While I'm confident that Barry Evans' recent Field Notes essay on malaria doesn't reflect his personal opinion of wetlands, it could have been interpreted as a diatribe against swamps and other "inadequately-drained" habitats ("The Vicious Circle of Malaria," March 31). As he pointed out, malaria was essentially eliminated from the U.S. and the Canal Zone in large part through the draining and intentional pollution of the swamps in which the mosquito vectors of the disease bred. Of course, those swamps were home to countless other organisms, too, and they suffered much the same fate as the mosquitoes. We lost such creatures as the Carolina Parakeet, the Ivory-billed Woodpecker, and Bachman's Warbler along with our swamps.
Throughout history and all over the world, creatures and habitats that have been deemed inconvenient or threatening to humans have simply been removed, with little thought to the consequences. In the case of wetlands, these consequences have included loss of nursery grounds for commercial fisheries, increased pollution of our coastal waters, and loss of buffers against hurricanes and tsunamis.
One other thing to consider when discussing eradication of disease-vector organisms is its direct effect on biodiversity. Most parasites are host-specific; thus, the inevitable consequence of eradicating these diseases is the extinction of the organisms responsible for them. Whether it be Plasmodium (malaria), Leptospira (yellow fever), Guinea worm, or any other, these are living creatures with just as much evolutionary history and inherent right to exist as we. Eliminating human malaria from the globe will result in the extinction of at least the 11 species of Plasmodium that cause it, if not also the 100-plus species of mosquito that transmit it. The environmental consequences of the resultant increase in human survivorship are fairly predictable; what might the unforeseen consequences of these extinctions be?
I'm not suggesting that we abandon efforts to eradicate debilitating diseases. Like every other species, we are programmed to put ourselves first. I myself have hosted two species of Plasmodium, so I know from personal experience that it's no fun. What I do urge is that we proceed with our eyes open, that we learn as much as we can about the valuable properties of the organisms we are wiping out, that we focus on education and health care rather than habitat destruction in combating these diseases, and that we not lose sight of the fact that what we are doing is intentionally wiping out species that happen to have the evolutionary misfortune of being dependent on the only creature capable of the task.
Ken Burton, Arcata