A guinea worm is a parasite that can do some pretty gross things to the human body. When a person harbors the nematode inside of them, the condition is known as guinea worm disease. Symptoms include fever, swelling, and pain—oh, and a white worm that pokes its heads out of your skin via a blister. 

The troublesome parasite has wreaked havoc in Africa and Asia, disabling individuals who develop a secondary infection. While currently there are no drugs to treat the disease, preventative measures can be taken, such as filtering any potentially contaminated water. Since 1986 that is exactly what The Carter Center has been doing with their international campaign to purge the planet of guinea worm disease.

Thankfully, as of 2015, the species is near eradication. To learn more, check out a video by Gross Science, a new PBS Digital Studios YouTube show: