Pathogens that cause acute febrile illness among children and adolescents in Burkina Faso, Madagascar and Sudan

BACKGROUND: The etiology and optimal clinical management of acute febrile illness (AFI) is poorly understood. METHODS: Blood samples taken from study participants with acute fever (>/=37.5 degrees C) or a history of fever and recruited into the previous Typhoid-Fever-Surveillance-in-Africa (TSAP) study were evaluated using a polymerase chain reaction (PCR)-based TaqMan-Array Card designed to detect a panel of bacterial, viral and parasitic pathogens. Clinical metadata were also assessed. RESULTS: A total of 615 blood samples available for analysis originated from Burkina Faso (n=53), Madagascar (n=364) and Sudan (n=198) and were taken from participants ranging from 0-19 years of age. Most individuals [86.4% (531/615)] presenting at healthcare facilities were outpatient adolescents (11-19 years-old). Leading clinical diagnoses were respiratory tract infections [45.9% (282/615)], malaria [27.3% (168/615)], and gastrointestinal tract infections [10.7% (66/615)]. Through the TaqMan-Array Card, at least one pathogen was detected in 62% (33/53), 24% (86/364), and 60% (118/198) of specimens, from Burkina Faso, Madagascar and Sudan, respectively. The leading identified pathogen overall was Plasmodium spp., accounting for 47% (25/53), 2.2% (8/364) and 45% (90/198) of AFI at respective sites. In Madagascar, dengue virus was the most prevalent pathogen (10.2%). Overall, 69% (357/516) of patients with clinical diagnoses of malaria, respiratory, or gastrointestinal infections were prescribed a WHO-guideline-recommended empiric antibiotic,whereas only 45% (106/237) of patients with pathogens detected were treated with an antibiotic exerting likely activity. CONCLUSIONS: A PCR-approach for identifying multiple bacterial, viral and parasitic pathogens in whole blood unveiled a diversity of previously undetected pathogens in AFI cases and carries implications for the appropriate management of this common syndrome

Detection of pathogens of acute febrile illness using polymerase chain reaction from dried blood spots

Quantitative polymerase chain reaction (qPCR) of dried blood spots (DBS) for pathogen detection is a potentially convenient method for infectious disease diagnosis. This study tested 115 DBS samples paired with whole blood specimens of children and adolescent from Burkina Faso, Sudan, and Madagascar by qPCR for a wide range of pathogens, including protozoans, helminths, fungi, bacteria, and viruses. Plasmodium spp. was consistently detected from DBS but yielded a mean cycle threshold (Ct) 5.7 +/- 1.6 higher than that from whole blood samples. A DBS qPCR Ct cutoff of 27 yielded 94.1% sensitivity and 95.1% specificity against the whole blood qPCR cutoff of 21 that has been previously suggested for malaria diagnosis. For other pathogens investigated, DBS testing yielded a sensitivity of only 8.5% but a specificity of 98.6% compared with whole blood qPCR. In sum, direct PCR of DBS had reasonable performance for Plasmodium but requires further investigation for the other pathogens assessed in this study

Changes in microphytobenthos fluorescence over a tidal cycle: implications for sampling designs

Intertidal microphytobenthos (MPB) are important primary producers and provide food for herbivores in soft sediments and on rocky shores. Methods of measuring MPB biomass that do not depend on the time of collection relative to the time of day or tidal conditions are important in any studies that need to compare temporal or spatial variation, effects of abiotic factors or activity of grazers. Pulse amplitude modulated (PAM) fluorometry is often used to estimate biomass of MPB because it is a rapid, non-destructive method, but it is not known how measures of fluorescence are altered by changing conditions during a period of low tide. We investigated this experimentally using in situ changes in minimal fluorescence (F) on a rocky shore and on an estuarine mudflat around Sydney (Australia), during low tides. On rocky shores, the time when samples are taken during low tide had little direct influence on measures of fluorescence as long as the substratum is dry. Wetness from wave-splash, seepage from rock pools, run-off, rainfall, etc., had large consequences for any comparisons. On soft sediments, fluorescence was decreased if the sediment dried out, as happens during low-spring tides on particularly hot and dry days. Surface water affected the response of PAM and therefore measurements used to estimate MPB, emphasising the need for care to ensure that representative sampling is done during low tide

The clinical presentation of culture-positive and culture-negative, qPCR-attributable shigellosis in the Global Enteric Multicenter Study and derivation of a Shigella severity score: implications for pediatric Shigella vaccine trials

