Objective This study investigated the epidemic characteristics and spatio-temporal dynamics of hemorrhagic fever with renal syndrome (HFRS) in Qingdao City,China. Methods Information was collected on HFRS cases in Qingdao City from 2010 to 2022. Descriptive epidemiologic,seasonal decomposition,spatial autocorrelation,and spatio-temporal cluster analyses were performed. Results A total of 2,220 patients with HFRS were reported over the study period,with an average annual incidence of 1.89/100,000 and a case fatality rate of 2.52％. The male:female ratio was 2.8:1. 75.3％ of patients were aged between 16 and 60 years old,75.3％ of patients were farmers,and 11.6％ had both "three red" and "three pain" symptoms. The HFRS epidemic showed two-peak seasonality:the primary fall-winter peak and the minor spring peak. The HFRS epidemic presented highly spatially heterogeneous,street/township-level hot spots that were mostly distributed in Huangdao,Pingdu,and Jiaozhou. The spatio-temporal cluster analysis revealed three cluster areas in Qingdao City that were located in the south of Huangdao District during the fall-winter peak. Conclusion The distribution of HFRS in Qingdao exhibited periodic,seasonal,and regional characteristics,with high spatial clustering heterogeneity. The typical symptoms of "three red" and"three pain" in patients with HFRS were not obvious.

Objective:To Isolate and identify human rhinovirus (HRV) in hospitalized children with pneumonia in Qingdao in 2020.Methods:A total of 98 throat swab samples were collected from hospitalized children with pneumonia in 2020. Common respiratory viruses were screened through RT-qPCR. The HRV positive samples were inoculated into H1-HeLa cells. Viruses with typical cytopathic effect (CPE) were identified by HRV specific RT-PCR. Subsequently, sequences of HRV-VP4/VP2 gene were used to construct phylogenetic trees and analyze homology with sequences of reference strains through MEGA software.Results:Among 98 hospitalized children with pneumonia, 11 samples were HRV positive in 98 throat swab samples. After the typical CPE appeared in HeLa cells, two strains of HRV were identified by specific RT-PCR. The HRV-A28 and HRV-A58 were confirmed by comparison and analysis of VP4/VP2 sequence. Phylogenetic tree found that the isolated HRV-A28 strain was genetically close to strains of Singapore in 2011, of Tunisia in 2017, and Kenya in 2017. The isolated HRV-A58 strain was genetically close to the strains of Australia in 2009, Venezuela in 2011, Mongolia in 2011, and the United States in 2014.Conclusions:The HRV-A28 and HRV-A58 strains were isolated from the throat swabs of children patients with pneumonia in Qingdao.

Objective:To analyze the epidemiological characteristics and genotypes of human rhinovirus (HRV) in patients with upper respiratory tract infection in Qingdao in the winter of 2020.Methods:Throat swab samples were collected from 101 patients with upper respiratory tract infection in Qingdao from November 2020 to January 2021. Quantitative PCR was used to detect 15 common respiratory viruses in the samples. HRV-positive samples were further analyzed with RT-PCR to amplify and sequence HRV VP4/VP2 gene. A phylogenetic tree was constructed based on the sequencing results and homology analysis was conducted.Results:Six common respiratory viruses were detected in the 101 patients. Thirty-four cases (34/101, 33.66%) were single pathogen infection and two cases were multiple infection (2/101, 1.98%). The positive rate of HRV was the highest (21.78%, 22/101). Twenty HRV VP4/VP2 sequences were successfully amplified. Phylogenetic analysis showed that there were 16 strains of HRV-A subtype and four strains of HRV-C subtype and 14 serotypes were involved.Conclusions:HRV was one of the leading viral pathogens causing upper respiratory tract infection in Qingdao in the winter of 2020 and the predominant subtype was HRV-A.

