#662
In this increasingly crowded world of ours, where there are large areas of poverty and poor medical care, there are literally scores of deadly pathogens that could spark the next epidemic, or pandemic. Bird flu, or the H5N1 virus, is high on the list of diseases we watch, but it is by no means the only one out there.
When we prepare for a bird flu pandemic, we are also preparing for any other disease outbreak.
We worry most about influenza viruses because they spread so rapidly. In 1918 the Spanish Flu managed to traverse the globe in 5 months without the benefit of air travel. What took months back then could well take only weeks today. The next pandemic may strike with little or no warning.
Among the influenza's, H5N1 is currently our main focus. It is a novel virus, it has become endemic in birds in many countries, and it has shown that it can jump species and infect humans. It has all of the criteria needed to spark a pandemic, save one; it hasn't developed the ability to be easily transmitted from human-to-human.
But influenza viruses mutate rapidly, and with each human infection there is a chance that the virus may acquire the ability to become easily transmissible. Whether that will ever happen with the H5N1 virus is unknown, but many scientists strongly believe it could happen.
Other influenza viruses with pandemic potential exist out there, among them are H9N2, which infected two children in Hong Kong in 1999 and another in 2003, H7N7 which infected 89 people (1 death) in the Netherlands in 2003, and H10N7 which infected two infants in Egypt in 2004.
Beyond Influenza we also watch for SARS, which broke out of China in 2003, and infected 8000 people worldwide, killing roughly 800. SARS wasn't as easily transmitted as influenza, but it does have pandemic potential. We hear very little about it today, but there is nothing to say that it couldn't jump back into the headlines tomorrow.
XDR-TB, a form of tuberculosis that is highly drug resistant, worries many health officials. It wouldn't spread at the speed of an influenza outbreak, but it could become another slow moving epidemic, like AIDS. TB was a scourge when I was a child, my grandmother had it and was in a TB hospital before I was born, but has been largely controlled over the past 40 years. No longer, TB is on the rise again, and it is deadlier than ever.
Viral fevers, now mostly seen in tropical developing countries, have the potential to end up anywhere in the world because of modern air travel. Lhassa fever, Rift Valley Fever, and even Ebola could end up in New York or London someday.
Old favorites, like polio, smallpox, yersinia (plague), and measles could return. We've seen outbreaks of pneumonic plague and polio in the last year in equatorial Africa. Measles and mumps have broken out both in the United States and Europe in recent months despite mass vaccinations of the populace.
Chikungunya, which is spread by mosquitos, has ravaged nations in and around the Indian Ocean over the past year. Yellow Fever is endemic in large areas of South America and Africa. Dengue fever is spreading in tropical countries like Indonesia, and of course Malaria kills millions every year. Those who live in developed nations would like to believe they are immune from these disease outbreaks, but they are not.
While some of these diseases are controllable, and not all of them have pandemic potential, they all would require a well mounted public health response to contain them.
And then there is always the possibility of pathogen X, the one we don't know about, that will suddenly pop up somewhere in the world and begin to spread, just as SARS did a few short years ago.
Pathogen X will most likely be a zoonotic disease, one that normally resides in animals, but jumps to humans. Over the past thirty years, more than two dozen of these zoonotic disease have been identified. There is a strong possibility that one of these zoonotic diseases will someday pose a major health threat.
If you think that's unlikely, I'd remind my readers that Lyme Disease is one of the fast growing emerging infectious diseases in the country. Each year more than 20,000 new cases are reported to the CDC, although they admit that the real number of infected is likely many times higher. Testing is woefully inadequate, and it is frequently misdiagnosed.
As a Lymie, I can attest to the damage that disease can do when it is not properly diagnosed and treated.
The next pandemic may come out of left field, and be completely unexpected. Our only defense is to have a strong global public health system that can monitor these diseases, and hopefully detect and contain them before they can spread.
The WHO, FAO, and our own CDC are at the forefront of this daily battle against emerging infectious diseases. They are limited, of course, by a finite budget, global politics, and the fact that many of these diseases come out of remote areas of the world where surveillance is poor. But despite these constraints, they are our best hope in preventing the next pandemic.
The focus of this blog will remain Avian Flu as long as that remains a threat. But from time to time, when conditions warrant, I'll bring you information on other emerging infectious diseases.
We don't know when the next pandemic will occur, or what pathogen it will spring from.
We just know that their are many emerging threats out there, and every day that passes brings us closer to the next global health crisis.
