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Background: Human defensin (HD) 5 and HD6, both Paneth cell alpha-defensins, contribute to the antimicrobial barrier against intestinal infection. We have previously demonstrated that levels of both HD5 and HD6 mRNA were reduced in adults living in urban Zambia, compared with those in adults living in London. The aim of the present study was to determine, during 2 years of follow-up, whether alpha-defensin expression in Zambian adults is related to susceptibility to diarrhea.Methods: We analyzed intestinal biopsy samples from a longitudinal cohort study conducted in 83 Zambian adults by quantitative reverse-transcription polymerase chain reaction, Western blotting, immunohistochemistry, and in situ hybridization, and we measured the incidence of diarrhea.Results: Levels of HD5 and HD6 mRNA in Paneth cells varied between participants, over time, and seasonally and were strongly correlated with mucosal architecture. Gene expression was almost exclusively restricted to Paneth cells. The median (interquartile range) HD5 mRNA level was 6.0 (5.6-6.7) log10 transcripts/microg of total RNA among 18 participants who experienced diarrhea within 2 months after biopsy-sample collection, compared with 6.8 (6.2-7.3) log10 transcripts/microg of total RNA among 94 participants who did not (P=.006). A similar observation was made for HD6.Conclusions: These data indicate that intestinal alpha-defensin expression is dynamic and seasonal and suggest that susceptibility to intestinal infection is related to alpha-defensin expression. [ABSTRACT FROM AUTHOR]

Abstract Background Treatment of cryptosporidiosis in HIV infected children has proved difficult and unsatisfactory with no drugs having demonstrable efficacy in controlled trials except nitazoxanide. We hypothesised that a prolonged course of treatment with high dose nitazoxanide would be effective in treating cryptosporidiosis in HIV positive Zambian children. Methods We performed a double-blind, randomised, placebo controlled trial in paediatric patients in the UTH in Lusaka. The study included HIV positive children between one and eleven years of age if 2 out of 3 stool samples were positive for oocysts of Cryptosporidium spp. Children were given nitazoxanide suspension in a dose of 200 mg twice daily (bid) for 28 days (if 1-3 years old) or 400 mg bid for 28 days (if 4-11 years old), or matching placebo. Results Sixty children were randomised and 52 were fully evaluated. Only five children were 4 years of age or over and received the higher dose. In the primary efficacy analysis, 11 out of 26 (42%) in the active treatment group achieved a 'Well' clinical response compared to 8 out of 26 (35%) in the placebo group. Parasitological response was declared as 'Eradicated' in 27% in the active group and 35% in the placebo group. Mortality (16/52, 31%) did not differ by treatment allocation. Conclusion We found no significant benefit in children with cryptosporidiosis despite high dose and longer treatment duration. This is the second randomised controlled trial to suggest that in Zambian children with HIV-related immunosuppression nitazoxanide does not eradicate this infection nor provide clinical symptom reduction. Trial Registration The trial was registered as ISRCTN41089957.

Abstract Background The HIV epidemic in sub-Saharan Africa has had a major impact on infectious disease, and there is currently great interest in the impact of HIV on intestinal barrier function. A three year longitudinal cohort study in a shanty compound in Lusaka, Zambia, carried out before anti-retroviral therapy was widely available, was used to assess the impact of HIV on susceptibility to intestinal infectious disease. We measured the incidence and seasonality of intestinal infection and diarrhoea, aggregation of disease in susceptible individuals, clustering by co-habitation and genetic relatedness, and the disease-to-infection ratio. Methods Adults living in a small section of Misisi, Lusaka, were interviewed every two weeks to ascertain the incidence of diarrhoea. Monthly stool samples were analysed for selected pathogens. HIV status and CD4 count were determined annually. Results HIV seroprevalence was 31% and the prevalence of immunosuppression (CD4 count 200 cells/μL or less) was 10%. Diarrhoea incidence was 1.1 episodes per year and the Incidence Rate Ratio for HIV infection was 2.4 (95%CI 1.7–3.3; p < 0.001). The disease-to-infection ratio was increased at all stages of HIV infection. Aggregation of diarrhoea in susceptible individuals was observed irrespective of immunosuppression, but there was little evidence of clustering by co-habitation or genetic relatedness. There was no evidence of aggregation of asymptomatic infections. Conclusion HIV has an impact on intestinal infection at all stages, with an increased disease-to-infection ratio. The aggregation of disease in susceptible individuals irrespective of CD4 count suggests that this phenomenon is not a function of cell mediated immunity.

