Co-authored with Catherine M. Machalaba, MPH
Novel diseases and pandemics have captured our global attention. Yet, for all we hear about them, what do we actually know -- or perhaps more accurately, not know about them? Here we dispel common myths about novel diseases and pandemics.
Myth 1. They're just a public health problem.
Novel diseases and pandemics typically are perceived to fall squarely into the public health realm. Paradoxically, they actually interface with nearly every other sector. For example, they raise major concerns for food production, biosecurity and environmental health. And their implications can be expensive; the costs of SARS to the global economy was estimated by BioERA at >$30-$50 billion, and the past decade of outbreaks has been responsible for hundreds of $US billions in losses.
They also have wide implications for society, livelihoods and productivity, as demonstrated by outbreaks of Marburg hemorrhagic fever (a highly fatal viral disease related to Ebola) that closed mining sites in the Democratic Republic of Congo for five years, markets repeatedly being shutdown in China after outbreaks of SARS and avian influenza, and now the Saudi Arabian government's recent advice to defer pilgrimages for the Hajj partly on the basis of concerns over the spread of the Middle East Respiratory Syndrome. Outbreaks can be highly disruptive to movement of people and goods, often leading to increased regulations and restrictions on trade and travel to reduce the potential for spread.
Myth 2. They're obscure, rare, and have short-term impacts.
While novel disease outbreaks occur infrequently (~3-5 times per year), they appear to be increasing, and they have tremendous impacts at local, regional and global scales. Just because an outbreak starts suddenly, it doesn't mean it always ends rapidly as well; it may re-emerge in humans (as seen with Ebola), emerge in a new location or from a new species, or become established as did the highly pathogenic H5N1 influenza (Bird Flu).
Most of the infectious human diseases today in fact emerged from animals at some point in time; and they now account for over one million deaths and more than one billion illnesses annually. And what about those cases ubiquitously diagnosed as "fever", "encephalitis", "pneumonia", or worse, "unknown"? There's a chance some are "novel" diseases that we just haven't had the tools to detect.
Myth 3. Our doctors already know all the infectious diseases.
No one knows all of the infectious diseases our planet harbors. While medical science has named >1,400 infectious disease-causing agents, this is only the tip of the iceberg. Over 60 percent of known infectious human diseases are shared with animals so there's potential for many more to be lurking in the wild. Encouragingly, our colleagues' work assessing viral diseases suggests there's not an infinite number of undiscovered viruses lurking in mammals... but we still have long way to go before we have a handle on what's out there.
Disease detection isn't as straightforward as we'd like. There are disincentives to viral detection, such as impacts on tourism and trade. We get it. If your lovely tourist revenue-generating location harbored a dangerous pathogen with the tiniest of possibility of spread to humans, would you want it hysterically broadcast to the world? Neither would we. But we do need to assess risks to know how to manage them, and we need to be comfortable with learning those risks, because not knowing sure isn't protecting us.
Additionally, overall investments in research are volatile, especially in light of government funding challenges. And there are persistent disparities around access to funding. Many new diseases arise in developing countries that do not have the resources for early detection, prevention or research, thus stalling opportunities for proactive discovery and intervention.
Myth 4. Our international organizations are protecting all of us.
Not so much. International organizations such as the U.N. World Health Organization and the Food and Agriculture Organization, as well as the World Organisation for Animal Health, do play extremely important roles in disease prevention and control. They can help coordinate efforts and provide guidance on pandemic prevention and response and may sanction countries for violating disease control efforts, but ultimately only sovereign nations have the authority to enact action on the ground. And even our international organizations have limited resources. A recent article in The Economist cited WHO's annual influenza budget at only $7.7m, a mere one-third of New York City's budget for public health emergencies.
Myth 5. We have the infrastructure in place to detect and effectively respond to them.
Au contraire. In fact, we barely even have the capacity to detect and respond to common diseases that we all know about, much less novel diseases. With the public health surveillance capacity and diagnostic technologies we have today, would we have detected the HIV-transmitting pathogen in non-human primates before it was transmitted to humans? Probably not, and that's because we simply haven't been looking for potential viruses in most places.
So what do we need to create infrastructure for detecting, responding to, and ideally, preventing novel diseases and pandemics? A 2009 World Bank/UN study estimated that an over $2 billion/year investment was needed through 2020 to get nations up to speed on diseases commonly shared between animals and people. That price tag seems steep, but pales in comparison to the costs of some recent outbreaks (see Myth 1). And there are potential cost-savings from tackling novel diseases in tandem across sectors through a "One Health" approach that considers links between humans, animals and the environment.
Myth 6. Disease emergence is inevitable, and we can't do anything about it.
And now for some (partially) good news. While spontaneous viral mutations/reassortment can and do occur (such as with the new H7N9 influenza), the root causes and spread of novel diseases isn't so spontaneous. These diseases don't just appear out of the blue without an opportunity existing for them to do so. The problem is, the human species is creating those opportunities far and wide, and increasingly so. We're seeing that land-use and food production changes, trade and travel, climate change, and other human-linked pressures are driving disease emergence, mainly because these put us into increased and new contacts with wildlife and our activities disturb ecosystem dynamics.
Since we have an idea of what's driving them, that's one piece of the puzzle that allows us to put prevention measures into place. Another is where to look for them before outbreaks occur, and in what species. USAID's Emerging Pandemic Threats program is currently investing in integrated disease surveillance and detection programs in developing countries that are "hotspots" for disease emergence. This will help us to find new viruses, learn more about their risks to humans, and work with local governments to take actions to reduce risks of emergence. But we're not going to find viruses where we're not looking- which is still the case in much of the world.
Myth 7. Globalization is only bad news for novel disease transmission and spread.
And for more good news... While there is potential for rapid spread around the world through trade and travel (as demonstrated by the scenario in the film Contagion), globalization can also enable rapid diagnostics and global response. Our connectedness is allowing us all to take an active role, whether we want to or not, in disease outbreaks. Want to find out what diseases are being reported in your backyard or across the earth? Tools such as HealthMap.org and the Program for Monitoring Emerging Diseases track infectious disease outbreaks globally in a transparent way, helping us to more quickly identify disease trends and pair resources with public health needs. The former even allows for social reporting of disease occurrence with programs like "Flu Near You."
As global citizens with concerns over novel diseases and pandemics, we can encourage our policy makers to do a better job of prioritizing upstream prevention efforts and our corporations to proactively consider risks when planning their operations and be accountable for damages from outbreaks. We can also participate directly by reducing our ecological "footprint" which contributes to the underlying "drivers" of disease emergence.
Nenhum comentário:
Postar um comentário