Molecular epidemiology of genogroup II norovirus infection among hospitalized children with acute gastroenteritis in Suzhou (Jiangsu, China) from 2010 to 2013.

Noroviruses (NoVs) are the most common cause of acute gastroenteritis in both sporadic and outbreak cases. Genotyping and recombination analyses were performed in order to help getting more knowledge of the distribution and genetic diversity of NoVs in Suzhou, located in Jiangsu province of China. All stool samples were collected from hospitalized children younger than 5 years old with acute gastroenteritis. For genotyping, the open reading frame (ORF) 1 and ORF2 were partially amplified and sequenced. 26.9% of stool samples were positive for genogroup II NoVs. The most common genotype was GII.4 and its variants included Den Haag-2006b, New Orleans-2009, and Sydney-2012. The Den Haag-2006b variants predominated during 2010-2012. In 2013, it was replaced by the Sydney-2012 variant. The second most common genotype was GII.12/GII.3. NoVs could be detected throughout the year, with GII.4 and GII.12/GII.3 coexisting during the cold months, and GII.4 was the main genotype during the warm months. The highest prevalence of NoV was detected in young children aged <24 months. Patients infected with GII.4 had a higher chance of getting moderate fever than other NoV-positive patients, while those infected with GII.12/GII.3 tended to have a mild degree of fever. NoV is an important pathogen responsible for viral gastroenteritis among children in Suzhou. Analyses of NoV circulating between 2010 and 2013 revealed a change of predominant variant of NoV GII.4 in each epidemic season and intergenotype recombinant strains represented an important part.

Emergence of two novel norovirus genotype II.4 variants associated with viral gastroenteritis in China.

Noroviruses (NoVs) are the principal cause of epidemic viral gastroenteritis worldwide, including industrialized and developing countries. Eight hundred and fifty sporadic specimens from hospitalized children with acute gastroenteritis and 131 specimens from seven gastroenteritis outbreaks were collected during 2011-2012 in Jiangsu, China. All specimens were tested for the presence of norovirus (NoV) by real time RT-PCR, and in these, 225/850 of sporadic specimens and 76/131 of outbreak specimens were positive. By sequencing, two novel variants termed JS2011/CHN variant and JS2012/CHN variant were found. By complete genome sequencing and phylogenetic analysis confirmed that both JS2011/CHN variant and JS2012/CHN variant shared more than 98% identity with GII.4 New Orleans/2009/USA strain and GII.4 Sydney/2012/AUS. Both of them had mutations in some key sites in nucleotide sequence and amino acid sequence of ORF1-ORF3. Whether two novel variants will cause epidemic of NoV outbreaks in China deserves further attention. A national surveillance network may be needed to identify trends in molecular evolution of NoVs for prevention of future epidemics.

Risk Factors for Bunyavirus-Associated Severe Fever with Thrombocytopenia Syndrome: A Community-Based Case-Control Study.

BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease caused by a novel bunyavirus. Previous studies about risk factors for SFTSV infection have yielded inconsistent results, and behavior factors have not been fully clarified. METHODS: A community-based, 1:4 matched case-control study was carried out to investigate the risk factors for SFTS in China. Cases of SFTS were defined as laboratory-confirmed cases that tested positive for real-time PCR (RT-PCR) for severe fever with thrombocytopenia syndrome bunyavirus (SFTSV) or positive for IgM antibodies against SFTSV. Controls of four neighborhood subjects were selected by matching for sex, age, and occupation. Standardized questionnaires were used to collect detailed information about their demographics and risk factors for SFTSV infection. RESULTS: A total of 334 subjects participated in the study including 69 cases and 265 controls. The median age of the cases was 59.5 years, 55.1% were male, and 87.0% were farmers. No differences in demographics were observed between cases and controls. In the final multivariate analysis, tick bites two weeks prior to disease onset (OR = 8.04, 95%CI 3.34-19.37) and the presence of weeds and shrubs around the house (OR = 3.46, 95%CI 0.96-12.46) were found to be risk factors for SFTSV infection; taking preventative measures during outdoor activities (OR = 0.12, 95%CI 0.01-1.01) provided greater protection from SFTSV infection. CONCLUSIONS: Our results further confirm that SFTSV is transmitted by tick bites and prove that preventative measures that reduce exposure to ticks can prevent SFTSV infection. More efforts should be directed toward health education and behavior change for high-risk populations, especially outdoor workers, in SFTS endemic areas.

