Updated estimate of the duration of the meningo-encephalitic stage in gambiense human African trypanosomiasis

Background: The duration of the stages of HAT is an important factor in epidemiological studies and intervention planning. Previously, we published estimates of the duration of the haemo-lymphatic stage 1 and meningo-encephalitic stage 2 of the gambiense form of human African trypanosomiasis (HAT), in the absence of treatment. Here we revise the estimate of stage 2 duration, computed based on data from Uganda and South Sudan, by adjusting observed infection prevalence for incomplete case detection coverage and diagnostic inaccuracy. Findings: The revised best estimate for the mean duration of stage 2 is 252 days (95% CI 171–399), about half of our initial best estimate, giving a total mean duration of untreated gambiense HAT infection of approximately 2 years and 2 months. Conclusions: Our new estimate provides improved information on the transmission dynamics of this neglected tropical disease in Uganda and South Sudan. We stress that there remains considerable variability around the estimated mean values, and that one must be cautious in applying these results to other foci

Omitting edema measurement: how much acute malnutrition are we missing?

BACKGROUND: Acute malnutrition is a major public health issue in low-income countries. It includes both wasting and edematous malnutrition, but the terms wasting and acute malnutrition are often used interchangeably. Little is known about the burden of edematous malnutrition, and few large-scale surveys measure it. OBJECTIVE: Most acute malnutrition might be captured by the measurement of wasting alone, but this is unknown. This article aims to fill this gap. DESIGN: This article presents a secondary data analysis of 852 nutrition cross-sectional survey data sets of children aged 6-59 mo. The data sets assembled included surveys from East, West, South, and Central Africa; the Caribbean; and Asia. The overlap between edematous malnutrition and wasting was assessed, and the impact of including/excluding edema on acute malnutrition prevalence estimates was evaluated. RESULTS: The prevalence of edematous malnutrition varied from 0% to 32.9%, and children were more likely to have bilateral edema in Central and South Africa (OR: 4; 95% CI: 2.8, 5.6). A large proportion of children with edematous malnutrition were not wasted [62% and 66% based on midupper arm circumference (MUAC) and weight-for-height (WFH), respectively], and most were not severely wasted (83% and 86% based on MUAC and WFH, respectively). When wasting and global acute malnutrition prevalence estimates as well as severe wasting and severe acute malnutrition prevalence estimates overall were compared, the differences between estimates were small (median of 0.0% and mean of 0.3% based on WFH and MUAC for global estimates and slightly higher median of 0.1% and mean of 0.4% based on MUAC and WFH, respectively, for the severe forms), but the picture was different at the regional level. CONCLUSIONS: The terms acute malnutrition and wasting should not be used interchangeably. The omission of the measurement of edema can have important repercussions, especially at the nutrition program level

Anthropometric indices and measures to assess change in the nutritional status of a population: a systematic literature review

Background: Undernutrition is a major public health issue highlighted by the 2015 Sustainable Development Goals, with target 2.2 aiming to 'end hunger' by 2030. On-going surveillance is essential detecting nutritional stress in a population and is key to planning consequent interventions. Whilst methodologies of nutritional surveillance systems vary across different settings, organisations and even within the same country, the direct evidence-base underpinning these practices is limited. This paper aims therefore to: 1) compare the performance of different anthropometric indices/measurements for detecting change in the nutritional situation at population level; 2) discuss their properties and appropriateness for use in a surveillance system. Methods: This systematic literature review considered peer-reviewed and grey literature. Evidence was compiled from standard electronic databases, websites and snowballing. The search was performed in November 2015 by a single reviewer using the following terms to capture two concepts: 1) Undernutrition and 2) Nutrition surveillance. The search was limited to children under five and the period considered started in 1980. Languages included English and French. Articles had to assess whether the changes or trend observed at population level were statistically significant. All study designs were included. Results: A total of 4563 articles were retrieved from the electronic database search. Most articles (3137, 89%) were not directly relevant based on title and abstract; 39 articles were reviewed in full. A total of 17 articles met the inclusion criteria and an additional 4 papers were added after snowballing. A number of measures and indices such as weight, weight-for-height/length, triceps skinfold and middle-upper arm circumference performed well in the detection of short term changes in the nutritional situation of a population. Height/Length-for-age responded the most to long term change. Applying a standard set of criteria (simplicity, acceptability, cost, independence of age, reliability and accuracy) to determine which is the most appropriate measure or index identified middle-upper arm circumference as the one with the greatest net benefits. Conclusions: Limited available evidence suggests that mid-upper arm circumference is the best measure to detect short term changes in the nutritional state of a population: this should receive higher priority in surveillance systems

Is Middle-Upper Arm Circumference "normally" distributed? Secondary data analysis of 852 nutrition surveys.

