How an obscure sexually transmitted parasite tangos with the immune system
Trichomonas vaginalis also enlists helpers to battle other microbes
TRICKY PARASITE Trichomonas vaginalis has a funny shape and some clever ways of infecting people.
David M. Phillips/Science Source
Frances Mercer runs a fight club.
In one corner, the parasite Trichomonas vaginalis, which causes a widespread sexually transmitted infection that many people have never heard of.