Studies on <i>Trypanosoma cruzi</i> isolated in the United States: A Review

Abstract

Studies on Trypanosoma cruzi isolated in the United States are reviewed. In the United States, nine species of triatomids and 14 species of mammals have been found infected with T. cruzi. Serologic studies for antibodies against T. cruzi in human beings are discussed. The epidemiology of T. cruzi infections in the United States differs from the classical pattern encountered in South America since infected insed hosts are found in trees and do not always defecate while feeding on the mammalian host. The infectivity and pathogenicity of "animal" strains of T. cruzi have been studied and are reviewed. Most strains are avirulent for mice. The cultural charaeteristics of several straii1s have been studied and the course of infection in mice examined. Differences among strains have been found. Immunologic studies have shown that avirulent North American strains of T. cruzi proteet mice against a virulent lethal South American strain. Attempts to differentiate strains serologically by the indireet hemagglutination test were not successful. Experiments to demonstrate that an infection with T. cruzi suppressed the development of mammary cancers in mice indicate that statistically significant differences between infected and uninfected groups of female mice were obtained. The basis for the protective relationship was not determined. T. cruzi in the United States is found in animals in the southern part of the country. Whether or not clinical disease in man takes place has not been demonstrated.