ABSTRACT
In this study, the swabs were collected among patients with an influenza-like illness (ILI) admitted to 2 sentinel surveillance hospitals of Yantai from April 2014 to August 2017. All specimen were cultured and identified by hemagglutination inhibition assay. Complete sequences of Hemagglutinin (HA) of influenza A were amplified, sequenced and analyzed using molecular and phylogenetic methods. The potential vaccine efficacy were calculated using Pepitope model. The results showed that the antigenicity of A (H3N2) had changed greatly. 8 strains of influenza A (H1N1) pdm09 belonged to subclade 6B.1 and 14 strains clustered in 6B.2. 12 strains of influenza A (H3N2) fell into subgroup 3C.3a and 33 strains clustered in 3C.2a. Several residues at antigen sites and potential glycosylation sites had changed in influenza A strains. Vaccine efficacy of influenza A (H1N1) pdm09 in 2015/2016 and 2016/2017 seasons were 77.29% and 79.11% of that of a perfect match with vaccine strain, meanwhile vaccine efficacy of influenza A (H3N2) in 2014/2015, 2015/2016 and 2016/2017 were-5.18%, 16.97% and 42.05% separately. In conclusion, the influenza A virus circulated in Yantai from 2014 to 2017 presented continual genetic variation. The recommended vaccine strains still afforded protection against influenza A (H1N1) pdm09 strains and provided suboptimal protection against influenza A (H3N2) strains.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the predominance ticks and the infectious status of severe fever with thrombocytopenia (SFTSV) in Penglai and Laizhou counties, Shandong province.</p><p><b>METHODS</b>Two towns with high incidence rate were selected in Penglai and Laizhou, respectively, then three villages were selected in each towns. Parasitic ticks were collected from the host skin by hand manually and free ticks manually with white cloth from the grassland, monthly, during April to December in 2011. Samples were classified by original, varieties, developmental stages, then extracted RNA, using Realtime RT-PCR to test severe fever thrombocytopenia syndrome virus, S fragments were amplified with nested PCR, then isolated virus. By neighbor joining method in the phylogenetic tree, the minimum infection rate (MIR) was used to represent the infection status of ticks in novel bunyavirus.</p><p><b>RESULTS</b>A total of 3 145 ticks were collected totally from 5 categories, there were 3 048(96.92%) of Haemaphysalis longicornis, 73(2.32%) of Rhinpicephalus sanguineus, 10(0.32%) of microplus Boophilus, 9(0.29%) of Haemaphysalis campanulata, 5(0.16%) of Dermacentor sinicus, respectively. The positive rate of nucleic acid of 2 044 samples was 6.16% (126/2 044), minimum infection rate (MIR) was 4.01%, there were 122(96.83%) of Haemaphysalis longicornis, 3(2.38%) of Rhinpicephalus sanguineus, and 1(0.79%) of microplus Boophilus, MIR was 4.00%, 4.11%, and 10.00%, respectively. There were no nucleic acid positive samples in Haemaphysalis campanulata and Dermacentor sinicus. The 11 S segments were amplified in 126 positive samples, the homology of S fragment was 95.6%-99.9% with 11 strains isolated from the identified SFTS cases in local area, 3 strains isolated from animals, and 11 strains isolated from other areas. There was no significant difference among original, varieties and developmental stages.</p><p><b>CONCLUSION</b>Haemaphysalis longicornis was the predominant species in Penglai and Laizhou counties, it could be propagation medium with Rhipicephalus sanguineus and microplus Boophilus, S sequence in ticks was higher homology with virus isolated from local SFTS cases.</p>
Subject(s)
Animals , China , Phlebovirus , Phylogeny , Real-Time Polymerase Chain Reaction , Ticks , Classification , VirologyABSTRACT
<p><b>OBJECTIVE</b>To learn the prevalence of infection of human and animals severe fever with thrombocytopenia syndrome bunyavirus (SFTSV) in Yantai, Shandong province, and to analyze the pathogenic features of SFTSV as well as its relationship between human and animal hosts.</p><p><b>METHODS</b>From April to November in 2011, 3 576 serum samples were collected from domesticated animals, including sheep, cattle, pigs, dogs, chickens, in Laizhou and Penglai areas where fever with thrombocytopenia syndrome frequently occurred among local residents. Total SFTSV antibodies and virus-specific nucleic acids of the serum were tested by ELISA and Real time RT-PCR, respectively. SFTSV infection on each animal was observed in different months. 2 590 human serum samples were also collected in Laizhou and Penglai areas, with IgG antibodies tested by ELISA. Virus was isolated with Vero cells from the serum which SFTSV viral nucleic acids were positive. S fragments were amplified by RT-PCR and sequenced, with homology analysis conducted on these sequences.</p><p><b>RESULTS</b>The overall positive rate of serum samples from animals on the total SFTSV antibodies was 40.24% (1 439/3 576) while the positive rate for specific nucleic acids was 4.56% (163/3 576). The positive rates for SFTSV antibodies were 62.78%, 52.97%, 45.56%, 28.73%, 1.45% and the positive rates for specific nucleic acids were 5.72%, 4.63%, 3.02%, 5.25% and 3.73%, in sheep, cattle, chickens, dogs, pigs, respectively. The antigens/antibodies for SFTSV in animals changed seasonally. The overall positive rate for SFTSV IgG antibody from 2 590 human samples was 5.41%. Thirteen virus strains were isolated from these serum samples (10 strains from human and 3 strains from animals). The nucleotide homology of 13S fragments' sequences ranged from 95.23% to 100.00% and the nucleotide homology with the isolates from other provinces were between 94.72% and 99.13%. The homology was considered to be high.</p><p><b>CONCLUSION</b>High prevalence of SFTSV infections occurred both in human and domestic animals in Yantai city. The nucleotide sequences of SFTSV were highly homologous among human and domestic animals. The findings suggested that domesticated animals might serve as SFTSV proliferation and the hosts for transmission thus should be attached great importance.</p>
