Evaluation of antibody response to Plasmodium falciparum in children according to exposure of Anopheles gambiae s.l or Anopheles funestus vectors

<p>Abstract</p> <p>Background</p> <p>In sub-Saharan areas, malaria transmission was mainly ensured by <it>Anopheles. gambiae </it>s.l. and <it>Anopheles. funestus </it>vectors. The immune response status to <it>Plasmodium falciparum </it>was evaluated in children living in two villages where malaria transmission was ensured by dissimilar species of <it>Anopheles </it>vectors (<it>An. funestus vs An. gambiae </it>s.l.).</p> <p>Methods</p> <p>A multi-disciplinary study was performed in villages located in Northern Senegal. Two villages were selected: Mboula village where transmission is strictly ensured by <it>An. gambiae </it>s.l. and Gankette Balla village which is exposed to several <it>Anopheles </it>species but where <it>An. funestus </it>is the only infected vector found. In each village, a cohort of 150 children aged from one to nine years was followed during one year and IgG response directed to schizont extract was determined by ELISA.</p> <p>Results</p> <p>Similar results of specific IgG responses according to age and <it>P. falciparum </it>infection were observed in both villages. Specific IgG response increased progressively from one-year to 5-year old children and then stayed high in children from five to nine years old. The children with <it>P. falciparum </it>infection had higher specific antibody responses compared to negative infection children, suggesting a strong relationship between production of specific antibodies and malaria transmission, rather than protective immunity. In contrast, higher variation of antibody levels according to malaria transmission periods were found in Mboula compared to Gankette Balla. In Mboula, the peak of malaria transmission was followed by a considerable increase in antibody levels, whereas low and constant anti-malaria IgG response was observed throughout the year in Gankette Balla.</p> <p>Conclusion</p> <p>This study shows that the development of anti-malaria antibody response was profoundly different according to areas where malaria exposure is dependent with different <it>Anopheles </it>species. These results are discussed according to i) the use of immunological tool for the evaluation of malaria transmission and ii) the influence of <it>Anopheles </it>vectors species on the regulation of antibody responses to <it>P. falciparum</it>.</p

Financing equitable access to antiretroviral treatment in South Africa

<p>Abstract</p> <p>Background</p> <p>While South Africa spends approximately 7.4% of GDP on healthcare, only 43% of these funds are spent in the public system, which is tasked with the provision of care to the majority of the population including a large proportion of those in need of antiretroviral treatment (ART). South Africa is currently debating the introduction of a National Health Insurance (NHI) system. Because such a universal health system could mean increased public healthcare funding and improved access to human resources, it could improve the sustainability of ART provision. This paper considers the minimum resources that would be required to achieve the proposed universal health system and contrasts these with the costs of scaled up access to ART between 2010 and 2020.</p> <p>Methods</p> <p>The costs of ART and universal coverage (UC) are assessed through multiplying unit costs, utilization and estimates of the population in need during each year of the planning cycle. Costs are from the provider’s perspective reflected in real 2007 prices.</p> <p>Results</p> <p>The annual costs of providing ART increase from US$1 billion in 2010 to US$3.6 billion in 2020. If increases in funding to public healthcare only keep pace with projected real GDP growth, then close to 30% of these resources would be required for ART by 2020. However, an increase in the public healthcare resource envelope from 3.2% to 5%-6% of GDP would be sufficient to finance both ART and other services under a universal system (if based on a largely public sector model) and the annual costs of ART would not exceed 15% of the universal health system budget.</p> <p>Conclusions</p> <p>Responding to the HIV-epidemic is one of the many challenges currently facing South Africa. Whether this response becomes a “resource for democracy” or whether it undermines social cohesiveness within poor communities and between rich and poor communities will be partially determined by the steps that are taken during the next ten years. While the introduction of a universal system will be complex, it could generate a health system responsive to the needs of all South Africans.</p

