OBJECTIVETo investigate the predominance ticks and the infectious status of severe fever with thrombocytopenia (SFTSV) in Penglai and Laizhou counties, Shandong province.

METHODSTwo 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.

RESULTSA 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.

CONCLUSIONHaemaphysalis 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.

Animals ; China ; Phlebovirus ; isolation & purification ; Phylogeny ; Real-Time Polymerase Chain Reaction ; Ticks ; classification ; virology

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.

Objective:To understand the spectrum of pathogens and epidemic characteristics of respiratory infectious diseases in influenza virus-negative influenza-like cases in Yantai, and provide reference for disease prevention and control and clinical diagnosis and treatment.Methods:From March 2020 to February 2021, nasopharyngeal swab samples of 233 influenza virus-negative influenza like cases were collected in all sentinel hospitals monitored by Yantai National Influenza Network Laboratory, and 22 respiratory pathogens were detected by multiple fluorescence quantitative polymerase chain reaction to analyze epidemiological characteristics.Results:The total pathogen detection rate of 233 samples was 69.96% (163/233). A total of 17 respiratory pathogens were detected. The top three pathogens were human coronavirus (HCoV, 32.62%), rhinovirus/enterovirus (RhV/EV, 17.17%) and Legionella pneumophila (LP, 16.74%). The detection rates in different age groups were 80.28% (57/71) in the 0-15 years old group, 62.65% (52/83) in the 16-30 years old group, 68.18% (30/44) in the 31-45 years old group, 64.28% (9/14) in the 46-60 years old group, and 71.43% (15/21) in the >60 years old group. There was no significant difference among the groups. Respiratory pathogens were detected throughout the year, mainly in a single pathogen carrying mode (44.21%), and there was no significant difference in the physical examination rate of respiratory pathogens in different seasons. The seasonal prevalence of various pathogens was different, and the detection rate of HCoV 229E was the highest in spring (68.75%); the detection rate of rhinovirus/enterovirus was higher in autumn (26.98%) and winter (23.08%); the detection rate of LP was high in spring (19.05%) and summer (27.27%); the detection rate of human parainfluenza virus (HPIV) in spring (22.22%) was significantly higher than that in summer (3.64%). The number of HPIV and Bordetella pertussis (Bp) detected in the 0-15 year old group was the highest, and the detection rate was statistically significant among different age groups. Conclusions:The continuous monitoring of respiratory pathogens such as HCoV, RhV, EV, LP, HPIV should be strengthened to understand their epidemiologic characteristics and the standardization of pathogenicity, which provides data support and reference for epidemiological investigation of outbreaks that may be caused by other pathogens.

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.

Objective To investigate the predominance ticks and the infectious status of severe fever with thrombocytopenia (SFTSV) in Penglai and Laizhou counties, Shandong province.Methods 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.Results 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.Conclusion 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.

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.

Objective To investigate the predominance ticks and the infectious status of severe fever with thrombocytopenia (SFTSV) in Penglai and Laizhou counties, Shandong province.Methods 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.Results 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.Conclusion 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.

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.

Objective:To investigate the pathogenic spectrum of enteroviruses associated with hand, foot and mouth disease (HFMD) in the Yantai region of Shandong province in 2016, and analyze the evolution of epidemic strains of coxsackie virus group A type 6 (CV-A6) in the pathogenic spectrum of HFMD enteroviruses and the variations of important amino acid sites in the VP1 region.Methods:A total of 738 samples were collected from the patients with HFMD in Yantai region in 2016 to conduct DNA and serotype tests of enterovirus (EV) by real-time RT-PCR and further count the number and proportion of each type of enterovirus positive specimens. Based on the predominant serotype of enteroviruses, eight serotypes of the CV-A6 strains were selected to carry out VP1 regions amplification for the determination and analysis of nucleotide sequencing and phylogenetic analysis.Results:A total of 460 enteroviruses strains were isolated from 738 samples, including pathogens strains: 258 CV-A16 (56.09%), 62 EV-A71 (13.48%), 49 CV-A10 (10.65%), 44 CV-A6 (9.57%) and 9 CV-A4 (1.96%). Eight CV-A6 positive specimens were isolated from the viruses and the nucleotide-sequence analysis of the whole VP1 region was conducted. The sequence analysis of eight CV-A6 strains demonstrated that the homologies of nucleotide and amino acid were 96.12% - 100% and 97.78% - 100% respectively. The phylogenetic analysis indicated that the eight CV-A6 strains were subdivided into the genotype D subtype D3. Compared with the reference strain, CVA6-Gdula-AY421764, amino acids of CV-A6 strains in Yantai city observed at sites 10, 14, 174, 194, 279, 283 and 305 in VP1 region appeared mutant.Conclusions:CV-A16, EV-A71, CV-A10 and CV-A6 were the main common pathogens of HFMD in Yantai region in 2016. All the CV-A6 strains isolated in this study belonged to subtype D3 in genotype D.

OBJECTIVETo 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.

METHODSFrom 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.

RESULTSThe 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.

CONCLUSIONHigh 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.

Animals ; Antibodies, Viral ; blood ; Bunyaviridae Infections ; epidemiology ; China ; epidemiology ; Humans ; Prevalence ; RNA, Viral ; blood ; Sequence Analysis, RNA