Seasonal variations of macrozoobenthic community trophic structure in the waters adjacent to the seaweed beds of Dalian Island in the North Yellow Sea.

To investigate the effects of algal detritus export on the trophic structure of macrozoobenthic community in the adjacent benthic habitat during the bloom and decline of macroalgae, we collected macrozoobenthos from the adjacent sea area of Dalian Island in the North Yellow Sea in May (the algal bloom period) and August (the algal decay period) of 2020. We quantifyied the seasonal changes in the trophic structure of macrozoobenthic community by using carbon and nitrogen stable isotope techniques. Results showed that δ13C and δ15N values of macrozoo-benthos in May ranged from -23.14‰ to -14.24‰, 6.21‰ to 12.90‰, respectively, and -22.36‰ to -14.13‰, 5.33‰ to 12.00‰, respectively in August. Results of PERMANOVA analysis showed that δ13C values of macrozoobenthos differed significantly between the two months, while δ15N values were not significantly different. Based on the Euclidean distance, the macrozoobenthic communities in both months could be classified into five trophic functional groups. The trophic levels of macrozoobenthos ranged from 2.00 (Nitidotellina minuta) to 3.97 (Glycera onomichiensis) in May and from 2.00 (N. minuta) to 3.96 (G. onomichiensis) in August. The δ13C range, δ15N range, mean centroid distance, total area and corrected standard ellipse areas which represented community trophic structure indices in August were higher than those in May. Our results indicated that the trophic diversity level and trophic niche width of the macrozoobenthic community in the adjacent sea area of the seaweed bed were higher in the algal decline season.

Detection of Severe Acute Respiratory Syndrome Coronavirus 2 RNA on Surfaces in Quarantine Rooms.

We investigated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) environmental contamination in 2 rooms of a quarantine hotel after 2 presymptomatic persons who stayed there were laboratory-confirmed as having coronavirus disease. We detected SARS-CoV-2 RNA on 8 (36%) of 22 surfaces, as well as on the pillow cover, sheet, and duvet cover.

[Analysis of evolution features of whole genome of influenza virus H3N2 in Qingdao between year 2007 and 2011].

OBJECTIVE: To investigate the evolution features of whole-genome of influenza virus H3N2 prevalent in Qingdao from year 2007 to 2011. METHODS: The RNA of 58 strains of influenza virus H3N2 prevalent in Qingdao between 2007 and 2011 was extracted and all segments amplified by RT-PCR. The sequence was then detected and assembled by software Sequencer. A total of 589 strains of influenza virus H3N2 with more than 300 amino acid recorded by GenBank were selected. The phylogeny and molecular features of all gene segments were analyzed by software Mega 5.0, referred by the heavy chain of hemagglutinin (HA1). RESULTS: Hemagglutinin (HA) genes of influenza virus H3N2 prevalent in Qingdao between year 2007 and 2011 formed a single trunk of phylogenetic tree. Every prevalent strain originated in last season. The analysis of the evolution of whole genome found that reassortment virus strains were prevalent between year 2009 and 2010, but between 2010 and 2011 there were two series of prevalent strains, which showed complicated reassortment. Compared with the vaccine strains, the variant amino acids of protein of virus HA1 between year 2007 and 2011 were 8, 6, 6, 8 and 11, involving 13 antigenic sites. The sequence analysis of M2 protein showed that the isolated influenza virus H3N2 mutated in amino acid site 31, from serine to asparagine (S31N). HA1 gene of influenza virus H3N2 isolated in Qingdao between 2007 and 2011 shared the similar phylogenetic tree with the globally prevalent strain. The comparison of the sequence and the analysis of the antigenicity found co-infection between H3N2 and A/H1N1 in the strain A/Qingdao/F521/2011. CONCLUSION: The evolution features of all segments of influenza virus H3N2 prevalent in Qingdao between year 2007 and 2011 were complicated.

[Analysis of characteristics of whole-genome of influenza A H1N1 virus in Qingdao between year 2009 and 2011].

