More than 2 1/2 years ago I wrote a blog entitled It Isn't Just Bird Flu, where I wrote about a number of possible pandemic and epidemic threats. I opened with:
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.
As it turned out, it was something other than H5N1 that leapt onto the global health stage, and many of our preparations for bird flu were quickly revised to deal with the swine flu threat.
The three years of pandemic planning have paid off, even if things haven’t always gone as smoothly as we’d like.
The swine flu pandemic of 2009 – while not the killer strain we feared would come – has given us an opportunity to see where we need to make improvements in our response.
But it is important that we take these lessons to heart. There is no guarantee that we have years or decades before the next pandemic strain emerges.
No guarantees at all.
Among the avian influenza's, H5N1 is currently our primary concern. 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.
And perhaps there is some biological barrier to prevent that from ever happening. We simply don’t know.
But we do know that viruses are constantly mutating, adapting, and evolving. What may not be possible today may become commonplace tomorrow.
Which brings us to this report in Monsters & Critics today, where the WHO warns not to become complacent about avian flu.
Nov 24, 2009, 6:48 GMT
Manila - The World Health Organization (WHO) warned Tuesday of a possible resurgence of bird flu amid new cases of the disease in poultry in Egypt, Indonesia, Thailand and Vietnam.
The Manila-based WHO Western Pacific Office said the presence of the H5N1 virus in poultry placed those in direct contact with the birds at risk of getting infected with the disease.
It added that it was also closely monitoring the risk of the H5N1 virus combining with the H1N1 swine-flu virus to produce a new and deadlier strain.
'We don't know if this is possible, but we are certainly aware of the risk,' said Shin Young-Soo, WHO regional director for the Western Pacific. 'We are on alert for this development.'
Of course, there are other avian influenza viruses out there – and some of those may have pandemic potential as well.
Earlier this month we saw another rare human infection by the H9 virus in Hong Kong, something that has been detected several times in that region over the past decade.
H7N7 infected 89 people and caused 1 death in the Netherlands in 2003, while two other H7 viruses were detected in humans in the UK in 2006 and 2007. And lastly H10N7 infected two infants in Egypt in 2004.
The best overview of avian influenzas that I’m aware of is CIDRAP’s
While it may be due, in part, to better surveillance – we are seeing more species jumping zoonotic diseases than ever before.
As man encroaches deeper into jungles and remote areas, and as he factory farms animals in crowded and often unsanitary conditions, he exposes himself to previously unknown animal borne diseases.
Consuming `bush meat’ is another potential source of zoonotic infection, something that Nathan Wolfe: Virus Hunter and a worldwide network of more than 100 scientists working with the Global Viral Forecasting Initiative (GVFI) hope to detect.
It was just this sort of human-animal interaction in Guangdong Province in 2002 that is believed to have precipitated the SARS outbreak which infected more than 8,000 people and killed roughly 800.
SARS apparently came about due to the penchant of some prosperous Chinese to dine on exotic animals. These animals were slaughtered, and served, in `Wild Flavor' restaurants, particularly in Guangdong Province.
A previously unknown coronavirus, which subsequently was discovered in civet cats served in these establishments, was determined to be the likely cause of the SARS outbreak.
SARS has since receded back into the wild, but the threat is certainly not gone. It could seep back into the human population again.
Nipah and Hendra are two particularly nasty pathogens that have caused outbreaks in South East Asia and Australia. In 2008 a new strain of ebola was discovered in Africa, and this year Ebola Reston (a strain which does not currently sicken humans) was found in pigs in the Philippines.
Earlier this year, a new arenavirus was isolated from 5 patients in South Africa and Zambia (see Lujo Virus: Newly Identified Arenavirus).
Ironically, in 1969, the Surgeon General of the United States, William H. Stewart, declared, "The war against diseases has been won."
He clearly was an optimist.
In the four decades since that proclamation, more than 3 dozen new zoonotic diseases have emerged or have been identified, including HIV, Hanta, Nipah, Hendra, West Nile Virus, Lyme Disease, H5N1, and now novel H1N1.
Old scourges are making a comeback as well.
Some, like Tuberculosis seemed as if they would be beaten by modern antibiotics, but now have become resistant. Polio continues to surface in Asia and Africa. And Dengue, Malaria, and now Chikungunya are all marching around the globe.
While some of these may seem like rare and exotic tropical diseases, I would remind my readers that Key West, Florida has recently seen dozens of Dengue Fever cases. Chikungunya showed up in Italy, of all places, a couple of years ago.
The Lloyds report takes pains to point out that while we worry about an influenza pandemic the most, there are other candidates out there that could spark a pandemic (or at least an epidemic).
- Hendra Virus
- Nipah Virus
- Small Pox
- Bubonic Plague
- Lassa fever
- Rift Valley fever
- Marburg virus
- Ebola virus
- Bolivian hemorrhagic fever
I could add Dengue, Chikungunya, and of course Pathogen X, the one we don't know about yet, to this list.
Not all of these are capable of sparking a worldwide pandemic, of course. Some, particularly the vector borne diseases and bacterial infections, are unable to spread globally the way that influenza viruses do.
But all of these are capable of producing, at the very least, serious regional epidemics or localized outbreaks.
Emerging infectious diseases are national, and global, security threats. They can also have immense economic ramifications.
Whether it is a new emerging disease, or an old foe making a comeback, the world must remain alert and prepared to deal with the next pathogenic threat.
And that means funding public health initiatives and scientific research both domestically and around the world.
And if we had any sense, we’d do it with the same commitment and vigor as we fund our military.
Because, while I can’t tell you which threat is coming next, I can assure you that nature’s biological laboratory is open 24/7 and is fully capable of serving up plenty of nasty surprises down the road.