Bird Flu's Environmental Components


This article was published by Newsletter, issue #13, 2005-11-10.

Avian influenza (a.k.a. bird flu) is a current health threat to humanity on a pandemic, even global scale, and there is little evidence that we are ready to deal with this crisis, should it become widespread. The highly pathogenic avian influenza (HPAI) is an especially dangerous virus that is extremely contagious among birds, and has an almost 100% mortality rate among them. It can remain viable at moderate temperatures for lengthy periods of time, and can survive indefinitely in frozen material — presumably that includes frozen meat. At this time, the known strains can infect humans only through contact with infected birds. Researchers and government officials fear that this particular avian influenza, H5N1, could mutate, as all viruses can do, and then begin spreading through human-to-human contact. If this were to happen, it could easily result in a global epidemic. As of this writing, there have been 114 registered human cases in 16 countries. That number is likely to escalate, especially now that many species of birds are flying to other countries as part of their fall migrations.

Aside from the countless deaths of infected birds, the threat to humanity is real. Disease experts predict that a full outbreak of bird flu among humans would be substantially more devastating than even the Spanish Flu of 1918, which killed well over 40 million people. This is partly due to higher population levels nowadays, greater living densities within cities, and modern transportation capabilities significantly reducing the time for people — and thus their communicable diseases — to move from one metropolitan area to another, on any continent.

Because this particular form of influenza is apparently originating and spreading among birds, an obvious question is: What are the ecological conditions, if any, that is causing, or at least exacerbating, the deadly disease? This important question has been taken up by at least one writer, Josh Rothstein of the Foundation for Environmental Security and Sustainability, in an article entitled "Environmental Factors Affecting the Spread of Bird Flu", published as a September 2005 Issue Brief by that organization. In that piece, he notes that discussing these environmental factors could provide information to reduce or possibly even prevent an all-out pandemic, especially for the poorer nations which have far less health care resources to deal with the threat, and are already seeing outbreaks, albeit on a still-limited scale.

Rothstein argues that there are four primary ecological factors underpinning this avian influenza: deforestation and other forms of habitat destruction that affect the routes of migratory birds; farming environments that enable the spread of bird flu; human utilization of potentially infected water; market environments that enable the spread of the disease. The first factor, habitat destruction, can force large numbers of migratory birds to seek alternative places for food and rest, including farms and cities. This greatly increases the contact between infected wild birds with uninfected domestic birds and other animals, including pigs, which are typically a required intermediary for any avian influenza to infect humans. However, even that porcine bridge is no longer needed in the case of H5N1 (one of the most virulent subtypes), as was discovered in 1997 with the first direct bird-to-human infection.

Another form of habitat destruction that affects waterfowl especially, is the drainage of wetlands, which is being vigorously pursued in most Asian countries. By indirectly and inadvertently forcing migratory birds to come into greater contact with humans, we are dramatically increasing the chances that a genetic mutation of the bird flu will arise that will prove more deadly to humans and more capable of bird-to-human and human-to-human transmission. In essence, as we systematically destroy the natural homes of other creatures, and commandeer more of their habitats for our own use, we are forcing them to become part of our artificial ecosystems. This is the root cause of the Black Death of the 14th century, which killed one third of Europe's population. The primary carrier was the oriental rat flea that infested the black rats living in the cities. Apparently we did not learn enough from that experience. One can only hope that we can avoid another such lethal pandemic, and heed its ecological warning.

Copyright © 2005 Michael J. Ross. All rights reserved.

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