Introduction: Zambia is facing a chronic shortage of health care workers. The paper aimed at understanding how the Medical Education Partnership Initiative (MEPI) program facilitated strengthening and expanding of the national capacity and quality of medical education as well as processes for retaining faculty in Zambia., Methods: Data generated through documentary review, key informant interviews and observations were analyzed using a thematic approach., Results: The MEPI program triggered the development of new postgraduate programs thereby increasing student enrollment. This was achieved by leveraging of existing and new partnerships with other universities and differentiating the old Master in Public Health into specialized curriculum. Furthermore, the MEPI program improved the capacity and quality of training by facilitating installation and integration of new technology such as the eGranary digital library, E-learning methods and clinical skills laboratory into the Schools. This technology enabled easy access to relevant data or information, quicker turn around of experiments and enhanced data recording, display and analysis features for experiments. The program also facilitated transforming of the academic environment into a more conducive work place through strengthening the Staff Development program and support towards research activities. These activities stimulated work motivation and interest in research by faculty. Meanwhile, these processes were inhibited by the inability to upload all courses on to Moodle as well as inadequate operating procedures and feedback mechanisms for the Moodle., Conclusion: Expansion and improvement in training processes for health care workers requires targeted investment within medical institutions and strengthening local and international partnerships.

Zambia is facing a crisis in its human resources for health, with deficits in the number and skill mix of health workers. The University of Zambia School of Medicine (UNZA SOM) was the only medical school in the country for decades, but recently it was joined by three new medical schools--two private and one public. In addition to expanding medical education, the government has also approved several allied health programs, including pharmacy, physiotherapy, biomedical sciences, and environmental health. This expansion has been constrained by insufficient numbers of faculty. Through a grant from the Medical Education Partnership Initiative (MEPI), UNZA SOM has been investing in ways to address faculty recruitment, training, and retention. The MEPI-funded strategy involves directly sponsoring a cohort of faculty at UNZA SOM during the five-year grant, as well as establishing more than a dozen new master's programs, with the goal that all sponsored faculty are locally trained and retained. Because the issue of limited basic science faculty plagues medical schools throughout Sub-Saharan Africa, this strategy of using seed funding to build sustainable local capacity to recruit, train, and retain faculty could be a model for the region.

Background: Intestinal helminthiasis modulates immune responses to vaccines and environmental allergens. To explore the impact on intestinal host defense, we assessed expression of antimicrobial peptide genes, together with T cell subset markers and cytokines, in patients with ascariasis before and after treatment., Methods: Case patients (n = 27) and control subjects (n = 44) underwent enteroscopy for collection of jejunal biopsy specimens, which were used in quantitative, real-time reverse-transcription polymerase chain reaction for a range of host defense genes; blood samples were also analyzed simultaneously., Results: The level of gene expression (mRNA) of HD5, hBD1, and LL-37 was lower in case patients than in control subjects, and the level of expression of HD6 was increased. However, after successful eradication, there was no trend to values seen in control subjects. Helminthiasis was associated with increased intestinal expression of the Th1 genes T-bet and interferon-γ. In peripheral blood mononuclear cells (PBMCs), a mixed profile of T cell markers and cytokines was increased. Ascaris-induced down-regulation of HD5 was observed in individuals with higher RORγt expression in PBMCs, but we found no evidence that this was mediated by circulating interleukin-22., Conclusions: Human ascariasis was associated with changes in antimicrobial peptide gene expression and immunological markers. Such changes may have implications for susceptibility to infectious disease and responsiveness to oral vaccines in tropical populations.

Background: Treatment of cryptosporidiosis in HIV infected children has proved difficult and unsatisfactory with no drugs having demonstrable efficacy in controlled trials except nitazoxanide. We hypothesised that a prolonged course of treatment with high dose nitazoxanide would be effective in treating cryptosporidiosis in HIV positive Zambian children., Methods: We performed a double-blind, randomised, placebo controlled trial in paediatric patients in the UTH in Lusaka. The study included HIV positive children between one and eleven years of age if 2 out of 3 stool samples were positive for oocysts of Cryptosporidium spp. Children were given nitazoxanide suspension in a dose of 200 mg twice daily (bid) for 28 days (if 1-3 years old) or 400 mg bid for 28 days (if 4-11 years old), or matching placebo., Results: Sixty children were randomised and 52 were fully evaluated. Only five children were 4 years of age or over and received the higher dose. In the primary efficacy analysis, 11 out of 26 (42%) in the active treatment group achieved a 'Well' clinical response compared to 8 out of 26 (35%) in the placebo group. Parasitological response was declared as 'Eradicated' in 27% in the active group and 35% in the placebo group. Mortality (16/52, 31%) did not differ by treatment allocation., Conclusion: We found no significant benefit in children with cryptosporidiosis despite high dose and longer treatment duration. This is the second randomised controlled trial to suggest that in Zambian children with HIV-related immunosuppression nitazoxanide does not eradicate this infection nor provide clinical symptom reduction., Trial Registration: The trial was registered as ISRCTN41089957.

