Ward Round - Recurrent anemia and infection in an HIVpositive woman

A 22 year old woman presented to Queen Elizabeth Central Hospital with a three days history of fever, headache and vomiting, with progressive difficulty in swallowin

Early Interferon-γ Production in Human Lymphocyte Subsets in Response to Nontyphoidal Salmonella Demonstrates Inherent Capacity in Innate Cells

Background Nontyphoidal Salmonellae frequently cause life-threatening bacteremia in sub-Saharan Africa. Young children and HIV-infected adults are particularly susceptible. High case-fatality rates and increasing antibiotic resistance require new approaches to the management of this disease. Impaired cellular immunity caused by defects in the T helper 1 pathway lead to intracellular disease with Salmonella that can be countered by IFNγ administration. This report identifies the lymphocyte subsets that produce IFNγ early in Salmonella infection. Methodology Intracellular cytokine staining was used to identify IFNγ production in blood lymphocyte subsets of ten healthy adults with antibodies to Salmonella (as evidence of immunity to Salmonella), in response to stimulation with live and heat-killed preparations of the D23580 invasive African isolate of Salmonella Typhimurium. The absolute number of IFNγ-producing cells in innate, innate-like and adaptive lymphocyte subpopulations was determined. Principal Findings Early IFNγ production was found in the innate/innate-like lymphocyte subsets: γδ-T cells, NK cells and NK-like T cells. Significantly higher percentages of such cells produced IFNγ compared to adaptive αβ-T cells (Student's t test, P<0.001 and ≤0.02 for each innate subset compared, respectively, with CD4+- and CD8+-T cells). The absolute numbers of IFNγ-producing cells showed similar differences. The proportion of IFNγ-producing γδ-T cells, but not other lymphocytes, was significantly higher when stimulated with live compared with heat-killed bacteria (P<0.0001). Conclusion/Significance Our findings indicate an inherent capacity of innate/innate-like lymphocyte subsets to produce IFNγ early in the response to Salmonella infection. This may serve to control intracellular infection and reduce the threat of extracellular spread of disease with bacteremia which becomes life-threatening in the absence of protective antibody. These innate cells may also help mitigate against the effect on IFNγ production of depletion of Salmonella-specific CD4+-T lymphocytes in HIV infection

Peasant farmer–raptor conflicts around Chembe Bird Sanctuary, Zambia, Central Africa: poultry predation, ethno–biology, land use practices and conservation