Objective:To investigate the contamination status of SARS-CoV-2 in imported frozen seafood from a Russia cargo ship in Qingdao and to analyze the risk factors for infection in local stevedores.Methods:The method of "two-stage, full coverage and mixed sampling" was used to collect the seafood packaging samples for the nucleic acid detection of SARS-CoV-2 by real-time fluorescent quantitative RT-PCR. A unified questionnaire was designed to investigate 71 stevedores in two shifts through telephone interview. The stevedores were divided into two groups, with 23 in the shit with two infections was group A and 48 in the shift without infection was group B. Software Epi Info7.2 was used to identify the risk factors for SARS-CoV-2 infections in the stevedores.Results:In the frozen seafood from a Russia cargo ship, the total positive rate of SARS-CoV-2 nucleic acid in the frozen seafood was 11.53% (106/919). The positive rate of SARS-CoV-2 nucleic acid in the frozen seafood unloaded by group A (14.29%,70/490) was significantly higher than that in the frozen seafood unloaded by group B (8.39%,36/429)( χ2=7.79, P=0.01) and the viral loads detected in the frozen seafood unloaded by group A were higher than those detected in the frozen seafood unloaded by group B. The scores of personal protection and behaviors in the stevedores in group A were significantly lower than those in group B ( P<0.05), and toilet use, smoking and improper hand washing before meals were the risk factors for the infection. Conclusions:The imported frozen seafood was contaminated by SARS-CoV-2 and the contamination distribution was uneven. Supervision and management of personal occupational protection and behaviors of workers engaged in imported frozen food transportation should be strengthened. It is suggested that a closed-loop monitoring and management system for the whole process of "fishing-transport- loading/unloading" should be established by marine fishery authority.

Objective:To understand the prevalence of coxsackievirus A6 (CV-A6) in hospitalized patients with hand, foot and mouth disease in autumn and winter of 2019, and the genetic characteristics of VP1 region and the relation-ship between germline evolution.Methods:A total of 104 throat swabs from hospitalized patients with hand, foot and mouth disease in Qingdao in autumn and winter of 2019, and screen positive specimens were collected using enterovirus universal real-time PCR technology. Then the universal typing primers in the VP1 region were used to amplify the positive samples, the amplified segments were sequenced and BLAST comparison was performed. CV-A6 VP1 full-length primers were used to amplify the BLAST comparison of CV-A6 positive samples, sequence the ampli-fied products, analyze the homology of nucleotides and amino acids through DNAstar and MEGA software, and construct a phylogenetic tree.Results:Among 104 throat swab samples, 60 were positive for enterovirus, and the overall positive rate was 57.7%, of which the positive rate of CV-A6 was 26.9% (28/104), and the rate of coxsackievirus A16 (CV-A6) was 30.8% (32/104). Twenty-eight CV-A6 positive samples were subjected to full-length amplification, sequencing, comparison and homology analysis of the VP1 region, and 22 positive sequences were obtained. The nucleotide homology was 93.6% to 99.9%, and the amino acid homology was 98.0%-100%. Phylogenetic analysis showed that 22 CV-A6 strains belonged to the D3 subtype in the D genotype.Conclusions:The pathogens causing hospitalized hand, foot and mouth disease in Qingdao in autumn and winter of 2019 were CV-A6 and CV-A16. The prevalent strains of CV-A6 were mainly D3 subtypes.

Objective:To analyze the epidemiological characteristics and co-infections of pathogens in children with pneumonia in autumn and winter of 2019 in Qingdao.Methods:From August to November in 2019, 77 children with pneumonia in three hospitals in Qingdao were selected as the research subjects. Throat swabs were collected, nucleic acid was extracted, and 20 common respiratory pathogens were detected by single tube multiplex PCR.Results:Among the 77 cases, the incidence of pneumonia in boys (53.2%) was slightly higher than that in girls (46.7%). Children aged 1-2 years accounted for 10.3% of the total cases, children aged 3-6 years accounted for 61%, and children aged 7-13 years accounted for 20.7%. Twenty-nine cases (38.10%) had high white blood cells; 16 cases (20.77%) had high neutrophil count; 30 cases (38.96%) had high lymphocyte count; the pathogen detection rate was 77.92% of cases, among whom Mycoplasma pneumoniae (MP) was 59.74%, Bocavirus was 10.39%(8/77), adenovirus was 7.79% (6/77), rhinovirus was 3.89% (3/77), parainfluenza virus type 4 was 3.89% (3/77), Bordetella pertussis was 3.89% (3/77), parainfluenza virus type 2 was 2 2.59% (2/77), coronavirus nl63/hku1 was 2.59% (2/77), coronavirus OC43 was 2.59% (2/77), human metapneumovirus was 1.29% (1/77), Parainfluenza virus type 3 was 1.29%(1/77). The 24 cases of virus infection accounted for 31.16% (24/77). The co-infection with two pathogens accounted for 18.18%.Conclusions:Many kinds of pathogens were detected in children with pneumonia in autumn and winter of 2019, in Qingdao. The prevalence of Mycoplasma pneumoniae infection was the highest. Many common viral infections were found in the cases. A high proportion of co-infection was detected in these pneumonia cases.

