Saint Roch’s Worm.In 2017, Italian researchers inspected a painting of Saint Roch. The 14th-century Frenchman was said to have cured people of the plague and then contracted it himself. He is often portrayed with a bubo, a swelling on the upper leg of plague victims. The medieval painting was different. Saint Roch’s leg shows a wound dripping with a long white goo. In the past, the strange filament was thought to be pus, but the recent study authors are convinced that it was a worm. The unknown painter did not use his imagination, either. This is possibly the earliest representation of a graphic parasite called Dracunculus medinensis. Also known as the Guinea worm, its larvae are ingested via infected water. After a year’s incubation, things get horrifying. The person’s leg blisters, and a worm up to 1-meter-long (3 ft) erupts through the skin. Though not fatal, it is an excruciating experience. No cases are known from Italy, but it’s likely that the artist saw it firsthand. Many travelers from infected countries visited Bari, where the painting still resides. The “fiery serpents” faced by Israelites during their exodus from Egypt could have been Guinea worms. At the time, they were rife in the Middle East and victims describe a severe burning when the parasite breaks out.