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The role of anthropometric status on dengue is uncertain. We investigated the relations between anthropometric characteristics (height, body mass index and waist circumference (WC)) and two dengue outcomes, seropositivity and hospitalisation, in a cross-sectional study of 2038 children (aged 2–15 years) and 408 adults (aged 18–72 years) from Bucaramanga, Colombia. Anthropometric variables were standardised by age and sex in children. Seropositivity was determined through immunoglobulin G antibodies; past hospitalisation for dengue was self-reported. We modelled the prevalence of each outcome by levels of anthropometric exposures using generalised estimating equations with restricted cubic splines. In children, dengue seropositivity was 60.8%; 9.9% of seropositive children reported prior hospitalisation for dengue. WC was positively associated with seropositivity in girls (90th vs. 10th percentile adjusted prevalence ratio (APR) = 1.19; 95% confidence interval (CI) 1.03–1.36). Among adults, dengue seropositivity was 95.1%; 8.1% of seropositive adults reported past hospitalisation. Height was inversely associated with seropositivity (APR = 0.90; 95% CI 0.83–0.99) and with hospitalisation history (APR = 0.19; 95% CI 0.04–0.79). WC was inversely associated with seropositivity (APR = 0.89; 95% CI 0.81–0.98). We conclude that anthropometry correlates with a history of dengue, but could not determine causation. Prospective studies are warranted to enhance causal inference on these questions.

Background: Use of RT-qPCR pool testing in the diagnosis of SARS-CoV-2 infection has been limited due to a lack of data on its sensitivity and efficiency. Methods: We mixed single specimens of extracted RNA positive for the SARS-CoV-2 E gene by RT-qPCR with negative specimens, in pools of 4 (n=89), 8 (n=92), 16 (n=102), and 32 (n=105) specimens each. We estimated the average change in Ct for each pool size and added it to the Ct values of the first 1,350 tests in our lab, to obtain dilution-corrected Ct values. We estimated pool sensitivity as the proportion of samples with dilution-corrected Ct>40, and used it in simulations of the efficiency (tests used/true case detected) of binary split pool testing. Findings: We tested 388 pools. Average Ct changes were 2.21, 2.51, 3.27, and 3.94 cycles, for pools of 4, 8, 16, and 32 specimens, respectively. Corresponding pool tests sensitivities were 91.1%, 89.6%, 85.8% and 82.5%. Pool testing was substantially more efficient than individual testing. For prevalence of 0.5% to 2.0%, the efficiency of pools of ≥8 specimens was 30% to 280% higher, and the number of people tested was 4.4 to 13.9 times higher than those of individual testing were. Interpretation: Binary split pool testing substantially increases the number of people tested and the number of true cases detected per test. This strategy is key to curtail the transmission of SAR-CoV-2, by increasing efficiency in the identification and isolation of symptomatic and asymptomatic infected individuals. Funding: Major Office of Bucaramanga, Colombia. Declaration of Interests: None. Ethics Approval Statement: The study was approved by both the UIS’ and the University of Wisconsin-Madison’s Institutional Review Boards.

PUFA might modulate inflammatory responses involved in the development of severe dengue. We aimed to examine whether serum PUFA concentrations in patients diagnosed with dengue fever (DF) were related to the risk of progression to dengue haemorrhagic fever/dengue shock syndrome (DHF/DSS). A secondary aim was to assess correlations between fatty acids (FA) and inflammatory biomarkers in patients with DF. We conducted a prospective case–control study nested within a cohort of patients who were diagnosed with DF and followed during the acute episode. We compared the distribution of individual FA (% of total FA) at onset of fever between 109 cases who progressed to DHF/DSS and 235 DF non-progressing controls using unconditional logistic regression. We estimated correlations between baseline FA and cytokine concentrations and compared FA concentrations between the acute episode and >1 year post-convalescence in a subgroup. DHA was positively related to progression to DHF/DSS (multivariable adjusted OR (AOR) for DHA in quintile 5v. 1=5·34, 95 % CI 2·03, 14·1;Ptrend=0·007). Dihomo-γ-linolenic acid (DGLA) was inversely associated with progression (AOR for quintile 5v. 1=0·30, 95 % CI 0·13, 0·69;Ptrend=0·007). Pentadecanoic acid concentrations were inversely related to DHF/DSS. Correlations of PUFA with cytokines at baseline were low. PUFA were lower during the acute episode than in a disease-free period. In conclusion, serum DHA in patients with DF predicts higher odds of progression to DHF/DSS whereas DGLA and pentadecanoic acid predict lower odds.