Background: The HIV epidemic in sub-Saharan Africa has had a major impact on infectious disease, and there is currently great interest in the impact of HIV on intestinal barrier function. A three year longitudinal cohort study in a shanty compound in Lusaka, Zambia, carried out before anti-retroviral therapy was widely available, was used to assess the impact of HIV on susceptibility to intestinal infectious disease. We measured the incidence and seasonality of intestinal infection and diarrhoea, aggregation of disease in susceptible individuals, clustering by co-habitation and genetic relatedness, and the disease-to-infection ratio., Methods: Adults living in a small section of Misisi, Lusaka, were interviewed every two weeks to ascertain the incidence of diarrhoea. Monthly stool samples were analysed for selected pathogens. HIV status and CD4 count were determined annually., Results: HIV seroprevalence was 31% and the prevalence of immunosuppression (CD4 count 200 cells/microL or less) was 10%. Diarrhoea incidence was 1.1 episodes per year and the Incidence Rate Ratio for HIV infection was 2.4 (95%CI 1.7-3.3; p < 0.001). The disease-to-infection ratio was increased at all stages of HIV infection. Aggregation of diarrhoea in susceptible individuals was observed irrespective of immunosuppression, but there was little evidence of clustering by co-habitation or genetic relatedness. There was no evidence of aggregation of asymptomatic infections., Conclusion: HIV has an impact on intestinal infection at all stages, with an increased disease-to-infection ratio. The aggregation of disease in susceptible individuals irrespective of CD4 count suggests that this phenomenon is not a function of cell mediated immunity.

Background: Diarrheal disease remains a major contributor to morbidity and mortality in Africa, but host defense against intestinal infection is poorly understood and may depend on nutritional status., Objective: To test the hypothesis that defense against intestinal infection depends on micronutrient status, we undertook a randomized controlled trial of multiple micronutrient supplementation in a population where there is borderline micronutrient deficiency., Design: All consenting adults (> or =18 y) living in a carefully defined sector of Misisi, Lusaka, Zambia, were included in a cluster-randomized (by household), double-blind, placebo-controlled trial with a midpoint crossover. There were no exclusion criteria. Participants were given a daily tablet containing 15 micronutrients at just above the recommended nutrient intake or placebo. The primary endpoint was the incidence of diarrhea; secondary endpoints were severe episodes of diarrhea, respiratory infection, nutritional status, CD4 count, and mortality., Results: Five hundred participants were recruited and followed up for 3.3 y (10,846 person-months). The primary endpoint, incidence of diarrhea (1.4 episodes/y per person), did not differ with treatment allocation. However, severe episodes of diarrhea were reduced in the supplementation group (odds ratio: 0.50; 95% CI: 0.26, 0.92; P = 0.017). Mortality was reduced in HIV-positive participants from 12 with placebo to 4 with supplementation (P = 0.029 by log-rank test), but this was not due to changes in CD4 count or nutritional status., Conclusion: Micronutrient supplementation with this formulation resulted in only modest reductions in severe diarrhea and reduced mortality in HIV-positive participants. The trial was registered as ISRCTN31173864.

To determine the response of the small intestinal mucosa to environmental conditions, we studied changes in mucosal architecture and function in a longitudinal cohort study in African adults. Over three consecutive years, 238 adults submitted monthly stool samples for parasitologic and bacteriologic analysis and underwent an annual endoscopic jejunal biopsy for mucosal morphometry. Absorption and permeability assays were performed on the same day as the enteroscopy. Variation in mucosal architecture and function was correlated with environmental factors and stool microbiology. The whole cohort had structural and functional evidence of tropical enteropathy, but structure and function were only weakly correlated. There were marked changes over time, and seasonal variation was observed in villous height (16%), xylose recovery (16%), and permeability (28%). Asymptomatic intestinal infections were common. Enteropathy was more severe in participants with Citrobacter rodentium or hookworm ova in the stool sample taken one month before the investigations were performed.