Economic burden and its associated factors of hospitalized patients infected with A (H7N9) virus: a retrospective study in Eastern China, 2013-2014.

BACKGROUND: H7N9 continues to cause human infections and remains a pandemic concern. Understanding the economic impacts of this novel disease is important for making decisions on health resource allocation, including infectious disease prevention and control investment. However, there are limited data on such impacts. METHODS: Hospitalized laboratory-confirmed H7N9 patients or their families in Jiangsu Province of China were interviewed. Patients' direct medical costs of hospitalization were derived from their hospital bills. A generalized linear model was employed to estimate the mean direct medical costs of patients with different characteristics. RESULTS: The mean direct cost of hospitalization for H7N9 was estimated to be ¥ 71 060 (95 % CI, 48 180-104 820), i.e., US$ 10 996 (95 % CI, 7 455-16 220), and was ¥12 060 (US$ 1 861), ¥136 120 (US$ 21 001) and ¥218 610 (US$ 33 728) for those who had mild or severe symptoms or who died, respectively. The principal components of the total fees differed among patients with different disease severity, although medication fees were always the largest contributors. Disease severity, proportion of reimbursement and family member monthly average income were identified as the key factors that contributed to a patient's direct medical cost of hospitalization. CONCLUSIONS: The direct medical costs of hospitalized patients with H7N9 are significant, and far surpass the annual per capita income of Jiangsu Province, China. The influencing factors identified should be taken into account when developing related health insurance policies and making health resource allocation. TRIAL REGISTRATION: Not applicable. This is a survey study with no health care intervention implemented on human participants.

Spatial distribution and risk factors of influenza in Jiangsu province, China, based on geographical information system.

Influenza poses a constant, heavy burden on society. Recent research has focused on ecological factors associated with influenza incidence and has also studied influenza with respect to its geographic spread at different scales. This research explores the temporal and spatial parameters of influenza and identifies factors influencing its transmission. A spatial autocorrelation analysis, a spatial-temporal cluster analysis and a spatial regression analysis of influenza rates, carried out in Jiangsu province from 2004 to 2011, found that influenza rates to be spatially dependent in 2004, 2005, 2006 and 2008. South-western districts consistently revealed hotspots of high-incidence influenza. The regression analysis indicates that railways, rivers and lakes are important predictive environmental variables for influenza risk. A better understanding of the epidemic pattern and ecological factors associated with pandemic influenza should benefit public health officials with respect to prevention and controlling measures during future epidemics.

Epidemiological and clinical characteristics and risk factors for death of patients with avian influenza A H7N9 virus infection from Jiangsu Province, Eastern China.

