Birds can catch malaria at least as far north as Fairbanks, Alaska, a new study confirms. And at the rate climate is expected to change, the risk zone for avian malaria might stretch beyond the Arctic Circle by 2080.
Throughout much of continental North America, malaria-causing Plasmodium parasites have been hitchhiking inside mosquitoes from bird to bird for eons. But many long-exposed bird species don’t get particularly sick because they’ve developed some degree of tolerance over time. What’s worrisome about the northward creep of malaria risk is that parasites might reach bird populations that haven’t been exposed, explains disease ecologist Ravinder Sehgal of San Francisco State University.
People aren’t at risk: The 80-plus species of Plasmodium that cause avian malaria don’t infect humans, nor do the five that cause human malaria affect birds. Climate may also change transmission risk for the human form of the disease, but with its own pattern.
Genuine made-in-Alaska malaria transmission showed up in several Fairbanks birds, Sehgal and his colleagues report September 19 in PLOS ONE. The researchers could tell the parasites had attacked locally because one bird, an infected myrtle warbler, was too young to have migrated yet and the remainder, all black-capped chickadees, stay in Alaska year-round.
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