Persistent Infections by Leishmania (Viannia) braziliensis

Ramı́rez, José Luis; Guevara, Palmira

doi:10.1590/s0074-02761997000300006

Cited by 32 publications

(22 citation statements)

References 35 publications

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“…These findings in chronic Chagas' disease reflect what is commonly found in leishmaniasis, where parasite persistence appears to be a characteristic of the species of the genus Leishmania, as judged by their tendency to persist after clinical resolution of the disease. 29 This fact, which is observed in acquired immunodeficiency syndrome-associated diseases, shows that an infection can remain asymptomatic or show relapses at different times in immunodepressed individuals.…”

Section: Discussionmentioning

confidence: 99%

Myocardial parasite persistence in chronic chagasic patients.

Áñez¹,

Carrasco²,

Parada³

et al. 1999

The American Journal of Tropical Medicine and Hygiene

131

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Abstract. The persistence of Trypanosoma cruzi tissue forms was detected in the myocardium of seropositive individuals clinically diagnosed as chronic chagasic patients following endomyocardial biopsies (EMBs) processed by immunohistochemical (peroxidase-anti-peroxidase [PAP] staining) and molecular (polymerase chain reaction [PCR]) techniques. An indirect immunofluorescent technique revealed antigenic deposits in the cardiac tissue in 24 (88.9%) of 27 patients. Persistent T. cruzi amastigotes were detected by PAP staining in the myocardium of 22 (84.6%) of 26 patients. This finding was confirmed with a PCR assay specific for T. cruzi in 21 (91.3%) of 23 biopsy specimens from the same patients. Statistical analysis revealed substantial agreement between PCR and PAP techniques (k ϭ 0.68) and the PCR and any serologic test (k ϭ 0.77). The histopathologic study of EMB specimens from these patients revealed necrosis, inflammatory infiltrates, and fibrosis, and made it possible to detect heart abnormalities not detected by electrocardiogram and/or cineventriculogram. These indications of myocarditis were supported by the detection of T. cruzi amastigotes by the PAP technique or its genome by PCR. They suggest that although the number of parasites is low in patients with chronic Chagas' disease, their potential for heart damage may be comparable with those present during the acute phase. The urgent necessity for testing new drugs with long-term effects on T. cruzi is discussed in the context of the present results.

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Section: Discussionmentioning

confidence: 99%

Myocardial parasite persistence in chronic chagasic patients.

Áñez¹,

Carrasco²,

Parada³

et al. 1999

The American Journal of Tropical Medicine and Hygiene

131

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“…It is important to highlight that one characteristic of all Leishmania species is the tendency for there to be non-manifested infection or parasite persistence after the lesion has healed 17 . Demonstration of such persistence, in material obtained from the scars of individuals who have achieved clinical cure, raises several issues concerning the clinical evolution and epidemiology of leishmaniasis and the strategies for controlling it 15 .…”

Section: Discussionmentioning

confidence: 99%

Clinical, epidemiological and laboratory aspects of patients with American cutaneous leishmaniasis in the State of Pernambuco

Reis

et al. 2008

Rev. Soc. Bras. Med. Trop.