BACKGROUND: A novel avian influenza A (H7N9) virus has caused great morbidity as well as mortality since its emergence in Eastern China in February 2013. However, the possible risk factors for death are not yet fully known. METHODS AND FINDINGS: Patients with H7N9 virus infection between March 1 and August 14, 2013 in Jiangsu province were enrolled. Data were collected with a standard form. Mean or percentage was used to describe the features, and Fisher's exact test or t-test test was used to compare the differences between fatal and nonfatal cases with H7N9 virus infection. A total of 28 patients with H7N9 virus infection were identified among whom, nine (32.1%) died. The median age of fatal cases was significant higher than nonfatal cases (P<0.05). Patients with older age were more strongly associated with increased odds of death (OR = 30.0; 95% CI, 2.85-315.62). Co-morbidity with chronic lung disease and hypertension were risk factors for mortality (OR = 14.40; 95% CI, 1.30-159.52, OR = 6.67; 95% CI, 1.09-40.43, respectively). Moreover, the presence of either bilateral lung inflammation or pulmonary consolidation on chest imaging on admission was related with fatal outcome (OR = 7.00; 95%CI, 1.10-44.61). Finally, dynamic monitoring showed that lymphopenia was more significant in fatal group than in nonfatal group from day 11 to week five (P<0.05). The decrease in oxygenation indexes were observed in most cases and more significantly in fatal cases after week three (P<0.05), and the value of nearly all fatal cases were below 200 mmHg during our evaluation period. CONCLUSIONS: Among cases with H7N9 virus infection, increased age accompanied by co-morbidities was the risk of death. The severity of lung infection at admission, the persistence of lymphocytopenia, and the extended duration of lower oxygenation index all contributed to worsened outcomes of patients with H7N9 virus infection.

[Molecular characteristics of acute gastroenteritis outbreaks caused by norovirus, in Jiangsu province].

OBJECTIVE: To study both the epidemiologic and molecular characteristics of outbreaks caused by norovirus (NoV) with its variants, in Jiangsu. METHODS: 67 specimens from seven gastroenteritis outbreaks were collected from October 2012 to March 2013 in Jiangsu. NoV gene group was detected by Real-Time RT-PCR. NoV portions of RdRp gene and VP1 gene were amplified under RT-PCR. RESULTS: Seven gastroenteritis outbreaks were caused by NoV. Among all the fecal specimens,45 (67.2%) showed positive to NoV G II. Study on the genotype was conducted through analyzing the nucleotide sequence of RdRp gene. Based on the RdRp region, 7 strains appeared to be G II, with 3 and 38 strains belonged to G II.4--Sydney variants. Results from phylogenetic analysis confirmed that 38 variants shared 99% identity with G II.4--Sydney. We also amplified the VP1 genes from 6 variants and comparing with 9 epidemic strains on the sequence amino acid sequence. All the strains showed mutation in amino acid sequence at some key sites which were closely related to the forming of neutralizing epitopes. CONCLUSION: The short interval periods between all 7 NoV outbreaks with identical viral strain indicated the emergence of a new NoV variant in Jiangsu province,that had caused a number of epidemics abroad. Results from our study suggested that the development of monitoring programs on this novel G II.4--Sydney variant should be a part of the NoV surveillance in Jiangsu province or even in the country.

[Molecular features of human bocavirus from infantile diarrhea in Suzhou area, Jiangsu province in 2010-2011].

OBJECTIVE: To investigate the status of human bocavirus and to identify its epidemiological characteristics as well as genotype distribution in patients with infantile viral diarrhea in Suzhou, Jiangsu province. METHODS: 832 fecal specimens from patients with infantile virus diarrhea cases were collected from Suzhou Children's Hospital in 2010-2011. Human bocavirus were detected by Real-Time RT-PCR, and genotype were determined by sequence analysis. RESULTS: Among all the fecal specimens, 51 (6.1%) cases were positive for human bocavirus. The peak season of rotavirus infection was between July and September. Of all the episodes on rotavirus diarrhea, 96% occurred before 2 years of age, with peaks in children with 7-12 months of age. Data from Nucleotide Sequence analysis showed that among 28 samples that carrying HBoV-1, 5 strains belonged to HBoV-2, HBoV type 3 but type 4 were absent. CONCLUSION: Human bocavirus were detected from fecal specimens of infantile virus diarrhea in Suzhou, with genotype HBoV-1 as the major strain. HBoV-2 genotype was also found.

Probable person to person transmission of novel avian influenza A (H7N9) virus in Eastern China, 2013: epidemiological investigation.

