Emily Blunt, Eddie Redmayne, Tom Felton for END7

More than 1 billion people suffer from natural tropical diseases that are so devastating, advocates who want to help can barely sit through a short video demonstrating their effects.

Emily Blunt, Eddie Redmayne and a number of other stars have joined END7’s campaign to fight and control the seven most prevalent tropical diseases, including hookworm, elephantiasis and river blindness. But instead of just showing the gruesome effects of these diseases (and be warned: the effects are very difficult to see), the producers first film the actors reacting to the havoc these diseases wreak, and then feature the people who are suffering from blindness, massive swelling and other crippling symptoms.

(If you’re the squirmy type, just watch until :56 and then fast forward to 1:43 to learn how you can get involved with the campaign.)

Advocates are working to wipe these diseases off the face of the earth by 2020 and are asking supporters to get involved via Facebook, YouTube, Twitter and by signing a pledge.

“Until recently, I didn’t even know these diseases existed,” Blunt said in a press release. “The serious disabilities and suffering they inflict on the world’s poorest people is heart-wrenching. But I was inspired to join the END7 campaign because, for once, the solution is simple and available now.”