scholarly journals Novel serologic biomarkers provide accurate estimates of recentPlasmodium falciparumexposure for individuals and communities

2015 ◽  
Vol 112 (32) ◽  
pp. E4438-E4447 ◽  
Author(s):  
Danica A. Helb ◽  
Kevin K. A. Tetteh ◽  
Philip L. Felgner ◽  
Jeff Skinner ◽  
Alan Hubbard ◽  
...  
Keyword(s):  
Malaria Control ◽  
Malaria Incidence ◽  
Low Cost ◽  
Protein Microarray ◽  
Area Under The Curve ◽  
Antibody Responses ◽  
Selection Strategy ◽  
Small Subset ◽  
Cross Sectional ◽  
Epidemiologic Surveillance

Tools to reliably measurePlasmodium falciparum(Pf) exposure in individuals and communities are needed to guide and evaluate malaria control interventions. Serologic assays can potentially produce precise exposure estimates at low cost; however, current approaches based on responses to a few characterized antigens are not designed to estimate exposure in individuals.Pf-specific antibody responses differ by antigen, suggesting that selection of antigens with defined kinetic profiles will improve estimates ofPfexposure. To identify novel serologic biomarkers of malaria exposure, we evaluated responses to 856Pfantigens by protein microarray in 186 Ugandan children, for whom detailedPfexposure data were available. Using data-adaptive statistical methods, we identified combinations of antibody responses that maximized information on an individual’s recent exposure. Responses to three novelPfantigens accurately classified whether an individual had been infected within the last 30, 90, or 365 d (cross-validated area under the curve = 0.86–0.93), whereas responses to six antigens accurately estimated an individual’s malaria incidence in the prior year. Cross-validated incidence predictions for individuals in different communities provided accurate stratification of exposure between populations and suggest that precise estimates of community exposure can be obtained from sampling a small subset of that community. In addition, serologic incidence predictions from cross-sectional samples characterized heterogeneity within a community similarly to 1 y of continuous passive surveillance. Development of simple ELISA-based assays derived from the successful selection strategy outlined here offers the potential to generate rich epidemiologic surveillance data that will be widely accessible to malaria control programs.

scholarly journals A novel model to quantify balance alterations in older adults based on the center of pressure (CoP) measurements with a cross-sectional study

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256129
Author(s):  
Ángel Gabriel Estévez-Pedraza ◽  
Lorena Parra-Rodríguez ◽  
Rigoberto Martínez-Méndez ◽  
Otniel Portillo-Rodríguez ◽  
Zoraida Ronzón-Hernández
Keyword(s):  
Older Adults ◽  
Fall Risk ◽  
Center Of Pressure ◽  
Low Cost ◽  
Area Under The Curve ◽  
Public Health Problem ◽  
Cross Sectional Study ◽  
Community Dwelling ◽  
Mean Velocity ◽  
Cross Sectional

Background The timely detection of fall risk or balance impairment in older adults is transcendental because, based on a reliable diagnosis, clinical actions can be taken to prevent accidents. This study presents a statistical model to estimate the fall risk from the center of pressure (CoP) data. Methods This study is a cross-sectional analysis from a cohort of community-dwelling older adults aged 60 and over living in Mexico City. CoP balance assessments were conducted in 414 older adults (72.2% females) with a mean age of 70.23 ± 6.68, using a modified and previously validated Wii Balance Board (MWBB) platform. From this information, 78 CoP indexes were calculated and analyzed. Multiple logistic regression models were fitted in order to estimate the relationship between balance alteration and the CoP indexes and other covariables. Results The CoP velocity index in the Antero-Posterior direction with open eyes (MVELAPOE) had the best value of area under the curve (AUC) to identify a balance alteration (0.714), and in the adjusted model, AUC was increased to 0.827. Older adults with their mean velocity higher than 14.24 mm/s had more risk of presenting a balance alteration than those below this value (OR (Odd Ratio) = 2.94, p<0.001, 95% C.I.(Confidence Interval) 1.68–5.15). Individuals with increased age and BMI were more likely to present a balance alteration (OR 1.17, p<0.001, 95% C.I. 1.12–1.23; OR 1.17, p<0.001, 95% C.I. 1.10–1.25). Contrary to what is reported in the literature, sex was not associated with presenting a balance alteration (p = 0.441, 95% C.I. 0.70–2.27). Significance The proposed model had a discriminatory capacity higher than those estimated by similar means and resources to this research and was implemented in an embedded standalone system which is low-cost, portable, and easy-to-use, ideal for non-laboratory environments. The authors recommend using this technology to support and complement the clinical tools to attend to the serious public health problem represented by falls in older adults.