OBJECTIVE: To determine whether the novel avian influenza H7N9 virus can transmit from person to person and its efficiency. DESIGN: Epidemiological investigations conducted after a family cluster of two patients with avian H7N9 in March 2013. SETTING: Wuxi, Eastern China. PARTICIPANTS: Two patients, their close contacts, and relevant environments. Samples from the patients and environments were collected and tested by real time reverse transcriptase-polymerase chain reaction (rRT-PCR), viral culture, and haemagglutination inhibition assay. Any contacts who became ill had samples tested for avian H7N9 by rRT-PCR. Paired serum samples were obtained from contacts for serological testing by haemagglutination inhibition assays. MAIN OUTCOMES MEASURES: Clinical data, history of exposure before the onset of illnesses, and results of laboratory testing of pathogens and further analysis of sequences and phylogenetic tree to isolated strains. RESULTS: The index patient became ill five to six days after his last exposure to poultry. The second patient, his daughter aged 32, who provided unprotected bedside care in the hospital, had no known exposure to poultry. She developed symptoms six days after her last contact with her father. Two strains were isolated successfully from the two patients. Genome sequence and analyses of phylogenetic trees showed that both viruses were almost genetically identical. Forty three close contacts of both patients were identified. One had mild illness but had negative results for avian H7N9 by rRT-PCR. All 43 close contacts tested negative for haemagglutination inhibition antibodies specific for avian H7N9. CONCLUSIONS: The infection of the daughter probably resulted from contact with her father (the index patient) during unprotected exposure, suggesting that in this cluster the virus was able to transmit from person to person. The transmissibility was limited and non-sustainable.

Spatial analyses of typhoid fever in Jiangsu province, People's Republic of China.

An analysis of the geographical distribution of typhoid incidence rates, based on various statistical approaches such as trend surface, spatial autocorrelation, spatial correlation and spatial regression, was carried out at the county level in Jiangsu province, People's Republic of China. Temperature, moisture content, proximity to water bodies and the normalized difference vegetation index in the autumn were the four underlying factors found to contribute the most to the development of the epidemic. Typhoid infection was most severe in the south-eastern region of Jiangsu and a significant hotspot with high positive autocorrelation was detected in Taicang county in the south-east of the province. To improve the typhoid situation, intervention efforts should be concentrated in the south-eastern region of the province, targeting the hotspot and include reduction of lake pollution.

[Epidemiologic characteristics of typhoid and paratyphoid fever on related drug resistance and molecular types regarding Salmonella typhi and S. paratyphi, in Jiangsu province].

OBJECTIVE: To explore the distribution of prevalence rates of typhoid and paratyphoid, with drug resistance and molecular types of Salmonella (S.) typhi and S. paratyphi in Jiangsu province. METHODS: Data, collected by the national infectious disease reporting system in Jiangsu province from 2007 to 2011, was analyzed. K-B method was used to test the sensibility to 9 kinds of antibiotics among 210 stains of S. typhi and S. paratyphi. 81 strains of S. typhi were classified by pulse-field gel electrophoresis (PFGE). RESULTS: The annual average incidence of typhoid and paratyphoid was 0.47 per 100 000 in the last five years, showing a decreasing trend. Highest incidence (1.70 per 100 000) was seen in the < 1 year age group, with S. typhi and S. paratyphi A accounted for 66.19% and 23.81% among the 210 stains. The rate of drug resistance to nalidixic acid appeared to be the highest as 66.19%. The drug resistant rates to 6 kinds of antibiotics were on average, lower than 10.00%. The multi-drug resistant rate of S. typhi and S. paratyphi was 30.00%. In the last 3 years, 37 types from 81 S. typhi strains had been classified into 4 clusters by PFGE. The predominant type was JPPX01. JS0027, accounted for 11.11%. JPPX01.JS0001 type had a specific regional distribution, but JPPX01.JS0014, JPPX01.JS0018 and JPPX01.JS0024 strains were widely spread. Results from the clustering analysis showed that cases in the 3 events tended to have a clustering nature. CONCLUSION: The morbidity of typhoid and paratyphoid was in a relatively low level in Jiangsu province. Although S. typhi and S. paratyphi were sensitive to most of the commonly used antibiotics, the resistance rates to some kinds of antibiotics were increasing. The distribution of typhoid was sporadic in Jiangsu and without the dominant strain, it was unlikely that typhoid could become epidemic in the future, in Jiangsu.