OBJECTIVE: To investigate characteristics of the whole-genome of influenza A H1N1 virus circulated in Qingdao from year 2009 to 2011. METHODS: RNA of 35 influenza A H1N1 virus isolates circulated in Qingdao between year 2009 and 2011 was extracted and all segments were amplified by RT-PCR. The sequence was then detected and assembled by software Sequencher.25 HA full-length sequences published on GenBank were selected as reference. While MEGA 5.0 software package was explored for phylogenetic analysis to characterize the molecular feature with reference to the whole-genome sequence and the hemagglutinin (HA).1068 HA sequences of influenza A H1N1 virus isolated worldwide from August 2010 to March 2011 were downloaded for amino acid mutation analysis. RESULTS: On the HA genes phylogenetic tree, the virus were separately divided into 4 clades in 2009-2010 and 2010-2011 surveillance season, each with a preponderant epidemic clade. The homogeneity of nucleotide and amino acids of HA isolates were 99.6%-99.9% and 99.1%-99.8% respectively in 2009-2010 surveillance season; 99.1%-99.6% and 98.2%-99.1% respectively in 2010-2011 surveillance season. The homogeneity of nucleotide and amino acids of the preponderant isolates were separately 98.8%-99.8% and 98.0%-99.6%. Compared with the vaccine strain, there were separately 14 and 12 variant amino acids of virus HA in the two surveillance season, involving 10 antigen sites and 5 positive selected sites. The sequence analysis of neuraminidase protein showed that the positions 247, 274 presented serine and histidine(S247, H274) respectively. The sequence analysis of M2 protein showed that the isolated A H1N1 viruses presented asparagine in amino acid site 31 (N31). CONCLUSION: All the A H1N1 influenza virus circulated in Qingdao from year 2009 to 2011 presented continual variation and therefore caused antigenic drift. All the isolations were adamantane-resistance, but susceptible to inhibitors of neuraminidase.

[Etiology of hand, foot and mouth disease in Qingdao during 2008-2009].

An etiology study on HFMD in Qingdao region during 2008-2009 was conducted. The virus RNA were isolated from throat swabs of HFMD,the EV, EV71 and CVA16 were detected by multiplex realtime RT-PCR. For those specimens with EV positive and both EV71 and CVA16 negative,a reverese transcription-seminested polymerase chain reaction (RT-snPCR) was perfomed to amplify part sequence of the VP1 gene for sabsequent analysis to identify the serotype. The results indicated that EV71 and CVA16 were the major pathogens of HFMD in Qingdao during 2008-2009. The proportion of EV71 was greater than CVA16 in either mild or serious HFMD cases. Sequence analysis showed that 5 non-EV71 and non-CVA16 serotypes (8 specimens) were obtained in 2008 including Coxsackievirus A5, A6, A10, A12 and Echovirus 9, which were well distributed. Three serotypes(13 specimens) were obtained in 2009 including Coxsackievirus A9, A12 and B2, of which CVA12 was of a big proportion (11/13). CVA12 became a new relatively major pathogen of HFMD in Qingdao during 2009.

[Interventional effect of vitamin A supplementation on re-vaccination to hepatitis B virus among rural infants and young children in China].

OBJECTIVE: The objective of this study was to observe the interventional effect of cod liver oil supplementation on re-vaccination to hepatitis B virus (HBV) among infants and young children. METHODS: All 7-36 months old infants and young children, who had been vaccinated with obligatory HBV vaccines routinely by the national technical and administrative procedures for HBV vaccination on children of China, were convened among villages in Linyi, Shandong province, from October 2008 to March 2009. After detection of serum anti-HBV, one hundred children with lower serum anti-HBV were picked out for the randomized, double blinded, placebo controlled vitamin A supplementation study. The children in the intervention group (50 subjects) took 0.5 g condensed cod liver oil (containing 25 000 IU vitamin A and 2500 IU vitamin D(2)) every 15 days for six times. The children in the control group (50 subjects) were given corn oil with same volume. All children were re-vaccinated at the 30th and the 60th day of the experiment. The serum samples were collected from each child at the 90th day of the experiment. Retinol concentration in serum samples was analyzed with HPLC method before and after the intervention. The levels of serum anti-HBs were detected by the electro-chemi-luminescence immunoassay (ECLIA). RESULTS: Total 74 children finished the supplemental experiment and blood collection, 37 subjects in each group, respectively. After intervention, the serum retinol level in the experimental and control group were (404.1 ± 123.1) and (240.8 ± 92.8) µg/L (t = 6.441, P < 0.01), respectively. The serum anti-HBs levels in the experimental and control group were (2737.2 ± 2492.6) and (1199.7 ± 2141.6) U/L (t = 2.846, P < 0.01), respectively. The rate of weak or no-answer case in experimental and control groups was 0.00% (0/37) and 10.81% (4/37) (χ(2) = 4.229, P = 0.040), respectively. CONCLUSION: The results showed that vitamin A supplementation might enhance the re-vaccination reaction against HB vaccine in infants and young children.