BACKGROUND: Shigella is a leading cause of childhood diarrhea and target for vaccine development. Microbiologic and clinical case definitions are needed for pediatric field vaccine efficacy trials. METHODS: We compared characteristics of moderate to severe diarrhea (MSD) cases in the Global Enteric Multicenter Study (GEMS) between children with culture positive Shigella to those with culture-negative, qPCR-attributable Shigella (defined by an ipaH gene cycle threshold <27.9). Among Shigella MSD cases, we determined risk factors for death and derived a clinical severity score. RESULTS: Compared to culture-positive Shigella MSD cases (n=745), culture-negative/qPCR-attributable Shigella cases (n=852) were more likely to be under 12 months, stunted, have a longer duration of diarrhea, and less likely to have high stool frequency or a fever. There was no difference in dehydration, hospitalization, or severe classification from a modified Vesikari score. Twenty-two (1.8%) Shigella MSD cases died within the 14-days after presentation to health facilities, and 59.1% of these deaths were in culture-negative cases. Age < 12 months, diarrhea duration prior to presentation, vomiting, stunting, wasting, and hospitalization were associated with mortality. A model-derived score assigned points for dehydration, hospital admission, and longer diarrhea duration but was not significantly better at predicting 14-day mortality than a modified Vesikari score. CONCLUSIONS: A composite severity score consistent with severe disease or dysentery may be a pragmatic clinical endpoint for severe shigellosis in vaccine trials. Reliance on culture for microbiologic confirmation may miss a substantial number of Shigella cases but is currently required to measure serotype specific immunity

The Childhood Acute Illness and Nutrition (CHAIN) network nested case-cohort study protocol: a multi-omics approach to understanding mortality among children in sub-Saharan Africa and South Asia

Introduction: Many acutely ill children in low- and middle-income settings have a high risk of mortality both during and after hospitalisation despite guideline-based care. Understanding the biological mechanisms underpinning mortality may suggest optimal pathways to target for interventions to further reduce mortality. The Childhood Acute Illness and Nutrition (CHAIN) Network ( www.chainnnetwork.org) Nested Case-Cohort Study (CNCC) aims to investigate biological mechanisms leading to inpatient and post-discharge mortality through an integrated multi-omic approach. Methods and analysis; The CNCC comprises a subset of participants from the CHAIN cohort (1278/3101 hospitalised participants, including 350 children who died and 658 survivors, and 270/1140 well community children of similar age and household location) from nine sites in six countries across sub-Saharan Africa and South Asia. Systemic proteome, metabolome, lipidome, lipopolysaccharides, haemoglobin variants, toxins, pathogens, intestinal microbiome and biomarkers of enteropathy will be determined. Computational systems biology analysis will include machine learning and multivariate predictive modelling with stacked generalization approaches accounting for the different characteristics of each biological modality. This systems approach is anticipated to yield mechanistic insights, show interactions and behaviours of the components of biological entities, and help develop interventions to reduce mortality among acutely ill children. Ethics and dissemination. The CHAIN Network cohort and CNCC was approved by institutional review boards of all partner sites. Results will be published in open access, peer reviewed scientific journals and presented to academic and policy stakeholders. Data will be made publicly available, including uploading to recognised omics databases. Trial registration NCT03208725

Causal Pathways from Enteropathogens to Environmental Enteropathy: Findings from the MAL-ED Birth Cohort Study

Background Environmental enteropathy (EE), the adverse impact of frequent and numerous enteric infections on the gut resulting in a state of persistent immune activation and altered permeability, has been proposed as a key determinant of growth failure in children in low- and middle-income populations. A theory-driven systems model to critically evaluate pathways through which enteropathogens, gut permeability, and intestinal and systemic inflammation affect child growth was conducted within the framework of the Etiology, Risk Factors and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development (MAL-ED) birth cohort study that included children from eight countries. Methods Non-diarrheal stool samples (N = 22,846) from 1253 children from multiple sites were evaluated for a panel of 40 enteropathogens and fecal concentrations of myeloperoxidase, alpha-1-antitrypsin, and neopterin. Among these same children, urinary lactulose:mannitol (L:M) (N = 6363) and plasma alpha-1-acid glycoprotein (AGP) (N = 2797) were also measured. The temporal sampling design was used to create a directed acyclic graph of proposed mechanistic pathways between enteropathogen detection in non-diarrheal stools, biomarkers of intestinal permeability and inflammation, systemic inflammation and change in length- and weight- for age in children 0–2 years of age. Findings Children in these populations had frequent enteric infections and high levels of both intestinal and systemic inflammation. Higher burdens of enteropathogens, especially those categorized as being enteroinvasive or causing mucosal disruption, were associated with elevated biomarker concentrations of gut and systemic inflammation and, via these associations, indirectly associated with both reduced linear and ponderal growth. Evidence for the association with reduced linear growth was stronger for systemic inflammation than for gut inflammation; the opposite was true of reduced ponderal growth. Although Giardia was associated with reduced growth, the association was not mediated by any of the biomarkers evaluated. Interpretation The large quantity of empirical evidence contributing to this analysis supports the conceptual model of EE. The effects of EE on growth faltering in young children were small, but multiple mechanistic pathways underlying the attribution of growth failure to asymptomatic enteric infections had statistical support in the analysis. The strongest evidence for EE was the association between enteropathogens and linear growth mediated through systemic inflammation

Global Health Education: a cross-sectional study among German medical students to identify needs, deficits and potential benefits (Part 2 of 2: Knowledge gaps and potential benefits)