scholarly journals Genetic Resistance to Malaria Is Associated With Greater Enhancement of Immunoglobulin (Ig)M Than IgG Responses to a Broad Array of Plasmodium falciparum Antigens

2015 ◽  
Vol 2 (3) ◽  
Author(s):  
Charles Arama ◽  
Jeff Skinner ◽  
Didier Doumtabe ◽  
Silvia Portugal ◽  
Tuan M. Tran ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Ethnic Groups ◽  
Protein Microarray ◽  
Genetic Resistance ◽  
Cross Sectional Study ◽  
Antibody Responses ◽  
Antigen Specificity ◽  
Cross Sectional ◽  
Host Genetics ◽  
Broad Array

Abstract Background.  People of the Fulani ethnic group are more resistant to malaria compared with genetically distinct ethnic groups, such as the Dogon people, in West Africa, and studies suggest that this resistance is mediated by enhanced antibody responses to Plasmodium falciparum antigens. However, prior studies measured antibody responses to &lt;0.1% of P falciparum proteins, so whether the Fulani mount an enhanced and broadly reactive immunoglobulin (Ig)M and IgG response to P falciparum remains unknown. In general, little is known about the extent to which host genetics influence the overall antigen specificity of IgM and IgG responses to natural infections. Methods.  In a cross-sectional study in Mali, we collected plasma from asymptomatic, age-matched Fulani (n = 24) and Dogon (n = 22) adults with or without concurrent P falciparum infection. We probed plasma against a protein microarray containing 1087 P falciparum antigens and compared IgM and IgG profiles by ethnicity. Results.  We found that the breadth and magnitude of P falciparum-specific IgM and IgG responses were significantly higher in the malaria-resistant Fulani versus the malaria-susceptible Dogon, and, unexpectedly, P falciparum-specific IgM responses more strongly distinguished the 2 ethnic groups. Conclusions.  These findings point to an underappreciated role for IgM in protection from malaria, and they suggest that host genetics may influence the antigen specificity of IgM and IgG responses to infection.

scholarly journals Research on Satellite Selection Strategy for Receiver Autonomous Integrity Monitoring Applications

2021 ◽  
Vol 13 (9) ◽  
pp. 1725
Author(s):  
Huibin Wang ◽  
Yongmei Cheng ◽  
Cheng Cheng ◽  
Song Li ◽  
Zhenwei Li
Keyword(s):  
Low Cost ◽  
Selection Strategy ◽  
Small Subset ◽  
Subset Size ◽  
Integrity Monitoring ◽  
Performance Requirement ◽  
Satellite Selection ◽  
Receiver Autonomous Integrity Monitoring ◽  
Similar Accuracy ◽  
The Impact

Satellite selection is an effective way to overcome the challenges for the processing capability and channel limitation of the receivers due to superabundant satellites in view. The satellite selection strategies have been widely investigated to construct the subset with high accuracy but deserve further studies when applied to safety-critical applications such as the receiver autonomous integrity monitoring (RAIM) technique. In this study, the impacts of subset size on the accuracy and integrity of the subset and computation load are analyzed at first to confirm the importance of the satellite selection strategy for the RAIM process. Then the integrated performance impact of a single satellite on the current subset is evaluated according to the performance requirement of the flight phase. Subsequently, a performance-requirement-driven fast satellite selection algorithm is proposed based on the impact evaluation to construct a relatively small subset that satisfies the accuracy and integrity requirements. Comparison simulations show that the proposed algorithm can keep similar accuracy and better integrity performances than the geometric algorithm and the downdate algorithm when the subset size is fixed to 12, and can achieve an average 1.0 to 2.0 satellites smaller subset in the Lateral Navigation (LNAV) and approach procedures with vertical guidance (APV-I) horizontal requirement trial. Thus, it is suitable for real-time RAIM applications and low-cost navigation devices.

