Airborne pollen concentration in Nanjing, eastern China, and its relationship with meteorological factors

This paper presents the results of airborne pollen and spore trapping in Nanjing city, eastern China, using a Burkard pollen trap during two consecutive years (2013–2014). A total of 103 pollen and spore taxa were identified. Two concentration peaks are observed in the annual cycle, a spring peak dominated by arboreal pollen types (Morus, Cupressaceae, Pinus, Pterocarya, and Quercus) and a fall peak dominated by upland herbs (Compositae, Poaceae, Humulus, and Cruciferae). Wetland herbs and ferns dominate summer assemblages and winter assemblages are characterized by sporadic records of Artemisia, Chenopodiaceae, and Pinus. Strong year‐to‐year differences in measured pollen concentration are seen, probably in response to interyear differences in weather. Compared to long‐term means, 2013 was comparatively hot and dry and 2014 had a higher than average number of rain days during the flowering periods. Rising temperatures in early spring are connected with the timing of flowering and therefore pollen release, while rainfall during the flowering period appeared to remove pollen from the air, leading to lower recorded pollen concentration values. Four taxa, Cupressaceae, Quercus, Pinus, and Humulus, were considered in more detail. Each has a different pattern of variation in pollen concentration between the studied years. Cross correlation between pollen concentration and daily temperature, relative humidity, and precipitation at lags from 0 to −30 days also showed different responses for each taxon, suggesting that pollen signal responses to weather conditions have to be considered at a taxon level rather than at the assemblage level

Prevalence and trend of hepatitis C virus infection among blood donors in Chinese mainland: a systematic review and meta-analysis

<p>Abstract</p> <p>Background</p> <p>Blood transfusion is one of the most common transmission pathways of hepatitis C virus (HCV). This paper aims to provide a comprehensive and reliable tabulation of available data on the epidemiological characteristics and risk factors for HCV infection among blood donors in Chinese mainland, so as to help make prevention strategies and guide further research.</p> <p>Methods</p> <p>A systematic review was constructed based on the computerized literature database. Infection rates and 95% confidence intervals (95% CI) were calculated using the approximate normal distribution model. Odds ratios and 95% CI were calculated by fixed or random effects models. Data manipulation and statistical analyses were performed using STATA 10.0 and ArcGIS 9.3 was used for map construction.</p> <p>Results</p> <p>Two hundred and sixty-five studies met our inclusion criteria. The pooled prevalence of HCV infection among blood donors in Chinese mainland was 8.68% (95% CI: 8.01%-9.39%), and the epidemic was severer in North and Central China, especially in Henan and Hebei. While a significant lower rate was found in Yunnan. Notably, before 1998 the pooled prevalence of HCV infection was 12.87% (95%CI: 11.25%-14.56%) among blood donors, but decreased to 1.71% (95%CI: 1.43%-1.99%) after 1998. No significant difference was found in HCV infection rates between male and female blood donors, or among different blood type donors. The prevalence of HCV infection was found to increase with age. During 1994-1995, the prevalence rate reached the highest with a percentage of 15.78% (95%CI: 12.21%-19.75%), and showed a decreasing trend in the following years. A significant difference was found among groups with different blood donation types, Plasma donors had a relatively higher prevalence than whole blood donors of HCV infection (33.95% <it>vs </it>7.9%).</p> <p>Conclusions</p> <p>The prevalence of HCV infection has rapidly decreased since 1998 and kept a low level in recent years, but some provinces showed relatively higher prevalence than the general population. It is urgent to make efficient measures to prevent HCV secondary transmission and control chronic progress, and the key to reduce the HCV incidence among blood donors is to encourage true voluntary blood donors, strictly implement blood donation law, and avoid cross-infection.</p