Subject(s)
Animals , Humans , Antibodies, Viral , Blood , Bunyaviridae Infections , Epidemiology , China , Epidemiology , Prevalence , RNA, Viral , Blood , Sequence Analysis, RNAABSTRACT
Objective To learn the prevalence of infection of human and animals severe fever with thrombocytopenia syndrome bunyavirus(SFTSV)in Yantai,Shandong province,and to analyze the pathogenic features of SFTSV as well as its relationship between human and animal hosts. Methods From April to November in 2011,3 576 serum samples were collected from domesticated animals,including sheep,cattle,pigs,dogs,chickens,in Laizhou and Penglai areas where fever with thrombocytopenia syndrome frequently occured among local residents. Total SFTSV antibodies and virus-specific nucleic acids of the serum were tested by ELISA and Real time RT-PCR,respectively. SFTSV infection on each animal was observed in different months. 2 590 human serum samples were also collected in Laizhou and Penglai areas,with IgG antibodies tested by ELISA. Virus was isolated with Vero cells from the serum which SFTSV viral nucleic acids were positive. S fragments were amplified by RT-PCR and sequenced,with homology analysis conducted on these sequences. Results The overall positive rate of serum samples from animals on the total SFTSV antibodies was 40.24%(1 439/3 576)while the positive rate for specific nucleic acids was 4.56%(163/3 576). The positive rates for SFTSV antibodies were 62.78%,52.97%,45.56%,28.73%,1.45%and the positive rates for specific nucleic acids were 5.72%,4.63%,3.02%,5.25%and 3.73%,in sheep,cattle,chickens,dogs, pigs,respectively. The antigens/antibodies for SFTSV in animals changed seasonally. The overall positive rate for SFTSV IgG antibody from 2 590 human samples was 5.41%. Thirteen virus strains were isolated from these serum samples(10 strains from human and 3 strains from animals). The nucleotide homology of 13S fragments’sequences ranged from 95.23%to 100.00%and the nucleotide homology with the isolates from other provinces were between 94.72%and 99.13%. The homology was considered to be high. Conclusion High prevalence of SFTSV infections occured both in human and domestic animals in Yantai city. The nucleotide sequences of SFTSV were highly homologous among human and domestic animals. The findings suggested that domesticated animals might serve as SFTSV proliferation and the hosts for transmission thus should be attached great importance.
ABSTRACT
Objective To learn the prevalence of infection of human and animals severe fever with thrombocytopenia syndrome bunyavirus(SFTSV)in Yantai,Shandong province,and to analyze the pathogenic features of SFTSV as well as its relationship between human and animal hosts. Methods From April to November in 2011,3 576 serum samples were collected from domesticated animals,including sheep,cattle,pigs,dogs,chickens,in Laizhou and Penglai areas where fever with thrombocytopenia syndrome frequently occured among local residents. Total SFTSV antibodies and virus-specific nucleic acids of the serum were tested by ELISA and Real time RT-PCR,respectively. SFTSV infection on each animal was observed in different months. 2 590 human serum samples were also collected in Laizhou and Penglai areas,with IgG antibodies tested by ELISA. Virus was isolated with Vero cells from the serum which SFTSV viral nucleic acids were positive. S fragments were amplified by RT-PCR and sequenced,with homology analysis conducted on these sequences. Results The overall positive rate of serum samples from animals on the total SFTSV antibodies was 40.24%(1 439/3 576)while the positive rate for specific nucleic acids was 4.56%(163/3 576). The positive rates for SFTSV antibodies were 62.78%,52.97%,45.56%,28.73%,1.45%and the positive rates for specific nucleic acids were 5.72%,4.63%,3.02%,5.25%and 3.73%,in sheep,cattle,chickens,dogs, pigs,respectively. The antigens/antibodies for SFTSV in animals changed seasonally. The overall positive rate for SFTSV IgG antibody from 2 590 human samples was 5.41%. Thirteen virus strains were isolated from these serum samples(10 strains from human and 3 strains from animals). The nucleotide homology of 13S fragments’sequences ranged from 95.23%to 100.00%and the nucleotide homology with the isolates from other provinces were between 94.72%and 99.13%. The homology was considered to be high. Conclusion High prevalence of SFTSV infections occured both in human and domestic animals in Yantai city. The nucleotide sequences of SFTSV were highly homologous among human and domestic animals. The findings suggested that domesticated animals might serve as SFTSV proliferation and the hosts for transmission thus should be attached great importance.