scholarly journals Distinct Antibody Signatures Associated with Different Malaria Transmission Intensities in Zambia and Zimbabwe

mSphere ◽  
2019 ◽  
Vol 4 (2) ◽  
Author(s):  
Tamaki Kobayashi ◽  
Aarti Jain ◽  
Li Liang ◽  
Joshua M. Obiero ◽  
Harry Hamapumbu ◽  
...  
Keyword(s):  
Malaria Transmission ◽  
Malaria Control ◽  
Protein Microarray ◽  
Small Sample ◽  
Antibody Responses ◽  
Transmission Intensity ◽  
Community Based ◽  
Content Type ◽  
Recent Exposure ◽  
Accurate Picture

ABSTRACT Antibodies to Plasmodium falciparum are specific biomarkers that can be used to monitor parasite exposure over broader time frames than microscopy, rapid diagnostic tests, or molecular assays. Consequently, seroprevalence surveys can assist with monitoring the impact of malaria control interventions, particularly in the final stages of elimination, when parasite incidence is low. The protein array format to measure antibodies to diverse P. falciparum antigens requires only small sample volumes and is high throughput, permitting the monitoring of malaria transmission on large spatial and temporal scales. We expanded the use of a protein microarray to assess malaria transmission in settings beyond those with a low malaria incidence. Antibody responses in children and adults were profiled, using a P. falciparum protein microarray, through community-based surveys in three areas in Zambia and Zimbabwe at different stages of malaria control and elimination. These three epidemiological settings had distinct serological profiles reflective of their malaria transmission histories. While there was little correlation between transmission intensity and antibody signals (magnitude or breadth) in adults, there was a clear correlation in children younger than 5 years of age. Antibodies in adults appeared to be durable even in the absence of significant recent transmission, whereas antibodies in children provided a more accurate picture of recent levels of transmission intensity. Seroprevalence studies in children could provide a valuable marker of progress toward malaria elimination. IMPORTANCE As malaria approaches elimination in many areas of the world, monitoring the effect of control measures becomes more important but challenging. Low-level infections may go undetected by conventional tests that depend on parasitemia, particularly in immune individuals, who typically show no symptoms of malaria. In contrast, antibodies persist after parasitemia and may provide a more accurate picture of recent exposure. Only a few parasite antigens—mainly vaccine candidates—have been evaluated in seroepidemiological studies. We examined antibody responses to 500 different malaria proteins in blood samples collected through community-based surveillance from areas with low, medium, and high malaria transmission intensities. The breadth of the antibody responses in adults was broad in all three settings and was a poor correlate of recent exposure. In contrast, children represented a better sentinel population for monitoring recent malaria transmission. These data will help inform the use of multiplex serology for malaria surveillance.

scholarly journals P. Falciparum Community Prevalence and Health Seeking Behaviors in Rural Sussundenga District, Mozambique

2021 ◽  
Author(s):  
Dominique E Earland ◽  
Albino Francisco Bibe ◽  
Anísio Novela ◽  
João Ferrão ◽  
Kelly M Searle
Keyword(s):  
Health Facility ◽  
Diagnostic Test ◽  
Malaria Control ◽  
Large Scale ◽  
Malaria Incidence ◽  
Community Level ◽  
Health Seeking ◽  
Cross Sectional ◽  
Health Seeking Behaviors ◽  
International Border

