Hepatitis A virus(HAV)is one of the most common infectious etiologies of acute hepatitis worldwide.The virus is known to be transmitted fecal-orally,resulting in symptoms ranging from asymptomatic infection to fulmina...Hepatitis A virus(HAV)is one of the most common infectious etiologies of acute hepatitis worldwide.The virus is known to be transmitted fecal-orally,resulting in symptoms ranging from asymptomatic infection to fulminant hepatitis.HAV can also be transmitted through oral-anal sex.Residents from regions of low endemicity for HAV infection often remain susceptible in their adulthood.Therefore,clustered HAV infections or outbreaks of acute hepatitis A among men who have sex with men and injecting drug users have been reported in countries of low endemicity for HAV infection.The duration of HAV viremia and stool shedding of HAV may be longer in human immunodeficiency virus(HIV)-positive individuals compared to HIV-negative individuals with acute hepatitis A.Current guidelines recommend HAV vaccination for individuals with increased risks of exposure to HAV(such as from injecting drug use,oral-anal sex,travel to or residence in endemic areas,frequent clotting factor or blood transfusions)or with increased risks of fulminant disease(such as those with chronic hepatitis).The seroconversion rates following the recommended standard adult dosing schedule(2doses of HAVRIX 1440 U or VAQTA 50 U administered6-12 mo apart)are lower among HIV-positive individuals compared to HIV-negative individuals.While the response rates may be augmented by adding a booster dose at week 4 sandwiched between the first dose and the 6-mo dose,the need of booster vaccination remain less clear among HIV-positive individuals who have lost anti-HAV antibodies.展开更多
The net anthropogenic nitrogen input(NANI) is an important nutrient source that causes eutrophication in water bodies. Understanding the spatio-temporal variation of NANI is important for regional environment assessme...The net anthropogenic nitrogen input(NANI) is an important nutrient source that causes eutrophication in water bodies. Understanding the spatio-temporal variation of NANI is important for regional environment assessment and management.This paper calculated NANI in the upper Yangtze River basin(YRB), upstream of the Three Gorges Dam(TGD), from1990 to 2012, and analyzed its spatio-temporal characteristics. Over the past 23 years of the study, the average annual NANI increased from 3200 kg N km^(-2) to 4931 kg N km^(-2). The major components were fertilizer N application, atmospheric N deposition,and net food and feed N import. In the northwest high mountainous region with a sparse population, the main component was atmospheric N deposition. Fertilizer N application and net food and feed N import were concentrated in the Chengdu Plain because of the high population density and large areas of farmland. This research found that NANI increased with rapid urbanization and increasing population. The Pearson correlation results illustrated that the spatial distributions of NANI and its major components were affected by land cover/use, agricultural GDP and total population. Increasing NANI has been the major cause of the degrading stream water quality over the past 20 years and is becoming a major threat to the water quality of the TGD reservoir.展开更多
文摘Hepatitis A virus(HAV)is one of the most common infectious etiologies of acute hepatitis worldwide.The virus is known to be transmitted fecal-orally,resulting in symptoms ranging from asymptomatic infection to fulminant hepatitis.HAV can also be transmitted through oral-anal sex.Residents from regions of low endemicity for HAV infection often remain susceptible in their adulthood.Therefore,clustered HAV infections or outbreaks of acute hepatitis A among men who have sex with men and injecting drug users have been reported in countries of low endemicity for HAV infection.The duration of HAV viremia and stool shedding of HAV may be longer in human immunodeficiency virus(HIV)-positive individuals compared to HIV-negative individuals with acute hepatitis A.Current guidelines recommend HAV vaccination for individuals with increased risks of exposure to HAV(such as from injecting drug use,oral-anal sex,travel to or residence in endemic areas,frequent clotting factor or blood transfusions)or with increased risks of fulminant disease(such as those with chronic hepatitis).The seroconversion rates following the recommended standard adult dosing schedule(2doses of HAVRIX 1440 U or VAQTA 50 U administered6-12 mo apart)are lower among HIV-positive individuals compared to HIV-negative individuals.While the response rates may be augmented by adding a booster dose at week 4 sandwiched between the first dose and the 6-mo dose,the need of booster vaccination remain less clear among HIV-positive individuals who have lost anti-HAV antibodies.
基金supported by the Basic Research Fund Program of the State key Laboratory of Hydroscience and Engineering (Grant Nos. 2014-KY-04 & 2013-KY-03)
文摘The net anthropogenic nitrogen input(NANI) is an important nutrient source that causes eutrophication in water bodies. Understanding the spatio-temporal variation of NANI is important for regional environment assessment and management.This paper calculated NANI in the upper Yangtze River basin(YRB), upstream of the Three Gorges Dam(TGD), from1990 to 2012, and analyzed its spatio-temporal characteristics. Over the past 23 years of the study, the average annual NANI increased from 3200 kg N km^(-2) to 4931 kg N km^(-2). The major components were fertilizer N application, atmospheric N deposition,and net food and feed N import. In the northwest high mountainous region with a sparse population, the main component was atmospheric N deposition. Fertilizer N application and net food and feed N import were concentrated in the Chengdu Plain because of the high population density and large areas of farmland. This research found that NANI increased with rapid urbanization and increasing population. The Pearson correlation results illustrated that the spatial distributions of NANI and its major components were affected by land cover/use, agricultural GDP and total population. Increasing NANI has been the major cause of the degrading stream water quality over the past 20 years and is becoming a major threat to the water quality of the TGD reservoir.
