Trypanosoma cruzi in the anal glands of urban opossums. I- isolation and experimental infections

Opossums (Didelphis marsupialis) captured in intensely urbanized areas of the city of Caracas, Venezuela, were found infected with Trypanosoma cruzi. The developmental cycle of trypomastigote-epimastigote-metacyclic infective trypomastigote, usually occurring in the intestine of the triatomine vector, was taking place in the anal odoriferous glands of the opossums. Material from the glands, inoculated in young, healthy opossums and white mice by different routes, subcutaneously, intraperitoneally, orally, and into the eye, induced T. cruzi infections in all animals. Parasitemia, invasion of cardiac and skeletal muscle, and intracellular multiplication of amastigotes were observed. Inoculation of metacyclics from anal glands, cultured in LIT medium, gave equivalent results. All opossums survived: all mice died. Excreta of opossums may thus transmit Chagas' disease by contamination, even in urban areas where insect vectors are not present.

Infecçäo natural das glândulas anais de gambás (Didelphis albiventris) pelo Trypanosoma cruzi no município de Bambuí - MG / Natural infection of opossum (Didelphis albiventris) anal glands by Trypanosoma cruzi at Bambuí-MG

De 87 gambás, didelphis albiventris, capturados na regiäo de Bambuí (MG), 32 (36,7%) estavam infectados pelo Trypanosoma cruzi. Os índices de infecçäo foram 34,9%, 81,8% e 7,7%, respectivamente, para animais capturados em ambiente silvestre, peridomiciliar rural e periodomiciliar urbano. Em 20 gambás infectados as glândulas anais foram examinadas repetidamente e apenas um (5%) animal (GA09) apresentou exame positivo. Foram positivos 7 dos 17 exames a fresco da secreçäo glandular desta animal ao longo de 18 meses. Material destas glândulas produziu parasitemia patente em gambás e infecçäo subpatente em camundongos. A análise isoenzimática realizada com amostras de T. cruzi do GA09, obtidas via hemocultura, xenodiagnóstico e glândulas anais demonstraram pertencerem rigorosamente ao mesmo Zimodema semelhante ao Zimodema Z1. As observaçöes mostram que a infecçäo das glândulas anias pelo T. cruzi em gambás naturalmente infectados da regiäo de Bambuí é baixa