Abstract Background: The large-scale effectiveness of malaria control interventions is differential at international border settings with varying policies, such as that between Mozambique and Zimbabwe. Impacts of nationally directed malaria control interventions hinge on understanding malaria transmission and prevention at the community level along international borders. Thus far, few studies have focused on central Mozambique. Our aim was to describe community level P. falciparum transmission dynamics and health seeking behaviors among residents of Sussundenga, Mozambique, a rural village bordering Zimbabwe in Manica Province with high malaria incidence reported at the Sussundenga-Sede health center (RHC). Methods: We conducted a cross-sectional community-based survey from December 2019 – February 2020. We used a random household sampling method, based on enumerated households from satellite imagery. All consenting participants completed a survey about malaria risk, prevention, and health seeking-behaviors, and received a P. falciparum malaria rapid diagnostic test (RDT). Results: We enrolled 96 households with 358 individuals. The P. falciparum prevalence was 31.6% (95% CI [26.6-36.5]). Ninety-three percent of participants reported using the Sussundenga-Sede RHC for healthcare. Sixty-six percent of participants (N=233) experienced at least one malaria symptom in the past month, with self-reported fever most frequently reported (19.3%). Of these, 176 (76.5%) sought care in a health facility and 174 (79%) received an RDT with 130 (63%) positive results. Of those with a positive RDT, 127 (97%) received Coartem®. Following treatment, 123 (97%) participants' symptoms resolved within a median of 3 days (IQR: 3-5) ranging from 2-14 days. In this high transmission setting, a high proportion of participants recognized malaria related symptoms then received a proper diagnostic test and treatment in a health facility. Conclusions: Future interventions that leverage this health seeking behavior and strengthen health systems for community interventions will improve malaria control and inform the efficacy of potential interventions at this particular international border.

scholarly journals Validation of olfactory deficit as a biomarker of Alzheimer disease

2016 ◽  
Vol 7 (1) ◽  
pp. 5-14 ◽  
Author(s):  
Matthew R. Woodward ◽  
Chaitanya V. Amrutkar ◽  
Harshit C. Shah ◽  
Ralph H.B. Benedict ◽  
Sanjanaa Rajakrishnan ◽  
...  
Keyword(s):  
Alzheimer Disease ◽  
Sensitivity And Specificity ◽  
Low Cost ◽  
Area Under The Curve ◽  
Disease Status ◽  
Cognitive Status ◽  
Class Iii ◽  
Cross Sectional ◽  
Olfactory Identification ◽  
Smell Identification

AbstractBackground:We evaluated smell identification as a biomarker for Alzheimer disease (AD) by assessing its utility in differentiating normal aging from an amnestic disorder and determining its predictive value for conversion from amnestic mild cognitive impairment (aMCI) to AD.Methods:Cross-sectional study (AD = 262, aMCI = 110, controls = 194) measuring smell identification (University of Pennsylvania Smell Identification Test [UPSIT]) and cognitive status was performed, as well as longitudinal analysis of aMCI participants (n = 96) with at least 1 year follow-up (mean 477.6 ± 223.3 days), to determine conversion by National Institute of Neurological and Communicative Disorders and Stroke–Alzheimer’s Disease and Related Disorders Association criteria.Results:Odor identification and disease status were highly correlated after correcting for age, sex, and APOE (p < 0.001). Receiver operating characteristic (ROC)/area under the curve (AUC) was similar for the 40-item UPSIT, the top 10 smells in our study, and the 10-item subset previously proposed. Smeller/nonsmeller based on the 10-item subset with a cutoff of 7 (≤7, nonsmeller; >7, smeller) had a sensitivity and specificity of 88% and 71% for identifying AD and 74% sensitivity and 71% specificity for identifying an amnestic disorder. A total of 36.4% of participants with impaired olfaction and 17.3% with intact olfaction converted to AD (p = 0.03). The ROC/AUC for prediction of conversion to AD was 0.62.Conclusions:Olfactory identification deficit is a useful screening tool for AD-related amnestic disorder, with sensitivity and specificity comparable to other established biomarkers, with benefits such as ease of administration and low cost. Olfactory identification deficit can be utilized to stratify risk of conversion from aMCI to AD and enrich clinical trials of disease-modifying therapy.Classification of evidence:This study provides Class III evidence that smell identification (10-item UPSIT subset) accurately identifies patients with amnestic disorders.

scholarly journals Rapid, large-scale species discovery in hyperdiverse taxa using 1D MinION sequencing

BMC Biology ◽  
2019 ◽  
Vol 17 (1) ◽  
Author(s):  
Amrita Srivathsan ◽  
Emily Hartop ◽  
Jayanthi Puniamoorthy ◽  
Wan Ting Lee ◽  
Sujatha Narayanan Kutty ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Large Scale ◽  
Low Cost ◽  
Small Body ◽  
Small Subset ◽  
Similar Species ◽  
Large Species ◽  
Morphological Examination ◽  
Species Discovery ◽  
Short Period