Los conflictos entre campesinos y rapaces alrededor del refugio de Chembe Bird, en Zambia, África central: depredación de aves de corral, etnobiología, prácticas de uso de la tierra y conservación Las rapaces prestan servicios ecosistémicos a las comunidades rurales de África: (1) depredando roedores, (2) regulando las poblaciones de serpientes dañinas, (3) configurando las creencias culturales y (4) formando parte de las atracciones turísticas. Sin embargo, los campesinos las relacionan con la disminución de las aves de corral, las profecías telepáticas y la brujería tradicional. En consecuencia, las rapaces son perseguidas por los humanos. Mediante una técnica de análisis cualitativo de contenido, analizamos la interacción entre los campesinos y las rapaces en zonas adyacentes al refugio de Chembe Bird. Nuestros resultados revelan las prácticas, actitudes y percepciones negativas que podrían poner en peligro de extinción a cinco rapaces en la zona de estudio. A fin de mejorar la coexistencia entre agricultores y rapaces, proponemos utilizar medidas transformadoras de carácter conceptual (por ejemplo, sensibilizar a las partes interesadas, garantizar el cumplimiento riguroso de la legislación relativa a las rapaces y proteger su hábitat, así como reforzar el capital social relacional) y medidas prácticas (como proporcionar cercados apropiados y aves de corral de fenotipos de alta resistencia).Los conflictos entre campesinos y rapaces alrededor del refugio de Chembe Bird, en Zambia, África central: depredación de aves de corral, etnobiología, prácticas de uso de la tierra y conservación Las rapaces prestan servicios ecosistémicos a las comunidades rurales de África: (1) depredando roedores, (2) regulando las poblaciones de serpientes dañinas, (3) configurando las creencias culturales y (4) formando parte de las atracciones turísticas. Sin embargo, los campesinos las relacionan con la disminución de las aves de corral, las profecías telepáticas y la brujería tradicional. En consecuencia, las rapaces son perseguidas por los humanos. Mediante una técnica de análisis cualitativo de contenido, analizamos la interacción entre los campesinos y las rapaces en zonas adyacentes al refugio de Chembe Bird. Nuestros resultados revelan las prácticas, actitudes y percepciones negativas que podrían poner en peligro de extinción a cinco rapaces en la zona de estudio. A fin de mejorar la coexistencia entre agricultores y rapaces, proponemos utilizar medidas transformadoras de carácter conceptual (por ejemplo, sensibilizar a las partes interesadas, garantizar el cumplimiento riguroso de la legislación relativa a las rapaces y proteger su hábitat, así como reforzar el capital social relacional) y medidas prácticas (como proporcionar cercados apropiados y aves de corral de fenotipos de alta resistencia).Raptors provide ecosystem services to African rural communities by: (1) preying on rodents, (2) regulating harmful snake populations, (3) shaping cultural beliefs, and (4) being part of tourist attractions. Peasant farmers, however, connect them with poultry depletion, telepathic omens, and traditional witchcraft. Consequently, raptors suffer human–induced persecution. Using a qualitative content analysis technique, we investigated the interaction between farmers and raptors in areas adjoining the Chembe Bird Sanctuary. Our results unravel negative perceptions, attitudes and practices that could threaten the extinction of five raptors in the study area. We propose the use of transformative cognitive measures (e.g., raising stakeholder awareness, ensuring stringent law enforcement for raptors and protecting their habitat, and strengthening relational social capital) and physical measures (e.g., providing appropriate fencing and poultry breeding of high resilient phenotypes) to improve the co–existence between farmers and raptors

Operational research (ers) in development: Growing a new generation of operational researchers

This paper explores the theme of training operational research (OR) practitioners in South Africa by critically evaluating a Masters program in Operational Research in Development (ORD), launched in 2005 at the University of Cape Town. This program was specifically focused on applying OR to the problems of the developing world in general and Africa in particular. We describe the program and review the practical work undertaken by students participating in the program. Topics range widely across domains including health (anti-malarial drug resistance); poverty (food banking); governance (NGO management structures and monitoring of local government performance) and sustainable livelihoods (spaza shop operations). We use the review to highlight strengths and weaknesses of the program, as well as challenges faced in the OR education in South Africa at a postgraduate level

Does exposure to aflatoxin constrain efforts to reduce stunting in Zambia?

On 8 June 2013, the Vice President of Zambia stated that his government ‘is fully committed to reducing chronic undernutrition by 50 per cent in the next ten years…’ What are the challenges to meeting this goal? Zambia has both a high consumption of groundnuts and high levels of aflatoxin contamination of this commodity. Recent studies indicate an association between stunting and aflatoxin exposure. If the association exists, then Zambia faces serious challenges to reaching its target of 50 per cent reduction in chronic undernutrition. Recent efforts to identify atoxigenic strains for biocontrol in maize and groundnuts give cause for cautious optimism. Nonetheless, the challenges ahead demand both a high level of political will to achieve effective multisectoral collaboration and the willingness of the agricultural and health sectors to undertake rigorous monitoring of aflatoxin contamination and growth of young children, as well as the agricultural sector’s commitment to reduce substantially levels of aflatoxin contamination and to promote agricultural diversification

Self-consistent simulation of high-brightness diode lasers with external optical feedback

This paper presents a model for simulating the impact of external optical feedback on large-optical cavity high-brightness diode lasers. The simulations are performed with our 2.5D simulation tool for high-brightness laser diodes. The external cavity is modelled using commercial coherent ray tracing software. We consider the impact of the optical feedback on the excitation of amplified spontaneous emission in the parasitic vertical modes

Design and protocol for a cluster randomised trial of enhanced diagnostics for tuberculosis screening among people living with HIV in hospital in Malawi (CASTLE study)

