No, not all kissing bugs transmit Chagas. There are some species that transmit the Chagas parasite and others that do not. Furthermore, even among the species that can transmit the parasite not all bugs are infected. Consequently some people who have been bitten or had contact with a kissing bug do not have Chagas disease. In many cases the bugs are born healthy and become infected when they bite a person infected with the parasite that causes Chagas disease.