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The year 2020 brought unimaginable challenges in public health, with the confluence of the COVID-19 pandemic and wildfires across the western United States. Wildfires produce high levels of fine particulate matter (PM2.5). Recent studies reported that short-term exposure to PM2.5 is associated with increased risk of COVID-19 cases and deaths. We acquired and linked publicly available daily data on PM2.5, the number of COVID-19 cases and deaths, and other confounders for 92 western U.S. counties that were affected by the 2020 wildfires. We estimated the association between short-term exposure to PM2.5 during the wildfires and the epidemiological dynamics of COVID-19 cases and deaths. We adjusted for several time-varying confounding factors (e.g., weather, seasonality, long-term trends, mobility, and population size). We found strong evidence that wildfires amplified the effect of short-term exposure to PM2.5 on COVID-19 cases and deaths, although with substantial heterogeneity across counties.

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BackgroundRecent studies indicate that ambient temperature could be a risk factor for infectious diarrhea, but evidence for such a relation is limited in China.MethodsWe investigated the short-term association between daily temperature and physician-diagnosed infectious diarrhea during 2008–2010 in Shanghai, China. We adopted a time-series approach to analyze the data and a quasi-Poisson regression model with a natural spline-smoothing function to adjust for long-term and seasonal trends, as well as other time-varying covariates.ResultsThere was a significant association between temperature and outpatient visits for diarrhea. A 1°C increase in the 6-day moving average of temperature was associated with a 2.68% (95% CI: 1.83%, 3.52%) increase in outpatient visits for diarrhea. We did not find a significant association between rainfall and infectious diarrhea.ConclusionsHigh temperature might be a risk factor for infectious diarrhea in Shanghai. Public health programs should focus on preventing diarrhea related to high temperature among city residents.

We developed silybin (SIL) emulsomes and evaluated their physicochemical properties and the in vivo pharmacokinetics of SIL delivered by emulsomes in rats. SIL emulsomes were prepared using the thin film dispersion method. SIL emulsomes were evaluated for their entrapment efficiency, particle size, zeta potential, morphology, in vitro release, and in vivo drug delivery in rats. The entrapment efficiency was above 80 %. The average particle size and zeta potential were 364.1 ± 20 nm and -34 ± 8 mV, respectively. Morphological analysis revealed that the SIL emulsomes were spherical in shape. Compared to an SIL solution, emulsomes produced sustained release of SIL for up to 48 h after an initial burst release in vitro. The pharmacokinetics of SIL emulsomes in rats were evaluated after intravenous injection, and the results were compared with those obtained for the control SIL solution. Following SIL delivery by emulsomes, the area under the curve was 2.2-fold higher and the mean residence time was 2.5-fold higher than the corresponding values recorded using SIL solution. Hence, emulsomes might represent a promising system for improving the bioavailability of lipophilic drugs. Moreover, emulsomes produce sustained drug release, which is advantageous in the clinical setting.