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The diagnosis for American cutaneous leishmaniasis is based on an association of clinical, epidemiological and laboratory characteristics. The present study identified the circulating species of Leishmania in the State of Pernambuco, described its clinical-epidemiological characteristics and diagnosed the disease. Nineteen patients presenting active lesions who had been diagnosed through clinical evaluation and laboratory tests were selected. The tests included direct investigation, in vitro culturing, Montenegro skin test, indirect immunofluorescence and polymerase chain reaction. The Montenegro Skin Test showed positive results in 89% of the patients; indirect immunofluorescence, in 79%; direct investigation, in 58%; and polymerase chain reaction in 75%. Seven Leishmania (Viannia) braziliensis samples were isolated from these patients and were characterized by means of specific monoclonal antibodies. These data confirm that a combination of different diagnosis techniques is needed in order to obtain efficient results and that, so far, Leishmania (Viannia) braziliensis is the only species responsible for American cutaneous leishmaniasis infection in Pernambuco. Thus, it is essential to identify the parasite species involved in cases of human disease in an endemic area in order to determine the clinical and epidemiological characteristics, especially with regard to diagnosis, therapy development and disease prognosis. Key-words:American cutaneous leishmaniasis. Leishmania (Viannia) braziliensis. Montenegro skin test. Indirect immunofluorescence. Polymerase chain reaction. RESUMOO diagnóstico da leishmaniose cutânea americana é baseado na associação dos aspectos clínicos, epidemiológicos e laboratoriais. O presente estudo identificou a espécie de Leishmania circulante no Estado de Pernambuco, descreveu os aspectos clínico-epidemiológicos e diagnosticou a doença. Foram selecionados 19 pacientes apresentando lesão ativa e diagnosticados através de avaliação clínica e pelos exames laboratoriais que incluíram a pesquisa direta, cultivo in vitro, intradermorreação de Montenegro, imunofluorescência indireta e reação em cadeia de polymerase. A intradermorreação de Montenegro apresentou resultado positivo em 89% dos pacientes. A imunofluorescência indireta apresentou 79% de positividade, a pesquisa direta apresentou 58% e a reação em cadeia de polymerase 75% de positividade. Sete amostras de Leishmania (Viannia) braziliensis foram isoladas desses pacientes e caracterizadas através de anticorpos monoclonais específicos. Esses dados confirmam que é necessário a combinação de diferentes técnicas diagnósticas para se obter resultados eficientes e que, até o momento, a Leishmania (Viannia) braziliensis é a única espécie responsável pela infecção da leishmaniose cutânea americana em Pernambuco. Portanto, a identificação da espécie do parasito envolvido nos casos da doença no homem em uma área endêmica é essencial para o conhecimento dos aspectos clínicos e epidemiológicos, sobretudo para o diagnóstico e para o desenvol...

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“…Parasite persistence may be related either to immune evasion or immunosuppression. It has been shown that both mice and humans continue to harbor parasites in the lymphoid tissue after spontaneous or chemotherapy-mediated healing (1,39,44). In the L. major model of infection, persisting parasites were associated with LN fibroblasts which, compared to macrophages, have a reduced ability to kill intracellular L. major.…”

Section: Discussionmentioning

confidence: 99%

Toward a Novel Experimental Model of Infection To Study American Cutaneous Leishmaniasis Caused byLeishmania braziliensis

et al. 2005

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Leishmania spp. cause a broad spectrum of diseases collectively known as leishmaniasis. Leishmania braziliensis is the main etiological agent of American cutaneous leishmaniasis (ACL) and mucocutaneous leishmaniasis. In the present study, we have developed an experimental model of infection that closely resembles ACL caused by L. braziliensis. In order to do so, BALB/c mice were infected in the ear dermis with 10 5 parasites and distinct aspects of the infection were evaluated. Following inoculation, parasite expansion in the ear dermis was accompanied by the development of an ulcerated dermal lesion which healed spontaneously, as seen by the presence of a scar. Histological analysis of infected ears showed the presence of a mixed inflammatory infiltrate consisting of both mononuclear and polymorphonuclear cells. In draining lymph nodes, parasite replication was detected throughout the infection. In vitro restimulation of draining lymph node cells followed by intracellular staining showed an up-regulation in the production of gamma interferon (IFN-␥) and in the frequency of IFN-␥-secreting CD4 ؉ and CD8 ؉ T cells. Reverse transcription-PCR of ears and draining lymph node cells showed the expression of CC chemokines. The dermal model of infection with L. braziliensis herein is able to reproduce aspects of the natural infection, such as the presence of an ulcerated lesion, parasite dissemination to lymphoid areas, and the development of a Th1-type immune response. These results indicate that this model shall be useful to address questions related to the concomitant immunity to reinfection and parasite persistence leading to mucocutaneous leishmaniasis.

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Persistent Infections by Leishmania (Viannia) braziliensis

Cited by 32 publications

References 35 publications

Myocardial parasite persistence in chronic chagasic patients.

Myocardial parasite persistence in chronic chagasic patients.

Clinical, epidemiological and laboratory aspects of patients with American cutaneous leishmaniasis in the State of Pernambuco

Toward a Novel Experimental Model of Infection To Study American Cutaneous Leishmaniasis Caused byLeishmania braziliensis

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