Population based serological surveys are the gold-standard to quantify dengue (DENV) transmission. The purpose of this study was to estimate the age-specific seroprevalence and the force of infection of DENV in an endemic area of Colombia. Between July and October 2014, we conducted a household based cross-sectional survey among 1.037 individuals aged 2 to 40 years living in 40 randomly selected locations in urban Piedecuesta, Santander, Colombia. In addition, we also enrolled 246 indviduals living in rural “veredas”. Participants were asked to answer a questionnaire that included demographic, socioeconomic and environmental questions and to provide a 5 ml blood sample. Sera were tested using the IgG indirect ELISA (Panbio) kit to determine past DENV infection. The overall DENV seroprevalence was 70% (95% CI = 67%-71%), but was significantly higher in urban (81%, 95% CI = 78%-83%) as compared to rural (21%, 95% CI = 17%-27%) locations. Age was a major predictor of seropositivity, consistent with endemic circulation of the virus. Using catalytic models we estimated that on average, 12% (95%CI = 11%-13%) of susceptible individuals living in the city are infected by DENV each year. Beyond age, the only predictor of seropositivity in urban locations was prior history of dengue diagnosed by a physician (aPR 1.15, 95% CI = 0.98–1.35). Among participants living in rural settings, those that reported traveling outside of their vereda were more likely to be seropositive (aPR 3.60, 95%CI = 1.54–8.42) as well as those who were born outside of Santander department (aPR = 2.77, 95%CI = 1.20–6.37). These results are consistent with long term endemic circulation of DENV in Piedecuesta, with large heterogeneities between urban and rural areas located just a few kilometers apart. Design of DENV control interventions, including vaccination, will need to consider this fine scale spatial heterogeneity., Author summary Dengue is the most rapidly expanding arbovirus in the world. Counts of reported dengue cases, as usually reported by surveillance systems, are a poor metric of the underlying transmission because most of the infections are asymptomatic. Population based serological surveys, where the prevalence of antibodies to dengue virus are measured in a random sample of the population, are considered the gold-standard to quantify dengue transmission. In this study, the authors conducted a population based serological survey in urban and rural areas of Piedecuesta, Santander, Colombia. Seropositivity was significantly higher in urban as compared to rural locations. Age was a major predictor of seropositivity, consistent with long-term circulation of the virus in this setting. They estimated that, on average, 12% of susceptible individuals living in urban locations get infected by dengue each year. The only predictor of prior dengue infection in urban inhabitants was self-reported history dengue. In rural locations, traveling regularly outside of their “vereda” (neighborhood) and having been born outside of Santander department were associated with seropositivity. These results show that the Piedecuesta municipality is an endemic area of dengue transmission, with large heterogeneities between urban and rural settings. Control interventions, including vaccination should be targeted at fine spatial scales.

Introduccion. El dengue es la infeccion transmitida por mosquitos mas importante en el mundo. Existe informacion de que las alteraciones bioquimicas pueden utilizarse como herramientas predictoras de gravedad del dengue. Objetivo. Evaluar las alteraciones bioquimicas como posibles marcadores predictores de gravedad del dengue. Materiales y metodos. Se llevo a cabo un estudio de casos y controles anidado en una cohorte. Se seleccionaron al azar 125 casos con dengue grave y 120 controles con dengue no grave para evaluar los niveles sericos de lactato-deshidrogenasa (LDH), creatina cinasa (CK), proteina C reactiva(PCR) y albumina, en sueros obtenidos en las primeras horas de la enfermedad. Para evaluar el valor diagnostico de cada biomarcador, se establecieron puntos de corte con una sensibilidad del 90 % enla deteccion de casos graves. Resultados. Se observo una asociacion entre los niveles de PCR por debajo de 9,8 mg/l (OR=0,04;IC95%=0,02-0,08; p=0,000), de LDH inferiores a 400 U/L (OR=0,49; IC95%=0,24-1,02; p=0,053) y de albumina menor de 4 mg/dl (OR=3,46; IC95%=1,96-6,12; p=0,000), con la gravedad del dengue. En contraste, los niveles de la CK no mostraron asociacion con la gravedad de la enfermedad. Conclusiones. Los hallazgos de nuestro estudio sugieren una asociacion de los niveles de PCR, LDH y albumina con la gravedad del dengue. Estas pruebas bioquimicas podrian ser utilizadas como herramientas predictoras del curso clinico de la infeccion. doi: http://dx.doi.org/ 10.7705/biomedica.v33i0.732

Dengue is the most important mosquito-borne infection in the world. There is evidence supporting the use of biochemical alterations as prediction tools for severity of illness in dengue.To evaluate biochemical alterations as potential prediction markers for severity in dengue.This was a case-control study nested in a cohort. We randomly selected 125 severe dengue cases and 120 controls with non-severe dengue for measuring LDH, CK, CRP and albumin serum levels using acute phase sera. To evaluate the predictive value for each biomarker, we established cut-off points with 90% sensitivity in detecting severe cases.There was association among the CRP levels9.8 mg/L (OR=0.04; 95%CI=0.02-0.08; p=0.000),400 U/L LDH levels (OR=0.49; 95%CI=0.24-1.02; p=0.053) and4 mg/dl albumin levels (OR=3.46; 95%CI=1.96-6.12; p=0.000) with the severity of dengue. In contrast, the CK levels showed no association with the severity of the disease.Our findings suggest an association of CRP, LDH and albumin levels with the severity of dengue. These biochemical tests could be used as predictive tools in the clinical course of the infection.