Susan Perkins at the American Museum of Natural History is almost done with a truly heroic feat: overseeing a blog that features a new parasite every day in 2010. As we glide towards the end of the year, she’s launched “The Twelve Parasites of Christmas.” So far, mistletoe (that botanical equivalent of a tapeworm!), two turtle doves (and their blood parasites), and the cauliflower mushroom, bane of Christmas trees. What gifts await us in the next week?

Originally published December 19, 2010. Copyright 2010 Carl Zimmer.