Abstract Background More than 80% of all animal species remain unknown to science. Most of these species live in the tropics and belong to animal taxa that combine small body size with high specimen abundance and large species richness. For such clades, using morphology for species discovery is slow because large numbers of specimens must be sorted based on detailed microscopic investigations. Fortunately, species discovery could be greatly accelerated if DNA sequences could be used for sorting specimens to species. Morphological verification of such “molecular operational taxonomic units” (mOTUs) could then be based on dissection of a small subset of specimens. However, this approach requires cost-effective and low-tech DNA barcoding techniques because well-equipped, well-funded molecular laboratories are not readily available in many biodiverse countries. Results We here document how MinION sequencing can be used for large-scale species discovery in a specimen- and species-rich taxon like the hyperdiverse fly family Phoridae (Diptera). We sequenced 7059 specimens collected in a single Malaise trap in Kibale National Park, Uganda, over the short period of 8 weeks. We discovered > 650 species which exceeds the number of phorid species currently described for the entire Afrotropical region. The barcodes were obtained using an improved low-cost MinION pipeline that increased the barcoding capacity sevenfold from 500 to 3500 barcodes per flowcell. This was achieved by adopting 1D sequencing, resequencing weak amplicons on a used flowcell, and improving demultiplexing. Comparison with Illumina data revealed that the MinION barcodes were very accurate (99.99% accuracy, 0.46% Ns) and thus yielded very similar species units (match ratio 0.991). Morphological examination of 100 mOTUs also confirmed good congruence with morphology (93% of mOTUs; > 99% of specimens) and revealed that 90% of the putative species belong to the neglected, megadiverse genus Megaselia. We demonstrate for one Megaselia species how the molecular data can guide the description of a new species (Megaselia sepsioides sp. nov.). Conclusions We document that one field site in Africa can be home to an estimated 1000 species of phorids and speculate that the Afrotropical diversity could exceed 200,000 species. We furthermore conclude that low-cost MinION sequencers are very suitable for reliable, rapid, and large-scale species discovery in hyperdiverse taxa. MinION sequencing could quickly reveal the extent of the unknown diversity and is especially suitable for biodiverse countries with limited access to capital-intensive sequencing facilities.

scholarly journals Prediction of the requirement of open reduction for developmental dysplasia of the hip

2017 ◽  
Vol 46 (1) ◽  
pp. 54-61 ◽  
Author(s):  
Nabil Alassaf
Keyword(s):  
Open Reduction ◽  
Area Under The Curve ◽  
Internal Validity ◽  
Developmental Dysplasia ◽  
Estimation Model ◽  
Cross Sectional ◽  
Noninvasive Treatment ◽  
Dysplasia Of The Hip ◽  
Logistic Regression Equation ◽  
Objective Tool

Objective Closed reduction (CR) is a noninvasive treatment for developmental dysplasia of the hip (DDH), and this treatment is confirmed intraoperatively. This study aimed to develop a preoperative estimation model of the probability of requiring open reduction (OR) for DDH. Methods The study design was cross-sectional by screening all patients younger than 2 years who had attempted CR between October 2012 and July 2016 by a single surgeon. Potential diagnostic determinants were sex, age, side, bilaterality, International Hip Dysplasia Institute (IHDI) grade, and acetabular index (AI). An intraoperative arthrogram was the reference standard. A logistic regression equation was built from a reduced model. Bootstrapping was performed for internal validity. Results A total of 164 hips in 104 patients who met the inclusion criteria were analysed. The prevalence of CR was 72.2%. Independent factors for OR were older age, higher IHDI grade, and lower AI. The probability of OR = 1/[1 + exp − (−2.753 + 0.112 × age (months) + 1.965 × IHDI grade III (0 or 1) + 3.515 × IHDI grade IV (0 or 1) − 0.058 × AI (degrees)]. The area under the curve was 0.79. Conclusion This equation is an objective tool that can be used to estimate the requirement for OR.