[Epidemiological characteristics and temporal-spatial clustering analysis on hand-foot-mouth disease in Jiangsu province, 2009 - 2011].

OBJECTIVE: To analyze the epidemic characteristics of hand-foot-mouth disease (HFMD) in Jiangsu province. METHODS: We downloaded the case-data of HFMD in Jiangsu province during 2009 - 2011 from the Chinese National Notifiable Infectious Disease Reporting System, and made a comprehensive analysis on the epidemiological features of it with descriptive epidemiological methods and retrospective space-time permutation scan statistics. RESULTS: A total of 285 414 cases were reported in Jiangsu, from 2009 to 2011, with an annual incidence of 122.66 per 100 000. There were 3686 severe cases in the 3 years a cumulatively, accounting for 1.29% of the total. Proportion of the cases being 5 years old or even younger was 93.64%. Scatteredly living children accounted for 64.08% of the total cases and 78.65% of the severe cases, respectively. The epidemics of HFMD were visible in each city of Jiangsu province, with a lowest annual incidence rate of 44.02 per 100 000 and a highest one up to 202.90 per 100 000. Regions as Suzhou, Nanjing, Wuxi had the highest incidence in the province, with cases in these three areas occupying almost 40% of all. The numbers of severe cases in Suqian and in Yancheng cities increased by 339.22% and 328.33% in 2011 compared to in 2010, respectively, and the rates of increase in these two cities were much higher than those in the other regions. Two peaks of incidence were observed every year, with the highest occurring between April and June and the second occurring in November. The spatial-temporal distribution of HFMD was not random in Jiangsu province, from 2009 to 2011. Clusters for general cases in August and 7 clusters for severe cases were detected, respectively. 12 359 cases of HFMD were laboratory confirmed in the said 3 years, including 10 414 common cases and 1945 severe cases. EV71 and CoxA16 accounted for 43.49% and 37.07% of common cases, respectively. In terms of the severe cases, the ratios were 80.82% and 5.96%, respectively. CONCLUSION: HFMD was highly endemic in Jiangsu province, and the situation of prevention and control for it is still grim. Scatteredly living children of 5 years old or younger were the major population at risk, and the epidemic in different regions and seasons was different. EV71 and CoxA16 were the major etiologic agents, but the etiologic constitute showed seasonal changes.

[Epidemiology and etiology of hand-foot-and-mouth disease seen in Jiangsu province from 2008 to 2010].

OBJECTIVE: To analyze the etiological and epidemiological characteristics of hand-foot-and-mouth disease (HFMD) seen in Jiangsu province from 2008 to 2010, and provide evidence for its prevention and control. METHODS: Based on the requirement of supervision program of HFMD, surveillance and report were done according to National Disease Supervision Information Management System. Descriptive epidemiological method, performed between 2008 and 2010, was used to analyze the time, region and population distribution and results of etiologic analysis of HFMD. Nucleic acid of enterovirus (EV) genome was detected by real-time RT-PCR. RESULTS: The average incidence rate of HFMD was 86.70 per million between 2008 and 2010, the peak incidence occurred in April to July. There were significant differences among the incidence in different districts (P<0.05), and the highest incidence was seen in the densely inhabited southern areas of Jiangsu province. Most of the cases were infants and children aged less than 5 years. The number of male cases (2008: 17,008, 2009: 48 768, 2010: 50,231) was much larger than that of the female cases 2008: 9662, 2009: 29 151, 2010: 30,655. The HFMD cases with mild symptoms were caused mainly by enterovirus 71 (EV71) and coxsackievirus A16 (Cox A16) and there was difference among different years. The severe HFMD cases and deaths were mainly caused by EV71 infection. CONCLUSIONS: The epidemiologic characteristics of HFMD in Jiangsu province from 2008 to 2010 had close relationship with season, population and region. The mild cases of HFMD were mainly infected with EV71 and Cox A16. However, EV71 illness seemed to be more severe and had significantly greater frequency of serious complications and fatality than the illness caused by Cox A16.