BACKGROUND: People living with HIV (PLHIV) have a high risk of death if hospitalised in low-income countries. Tuberculosis has long been the leading cause of admission and death, in part due to suboptimal diagnostics. Two promising new diagnostic tools are digital chest Xray with computer-aided diagnosis (DCXR-CAD) and urine testing with Fujifilm SILVAMP LAM (FujiLAM). Neither test has been rigorously evaluated among inpatients. Test characteristics may be complementary, with FujiLAM especially sensitive for disseminated tuberculosis and DCXR-CAD especially sensitive for pulmonary tuberculosis, making combined interventions of interest. DESIGN AND METHODS: An exploratory unblinded, single site, two-arm cluster randomised controlled trial, with day of admission as the unit of randomisation. A third, smaller, integrated cohort arm (4:4:1 random allocation) contributes to understanding case-mix, but not trial outcomes. Participants are adults living with HIV not currently on TB treatment. The intervention (DCXR-CAD plus urine FujiLAM plus usual care) is compared to usual care alone. The primary outcome is proportion of participants started on tuberculosis treatment by day 56, with secondary outcomes of mortality (time to event) measured to to 56 days from enrolment, proportions with undiagnosed tuberculosis at death or hospital discharge and comparing proportions with enrolment-day tuberculosis treatment initiation. DISCUSSION: Both DCXR-CAD and FujiLAM have potential clinical utility and may have complementary diagnostic performance. To our knowledge, this is the first randomised trial to evaluate these tests among hospitalised PLHIV

Design and simulation of high-speed nanophotonic electro-optic modulators

In this work, an ultracompact electro-optic modulator based on refractive index modulation by plasma dispersion effect in PhC all-optical gate (AOG) is proposed. The index modulation is achieved by applying a time-varying bias voltage across the electrical contacts of the AOG. The proposed modulator has potential for high-speed operation, with bandwidths in excess of 30GHz achievable

Case Report-Right iliac fossa mass in an HIV-positive woman

No Abstrac

Loss of Humoral and Cellular Immunity to Invasive Nontyphoidal Salmonella During Current or Convalescent Plasmodium falciparum Infection in Malawian Children.

Invasive nontyphoidal Salmonella (iNTS) infections are commonly associated with Plasmodium falciparum infections, but the immunologic basis for this linkage is poorly understood. We hypothesized that P. falciparum infection compromises the hosts' humoral and cellular immunity to NTS which increases their susceptibility to iNTS infection. We prospectively recruited children aged between 6 and 60 months at a Community Health Centre in Blantyre, Malawi and allocated them to the following groups; febrile with uncomplicated malaria, febrile malaria-negative, non-febrile malaria-negative. S Typhimurium (STm)-specific; serum bactericidal activity (SBA) and blood bactericidal activity (WBBA), complement C3 deposition and neutrophil respiratory burst activity (NRBA) were measured. SBA to STm was reduced in febrile P. falciparum infected (Median -0.201og10, IQR [-1.85, 0.32]) compared to non-febrile malaria-negative (Median -1.42log10, IQR [-2.0, -0.47], p=0.052). In relation to SBA, C3 deposition on STm was significantly reduced in febrile P. falciparum infected (Median 7.5%, IQR [4.1, 15.0]) compared to non-febrile malaria-negative (Median 29%, IQR [11.8, 48.0], p=0.048). WBBA to STm was significantly reduced in febrile P. falciparum infected (Median 0.25log10, IQR [-0.73, 1.13], p=0.0001) compared to non-febrile malaria-negative (Median -1.0log10, IQR [-1.68, -0.16]). In relation to WBBA, STm-specific NRBA was reduced in febrile P. falciparum infected (Median 8.8% IQR [3.7, 20], p=0.0001) compared to non-febrile malaria-negative (Median 40.5% IQR [33, 65.8]). P. falciparum infection impairs humoral and cellular immunity to STm in children during malaria episodes, which may explain the increased risk of iNTS observed in children from malaria endemic settings. The mechanisms underlying humoral immunity impairment are incompletely understood and should be explored further