Patterns and correlates of ownership and utilization of insecticide-treated bed-nets for malaria control among women of reproductive age (15–49 years) in Malawi

2021 ◽  
pp. 1-10
Author(s):  
James Forty ◽  
Mpho Keetile
Keyword(s):  
Primary Education ◽  
Malaria Control ◽  
Multivariate Logistic Regression Analysis ◽  
Reproductive Age ◽  
Health Concern ◽  
Bed Nets ◽  
Women Of Reproductive Age ◽  
Cross Sectional ◽  
Malaria Indicator Survey ◽  
Poor Women

Abstract Malaria is a major public health concern in Malawi. This study explored the patterns and correlates of ownership and utilization of ITNs for malaria control among women of reproductive age in Malawi. Data were derived from the multi-stage cross-sectional Malaria Indicator Survey (MIS) conducted in 2017, which followed ITN distribution in 2012 and 2015. Of the 3860 sampled women aged 15–49 years, 88% (3398/3860) and 64% (2473/3860) reported that they owned and utilized ITNs, respectively. Adjusted multivariate logistic regression analysis showed that the odds of ownership of ITNs were significantly low among women with no education (AOR = 0.36, CI = 0.18–0.72), those with primary education (AOR = 0.50, CI = 0.27–0.94) and poor women (AOR = 0.70, CI = 0.51–0.97). Similarly, the odds of utilization of ITNs were significantly low among women with no education, (AOR = 0.40, CI = 0.26–0.63), primary education (AOR = 0.53, CI = 0.36–0.78) and poor women (AOR = 0.70, CI = 0.51–0.97). Furthermore, the odds of utilization of ITNs were significantly low among women living in households without a radio (AOR = 0.79, CI = 0.67–0.93) and those who have not seen or heard a malaria message in the last 6 months (AOR = 0.74, CI = 0.64–0.87). In order to prevent malaria morbidity and mortality among women of reproductive age, especially those from poor households, the Malawi government and relevant stakeholders need to continue the free distribution of ITNs to the poor and encourage social behaviours that promote the ownership and utilization of ITNs.

scholarly journals The Economic Cost of Diet and Its Association with Adherence to the Mediterranean Diet in a Cohort of Spanish Primary Schoolchildren

2021 ◽  
Vol 18 (3) ◽  
pp. 1282
Author(s):  
Rosario Pastor ◽  
Noemi Pinilla ◽  
Josep A. Tur
Keyword(s):  
Mediterranean Diet ◽  
Fast Food ◽  
Area Under The Curve ◽  
Economic Cost ◽  
Food Prices ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Old Spanish ◽  
Total Economic Cost ◽  
Data Frequency

Background: Adoption of a certain dietary pattern is determined by different factors such as taste, cost, convenience, and nutritional value of food. Objective: To assess the association between the daily cost of a diet and its overall quality in a cohort of 6–12-year-old Spanish schoolchildren. Methods: A cross-sectional survey was conducted on a cohort (n = 130; 47% female) of 6–12-year-old children schooled in primary education in the central region of Spain. Three-day 24 h records were administered, and the nutritional quality of the diet was also determined by means of Mediterranean Adequacy Index (MAI). A questionnaire on sociodemographic data, frequency of eating in fast-food restaurants, and supplement intake were also recorded. The person responsible for the child’s diet and the schooler himself completed the questionnaires, and homemade measures were used to estimate the size of the portions. Food prices were obtained from the Household Consumption Database of the Spanish Ministry of Agriculture, Fisheries and Food. The economic cost of the diet was calculated by multiplying the amount in grams of the food consumed by each child by the corresponding price in grams and adding up the total amount for each participant. The total economic cost of the diet was calculated in €/day and in €/1000 kcal/day. Results: The area under the curve (AUC) for €/day and €/1000 kcal/day represent 62.6% and 65.6%, respectively. According to AUC values, adherence to Mediterranean diet (MD) is a moderate predictor of the monetary cost of the diet. A direct relationship between the cost of the diet and the adherence to MD was observed [OR (€/1000 kcal/day) = 3.012; CI (95%): 1.291; 7.026; p = 0.011]. Conclusions: In a cohort of Spanish schoolchildren with low adherence to the MD, a higher cost of the diet standardized to 1000 kcal was associated with above-average MAI values.

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