Malaria in Africa: Vector Species' Niche Models and Relative Risk Maps

A central theoretical goal of epidemiology is the construction of spatial models of disease prevalence and risk, including maps for the potential spread of infectious disease. We provide three continent-wide maps representing the relative risk of malaria in Africa based on ecological niche models of vector species and risk analysis at a spatial resolution of 1 arc-minute (9 185 275 cells of approximately 4 sq km). Using a maximum entropy method we construct niche models for 10 malaria vector species based on species occurrence records since 1980, 19 climatic variables, altitude, and land cover data (in 14 classes). For seven vectors (Anopheles coustani, A. funestus, A. melas, A. merus, A. moucheti, A. nili, and A. paludis) these are the first published niche models. We predict that Central Africa has poor habitat for both A. arabiensis and A. gambiae, and that A. quadriannulatus and A. arabiensis have restricted habitats in Southern Africa as claimed by field experts in criticism of previous models. The results of the niche models are incorporated into three relative risk models which assume different ecological interactions between vector species. The “additive” model assumes no interaction; the “minimax” model assumes maximum relative risk due to any vector in a cell; and the “competitive exclusion” model assumes the relative risk that arises from the most suitable vector for a cell. All models include variable anthrophilicity of vectors and spatial variation in human population density. Relative risk maps are produced from these models. All models predict that human population density is the critical factor determining malaria risk. Our method of constructing relative risk maps is equally general. We discuss the limits of the relative risk maps reported here, and the additional data that are required for their improvement. The protocol developed here can be used for any other vector-borne disease

Rangelands in Zimbabwe’s initial resettlement schemes: Spatial and temporal change analyses

Change in size and extent of cultivation and vegetation cover was analysed in three villages of an initial resettlement scheme in Zimbabwe using change detection depicted on serial aerial photographs taken at eight-year intervals from inception in 1981 to 1997. A geographic information system was used as an analytical tool. Interpretations were done using aerial photographs and 1995 Spot Images. The spot images were geo-referenced to Universal Transverse Mercator (UTM) coordinate system to ensure continuity of features. All images were enhanced using TNTmips to come up with clearer images. Aerial photographs for the three selected villages were scanned and geo-referenced and then exported to ARC VIEW 3.2 for on-screen digitising of land parcels as cultivated and vegetation theme layers. Overlay and spatial analysis were also done in ARC VIEW 3.2 for change detection. Results showed an average increase in size of cultivated areas by 281% between 1981 and 1997 and a increase of 52% between 1989 and 1997 in the three villages. Rangelands declined by a mean 42% during 1981 and 1997. There was a shift in land-use in 1987/8, which exaggerated cultivated areas due to fuzzy classification of land reverting to grazing areas by 1989. This shift in cultivation sites was adequately captured on overlaid aerial photographs for each of the three villages. It was concluded that spatial and temporal changes occurred in resettlement schemes rangelands and were due to the actions of resettled farmers. Keywords: Resettlement schemes, change detection, spatial analysis

Minimal disease activity among active psoriatic arthritis patients treated with secukinumab: 2‐year results from a multicenter, randomized, double‐blind, parallel‐group, placebo‐controlled phase III study

Objective To evaluate minimal disease activity (MDA) among psoriatic arthritis (PsA) patients receiving secukinumab through 2 years in the FUTURE 2 study. Methods Patients with active PsA were randomized to receive subcutaneous secukinumab 300, 150, or 75 mg or placebo. MDA was assessed in the overall population (anti–tumor necrosis factor [anti‐TNF]–naive and inadequate responders [anti–TNF‐IR]) and in patients stratified by prior anti‐TNF exposure and by time since diagnosis at weeks 16, 24, 52, and 104. Function and patient‐reported outcomes (PROs), including health‐related quality of life (QoL) and work productivity, were assessed in MDA responders versus nonresponders. Results Overall, 28% of patients (27 of 98) and 23% (23 of 100) achieved MDA at week 16 with secukinumab 300 and 150 mg, respectively, versus 10% (9 of 94) with placebo. In the anti–TNF‐naive cohort, a higher proportion of patients achieved MDA at week 16 with secukinumab 300 and 150 mg (34% and 32%, respectively) versus placebo (13%). The corresponding value in the anti–TNF‐IR cohort was 15% and 8% with secukinumab 300 and 150 mg, respectively, versus with placebo (3%). At week 16, 27.1% of MDA responders (16 of 59) achieved a very low disease activity (VLDA) response, with the percentage being numerically greater with secukinumab 300 and 150 mg (30% [8 of 27] and 26% [6 of 23], respectively) versus placebo (22% [2 of 9]). The MDA and VLDA responses with secukinumab 300 and 150 mg were sustained through 2 years. MDA responders showed greater improvements in QoL outcomes compared to nonresponders through 2 years. Conclusion A greater proportion of patients achieved MDA with secukinumab versus placebo at week 16, with response rates sustained through 2 years. MDA was associated with improved PROs, including QoL, through 2 years