A comprehensive control strategy based on interventions to reduce the rate of transmission of S. japonicum infection from cattle and humans to snails was highly effective. These interventions have been adopted as the national strategy to control schistosomiasis in China.
A point prevalence study of hepatitis E virus (HEV) in Chinese blood donors was conducted, and the prevalences of antibodies against HEV immunoglobulin G (IgG) and IgM among Chinese blood donors were 32.60% and 0.94%, respectively. HEV viremia was 0.07%.Hepatitis E virus (HEV) can cause sporadic as well as epidemic hepatitis. While HEV transmission usually occurs by eating and drinking contaminated foods and water (4), blood transfusion is another route of infection (1).During HEV infection, the first antibody to appear is immunoglobulin M (IgM) at week 4, followed by IgG at week 5 (2). The usual length of IgM positivity is between 2 and 3 months. Viremia appears during acute HEV infection at week 2 and normally lasts for 2 to 3 weeks but can last for up to 112 days (1).In China, HEV seroprevalence of the general population is about 40% and increases with age at a rate of about 1% per year (3). Acute infection, as estimated by the prevalence of IgM anti-HEV and the spontaneous rise of IgG anti-HEV levels, occurs at about 4% per year. Asymptomatic viremia has been estimated to be approximately 0.3% (5). With such figures, an appreciation of the prevalence of HEV in Chinese blood donors seems prudent from a public health perspective.
Anti-HEV IgM is a diagnostic for recent or ongoing HEV infection. However, some patients with acute hepatitis E (AHE) negative for anti-HEV IgM in acute period were often observed in clinical practice. In this study, we constructed the anti-HEV IgA indirect ELISA assay to evaluate the significance of anti-HEV IgA. The specificity of anti-HEV IgA was 99.6%. Among 245 AHE patients, 84 samples from 84 patients were positive for HEV RNA. The positive rate of anti-HEV IgA, anti-HEV IgM and anti-HEV IgG in 84 samples positive for HEV RNA was 96.3, 97.6, and 88.1%, respectively, and no sample was negative for anti-HEV IgA and anti-HEV IgM simultaneously. Among 245 AHE patients, we found nine samples collected from nine patients in acute period were negative for anti-HEV IgM but positive for anti-HEV IgA and two samples were positive for HEV RNA. Detection of anti-HEV IgA can be a useful supplement for diagnosis of acute HEV infection especially in patients negative for anti-HEV IgM.
The application of Natural Ventilation (NV) as a measure to improve comfort conditions in transition and summer periods has been a topic of research on the spotlight for years. However, there is a lack of knowledge about how the combined effect of a dense urban layout with high pollutant concentrations may affect its potential. This paper addresses this gap by running detailed thermal simulations for a typical apartment flat located in the Yuzhong district of Chongqing city (China) using a holistic approach that makes use of: i) wind pressure coefficients on building facades from urban-scale CFD simulations, ii) hourly measured values of PM2.5 concentrations and weather variables and iii) indoor environment measurements for validation purposes. Scenario analysis revealed the average amount of air change rates achievable in a year varies from 8 to 15 ACH according to the windows orientation. These figures drop down to around 2 ACH when taking into account reduced windows opening time when outdoor PM2.5 concentrations are too high. The resulting natural ventilation potential of the case study decreases from 4234 hours when outdoor pollution is neglected to 2707 and 529 hours when considering the exposure thresholds set by the Chinese government and the WHO respectively.
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