Why do warmer Arctic summers give musk oxen nosebleeds?
As climate and animal movements are changing, so are the organisms that play a key role in disease ecology: parasites. Often carried by insects or other animals to their hosts, parasites are the infectious agents behind many human and wildlife diseases. And as climate change begins to alter the life cycles and biodiversity of these organisms, scientists say, it could have a powerful impact on disease patterns. Susan Kutz, a wildlife parasitologist at the University of Calgary, began studying one Arctic parasitic worm in 1994. The worm penetrates the feet of slugs, using them as a growth chamber until the slugs are eaten by musk oxen. The worms then take up residence inside the musk oxen’s lungs, causing nosebleeds, weakening the animals, and making them vulnerable to predators such as grizzly bears. To investigate how climate change might affect the parasite’s life cycle, Kutz spent two summers on the Arctic tundra, tracking the worm’s growth. She calculated that a couple of decades ag
