Experimental transmission of Trypanosoma cruzi through the genitalia of albino mice

Trypanosoma cruzi is usually transmitted by contact with the excreta of inf ected Triatominae: among non-vectorial infections, direct transmission thro ugh coitus has been proposed. We investigated this possibility by instillin g, through the external meatus of the vagina and the penis of previously an esthetized NMRI albino mice, blood of mice infected with strains isolated f rom Didelphis marsupialis (opossum. strain CO57), Rattus rattus (rat, strai n CO22) and human (strain EP). Some animals were allowed to copulate the sa me day of the instillation. In other experiments, the strains were inoculat ed in the scrotum. To determine the effect of immunosuppression, some mice were treated with cyclophosphamide 30 days post-instillation. Controls were instilled orally and ocularly. Vaginal instillation with strain CO22 produ ced systemic infection with tropism to the heart, skeletal muscle, skin, du odenum, pancreas. ovary and sternum. Scrotal inoculation with strain EP lik ewise invaded liver, spleen, lung, lymph nodes and urogenital organs; while strain CO57 invaded skeletal and cardiac muscle, pancreas, testis, and vas deferens. Penile infection with strain CO22 was detected xenodiagnosis. Im munosuppression did not increase parasitemia of vaginally infected mice or controls. Mating did not produce infection. Our results show that contact o f blood trypomastigotes of T. cruzi with genital mucosa can produce blood a nd tissue infections. These results are discussed in relation to reports of frequent experimental tropism of T. cruzi toward urogenital organs.