Thursday, October 27, 2005
Avian Flu, a new type of virus, could cause a global epidemic
By Dr. Anthony Policastro
Nanticoke Memorial Hospital

Last year, I wrote about how the concern about flu vaccine shortage was being exaggerated compared to actual needs. Ultimately, that proved to be the case. Then about nine months ago, I wrote the attached article about the newest flu bug. Given the recent news, it is worthwhile to publish it again. Our bodies fight infection through our immune system. The immune system works best when it is exposed to things that other humans already have immunity for. There are several reasons for this. However, the bottom line is that it is a lot better to be exposed to a common germ than an unusual one. For example, when measles was introduced by the settlers to the American Indian population, it had a high fatality rate. The same thing is true with the flu. Every year the flu strains that spread around the world are a little bit different. However, for the most part flu viruses are similar. They are Type A or Type B. We all have some protection against these types. Therefore, even though they may make us ill, it is not as bad as it could be. When a new type of flu virus comes along, it produces significant disease in the population. That only happened three times in the 20th Century. One of those times was the great flu pandemic (a worldwide epidemic) that occurred in 1918. The world population was much lower in those days. Even with that lower population number, the total death toll for that pandemic was between 20 million and 40 million people worldwide. Many of those people died from secondary infections. We can now control those with antibiotics that were not available then. In addition, many of those people were young and healthy. It did not affect only high-risk individuals.

We also had the Asian flu in 1957 and the Hong Kong flu in 1968. Each of these three flu viruses was a little different than the previous ones that were prevalent. Therefore, they caused significant illness. In 1997 the first example of avian flu going from birds to people occurred. Because the human immune system was not used to this virus, it caused significant illness. It has appeared intermittently since 1997. However, in the not too distant future, it will likely be the next cause of a flu pandemic. The two most recent outbreaks of avian flu occurred in Southeast Asia. In one of them 12 of the 13 infected individuals died. In the other nine of the 10 individuals died. Overall, the current reported mortality of individuals infected with avian flu is about 72 percent. That would mean that about three out of four victims would die. Because of this, there is a big push to develop a good avian flu vaccine. However, it is likely that there will not be enough of the vaccine available in time for a pandemic if it occurs soon. Flu spreads a lot easier than the SARS epidemic that was able to be controlled. Right now avian flu is a major public health concern. One of headlines in a medical news journal when I wrote this nine months ago read: "Avian flu world's No. 1 threat, CDC head says." This may not be an exaggeration.

Dr. Anthony Policastro is medical director at Nanticoke Memorial Hospital.