[Molecular epidemiology of human enterovirus 71 strains in Qingdao region, Shandong province, 2007 - 2009].

OBJECTIVE: To study the molecular epidemiology of human enterovirus 71 (EV71) isolated from patients with hand-foot-mouth disease (HFMD) in Qingdao region between 2007 and 2009. METHODS: Throat swabs of HFMD were detected for total enterovirus (EV), EV71 and CA16 by fluorescence reverse transcription-polymerase chain reaction (RT-PCR). The VP1 region was amplified from positive EV71 specimens and 51 nucleotide sequences of VP1 gene were successfully sequenced. EV71 genotypes were characterized by phylogenetic analysis. RESULTS: 51 Qingdao EV71 strains identified between 2007 and 2009 belonged to C4a cluster of subgenotype C4 and 5.3% nucleotide divergence and 1.7% amino acid divergence were found among them. The strains in 2008 and 2009 were respectively divided into several lineages on phylogenetic trees but there was a main lineage (namely prominent strain) every year. The Qingdao prominent strains identified in 2008 had high identities with the Linyi prominent strains in 2007. The Qingdao prominent strains in 2009 and the secondary prominent strains in 2008 had high identities with the Fuyang prominent strains in 2008. Two Qingdao strains in 2007 had high identities with the Linyi popular strains in 2007. CONCLUSION: Data showed that several EV71 transmission chains were co-circulating in Qingdao between 2008 and 2009. The main transmission chain in 2008 became the minor one but the minor transmission chain in 2008 was transferred into the main transmission chain in 2009.

Emergency surveillance of influenza during 2009 in the Chinese city of Qingdao.

BACKGROUND: In April, 2009, a new influenza pandemic caused by a swine-origin H1N1 subtype influenza virus was imminent. We thereby carried out an emergency surveillance study in a Chinese city of Qingdao. METHODS: Pharyngeal swab samples were collected from four targeted groups and tested by reverse-transcription polymerase chain reaction. Each laboratory-confirmed pandemic H1N1 case or cluster was investigated, and the hemagglutinin genes of some of the viruses were sequenced and analyzed. RESULTS: A total of 140 pandemic H1N1 cases including 92 from 7 clusters were identified in the four targeted groups. None of them developed into severe infections. Meanwhile, 103 cases of seasonal influenza (98 H3N2 and 5 H1N1) and 10 clusters of seasonal H3N2 influenza were also identified. Among them, 38 pandemic H1N1 and two seasonal H3N2 influenza cases were air travellers, suggesting that air travel facilitates the spread of pandemic and seasonal influenza even in the northern hemisphere summer. In addition, it was found that pandemic H1N1 and seasonal H3N2 influenza viruses co-circulated in two clusters. No significant mutations were found in the hemagglutinin gene sequences of pandemic H1N1 viruses, but the seasonal H3N2 influenza viruses have become genetically distinguishable from those circulating in 2007-2008.

Increased prevalence of a rare mutant of pandemic H1N1 influenza virus in a Eurasian region.

In 2009, a novel swine-origin H1N1 influenza virus sparked an influenza pandemic. The emergence of mutations in the viral genome is therefore of ongoing concern. In this study, the hemagglutinin (HA) gene sequences of 3444 pandemic H1N1 influenza viruses reported to the GenBank database and the sequences of 48 pandemic H1N1 influenza viruses detected in the Chinese city of Qingdao were analyzed. Among the 3492 viruses, 101 carried a serine to proline substitution at position 128 (S128P) in the viral HA gene. All the 101 S128P mutants belonged to Clade 7 which has become dominant worldwide since the summer of 2009. Among the 3492 viruses, 1646 were collected before July 25, 2009, and none of these viruses carried the S128P mutation. Furthermore, after July 25, 2009, the prevalence of the S128P mutant was 33.56% (99/295) in a region of Eurasia including Russia, Mongolia, mainland China and South Korea, but only 0.11% (2/1846) in the rest of the world. The data suggested that the originally rare S128P mutant has become prevalent in the Eurasia region, indicating that the S128P mutant likely transmitted more efficiently than other strains of the virus. Therefore, it is of significance to observe whether the S128P mutant will be more dominant worldwide in the coming future and investigate the exact effects of the S128P mutation.