Objective:To investigate the different outcomes of two types of acute kidney injury (AKI) according to standard of Kidney Disease: Improving Global Outcomes-AKI (KDIGO-AKI), and to analyze the risk factors that affect the prognosis of intensive care unit (ICU) patients in China.Methods:A secondary analysis was performed on the database of a previous study conducted by China Critical Care Clinical Trial Group (CCCCTG), which was a multicenter prospective study involving 3 063 patients in 22 tertiary ICUs in 19 provinces and autonomous regions of China. The demographic data, scores reflecting severity of illness, laboratory findings, intervention during ICU stay were extracted. All patients were divided into pure AKI (PAKI) and acute on chronic kidney disease (AoCKD). PAKI was defined as meeting the serum creatinine (SCr) standard of KDIGO-AKI (KDIGO-AKI SCr) and the estimated glomerular filtration rate (eGFR) at baseline was ≥ 60 mL·min -1·1.73 m -2, and AoCKD was defined as meeting the KDIGO-AKI SCr standard and baseline eGFR was 15-59 mL·min -1·1.73 m -2. All-cause mortality in ICU within 28 days was the primary outcome, while the length of ICU stay and renal replacement therapy (RRT) were the secondary outcome. The differences in baseline data and outcomes between the two groups were compared. The cumulative survival rate of ICU within 28 days was analyzed by Kaplan-Meier survival curve, and the risk factors of ICU death within 28 days were screened by Cox multivariate analysis. Results:Of the 3 063 patients, 1 042 were enrolled, 345 with AKI, 697 without AKI. The AKI incidence was 33.11%, while ICU mortality within 28 days of AKI patients was 13.91% (48/345). Compared with PAKI patients ( n = 322), AoCKD patients ( n = 23) were older [years old: 74 (59, 77) vs. 58 (41, 72)] and more critical when entering ICU [acute physiology and chronic health evaluation Ⅱ (APACHEⅡ) score: 23 (19, 27) vs. 15 (11, 22)], had worse basic renal function [eGFR (mL·min -1·1.73 m -2): 49 (38, 54) vs. 115 (94, 136)], more basic complications [Charlson comorbidity index (CCI): 3 (2, 4) vs. 0 (0, 1)] and higher SCr during ICU stay [peak SCr for diagnosis of AKI (μmol/L): 412 (280, 515) vs. 176 (124, 340), all P < 0.01]. The mortality and RRT incidence within 28 days in ICU of AoCKD patients were significantly higher than those of PAKI patients [39.13% (9/23) vs. 12.11% (39/322), 26.09% (6/23) vs. 4.04% (13/322), both P < 0.01], while no significant difference was found in the length of ICU stay. Kaplan-Meier survival curve analysis showed that the 28-day cumulative survival rate in ICU in AoCKD patients was significantly lower than PAKI patients (Log-Rank: χ2 = 5.939, P = 0.015). Multivariate Cox regression analysis showed that admission to ICU due to respiratory failure [hazard ratio ( HR) = 4.458, 95% confidence interval (95% CI) was 1.141-17.413, P = 0.032], vasoactive agents treatment in ICU ( HR = 5.181, 95% CI was 2.033-13.199, P = 0.001), and AoCKD ( HR = 5.377, 95% CI was 1.303-22.186, P = 0.020) were independent risk factors for ICU death within 28 days. Conclusion:Further detailed classification (PAKI, AoCKD) based on KDIGO-AKI SCr standard combined with eGFR is related to ICU mortality in critical patients within 28 days.

Objective:To compare the diagnostic performance of four IgM antibody diagnostic kits for hepatitis E virus (HEV) in an outbreak.Methods:Four reagent kits were used to detect the IgM antibody to HEV in serum samples of the subjects in an outbreak of hepatitis E, and the HEV RNA was detected; statistical analysis was carried out.Results:The detection rates of HEV IgM antibody with MP, Kehua, Wantai and Beier′s reagent kits were 40.00% (108/270), 29.26% (79/270), 28.52% (77/270) and 20.37% (55 /270), respectively, with a consistency rate of 78.52% (212/270). For HEV RNA positive samples, the sensitivity of MP, Kehua and Wantai’s reagents was 66.67% (32/48) and that of Beier’s reagent was 58.33% (28/48). The sensitivity of MP, Kehua and Wantai’s reagents was 69.81% (37/53) and that of Beier’s reagent was 60.38% (32/53) for sera from patients with acute hepatitis E. The detection rates of HEV IgM antibody in serum samples of RNA positive or acute hepatitis E clinical diagnosis cases of Beier-Kehua and Beier-Wantai were significantly different (McNemar’s test: P<0.05), but there was no significant difference between the detection rates of other reagents (McNemar’s test: P>0.05); for serum samples of HEV RNA negative or clinically excluded cases of acute hepatitis E, the detection rates of HEV IgM antibody of Kehua and Wantai’s reagents were the most similar (McNemar’s test: P>0.05), but the detection result of other reagents were significantly different (McNemar’s test: P<0.05). Conclusions:The diagnostic kits of MP, Kehua and Wantai for HEV IgM antibody have high sensitivity and are suitable for the early serological screening of acute hepatitis E. In the outbreak of hepatitis E, comprehensive diagnosis should be made by combining the detection result of HEV IgM antibody and HEV RNA.