<p>Abstract</p> <p>Background</p> <p>In Germany, educational deficits or potential benefits involved in global health education have not been analysed till now.</p> <p>Objective</p> <p>We assess the importance medical students place on learning about social determinants of health (SDH) and assess their knowledge of global health topics in relation to (i) mobility patterns, their education in (ii) tropical medicine or (iii) global health.</p> <p>Methods</p> <p>Cross-sectional study among medical students from all 36 medical schools in Germany using a web-based, semi-structured questionnaire. Participants were recruited via mailing-lists of students' unions, all medical students registered in 2007 were eligible to participate in the study. We captured international mobility patterns, exposure to global health learning opportunities and attitudes to learning about SDH. Both an objective and subjective knowledge assessment were performed.</p> <p>Results</p> <p>1126 online-replies were received and analysed. International health electives in developing countries correlated significantly with a higher importance placed on all provided SDH (p ≤ 0.006). Participation in tropical medicine (p < 0.03) and global health courses (p < 0.02) were significantly associated with a higher rating of 'culture, language and religion' and the 'economic system'. Global health trainings correlated with significantly higher ratings of the 'educational system' (p = 0.007) and the 'health system structure' (p = 0.007), while the item 'politics' was marginally significant (p = 0.053).</p> <p>In the knowledge assessment students achieved an average score of 3.6 (SD 1.5; Mdn 4.0), 75% achieved a score of 4.0 or less (Q₂₅= 3.0; Q₇₅= 4.0) from a maximum achievable score of 8.0. A better performance was associated with international health electives (p = 0.032), participation in tropical medicine (p = 0.038) and global health (p = 0.258) courses.</p> <p>Conclusion</p> <p>The importance medical students in our sample placed on learning about SDH strongly interacts with students' mobility, and participation in tropical medicine and global health courses. The knowledge assessment revealed deficits and outlined needs to further analyse education gaps in global health. Developing concerted educational interventions aimed at fostering students' engagement with SDH could make full use of synergy effects inherent in student mobility, tropical medicine and global health education.</p

Epidemiology and Molecular Relationships of Cryptosporidium spp. in People, Primates, and Livestock from Western Uganda

Cryptosporidium is a common gastrointestinal parasite known for its zoonotic potential. We found Cryptosporidium in 32.4% of people, 11.1% of non-human primates, and 2.2% of livestock in the region of Kibale National Park, Uganda. In people, infection rates were higher in one community than elsewhere, and fetching water from an open water source increased the probability of infection. Phylogenetic analyses identified clusters of Cryptosporidium with mixed host origins in people, primates, and livestock outside the park; however, parasites from primates inside the park were genetically divergent, suggesting a separate sylvatic transmission cycle. Infection was not associated with clinical disease in people, even in the case of co-infection with the gastrointestinal parasite Giardia duodenalis. Parasites such as Cryptosporidium may be maintained through frequent cross-species transmission in tropical settings where people, livestock, and wildlife interact frequently, but the parasite may undergo more host-specific transmission where such interactions do not occur. Persistent low-level shedding and immunity may limit the clinical effects of infection in such settings

Does parallel item content on WOMAC's Pain and Function Subscales limit its ability to detect change in functional status?

BACKGROUND: Although the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) is considered the leading outcome measure for patients with osteoarthritis of the lower extremity, recent work has challenged its factorial validity and the physical function subscale's ability to detect valid change when pain and function display different profiles of change. This study examined the etiology of the WOMAC's physical function subscale's limited ability to detect change in the presence of discordant changes for pain and function. We hypothesized that the duplication of some items on the WOMAC's pain and function subscales contributed to this shortcoming. METHODS: Two eight-item physical function scales were abstracted from the WOMAC's 17-item physical function subscale: one contained activities and themes that were duplicated on the pain subscale (SIMILAR-8); the other version avoided overlapping activities (DISSIMILAR-8). Factorial validity of the shortened measures was assessed on 310 patients awaiting hip or knee arthroplasty. The shortened measures' abilities to detect change were examined on a sample of 104 patients following primary hip or knee arthroplasty. The WOMAC and three performance measures that included activity specific pain assessments – 40 m walk test, stair test, and timed-up-and-go test – were administered preoperatively, within 16 days of hip or knee arthroplasty, and at an interval of greater than 20 days following the first post-surgical assessment. Standardized response means were used to quantify change. RESULTS: The SIMILAR-8 did not demonstrate factorial validity; however, the factorial structure of the DISSIMILAR-8 was supported. The time to complete the performance measures more than doubled between the preoperative and first postoperative assessments supporting the theory that lower extremity functional status diminished over this interval. The DISSIMILAR-8 detected this deterioration in functional status; however, no significant change was noted for the SIMILAR-8. The WOMAC pain scale demonstrated a slight reduction in pain and the performance specific pain measures did not reflect a change in pain. All measures showed substantial improvement over the second assessment interval. CONCLUSIONS: These findings support the hypothesis that activity overlap on the pain and function subscales plays a causal role in limiting the WOMAC physical function subscale's ability to detect change