The dengue virus （DENV） is a vital global public health issue. The 2014 dengue epidemic in Guangzhou, China, caused approximately 40,000 cases of infection and five deaths. We carried out a comprehensive investigati...The dengue virus （DENV） is a vital global public health issue. The 2014 dengue epidemic in Guangzhou, China, caused approximately 40,000 cases of infection and five deaths. We carried out a comprehensive investigation aimed at identifying the transmission sources in this dengue epidemic. To analyze the phylogenetics of the 2014 dengue strains, the envelope （E） gene sequences from 17 viral strains isolated from 168 dengue patient serum samples were sequenced and a phylogenetic tree was reconstructed. All 17 strains were serotype I strains, including 8 genotype I and 9 genotype V strains. Additionally, 6 genotype I strains that were probably introduced to China from Thailand before 2009 were widely transmitted in the 2013 and 2014 epidemics, and they continued to circulate until 2015, with one affinis strain being found in Singapore. The other 2 genotype I strains were introduced from the Malaya Peninsula in 2014. The transmission source of the 9 genotype V strains was from Malaysia in 2014. DENVs of different serotypes and genotypes co-circulated in the 2014 dengue outbreak in Guangzhou. Moreover, not only had DENV been imported to Guangzhou, but it had also been gradually exported, as the viruses exhibited an enzootic transmission cycle in Guangzhou.展开更多
The combination of preozonation and subsequent biological granular activated carbon （O3/BAC） filtration is well known as a promising method for the removal of many pollutants. Temperature and nutrients are the domin...The combination of preozonation and subsequent biological granular activated carbon （O3/BAC） filtration is well known as a promising method for the removal of many pollutants. Temperature and nutrients are the dominant factors in external conditions to influence the biological communities. To explore the influence of preozonation under low temperature, the factors such as dissolved oxygen （DO）, dissolved organic carbon （DOC） and NH4^＋-N were analyzed from the sampling ports every week; triphenyl tetrazolium ehloride-dehydrogenase activity （TTC-DHA） and the nitrifying activity were detected along the bed height ofbiofilter at four levels （10. 40. 70 and i 10 cm） on the 90th, 110th, and 130th day; ~nicrobial community, based on 16S rRNA gene-denaturing gradient gel electrophoresis （DGGE）, was monitored on the 130th day of the operation. The observed microbial property showed that preozonation had a positive influence on bioactivity, biomass and nitrifying activity. Community analysis showed no significant difference on the biodiversity of nitrifying bacteria between the parallel filters in the inlet end based on the method employed. This result showed that biofilters＇ performance is not correlated well with microbial biodiversity. The elevated functionality in O3/BAC filters can be a result of increased microbial activity, which was promoted by preozonation.展开更多
基金supported by the Guangdong Natural Science Foundation (No. S2012030006598)the Science & Technology Planning Project of Guangdong Province of China (No. 2013A020229007)the Innovative Program of the State Key Laboratory of Virology (No. 2016KF001)
文摘The dengue virus （DENV） is a vital global public health issue. The 2014 dengue epidemic in Guangzhou, China, caused approximately 40,000 cases of infection and five deaths. We carried out a comprehensive investigation aimed at identifying the transmission sources in this dengue epidemic. To analyze the phylogenetics of the 2014 dengue strains, the envelope （E） gene sequences from 17 viral strains isolated from 168 dengue patient serum samples were sequenced and a phylogenetic tree was reconstructed. All 17 strains were serotype I strains, including 8 genotype I and 9 genotype V strains. Additionally, 6 genotype I strains that were probably introduced to China from Thailand before 2009 were widely transmitted in the 2013 and 2014 epidemics, and they continued to circulate until 2015, with one affinis strain being found in Singapore. The other 2 genotype I strains were introduced from the Malaya Peninsula in 2014. The transmission source of the 9 genotype V strains was from Malaysia in 2014. DENVs of different serotypes and genotypes co-circulated in the 2014 dengue outbreak in Guangzhou. Moreover, not only had DENV been imported to Guangzhou, but it had also been gradually exported, as the viruses exhibited an enzootic transmission cycle in Guangzhou.
文摘The combination of preozonation and subsequent biological granular activated carbon （O3/BAC） filtration is well known as a promising method for the removal of many pollutants. Temperature and nutrients are the dominant factors in external conditions to influence the biological communities. To explore the influence of preozonation under low temperature, the factors such as dissolved oxygen （DO）, dissolved organic carbon （DOC） and NH4^＋-N were analyzed from the sampling ports every week; triphenyl tetrazolium ehloride-dehydrogenase activity （TTC-DHA） and the nitrifying activity were detected along the bed height ofbiofilter at four levels （10. 40. 70 and i 10 cm） on the 90th, 110th, and 130th day; ~nicrobial community, based on 16S rRNA gene-denaturing gradient gel electrophoresis （DGGE）, was monitored on the 130th day of the operation. The observed microbial property showed that preozonation had a positive influence on bioactivity, biomass and nitrifying activity. Community analysis showed no significant difference on the biodiversity of nitrifying bacteria between the parallel filters in the inlet end based on the method employed. This result showed that biofilters＇ performance is not correlated well with microbial biodiversity. The elevated functionality in O3/BAC filters can be a result of increased microbial activity, which was promoted by preozonation.
