As you may have read in Jamie Kirchick's column, it's never the case that Israel's critics get smeared as anti-semites. Or, as Kirchick's boss, New Republic editor in chief Martin Peretz put it, either "Carter is actually batty" or else "he is animated by a very strong animus towards Jews."
Here on the CDC's website you can read about dracunculiasis, Guinea Worm Disease, an ailment found in Africa where contaminated water leads to worm larvae getting inside your body. "During the next 10-14 months, the female Guinea worm grows to a full size adult 60-100 centimeters (2-3 feet) long and as wide as a cooked spaghetti noodle," at which point "a blister develops on the skin at the site where the worm will emerge" that "causes a very painful burning sensation." After a day or two, it ruptures and the worm emerges after which time you "may be unable to work or resume daily activities for an average of 3 months." What's more, "Almost invariably the skin lesions caused by the worm develop secondary bacterial infections, which exacerbate the pain, and extend the period of incapacitation to weeks or months-causing in some cases disabling complications, such as locked joints and even permanent crippling."
The good news, is that, as Nicholas Kristof reports, "because of [Jimmy] Carter’s two-decade battle against Guinea worm disease, it is expected to be eradicated worldwide within the next five years. It will be the first ailment to be eliminated since smallpox in 1977." The point is that there's a real cost to these smear campaigns. Carter does many good works around the world through his leadership of the Carter Center. Obviously, though, if the idea gets out there that Carter is motivated by hatred of Jews, then people aren't going to want to be associated with Carter or the Carter Center which would be a very bad thing for, for examples, victims of horrifying parasite infections.