Climate, Environment, and Infectious Diseases: A Report from the AIBS 2008 Annual Meeting

摘要

The American Institute of Biological Sciences dedicated this year's annual meeting to the challenge of Earth's changing climate and its effects on the environment, and the spread of infectious diseases. The conference, held in May in Arlington, Virginia, attracted more than 250 biologists, climatologists, and other scientists, as well as physicians and public health officials.nnMalaria. Dengue fever. West Nile virus. Lyme disease. These and other infectious diseases are on the rise in humans. Is our interaction with Earth's environment somehow responsible? What factors are involved in the emergence and transmission of infectious diseases? How are climate change and other environmental parameters involved? These complexities have created a tangled web that scientists must soon unravel.nnIf biologists, climatologists, physicians, and other researchers work closely together, said Richard O'Grady, executive director of the American Institute of Biological Sciences (AIBS), “we have the potential to predict disease outbreaks and to mitigate their effects. Accelerating climate change and threats to health are now two [sides] of the same coin.”nnLinks among the environment and infectious diseases were demonstrated in many ways and for many locations by AIBS conference speakers; they made connections between microbes, environmental events such as El Niño, and disease incidence in people. Large-scale environmental events—global climate change, land-use change and habitat destruction, and human population growth and urbanization—alter the risks of viral, parasitic, and bacterial diseases. Agricultural intensification, deforestation and reforestation, increased precipitation, and ocean warming all play a role.nnFor example, in a case that might be called “CSI: Infectious Diseases and Climate Change,” otherwise healthy people began dying of a mysterious respiratory disease in 1993 in the US Southwest. Tests yielded surprising results: The victims had hantavirus pulmonary syndrome, a result of a previously undetected type of hantavirus.nnResearch by biologist Terry Yates of the University of New Mexico, honored posthumously at this year's meeting with the AIBS Distinguished Scientist Award, showed that the outbreak was connected to the El Niño climate phenomenon, a pattern of changes in ocean circulation and atmospheric weather. Increased rainfall led to more plants, more mice, and more opportunities for people to come into contact with the rodents' droppings and urine, which contain the virus. Named for the Hantaan River in Korea, hantaviruses were known to spread from mice to humans in Asia and Europe, but until the 1993 outbreak, hantaviruses had been seen only outside America.nn“We can no longer discuss infectious diseases simply as those that affect the US, or that affect New York City, or Washington, DC,” said scientist and cholera expert Rita Colwell, of the University of Maryland and Johns Hopkins University Bloomberg School of Public Health. “Infectious diseases that arise in Africa or in Asia reach the United States, as evidenced by the SARS [severe acute respiratory syndrome] episodes,” she said. “The connections to the environment are very dramatic. For example, the origin of SARS was tracked to bats in caves in Asia.”nnColwell, who is also the president of AIBS, spoke of cholera as a disease not just restricted to Bangladesh or India but prevalent also in Latin America and Africa. The environmental burden of disease falls on those least prepared to deal with it, she said. Countries in Africa and in Asia, where populations are large and poverty is high, are particularly affected, as shown in studies by the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia. Dealing with the effects of climate change on infectious disease falls—so far—mostly on these populations.nnHow long will it be before the rest of the world follows suit? That depends, Colwell believes, on decisions we make now about our environmental future. Climate change poses risks to ecosystems and the life support they provide to people, and to all animals and plants on Earth. The bottom line, AIBS meeting participants agreed, is that to safeguard human health, we must live within our planet's environmental limits