GONORRHEA GRANDMA: Study Suggests We Have This STI to Thank For The Evolution of Grandmothers. “In 2015, a team of researchers led by molecular medicine professor Ajit Varki discovered that humans have a unique type of immune receptor that protects against Alzheimer’s disease and sets us apart from other primates. . . . The likely culprits are infectious human-specific pathogens like Neisseria gonorrhoeae that try to disguise themselves by dressing in the same sugar coating as human cells, which fools patrolling immune cells into thinking the bacteria are harmless.”