06 December 2010

Extinctions threaten human health

Scientists warn that the current rapid loss of plants and animals could increase the spread of infectious diseases.


Current rapid species extinctions will likely remove many plants and animals that act as a buffer against the transmission of infectious disease, leaving behind species that encourage spread of disease, new research suggests.

The exploration, funded by the U.S. National Science Foundation and National Institutes of Health's Ecology of Infectious Diseases (EID) programme and the U.S. Environmental Protection Agency, focused on how the loss of biodiversity might affect people, and found that the loss of critical forest and field ecosystems could trigger an increase in the spread of disease-causing viruses, bacteria and fungi.

"Global change is accelerating, bringing with it a host of unintended consequences," study author Sam Scheiner, programme director of the EID program at the National Science Foundation, said in a news release from the foundation. "This paper demonstrates the dangers of global change, showing that species extinctions may lead to increases in disease incidence for humans, other animals and plants."

"A better understanding of the role of environmental change in disease emergence and transmission is key to enabling both prediction and control of many infectious diseases," study co-author Josh Rosenthal, EID program director at the National Institutes of Health, added in the same release. "This thoughtful analysis is an important contribution toward those goals."

First author of the report Felicia Keesing, an ecologist at Bard College in Annandale-on-Hudson, N.Y., and colleagues published their observations in the Dec. 2 issue of Nature.

Keesing's team noted that with the advent of land-use changes and human population growth, biodiversity has been subject to a remarkable decline for the last 60 years, with current extinction rates exceeding historical precedent by a factor of 100 to 1,000.

And the authors pointed out that, unfortunately, the first species to go are the ones whose presence is most likely to have a protective impact on the spread of disease. By contrast, the ones left behind -- the most resilient -- are exactly those plants and animals most likely to spark ever-greater transmission of diseases such as West Nile virus, Lyme disease and hantavirus.

Why this is the case remains a mystery, the authors added. What isn't a mystery is the need to counter the extinction scenario by working to closely monitor the potential spread of infectious disease while preserving natural habitats. (- HealthDay News, December 2010)


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