Biology subjects

Sharp, S.

Publications and source records attributed to Sharp, S..

4 recordsLinked to original sources

bioRxiv2026

Live triatomine bug, vector of Trypanosoma cruzi (Chagas disease), found engorged in Lisbon hotel room: A first for Portugal and for Europe

Triatomine bugs are blood feeding insects that transmit the parasite Trypanosoma cruzi, causative agent of Chagas disease. The bugs are found primarily in the Americas with a few species in Asia and Africa. Here we report the first case of a live triatomine bug in Europe, found in a Lisbon hotel room. In August, 2025, the hotel room occupants discovered a triatomine bug perched on the headboard of their bed. Upon capture, bright red blood emerged from the bug; the occupants suspected that it had bitten them during the night. The bug was identified morphologically as triatomine species Hospesneotomae protracta, which was confirmed molecularly. Hospesneotomae protracta is native to the southwestern United States where it is a competent T. cruzi vector. Trypanosoma cruzi was not detected in this specimen. Although this case likely represents an accidental importation, it illustrates the ease with which disease vectors can be unknowingly transported globally. Ergo it is crucial to document and share these findings to prevent introductions of non-native arthropods of medical importance.

ecology↗

bioRxiv2019

Harmonisation of Physical Activity Variables by Indirect Validation: A Doubly Labelled Water Study

Harmonisation of data for pooled analysis relies on the principle of inferential equivalence between variables from different sources. Ideally, this is achieved using models of the direct relationship with gold standard criterion measures, but the necessary validation data are often unavailable. This study examines an alternative method of harmonisation by indirect validation. Starting methods were self-report or accelerometry, from which we derived indirect models of relationships with doubly labelled water (DLW)-measured physical activity energy expenditure (PAEE) using sets of two bridge equations via one of three intermediate measures. Coefficients and performance of indirect models were compared to corresponding direct validation models (linear regression of DLW-measured PAEE on starting methods). Indirect model beta coefficients were attenuated compared to direct model betas (10-63%), narrowing the range of PAEE values; attenuation was greater when bridge equations were weak. Directly and indirectly harmonised models had similar error variance but most indirectly derived values were biased at group-level. Correlations with DLW-measured PAEE were identical after harmonisation using continuous linear but not categorical models. Wrist acceleration harmonised to DLW-measured PAEE via combined accelerometry and heart rate sensing had lowest error variance (24.5%) and non-significant mean bias 0.9 (95%CI: -1.6; 3.4) kJ*day-1*kg-1. Associations between PAEE and BMI were similar for directly and indirectly harmonised values, but most fell outside the confidence interval of the criterion PAEE-to-BMI association. Indirect models can be used for harmonisation. Performance depends on the measurement properties of original data, variance explained by available bridge equations, and similarity of population characteristics.

epidemiology↗

bioRxiv2018

Genetic studies of accelerometer-based sleep measures in 85,670 individuals yield new insights into human sleep behaviour

Sleep is an essential human function but its regulation is poorly understood. Identifying genetic variants associated with quality, quantity and timing of sleep will provide biological insights into the regulation of sleep and potential links with disease. Using accelerometer data from 85,670 individuals in the UK Biobank, we performed a genome-wide association study of 8 accelerometer-derived sleep traits, 5 of which are not accessible through self-report alone. We identified 47 genetic associations across the sleep traits (P<5x10-8) and replicated our findings in 5,819 individuals from 3 independent studies. These included 26 novel associations for sleep quality and 10 for nocturnal sleep duration. The majority of newly identified variants were associated with a single sleep trait, except for variants previously associated with restless legs syndrome that were associated with multiple sleep traits. Of the new associated and replicated sleep duration loci, we were able to fine-map a missense variant (p.Tyr727Cys) in PDE11A, a dual-specificity 3,5-cyclic nucleotide phosphodiesterase expressed in the hippocampus, as the likely causal variant. As a group, sleep quality loci were enriched for serotonin processing genes and all sleep traits were enriched for cerebellar-expressed genes. These findings provide new biological insights into sleep characteristics.

genetics↗

bioRxiv2017

A common allele in FGF21 associated with preference for sugar consumption lowers body fat in the lower body and increases blood pressure

Fibroblast Growth Factor 21 (FGF21) is a hormone that induces weight loss in model organisms. These findings have led to trials in humans of FGF21 analogues with some showing weight loss and lipid lowering effects. Recent genetic studies have shown that a common allele in the FGF21 gene alters the balance of macronutrients consumed but there was little evidence of an effect on metabolic traits. We studied a common FGF21 allele (A:rs838133) in 451,099 people from the UK Biobank study. We replicated the association between the A allele and higher percentage carbohydrate intake. We then showed that this allele is more strongly associated with body fat distribution, with less fat in the lower body, and higher blood pressure, than it is with BMI, where there is only nominal evidence of an effect. These human phenotypes of naturally occurring variation in the FGF21 gene will inform decisions about FGF21s therapeutic potential.

genetics↗