Mechanistic Plug-And-Play Models for Understanding the Impact of Control and Climate on Seasonal Dengue Dynamics in Iquitos, Peru

Dengue virus is a mosquito-borne multi-serotype disease whose dynamics are not precisely understood despite half of the world’s human population being at risk of infection. A recent dataset of dengue case reports from an isolated Amazonian city— Iquitos, Peru—provides a unique opportunity to assess dengue dynamics in a simpli- fied setting. Ten years of clinical surveillance data reveal a specific pattern: two novel serotypes, in turn, invaded and exclusively dominated incidence over several seasonal cycles, despite limited intra-annual variation in climate conditions. Together with mechanistic mathematical models, these data can provide an improved understand- ing of the nonlinear interactions between the environmental and biological factors underlying dengue transmission as well as aid in the prediction of future epidemics. To examine the drivers of dengue in Iquitos we develop several stochastic discrete- time models and use likelihood-based plug-and-play inference techniques to explore potential factors that may explain the seasonal transmission pattern. By including climate-informed variables and accounting for known vector control measures in our model, we illustrate scenarios that can replicate the observed data and uncover the contribution of previously overlooked factors, such as the role of disease importation from human population migration. We discuss the implications of these results for understanding dengue dynamics in other endemic settings

Statistical physics of cerebral embolization leading to stroke

We discuss the physics of embolic stroke using a minimal model of emboli moving through the cerebral arteries. Our model of the blood flow network consists of a bifurcating tree, into which we introduce particles (emboli) that halt flow on reaching a node of similar size. Flow is weighted away from blocked arteries, inducing an effective interaction between emboli. We justify the form of the flow weighting using a steady flow (Poiseuille) analysis and a more complicated nonlinear analysis. We discuss free flowing and heavily congested limits and examine the transition from free flow to congestion using numerics. The correlation time is found to increase significantly at a critical value, and a finite size scaling is carried out. An order parameter for non-equilibrium critical behavior is identified as the overlap of blockages' flow shadows. Our work shows embolic stroke to be a feature of the cerebral blood flow network on the verge of a phase transition.Comment: 11 pages, 11 figures. Major rewrite including improved justification of the model and a finite size scalin

Hepatitis viruses overview

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How to interpret liver function tests

Careful interpretation of liver function tests within the clinical context can help elucidate the cause and severity of the underlying pathology. Predominantly raised alkaline phosphatase represents the cholestatic pattern of biliary pathology, whilst predominantly raised alanine aminotransferase and aspartate aminotransferase represent the hepatocellular pattern of hepatocellular pathology. The severity of liver dysfunction or biliary obstruction is reflected in the bilirubin level and the degree of liver synthetic function can also be indicated by the albumin level. Beyond the liver function tests, prothrombin time provides another marker of liver synthetic function and a low platelet count suggests portal hypertension.Key words: Liver function test, cholestatic pattern, hepatocellular pattern, liver synthetic function