The topic for this blog is Tracking Disease Epidemics, for which we have two very relevant (and very opposite) case studies. The assigned readings included papers on the Global Obesity Epidemic and website reviews on Avian Flu. At first, I was struck by the combination of these subjects but as I began thinking about it they are actually quite complimentary. Both epidemics are extremely important to think about (now more than ever), yet their development, surveillance and control require starkly different strategies. In this paper I will attempt to address these differences and also demonstrate any similarities that may be useful when considering concepts like global surveillance.
I am particularly intrigued by global disease surveillance and tracking, which is why I chose this topic for my first blog paper. I suppose this interest comes from my fascination with the whole Globalization Phenomena which we all have the privilege of watching develop exponentially. Without digressing too much, I’d like to look at some of the implications we are seeing from this thing called globalization. With the advent of the internet and the widespread availability of satellite communication, we as global citizens (I always like using that term) are able to instantaneously access information from anywhere on the planet like it was right there in the room with us the whole time.
Air transportation and the technology involved has gone from a wooden bench with paper wings to sophisticated jets in less than two lifetimes, and can now put you anywhere on the planet in less than twenty four hours. The world is truly growing smaller by the minute interweaving business practice, research, markets, culture, and everything in between.
Efficiency is one of my big mantras, and globalization will continue to develop the ability to streamline the best open-source knowledge: technology, research findings, and all the other ideas, innovations, and actions that civilization needs to advance for the better. From a public health perspective, this makes for promising opportunities in global health like global vaccinations, disease eradication, health infrastructure development, and (of course) surveillance just to name a few. With truly global organizations like Google(1) entering the mix, along with traditional members like the WHO and CDC, the development of Collective Intelligence in health and otherwise now seems inevitable (I’ll leave C.I. for another blog, but Google it when you can!).
Globalization also has some negative side effects, as we are especially attuned to in Public Health. The effects of the global marketing and distribution of not-so-healthy products like Big Macs, Pepsi, and Marlboros are already taking shape (pun intended) and their increasingly intentional focus on the developing world are cause for even greater concern. As the planet becomes easier to navigate, so holds true for infectious agents like the virus making for daunting potential of pandemics. Global Surveillance is clearly a tool to combat these forces, and is useful for both the Obesity Epidemic and the Avian Flu.
Compared to the run-of-the-mill epidemics, obesity is in a category of its own. The connotations of the term ‘epidemic’ spur scenes of panic, quarantine, economic arrest, and people dropping like flies. Not so with obesity; it is the tortoise of epidemics. By no means does this discount its significance, though, as it is a growing global concern that most certainly needs to be combated. This epidemic is extremely complex, as it includes factors from many facets of society such as diet, genetics, education, income, transportation, and occupation. In addition, the long-lasting health effects of obesity have been well documented. Popkin and Mendez explain this epidemic(2) through a combination of global transitions associated with the increasing urban-industrial lifestyle: the demographic transition (high fertility/mortality to low fertility/mortality), the epidemiological transition (infectious disease to chronic disease), and the nutrition transition (receding famine to degenerative disease (obesity) to Behavioral Change (healthy)). These transitions occur alongside the processes of urbanization, economic growth, technological changes for work, increased leisure, food processing, and mass media growth creating the perfect storm of sedentary overconsumption.
Obesity surveillance has proven to be a tricky affair, as its incidence and prevalence don’t quite create the same radar blips as other epidemics do. A true prevalence has not been confidently achieved, though Kelly, et al(3) has estimated the global burden at 23.2% overweight and 9.8% obese (937 million adults and 396 million adults, repectively) and projected to significantly increase up to 57.3% overweight or obese by 2030. Much of this estimate follows historical trends linked to Gross National Income, so this is predictable as the developing world continues to, well, develop. I found it particularly interesting that now overweight persons outnumber the underweight in developing countries. In this sense, surveillance is used more as a justification for future efforts in control. Both Popkin and Kelly conclude that primary prevention may be more feasible and cost-effective in curbing the epidemic than direct weight reduction efforts.
Where the obesity epidemic is creeping over decades, the avian flu has the impact of an atomic bomb. I must say that flipping through the assigned websites left me a bit paranoid, though that may be the intent of their creators. We have all heard of the potentials of H5N1, though it still seems to be a distant concern as only 2% of the US population has begun to prepare for a human outbreak.(4) Avian flu has not mutated to a form where it can be transmitted from human to human, but it is transmitted readily in birds. I found it surprising, looking at the list of countries with human fatalities from Bird Flu like Indonesia (78), Vietnam (42), China (15), and Egypt (14) now totaling 194 worldwide.
In this case, surveillance will be crucial in detecting early outbreaks and ideally preventing pandemic. There are some excellent surveillance systems such as HEDDS (http://wildlifedisease.nbii.gov/ai/index.jsp ) and the Global Avian Influenza Network for Surveillance (http://www.gains.org/Home/tabid/36/language/en-US/Default.aspx ) that monitor viral strains and disseminate information to local authorities. Unlike obesity surveillance, avian flu surveillance is meant for preemptive actions like early detection, quarantine, and other responses. But how bad could an outbreak actually be? Unfortunately, I think we have already been numbed to the estimates of millions dead and billions of dollars in cost. Currently, we are in Phase 3 of the WHO Pandemic Alert (http://www.who.int/csr/disease/avian_influenza/phase/en/index.html) meaning there is no or very limited human-to-human transmission. Lucky for us on a national level, the United States is at Phase 0 (no detection).
This brings us back to the scary side of globalization. If (some would say when) an outbreak occurs, the virus has the ability to reach every corner of the planet in less than 24 hours. Ideally, collaborations with organizations like Google will develop to the point where the global response will be quick enough. Surveillance and response seem to be on the right track, and if these Phases progress I imagine planning will become more relevant to the population as well.
Though very different, the two epidemics presented here are incredibly important to global health. Where the tracking of obesity is most useful for policies and prevention, avian flu monitoring prepares for a much more “momentary” action. Global surveillance is an important aspect of global health, and its development should continue to be a priority of resources.
(1) http://www.google.org/flutrends/
(2) Popkin and Mendez, The Rapid Shifts in Stages of Nutrition Transition: The Global Obesity Epidemic, The Health Consequences of Globalization
(3) Kelly, Yang, Chen, Reynolds, and He, Global Burden of Obesity in 2005 and Projections to 2030, International Journalof Obesity, 32:1431-1437
(4) http://www.birdfludefense.com/
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