more than 50.
One of the first signs of an impending pandemic is the crossing over of the disease from birds to humans. WHO is closely keeping its eye on the occurrence of a first case of human to human transmission of the bird flu virus. The human to human transmission of the disease will pose greater risks of infection to humans, which would effectively signal the start of a pandemic. To date, there are no recorded cases of bird flu being transmitted from an infected human to another.
To date, all human cases of bird flu were contracted by victims after having direct contact with infected animals and their secretions. However, the global health community is very much concerned because the bird flu virus mutates easily and is constantly evolving, and the first human to human transmission of the virus may just be around the corner.
Three global influenza pandemics: a brief history
Three major influenza pandemics have occurred: in 1918, 1957 and 1968. The first pandemic, the Spanish Flu of 1918-1919, had the highest mortality among the three pandemics. In less than a year, 20 to 40 million people died from the Spanish Flu, with over 50,000 lives claimed in the United States alone. Simultaneous outbreaks of the Spanish Flu were first detected in Europe and some parts of the United States. The infection spread to more areas through ships that traveled between the United States and Europe. Asia and Africa were eventually affected. The first wave of the pandemic was highly contagious although it was not deadly. The second wave, however, was deadly and occurred shortly in France, Sierra Leona and United States. It registered a ten-fold increase in mortality.
In 1957, a second pandemic occurred. Called the Asian Flu because it was first detected in Hong Kong and Singapore, it was much milder than the Spanish Flu, claiming between one and four million lives. When the second pandemic hit, the people were more prepared and knew what to expect. This was due largely to the world’s experience with the first pandemic. The Asian Flu virus was soon isolated in Japanese and Singaporean laboratories. The findings helped the World Health Organization alert the world about the onset of a pandemic and vaccines were immediately produced and distributed.
The most recent influenza pandemic happened in 1968 and lasted for a year. Dubbed as the Hong Kong Flu, it was first detected in China and later spread to Hong Kong where it escalated at an alarming rate. Like the Asian Flu, the Hong Kong Flu claimed between one and four million lives. It reached Canada, the United Kingdom and the United States, particularly California.
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