An emerging virus, an obscure toxin and a novel bacterium:Three new diseases are cause for alarm and demand pause for analysis. As if this summer's contaminated water and heat- and flood-related deaths were not enough, an altered climate may already be having an impact on the pattern and proliferation of disease.
In the Four Corners area of the southwest United States, an unusual viral infection has been confirmed in 12 persons, nine of whom died. It is the likely agent afflicting a total of 32 persons, killing at least 17.
This family of viruses was first identified in the 1950s, when one strain infected thousands of U.N. military personnel. In the 1980s, this kind of virus was isolated in rodents and in human blood samples in the United States, but this is the first outbreak of acute illness here.
A likely scenario is that when heavy rains followed six years of drought, pine nuts flourished, nourishing rodents. Driven by flooding from their underground burrows, the swollen population rodents enhanced the chance for the virus to thrive and pass on. Whatever the route of entry, changes in the environment and in the balance of predators with deer mouse prey have apparently led to the emergence of a new viral strain.
One Navajo chief reflected: "We suffer for our people have lost balance with nature." The Navajo once garnered rainwater from rocky outcroppings to irrigate their fields below; but the landscape has declined from over-grazing, deforestation and desiccation. Large climatological swings and a year of epic storms may reflect even greater disturbances in earth's natural systems.
In Cuba, an epidemic of optic and peripheral neuropathy has affected more than 46,000 people. The syndrome is reminiscent of previous cases of toxic nerve damage. Some affecting motor function, others the senses, they were first reported in the Caribbean a century ago; arose among malnourished POWs in the Far East during World War II; appeared in Nigeria in the 1960s during a famine; and, in 1981, in drought- and war-stricken Mozambique, where cassava containing cyanide (a natural plant pesticide) was harvested prematurely and cured improperly by malnourished peasants. In Cuba, where there are growing reports of scurvy and beri-beri, food toxins are the chief suspects, with underlying nutritional deficiencies that retard detoxification.
In India and Bangladesh, a new strain of cholera erupted in January. By mid-April this vigorous form of Vibrio cholerae had invaded Calcutta (15,000 cases, leaving 230 dead), and permeated Dhaka (600 new cases per day at its peak).
Sea weeds, marine plants and algae harbor cholera bacteria. Nourished by nitrogen-rich waste water, fertilizers, run-off soil and acid rain, and deprived of effluent cleansing by the %o development in coastal wetlands ("nature's kidneys"), algal blooms are increasing in magnitude and duration worldwide. In some regions, elevated sea-surface temperatures are shifting the community of organisms toward more toxic species, causing "red tides" and shellfish poisoning. More antibiotic-resistant forms of cholera have emerged, and a chlorine-defiant variant has surfaced in Peru, penetrating poor populations who enjoy little potable water.
(Having hitchhiked in the hulls of arriving vessels, another, more familiar form of cholera is now present along the Gulf Coast of the United States.)
Changes in coastal ecology have generated "hot systems," in which selections for mutations are being made under new environmental pressures. The new cholera strain has the potential to spread across the globe, and to mature into the agent of a world pandemic.
"Epidemics," wrote Dr. Rudolph Virchow, a pathologist and public health activist, in 1948, "are like sign-posts from which the statesman of stature can detect a disturbance in the development of his nation."
These three new diseases reflect accelerating climate changes, dietary deterioration in a dwindling economy and alterations in the world's large marine ecosystems. Our forms of development and terms of trade lie at the core. As felled forests and paper mills foul fisheries, and factories keep fossil fuels inflamed, we fall vulnerable to insults. The intricate web of species threatens to unravel.
Financial incentives can redirect our course; removing financial disincentives -- the debts owed 'round the world -- gets closer to the source.
We must not wait for proof of global warming to deduce that ecological changes and economic disparities threaten to cost us our health. The only remedy is to reform our energy, industrial
and forestry policies to curb climatic change.
Paul Epstein is a doctor at Harvard Medical School and a member of the Harvard School of Public Health Working Group on New and Resurgent Disease. He wrote this commentary for Newsday. Sara Engram, whose column usually appears here, is