BACKGROUND: Wasting is a major public health issue throughout the developing world. Out of the 6.9 million estimated deaths among children under five annually, over 800,000 deaths (11.6 %) are attributed to wasting. Wasting is quantified as low Weight-For-Height (WFH) and/or low Mid-Upper Arm Circumference (MUAC) (since 2005). Many statistical procedures are based on the assumption that the data used are normally distributed. Analyses have been conducted on the distribution of WFH but there are no equivalent studies on the distribution of MUAC. METHODS: This secondary data analysis assesses the normality of the MUAC distributions of 852 nutrition cross-sectional survey datasets of children from 6 to 59 months old and examines different approaches to normalise "non-normal" distributions. RESULTS: The distribution of MUAC showed no departure from a normal distribution in 319 (37.7 %) distributions using the Shapiro-Wilk test. Out of the 533 surveys showing departure from a normal distribution, 183 (34.3 %) were skewed (D'Agostino test) and 196 (36.8 %) had a kurtosis different to the one observed in the normal distribution (Anscombe-Glynn test). Testing for normality can be sensitive to data quality, design effect and sample size. Out of the 533 surveys showing departure from a normal distribution, 294 (55.2 %) showed high digit preference, 164 (30.8 %) had a large design effect, and 204 (38.3 %) a large sample size. Spline and LOESS smoothing techniques were explored and both techniques work well. After Spline smoothing, 56.7 % of the MUAC distributions showing departure from normality were "normalised" and 59.7 % after LOESS. Box-Cox power transformation had similar results on distributions showing departure from normality with 57 % of distributions approximating "normal" after transformation. Applying Box-Cox transformation after Spline or Loess smoothing techniques increased that proportion to 82.4 and 82.7 % respectively. CONCLUSION: This suggests that statistical approaches relying on the normal distribution assumption can be successfully applied to MUAC. In light of this promising finding, further research is ongoing to evaluate the performance of a normal distribution based approach to estimating the prevalence of wasting using MUAC

The burden of tuberculosis in crisis-affected populations: a systematic review.

Crises caused by armed conflict, forced population displacement, or natural disasters result in high rates of excess morbidity and mortality from infectious diseases. Many of these crises occur in areas with a substantial tuberculosis burden. We did a systematic review to summarise what is known about the burden of tuberculosis in crisis settings. We also analysed surveillance data from camps included in UN High Commissioner for Refugees (UNHCR) surveillance, and investigated the association between conflict intensity and tuberculosis notification rates at the national level with WHO data. We identified 51 reports of tuberculosis burden in populations experiencing displacement, armed conflict, or natural disaster. Notification rates and prevalence were mostly elevated; where incidence or prevalence ratios could be compared with reference populations, these ratios were 2 or higher for 11 of 15 reports. Case-fatality ratios were mostly below 10% and, with exceptions, drug-resistance levels were comparable to those of reference populations. A pattern of excess risk was noted in UNHCR-managed camp data where the rate of smear testing seemed to be consistent with functional tuberculosis programmes. National-level data suggested that conflict was associated with decreases in the notification rate of tuberculosis. More studies with strict case definitions are needed in crisis settings, especially in the acute phase, in internally displaced populations and in urban settings. Findings suggest the need for early establishment of tuberculosis services, especially in displaced populations from high-burden areas and for continued innovation and prioritisation of tuberculosis control in crisis settings

Bone texture modifications during bone regeneration and osteocyte cell-signaling changes in response to treatment with Teriparatide

Bone texture modifications during bone regeneration and osteocyte cell-signaling changes in response to treatment with Teriparatid

Implementation and Utilisation of Community-based Mortality Surveillance: a case study from Chad

