Helminths and HIV infection: epidemiological observations on immunological hypotheses

Parasitic helminths have co-evolved with the mammalian immune system. Current hypotheses suggest that immunological stimulation in the presence of helminths is balanced by immuno-regulation and by the broad spectrum of mechanisms possessed by helminths for countering the host immune response. The degree to which this balance is perfected, and the mechanisms by which this is achieved, vary between helminth species; we suggest that this is reflected not only in the degree of pathology induced by helminths but also in a variety of relationships with HIV infection and HIV disease. Available epidemiological data regarding interactions between helminths and HIV are largely observational; results are variable and generally inconclusive. Well designed, controlled intervention studies are required to provide definitive information on the species-specific nature of these interactions and on the advantages, disadvantages and optimal timing of de-worming in relation to HIV infection

Ecological phytochemistry of Cerrado (Brazilian savanna) plants

The Cerrado (the Brazilian savanna) is one of the vegetation formations of great biodiversity in Brazil and it has experienced strong deforestation and fragmentation. The Cerrado must contain at least 12,000 higher plant species.We discuss the ecological relevance of phytochemical studies carried out on plants from the Cerrado, including examples of phytotoxicity, antifungal, insecticidal and antibacterial activities. The results have been classified according to activity and plant family. The most active compounds have been highlighted and other activities are discussed. A large number of complex biochemical interactions occur in this system. However, only a small fraction of the species has been studied from the phytochemical viewpoint to identify the metabolites responsible for these interactions

Strongyloides stercoralis : global distribution and risk factors

The soil-transmitted threadworm, Strongyloides stercoralis, is one of the most neglected among the so-called neglected tropical diseases (NTDs). We reviewed studies of the last 20 years on S. stercoralis's global prevalence in general populations and risk groups.; A literature search was performed in PubMed for articles published between January 1989 and October 2011. Articles presenting information on infection prevalence were included. A Bayesian meta-analysis was carried out to obtain country-specific prevalence estimates and to compare disease odds ratios in different risk groups taking into account the sensitivities of the diagnostic methods applied. A total of 354 studies from 78 countries were included for the prevalence calculations, 194 (62.4%) were community-based studies, 121 (34.2%) were hospital-based studies and 39 (11.0%) were studies on refugees and immigrants. World maps with country data are provided. In numerous African, Asian and South-American resource-poor countries, information on S. stercoralis is lacking. The meta-analysis showed an association between HIV-infection/alcoholism and S. stercoralis infection (OR: 2.17 BCI: 1.18-4.01; OR: 6.69; BCI: 1.47-33.8), respectively.; Our findings show high infection prevalence rates in the general population in selected countries and geographical regions. S. stercoralis infection is prominent in several risk groups. Adequate information on the prevalence is still lacking from many countries. However, current information underscore that S. stercoralis must not be neglected. Further assessments in socio-economic and ecological settings are needed and integration into global helminth control is warranted