Thursday, August 4, 2011
The Biological Nightmares of Climate Change
While those suffering in the record breaking high temperatures from the 'heat dome' over the central plains may attest that's the worst part of global warming, they might want to think again. Since major research began on the topic more than 15 years ago, we've known there's also a biological dimension attendant on warmer climate which will inevitably lead to infestations of intruder insects and new vectors of disease. The warmer the temperatures become the more pests and diseases we can expect.
With current CO2 concentrations hovering near 550 ppm, and the first clear sign (with this summer's global heat waves) that global warming is being reinforced - likely also because of abatement of aerosols and pollutants which enabled an offsetting cooling effect- we may well be on the cusp of the Runaway Greenhouse Effect.
Long before the actual Runaway emerges, we can expect a host of exotic diseases will spread across the world and wreak havoc - and all the fools clamoring for warm temperatures (e.g. for "longer growing seasons") will wish they were dead. Especially as we're already losing efficacy of anti-biotics from over-use(See, e.g. Global Climate and Infectious Disease:The Cholera Paradigm, in Science, Vol. 274, 20 December, 1996, p. 2025.)
If people think the current invasion of West Nile fever is bad, wait until they're faced with dengue fever (which I caught in the West Indies - and which can - after the 3rd successive bite-infection - lead to hemorraghing from all body orifices). Wait until cholera becomes endemic and other hitherto unseen (and unheard of) diseases appear. Then the morons will understand the enormous downsides of their 'warmer' world and huge price for their 'longer growing seasons'.
Mostly understated in all the talk of exotic disease incursions, is the real risk we will be swamped by parasites- throughout the country and even the world. Right now, there are in excess of 9 BILLION worm parasites inhabiting the vertebrates of our world, according to the author of Parasite REX. The human population alone may carry within it up to 2 billion worm parasites, including: hook worm, one of 5,000 forms of tape worm, round worm, trypanosomes, schistosomiasis-causing flukes and the protozoan that causes Toxoplasma (which over 1 billion may carry, mostly in their brains.)
Truthfully, the threat from parasitic worms as climate warms will only materialize if too many cuts to public health expenditures are also made. In that case, the public health resources may simply not be available to battle worm- infestations such as from tapeworm, hook worm and particularly schistosomiasis. Bear in mind that barely 80 years ago, most people in the southern U.S. suffered from hook worm infections - part of the reason Southerners were dismissed as "dumb and lazy" by arrogant Yankees. The latter had little sympathy because they didn't have to battle the lassitude and mental slowness that accompanies worm infections.
Meanwhile, I've already beheld the "handiwork" of the river fluke (see photo) that causes schistosomiasis when I spent time in St. Lucia, in 1972. In order to infest U.S. freshwater streams, rivers and lakes all that's needed is the accidental invasion of a particular snail (e.g. Bulinus truncatus) that serves as the intermediary host for the parasite.
Once the snail appears, and harbors but one parasite within it, then if stringent health measures aren't brought to bear quickly it can spread like wildfire. Once the ciliated larva or Miracidium semi-matures inside the body of the right snail and escapes into the water, it will have 2 suckers and a forked digestive tube, called "cercarias". Any hapless humans wading or swimming in the affected waters will not last long before being infested.
The cercerias then attach themselves to the skin as the fluke digests its way through it to a blood vessel. It's then carried in the blood stream to the blood vessels of the intestine. There, the young fluke will feed and grow into an adult, finally mating (usually with another that entered at the same time). As Carl Zimmer, author of 'Parasite REX' observes (p. 26):
"Heterosexual flukes mate every day of their long lives and whenever the female is ready to lay her eggs, the male makes his way along the walls of the bowels until he finds a good spot. ...Some of the eggs are carried away by the bloodstream and end up back in the liver where they lodge and inflame the tissue, causing much of the agony of schistosomiasis. But the rest of the eggs work their way into the intestines and escape their host, ready to slice open their shells and find a new snail'.
Of course, degraded hygiene conditions are part and parcel of the flukes' spread, which is also why we need - as Americans- to ensure massive homelessness doesn't also emerge from the current spending cut policies! As we've learned locally, if care isn't taken, homeless camps will spring up and people will tend to use rivers, streams (near where they pitch their tents) as 'outhouses'. If they become infected with an invasive river fluke, then the stage is set for pandemic schistosomiasis spread.
Can all this be avoided? Yes, but I warrant it will take money...lots of it. Not merely for ensuring our public health (and regulatory) services aren't degraded during the current spending cut frenzy but that it is also available to avoid the worst effects of imminent climate change.
Alas, the time grows short and the endemic, pervasive austerity national mindset does not bode well for us all.