Malaria may accelerate aging in birds

By February 12, 2015Avian malaria, Workgroup 1

Author(s): Gretchen Vogel

Publication: Science Magazine

Publication Date: 2015

Introduction: Malaria is a scourge of humankind, but many birds seem to shrug it off. Although they are chronically infected with malaria parasites, their behavior seems unaffected, and they mostly reproduce and raise young just as well as noninfected birds. That was a puzzle not just for ornithologists but also for evolutionary biologists, who have long theorized that parasites inevitably take a toll on fitness. The birds’ healthy appearance turns out to be deceiving, however. Drawing on data from a 3-decade study of great reed warblers in southern Sweden, researchers report on page 436 that long-term infection with malaria significantly shortened the birds’ lives. The analysis also revealed a possible explanation: The blood cells of infected birds had shorter telomeres, stretches of DNA that cap the ends of chromosomes and protect them during cell division. In many species, shorter telomeres are associated with aging and shorter life span. The work “is an almost deceptively simple study that puts the nail in the coffin of the idea of benign parasites,” says Marlene Zuk, an evolutionary biologist at the University of Minnesota, Twin Cities. And although it’s not clear exactly how malaria infection influences telomere length, the study raises the question of whether other mild, but chronic, infections have similar hidden costs in different animals, even humans.

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