Objective To explore the influence of agricultural mechanization progress on epidemic intensity of hemorrhagic fever with renal syndrome (HFRS) so as to provide reference for prevention and control of HFRS in rural areas.Methods Data of HFRS epidemics and agricultural mechanization progress of Qingdao City and five main epidemic areas of HFRS were collected by retrospective analysis methods.Agricultural mechanization progress,time distribution,incidence rate of HFRS and capture rate of rats were compared,respectively.Risk factors were analyzed by case-control study using simple random sampling method.Cases of case group were selected from HFRS cases of Jiaonan County recovered between 2012 and 2013.The control group was healthy residents with a equal number of the case group.Residential locations,work ways,rodent infestation at work locations and in residential areas and skin injury conditions were surveyed by a household questionnaire survey.Results Agricultural machinery gross power of Qingdao City was developed from 174.76 megawatts of electricity (mwe) in 1985 to 854.00 mwe in 2015.The comprehensive mechanization degree marched from 60.0％ in 1994 to 90.2％ in 2015.HFRS incidence in Qingdao City declined from the first epidemic peak (1986) of 32.97/100 000 to the third peak (2012) of 3.54/100 000.HFRS incidence in Jiaonan,Jiaozhou,Pingdu,Laixi,Jimo cities reduced from the first epidemic peak (1985 or 1986) of 101.25/100 000,86.37/100 000,35.80/100 000,11.55/100 000,8.13/100 000 to the third peak(2012) of 14.68/100 000,4.43/100 000,2.33/100 000,6.02/100 000,3.26/100 000.The platform stage of epidemic peak in autumn and winter shortened from 4 or 5 months to 2 months.The capture rate of rats fluctuated around 2％.The infection risk of small farm implements or handwork was greater than huge mechanization (OR =0.01,P ＜ 0.01).Conclusions Agricultural mechanization changes the agricultural activity patterns to a large extent and lowers the HFRS epidemic by minimizing the risk of infection and shortening the platform stage of epidemic peak.The higher the degree of mechanization,the lower the epidemic intensity.

Objective To investigate the influence of host animals on epidemics of hemorrhagic fever with renal syndrome (HFRS) so as to provide a basis for effective control of HFRS.Methods From the national infectious disease network direct reporting system,the incidence of HFRS cases diagnosed by direct diagnosis of medical institutions in Qingdao was collected from 2011-2015.We captured rats indoor and outdoor by night trapping method quarterly and calculated the capture rates from 2011-2015 in Qingdao areas.The incidence of HFRS in different regions and the change of seasonal growth,the distribution of host animals,the characteristics and distribution of animals,and the seasonal variation of dominant species were analyzed and a database was set up and statistic analysis was conducted by SPSS 13.0.Results The peak incidence rate of HFRS in Qingdao areas occurred in 2012 (3.54/100 000) and presented a decrease trend year by year (x2 =64.15,P ＜ 0.05),but there were different characteristics among the epidemic areas,and lowest in 2015 (1.68/100 000).And the peak presented a two-peak pattern which was mainly an autumn peak and a gentle peak in late spring and early summer.The epidemics were gradually decreased from the rural areas to the urban fringes and then the urban areas.The seasonal variation was disappeared gradually.There was a heavy epidemic intensity in areas with a high capture rate and a complex type of host animals.The epidemic peak was in consistence with the distribution of rats.Capture rates were different among the epidemic areas.The capture rate in Jiaonan was the highest [5.32％(2 886/54 287)] and lowest in Pingdu [1.77％ (258/14 584)].The mean (x2 =820.39,P ＜ 0.05) and annual capture rates (x22011-2015 =32.61,356.24,233.07,129.33,33.42,all P ＜ 0.05) among epidemic areas were different.In the third quarter the accumulated capture rate was the highest [4.69％ (1 187/25 301)].In total 8 kinds of host animals were captured and the dominant species were brown rat [30.27％ (1 235/4 080)],house mouse[29.75％ (1 214/4 080)] and striped field mouse [16.25％ (663/4 080)].Conclusions The epidemic intensity of HFRS is related to the densities and the types of host animals.The gradually decreased epidemic pattern from the rural areas to the urban fringes and then the urban areas may be related to urbanization and improved health behaviors.