The TcI and TcII Trypanosoma cruzi experimental infections induce distinct immune responses and cardiac fibrosis in dogs

Trypanosoma cruzi infection may be caused by different strains with distinct discrete typing units (DTUs) that can result in variable clinical forms of chronic Chagas disease. The present study evaluates the immune response and cardiac lesions in dogs experimentally infected with different T. cruzi strains with distinct DTUs, namely, the Colombian (Col) and Y strains of TcI and TcII DTU, respectively. During infection with the Col strain, increased levels of alanine aminotransferase, erythrocytes, haematocrit and haemoglobin were observed. In addition, CD8+ T-lymphocytes isolated from the peripheral blood produced higher levels of interleukin (IL)-4. The latter suggests that during the acute phase, infection with the Col strain may remain unnoticed by circulating mononuclear cells. In the chronic phase, a significant increase in the number of inflammatory cells was detected in the right atrium. Conversely, infection with the Y strain led to leucopoenia, thrombopoenia, inversion of the ratio of CD4+/CD8+ T-lymphocytes and alterations in monocyte number. The Y strain stimulated the production of interferon-γ by CD4+ and CD8+ T-lymphocytes and IL-4 by CD8+ T-cells. In the chronic phase, significant heart inflammation and fibrosis were observed, demonstrating that strains of different DTUs interact differently with the host.

Descriptive study of American tegumentary leishmaniasis in the urban area of the Municipality of Governador Valadares, Minas Gerais State, Brazil / Estudo descritivo sobre a leishmaniose tegumentar americana na área urbana do Município de Governador Valadares, Estado de Minas Gerais, Brasil

To understand the emergence and re-emergence pattern of American tegumentary leishmaniasis (ATL), the clinical and epidemiological profiles and the spatial distribution of the disease were evaluated between 2001 and 2006 in an endemic area located in the Rio Doce valley in the north-eastern part of the Minas Gerais State, Brazil. The number of reported cases increased from six in the first year to 111 in the last year during this period. Disease cases predominated in the urban area (75.9 per cent) and affected males and females equally in all age groups. The transmission of ATL occurred within dwellings and the surrounding areas, with the largest number of reported cases originating from poor areas, particularly those located on the margins of the Rio Doce lacking suitable sanitary infrastructure. Diagnosis was based on clinical criteria and the Montenegro skin test, with most patients (93.8 per cent) exhibiting the cutaneous form of ATL. First-line treatment involved administration of pentavalent antimonial drugs (99.1 per cent), and these provided a cure for > 75 per cent of patients. The prevalence of ATL varied between 11.38 and 15.99 cases per 100,000 inhabitants, which is high in comparison with the national average. Urgent measures, including improved means of diagnosis at the local health units, education of schoolchildren and motivation of the general population, are required to decrease transmission and control the disease.

Para entender os padrões de emergência e re-emergência da leishmaniose tegumentar americana (LTA), foram avaliados os perfis clínico e epidemiológico e a distribuição espacial da doença entre 2001 e 2006 em uma área endêmica situada no vale do Rio Doce, no nordeste do Estado de Minas Gerais, Brasil. O número de casos notificados aumentou de seis, no primeiro ano, para 111 no último ano do período estudado. Os casos da doença predominaram na área urbana (75,9 por cento) e atingiram igualmente homens e mulheres em todas as faixas etárias. A transmissão de LTA ocorreu dentro de residências e em áreas vizinhas, com o maior número de casos registrados oriundo de áreas pobres, sobretudo as localizadas às margens do Rio Doce, sem uma infraestrutura sanitária adequada. O diagnóstico baseou-se em critérios clínicos e no teste de Montenegro. A maioria dos pacientes apresentou a forma cutânea da LTA. O tratamento de primeira linha abrangeu a utilização de drogas antimoniais pentavalentes (99,1 por cento), que foram responsáveis pela cura de > 75 por cento dos pacientes. A incidência da LTA variou entre 11,38 e 15,99 casos por 100.000 habitantes, valor alto em comparação com a média nacional. Medidas urgentes, incluindo a melhoria de técnicas de diagnóstico nas unidades de saúde locais, a conscientização de crianças em idade escolar e a motivação da população em geral, são necessárias para reduzir a transmissão da doença e controlá-la.