[horizontal ellipsis]And what rough beast, its hour come 'round at last, Slouches towards Bethlehem to be born? - -The Second Coming, 1920, William Butler Yeats
While perusing listservs and journals for contents related to the expected surge in West Nile virus (WNV) infections in humans this past summer, I was struck by the appearance of reports about Eastern Equine Encephalitis (EEE). EEE has a high rate of mortality (1/3) and morbidity (1/3). A "normal" year averages about 3-5 reports across the United States.1 But, some years are worse than others, and this may be one.
Of course, we had the unprecedented nationwide outbreak of WNV last year (2002), with about 3,400 cases and 201 deaths. This was the largest outbreak of meningo-encephalitis ever recorded in the western hemisphere, and the largest outbreak of WNV infection ever, anywhere.2 Given that about 80% of WNV infections are basically asymptomatic and that only about 1 in 150 of those infected get encephalitis, the numbers of people actually infected must have been quite large, in the range of 350,000 to 500,000.
West Nile virus infections have also felled unknown thousands of corvid birds and a significant number of horses and other secondary targets. While we have all been waiting for, talking about, and-to some degree-preparing for a new influenza pandemic, we have witnessed avian flu in China and Hong Kong in two different years that infected humans directly: an avian flu outbreak in Dutch poultry that infected a few workers, and this past winter (2002-03) we were startled by SARS, severe acute respiratory syndrome. Worldwide, the resurgence of dengue and dengue hemorrhagic fever is affecting the public's health in scores of countries.
The July 28, 2003, ProMed Digest (International Society for Infectious Diseases listserv) reported an outbreak of blue-green algae toxicity in the Baltic Sea around Finland, thought to be related in large part to pollution and episodic warming of the sea. Blue-green algae emit cyanobacterial toxins that are neurotoxic to animals, including humans. Vibrio parahaemolyticus has now appeared a few times in Long Island Sound, a new and water temperature-related phenomenon. Who knew we needed to prepare for such public health events? Environmental change is already having major effects on our health.
When the Institute of Medicine's (IOM) report3 on emerging infectious diseases came out 11 years ago, it listed over 50 human pathogens, many of them totally new, as emerging or re-emerging. Some were just old dogs with new tricks. At least 30 previously unknown disease agents, for which we have no curative therapy, have been identified since 1973.4 And they're still coming ashore, so to speak, since neither WNV or SARS had visited the western hemisphere at the time of either of the above publications.
The article by Diaz, in this issue of Family & Community Health, is a fresh reminder that there are elements at work that have the capacity to cause great upsurges in vector-borne disease, population displacement, refugee populations, and other sources of major public health problems. Global climate change affects land use and economic development, human demographics and behavior, travel and commerce, microbial adaptation and change, and can itself exacerbate the breakdown of public health measures-all things identified in the IOM3 report as factors related to emerging infections.
It is clear that much of the burden of infectious disease weighs on those areas of the world least able to deal with them. So it is, as well, with the effects of global climate change on human health. The 1 billion people living on less than a dollar a day and the roughly 2.5 billion living on less than two dollars a day are bearing the brunt of our familiar ravagers, malaria, tuberculosis, HIV/AIDS, diarrhea, and respiratory disease. They will bear the brunt of future infectious disasters, as well. But in these days, if any one country harbors an emerging disease, all countries are at risk.
The Diaz article thus reminds us of the words in John Donne's sermon, written in response to a fellow's inquiry about why the funeral bells were tolling in a nearby church.
No man is an Iland, intire of it selfe; [horizontal ellipsis] any man's death diminishes me, because I am involved in Mankinde; and therefore never send to know for whom the bell tolls; It tolls for thee. - -John Donne, Devotions upon Emergent Occasions XVII: Meditation (1624)
We live in an age in which we should be striving towards global biological security, not just dealing with the most immediate/current issues on bioterrorism. We don't have a comprehensive strategy for such security-the protection of people and agriculture against disease threats, natural or intentional. A concentrated effort on "WMD" is thus misplaced if it comes at the expense of true global biological security. Like politics, biological outbreaks are local, at least at the beginning. But, they don't stop at the edge of a city, or state, or even a coast or national boundary. It won't take the better part of a year for the next influenza pandemic to work its way around the world.
Finally, the Diaz paper also sadly reminds me that the last and hardest thing I learned about public health is that its basic science is about politics and choices, not epidemiology and confidence intervals. We need to do much more to inform our public and, most especially, our policy makers about these concerns. The choices we make at a policy level will have a very direct impact on the health of our families, our friends, and our future. We should emulate the framers of our Declaration of Independence and pledge towards this end "[horizontal ellipsis] our Lives, our Fortunes, and our sacred Honour."
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