Chagas disease and HIV co-infection: genetic analyses of two Trypanosoma cruzi strains under experimental immunosuppression

BACKGROUND: Recently new aspects of the immunopathology of Chagas disease have been described in patients infected with HIV and unusual clinical manifestations such as cutaneous lesions, involvement of central nervous system and/or serious cardiac lesions related to the reactivation of the parasite have been reported. Two uncloned Trypanosoma cruzi strains previously isolated from chronic chagasic patients with HIV co-infection were studied in order to evaluate the impact of the immunosuppression on the genetic diversity of the parasite. RESULTS: We have exploited an experimental model to determine whether genetically distinct populations appear after immunosuppression as a consequence of in vivo selection or in vitro propagation. The in vitro and in vivo conditions have allowed us to study the selected populations. The first strain was isolated from a case of reactivation of Chagas disease in a patient which presented four cerebral lesions. It was possible to demonstrate that the patient was infected with at least three distinct populations of T. cruzi. The population, recovered after immunosuppression, in mice was genetically divergent from the primary human isolate. The second strain, isolated from a hemophiliac/HIV positive patient presenting cardiac manifestation of Chagas disease showed no marked genetic difference after experimental immunosuppression. CONCLUSION: The immunological condition of the patient, associated or not to the reactivation of the infection, and also the strain of the parasite may have an important role during the course of the disease. The in vivo mechanism that generates parasite genetic variability or the participation of the selection under stress conditions will require further investigation

Casos de leishmaniose tegumentar americana por Leishmania (viannia) braziliensis nos municípios de cosmópolis e Indaiatuba - região de Campinas, estado de São Paulo, Brasil

Com o objetiiro de identificar a espécie de Leishmania envolvida nas afecções cutâneas de indivíduos residentes nos municípios de Cosmópolis e Indaiatuba, região de Campinas, Estado de São Paulo, correlacionamos dados clínicos, histopatológicos e testes de bibridização in situ. Os expressivos índices de incidência de leishmaniose tegumentar americana obsewados nesses municípios nos levaram a iniciar esses estudos. Nesse trabalho, apresentamos os dados relativos a seis indivíduos. As características das lesões, ulceradas, de dificil cicatrização e presentes em locais expostos do corpo sugeriram quadros de leishmaniose tegumentar americana. Os testes de intradermoreação de Montenegro, positivos em cinco dos seis pacientes analisados também reforçaram a suspeita de leishmaniose tegumentar americana. Os padrões histopatológicos, como reação exsudativa celular e granulomatosa e a dificuldade de isolamento dos parasitas obtidos de biópsias de lesões são compatíveis com aqueles descritos para Leishmania (Viannia) braziliensis. Em testes de bibridização in situ do DNA do cinetoplasto de amastigotas das lesões dos seis pacientes, obseivamos que quatro deles apresentavam sinais de bibridização com a sonda de L. (Viannia) braziliensis, confirmando as suspeitas de que a Leishmania responsável pelas afecções cutâneas nos pacientes analisados era do subgenêro Viannia e do complexo braziliensis

Parasite Genotypically Related to a Monoxenous Trypanosomatid of Dog's Flea Causing Opportunistic Infection in an HIV Positive Patient

An HIV positive patient presenting a clinical picture of visceral leishmaniasis co-infection was submitted to a bone marrow aspiration after admission to hospital. Amastigotes forms were seen in the bone marrow aspirate and the parasite grew in culture as promastigotes. Molecular analyses showed that the flagellates isolated did not belong to the genera Leishmania, Trypanosoma or Sauroleishmania. It was not possible to establish infection in laboratory animals. In vitro culture of mouse peritoneal macrophages revealed the invasion of the host cells by the flagellates and their killing 48 hr after infection. Opportunistic infection with an insect trypanosomatid was suspected. Further hybridization analyses against a pannel of different monoxenous and heteroxenous trypanosomatids showed kDNA cross-homology with Leptomonas pulexsimulantis a trypanosomatid found in the dog's fle