The fire next time: Hard work, luck may prevent pandemic
God gave Noah the rainbow sign, no more water but fire next time.’ - African-American spiritual
By Gary Evans, Executive Editor
Despite all the accolades and academic honors, Nathan Wolfe, PhD, is disarmingly down to a very different Earth — one teeming with microbes that are ever interacting with animals and man.
In the world of Wolfe’s work, we are but a few viral mutations away from the next pandemic of infectious disease, perhaps the index case is even now spiking a fever on an inbound plane. And despite our revered national and international public health institutions — the armies of epidemiologists at the CDC and the WHO — we actually know very little about what happens next. Our collective fate may be in the bloody hands of a destitute African hunter skinning a freshly killed baboon to bring his family a few precious pounds of protein.
This is the hot zone for pandemic emergence, whether Wolfe and colleagues are looking for the next retroviral plague or listening to "viral chatter" that may signal an emerging respiratory virus like SARS or a sudden antigenic shift in a novel strain of influenza. It is the work of a far-flung network called the Global Viral Forecasting Initiative, which he founded in 2008 after leaving the security of a life-time tenured position in the world of academia. "My colleagues thought I was crazy," he says. "Sometimes you have to take risks."
Why did SARS arise and vanish so quickly?
We sat down with Wolfe recently in Fort Lauderdale, FL shortly before he delivered the closing keynote at the 40th annual conference of the Association for Professionals in Infection Control and Epidemiology (APIC). In an interview with Hospital Infection Control & Prevention, we asked Wolfe about his field work and his recently published book, The Viral Storm, in which he predicts that we will see more and more pandemics and emerging infectious diseases.
Q. We have two new emerging infections on the radar right now, the Middle East Respiratory Syndrome Coronavirus (MERS-CoV) and Influenza A (H7N9) in China. Both of these seem to have a transmission problem in humans — they seem to have high mortality but very little human transmission. Is the primary concern that they will mutate and become more transmissible?
A. "There are two variables — how many people does it kill or harm and how easy is it to transmit from one individual to the other. And both are obviously important features, but something that is very highly transmissible can kill fewer people [but do] more damage. Some strains of Ebola will kill upwards of three-quarters of the individuals that they infect. Compare that to something like human papillomavirus (HPV) and the impact it has on global populations. Though it doesn’t kill in as dramatic a way — it takes a lot of time — it has so much more of a huge impact on global public health. Some of the particular variants of HPV cause cervical cancers. It spreads silently but it ends up being a huge killer because it is so transmissible. It is estimated that roughly one of three sexually active adults are infected with one or another [form of] HPV. So sometimes our instincts as to what’s most risky can be sort of counter to the reality of these things.
For the novel coronavirus and H7N9, it is in the early days for both of them in terms of estimating mortality and determining transmissibility. I think it is a very important point to make that these kind of viruses have a lot of capacity to mutate and swap genes around in recombination and assortment. That means that the virus that you see today is not necessarily the same virus that you are going to see in weeks or months."
Q. The original SARS coronavirus in 2002-2003 seemed to have a lot of the classic pandemic characteristics and it did emerge. Why did it vanish in a relatively short period of time and why hasn’t it come back?
A. "Well, I do think that our public health system responded in a fairly strong way to SARS. But also probably there was some good luck. Some people have postulated that the timing of the outbreak relative to seasonal fluctuations in respiratory virus season [worked in our favor]. We don’t fully understand why it is — it probably has to do with the density of human populations in the Northern Hemisphere in relation to the seasons — but there really are these seasonal effects. The Northern Hemisphere’s winter is when you see really the most important respiratory virus season in the world. You get a little bit in the Southern Hemisphere during their winter, but there is some postulation that SARS second peak’ was at the wrong time. It was the end of the respiratory virus season. Some folks argue that had it come along a little bit earlier we might still be living with the virus.
The second question is how come it hasn’t reared its head again. The way that we think about these things is that there is this constant process by which these viruses are pinging’ at human populations from the animal reservoirs that they come from. The events that we see are an incredibly small percentage of the events that are occurring. So it may very well be that there has been zoonotic transmission of SARS from animals to humans, but until we are really doing the right kind of surveillance we might be missing them."
Q. Many outbreaks have been discovered by astute clinicians looking at a single unusual case or by infection preventionists and health care epidemiologists trying to prevent patient infections. How do these IPs fit into your model of pandemic prevention?
A. "To me the infection preventionists are really at the frontline of this. That is kind of where the rubber hits the road and from our perspective we have an incredible respect for that kind of work and recognize its huge importance. They will continue to be very important. As you said, clinicians have played very important roles in identifying these outbreaks. As a biologist I am focused on these microbial populations, both the bad actors and the good actors. I think as we identify more and more of the positive sides of the microbial world it may very well be that IPs and other folks that are members in APIC might be in a perfect position to not only stop the nasty ones but also try to promote some of the positive ones."