Geographical information systems-based spatial analysis and implications for syphilis interventions in Jiangsu province, People's Republic of China.

Spatial distribution rules and risk factors for syphilis were studied in Jiangsu province, People's Republic of China during 2005 and 2009. Trend surface analysis, spatial autocorrelation analysis and spatio-temporal clustering were applied with the incidence rates of the various counties in the province to determine spatial distribution rules and risk factors. Syphilis was found to be most severe in the southern region of the province where many counties could be shown to be hotspots with positive autocorrelation. Clusters were detected in the south-western region of Jiangsu with the county-level city of Yixing as the centre. Temperature, distance from railways and highways, and the normalised difference vegetation index were determined as supporting variables with regard to the transmission of the disease by both univariate and multivariate spatial correlation analyses. Interventions, including health education and awareness campaigns, should be strengthened throughout the province targeting the south-western areas, especially the clusters and hotspots detected in order to improve the situation.

[Serologic survey on pandemic influenza A (H1N1) virus among aged ≥ 3 years population from Jiangsu province in 2009, China].

OBJECTIVE: To understand the antibody levels against pandemic influenza A (H1N1) virus (2009 H1N1) among aged ≥ 3 years population in 2009, from Jiangsu province, and to describe the distribution of 2009 H1N1. METHODS: Serum specimens were collected from natural populations at four different periods in Jiangsu, and tested with hemagglutination-inhibition (HI) assays. Rates of protective antibody against 2009 H1N1 and Geometric mean titers (GMTs) were estimated. RESULTS: The rates of protective antibody against 2009 H1N1 rose with the progress of epidemics in Jiangsu, which were 3.46%, 7.59%, 16.94%, respectively in July, August and November, 2009. There were no significant differences on the rates of protective antibody between males and females at four different cross-sectional periods (P > 0.05), and no significant differences on GMTs were observed at different periods except for November 2009. Significant differences on rates of protective antibody and GMTs among various age groups were observed at four different periods (P < 0.05), and similar results were observed among different periods in various age groups (P < 0.05). There were significant differences on rates of protective antibody and GMTs among different areas (P < 0.05). CONCLUSION: The 2009 H1N1 strain had been widely spread out in Jiangsu province since July 2009. People aged 12 - 17 years became the major victims after August. As of November 2009, the rate of protective antibody against 2009 H1N1 was still low, predicting that the epidemic might continue to exist for a certain period of time.

[Study on the strategy of Japanese encephalitis immunization using live attenuated vaccine combined with inactivated vaccine].

OBJECTIVE: Using the advantages of Japanese encephalitis live attenuated and inactivated vaccine, to reduce the rate of immunization reaction and to increase the effect, we conducted a study on the strategy of immunization in Japanese encephalitis using live attenuated vaccine combined with inactivated vaccine. METHODS: Observing the safety and immune effects of different groups. RESULTS: Data on side effect showed that the rate of moderate and severe systematic reactions of the group who were inoculated with combined vaccine was 0.73%, with local reaction 1.46% while the combined rate of moderate and severe systematic reaction of the group who were inoculated with inactivated vaccine was 2.8%. Under the detection of serum neutralizing antibody, the GMT rose from 1:1.05 - 1:3.35 before vaccination to 1:47.34 - 1:101.30 after vaccination in the different groups. Neutralizing antibody was detected in 97.67% of the combined group. There was a significant difference by comparing neutralizing antibody seroconversion rate of the combined group with the inactivated group (chi(2) = 3.89, P < 0.05), but no significant difference with attenuated group (chi(2) = 0.74, P > 0.05). CONCLUSION: Results showed that in children who previously had been immunized with two doses of inactivated vaccine, the booster administration of live attenuated vaccine was both effective and safe.