No abstract

Co-infections with human immunodeficiency virus (HIV) and Mycobacterium leprae represent unique opportunities to investigate the interaction of both pathogens. We determined the immunologic, virologic, and histopathologic characteristics of 22 co-infected Brazilian patients (median age = 38 years, 81.8% males, 72.2% with paucibacillary leprosy, and 95.4% with acquired immunodeficiency syndrome). The HIV-1 subtypes B and BF predominated in envelope and gag heteroduplex mobility analysis. Borderline tuberculoid (BT), tuberculoid, lepromatous, and indeterminate morphology with CD3+, CD8+, and CD68+ cell distributions compatible with leprosy patients not infected with HIV were observed. Histologic evidence of nerve damage was observed in BT lesions. IgM antibody to M. leprae-specific phenolic glycolipid I was not detected. Two of six co-infected patients monitored during highly active antiretroviral therapy (HAART) developed a leprosy type 1 reaction after an increase in CD4+ cells, suggesting an immune restoration phenomenon. Clinical, immunologic, histopathologic, and virologic features among these HIV-leprosy co-infected patients indicate that each disease progressed as in single infection. However, HAART immune reconstitution may trigger potential adverse effects, such as leprosy acute inflammatory episodes.

Inadequate soil management practices adopted in the Brazilian semi-arid region contribute to erosive processes. Agroforestry systems (AFs) have been considered an alternative to reduce water erosion. This study aimed to evaluate the impact of two alternatives AFs, a traditional and an intensive cropping system on the losses of sediments, water, organic carbon and nutrients caused by water erosion in comparison to the natural vegetation (caatinga) in a semi-arid region of northeastern Brazil. The agroecosystems studied were: agrosilvopasture (AGP) which consisted of an alley cropping system, cultivated with Leucaena leucocephala and maize, within an area composed by 22% of native trees (200 native trees per hectare) which was grazed during the dry season; silvopasture (SILV) that was composed by 38% of native trees (260 trees per hectare) with a stocking rate of 20 ewes during whole year; traditional agrosilvopasture (TRAG) being managed as following: total deforestation, burning of the residues, cropped with maize for 2 years (1998 and 1999) and fallow during 8-10 years; and intensive cropping (IC) system which was deforested and burned in 1997 followed by cultivation of maize from 1998 to 2002, and thereafter by a fallow period of 8-10 years similar to TRAG. Two areas of native forest (NF1, NF2) known as 'caatinga', used as grassland during the dry season and as a source of wood, were selected and used as reference of steady state in the comparative study in relation to the cultivated sites. Sediment and water losses as a result of erosion were collected during two rainy seasons, i.e. 2003 and 2004, and nutrients and organic carbon contents were determined. Soil samples were collected and organic carbon, pH in water, pH in KCl, water dispersible clay (WDC) and hydraulic conductivity (K 0 ) were measured. In 2003, sediment and water losses did not differ significantly among all treatments. However, in 2004, TRAG (0.70 Mg ha -1 ) and NF1 (1.37 Mg ha -1 ) showed the highest sediment losses, whereas TRAG and IC presented the highest water losses. On average, nutrients losses in cropped areas were lower than in natural vegetation (NF1, NF2).

Os sistemas agroflorestais têm sido amplamente promovidos como sistemas de produção agrícola sustentáveis, principalmente para regiões subdesenvolvidas, onde o uso de insumos externos é inviável. Este trabalho objetivou avaliar o impacto de quatro sistemas agroflorestais e um sistema convencional sobre os teores de N total, mineral e em diferentes frações orgânicas, após cinco anos de uso de um Luvissolo na região semi-árida cearense, em experimento instalado na Embrapa Caprinos, em Sobral (CE). Os sistemas testados foram: agrossilvipastoril (AGP); silvipastoril (SILV); tradicional cultivado em 1998 e 1999 (TR98); tradicional cultivado em 2002 (TR02); cultivo convencional (CC); e uma área de Caatinga (CA). Nas amostras de solo, avaliaram-se os teores de N total, N-NH4+, N-NO3-, N microbiano, N da matéria orgânica leve (livre e oclusa) e o N das substâncias húmicas. Os resultados indicaram que todos os tratamentos condicionaram elevados teores de N-NO3-, representando entre 10,3 e 23,5 % dos teores de N total. O sistema CC reduziu os teores de N total e das frações das substâncias húmicas em 38 e 44 %, respectivamente, na camada superficial do solo. Dentre os sistemas agroflorestais, os sistemas AGP e TR98 causaram redução significativa dos teores de N total, N da matéria orgânica leve (livre e oclusa) e N das substâncias húmicas. O tratamento SILV preservou e, em alguns casos, aumentou os teores de N do solo e, portanto, constituiu um sistema que pode ser recomendado como uma alternativa sustentável de manejo do solo para o semi-árido cearense.