MODERN PLAGUES: And How We Are Causing Them

The SARS outbreak earlier this year was a classic illustration of how disease can spread around the world via intercontinental travelers and how diseases can jump from animals to humans. Walters, a veterinarian and Harvard Medical School visiting lecturer, describes how human actions affecting the environment and the animals that live in it have exacerbated the spread of six diseases that have jumped in similar fashion to our species from their original hosts, creating serious new threats to public health. He begins with perhaps the most frightening one of all, mad cow disease, which attacks victims' brains. Many scientists believe the biological agent that causes the disease spread from scrapie-infected sheep to cows when sheep by-products were put in high-protein livestock feed. A virulent new strain of salmonella, DT104, has been created in part through the food industry's feeding antibiotics to chickens and livestock. Walters also explains that as hunters and laborers in central Africa continue to eat bush meat, new diseases will almost surely emerge from out of the jungles, as HIV did. The author also looks at hantavirus, its outbreaks thus far restricted to parts of the Southwest; Lyme disease, spread by deer ticks that live on and are spread by mice; and the mosquito-borne West Nile virus, which made its way to America from the eastern Mediterranean a few years ago. Walters presents a compelling case that the "deep ecological, demographic, and industrial roots" of these diseases must be considered if we are to minimize the danger of future emerging diseases. (Sept. 24)