<p>Abstract</p> <p>Background</p> <p>Prospective surveillance is a recognised approach for measuring death rates in humanitarian emergencies. However, there is limited evidence on how such surveillance should optimally be implemented and on how data are actually used by agencies. This case study investigates the implementation and utilisation of mortality surveillance data by Médecins Sans Frontières (MSF) in eastern Chad. We aimed to describe and analyse the community-based mortality surveillance system, trends in mortality data and the utilisation of these data to guide MSF’s operational response.</p> <p>Methods</p> <p>The case study included 5 MSF sites including 2 refugee camps and 3 camps for internally displaced persons (IDPs). Data were obtained through key informant interviews and systematic review of MSF operational reports from 2004–2008.</p> <p>Results</p> <p>Mortality data were collected using community health workers (CHWs). Mortality generally decreased progressively. In Farchana and Breidjing refugee camps, crude death rates (CDR) decreased from 0.9 deaths per 10,000 person-days in 2004 to 0.2 in 2008 and from 0.7 to 0.1, respectively. In Gassire, Ade and Kerfi IDP camps, CDR decreased from 0.4 to 0.04, 0.3 to 0.04 and 1.0 to 0.3. Death rates among children under 5 years (U5DR) followed similar trends. CDR and U5DR crossed emergency thresholds in one site, Kerfi, where CDR rapidly rose to 2.1 and U5DR to 7.9 in July 2008 before rapidly decreasing to below emergency levels by September 2008.</p> <p>Discussion</p> <p>Mortality data were used regularly to monitor population health status and on two occasions as a tool for advocacy. Lessons learned included the need for improved population estimates and standardized reporting procedures for improved data quality and dissemination; the importance of a simple and flexible model for data collection; and greater investment in supervising CHWs.</p> <p>Conclusions</p> <p>This model of community based mortality surveillance can be adapted and used by humanitarian agencies working in complex settings. Humanitarian organisations should however endeavour to disseminate routinely collected mortality data and improve utilisation of data for operational planning and evaluation. Accurate population estimation continues to be a challenge, limiting the accuracy of mortality estimates.</p

Updated estimate of the duration of the meningo-encephalitic stage in gambiense human African trypanosomiasis.

BACKGROUND: The duration of the stages of HAT is an important factor in epidemiological studies and intervention planning. Previously, we published estimates of the duration of the haemo-lymphatic stage 1 and meningo-encephalitic stage 2 of the gambiense form of human African trypanosomiasis (HAT), in the absence of treatment. Here we revise the estimate of stage 2 duration, computed based on data from Uganda and South Sudan, by adjusting observed infection prevalence for incomplete case detection coverage and diagnostic inaccuracy. FINDINGS: The revised best estimate for the mean duration of stage 2 is 252 days (95% CI 171-399), about half of our initial best estimate, giving a total mean duration of untreated gambiense HAT infection of approximately 2 years and 2 months. CONCLUSIONS: Our new estimate provides improved information on the transmission dynamics of this neglected tropical disease in Uganda and South Sudan. We stress that there remains considerable variability around the estimated mean values, and that one must be cautious in applying these results to other foci

Estimates of the duration of the early and late stage of gambiense sleeping sickness.

BACKGROUND: The durations of untreated stage 1 (early stage, haemo-lymphatic) and stage 2 (late stage, meningo-encephalitic) human African trypanosomiasis (sleeping sickness) due to Trypanosoma brucei gambiense are poorly quantified, but key to predicting the impact of screening on transmission. Here, we outline a method to estimate these parameters. METHODS: We first model the duration of stage 1 through survival analysis of untreated serological suspects detected during Médecins Sans Frontières interventions in Uganda and Sudan. We then deduce the duration of stage 2 based on the stage 1 to stage 2 ratio observed during active case detection in villages within the same sites. RESULTS: Survival in stage 1 appears to decay exponentially (daily rate = 0.0019; mean stage 1 duration = 526 days [95%CI 357 to 833]), possibly explaining past reports of abnormally long duration. Assuming epidemiological equilibrium, we estimate a similar duration of stage 2 (500 days [95%CI 345 to 769]), for a total of nearly three years in the absence of treatment. CONCLUSION: Robust estimates of these basic epidemiological parameters are essential to formulating a quantitative understanding of sleeping sickness dynamics, and will facilitate the evaluation of different possible control strategies.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are