The changing epidemiology of dengue in China, 1990-2014: a descriptive analysis of 25 years of nationwide surveillance data.

BACKGROUND: Dengue has been a notifiable disease in China since 1 September 1989. Cases have been reported each year during the past 25 years of dramatic socio-economic changes in China, and reached a historical high in 2014. This study describes the changing epidemiology of dengue in China during this period, to identify high-risk areas and seasons and to inform dengue prevention and control activities. METHODS: We describe the incidence and distribution of dengue in mainland China using notifiable surveillance data from 1990-2014, which includes classification of imported and indigenous cases from 2005-2014. RESULTS: From 1990-2014, 69,321 cases of dengue including 11 deaths were reported in mainland China, equating to 2.2 cases per one million residents. The highest number was recorded in 2014 (47,056 cases). The number of provinces affected has increased, from a median of three provinces per year (range: 1 to 5 provinces) during 1990-2000 to a median of 14.5 provinces per year (range: 5 to 26 provinces) during 2001-2014. During 2005-2014, imported cases were reported almost every month and 28 provinces (90.3%) were affected. However, 99.8% of indigenous cases occurred between July and November. The regions reporting indigenous cases have expanded from the coastal provinces of southern China and provinces adjacent to Southeast Asia to the central part of China. Dengue virus serotypes 1, 2, 3, and 4 were all detected from 2009-2014. CONCLUSIONS: In China, the area affected by dengue has expanded since 2000 and the incidence has increased steadily since 2012, for both imported and indigenous dengue. Surveillance and control strategies should be adjusted to account for these changes, and further research should explore the drivers of these trends.

[Analysis of epidemiology characteristics of norovirus among diarrheal outpatients in 27 provinces in China, 2009-2013].

OBJECTIVE: To investigate the epidemiology characteristics of norovirus among diarrheal outpatients in China. METHODS: Diarrhea cases were monitored at emergency/outpatient departments at 173 hospitals in 27 provinces of China, with clinical and epidemiological data, and fecal specimens collected and sent to 58 network-laboratories to detect norovirus by RT-PCR method, and to analyze the positive rate of norovirus in various regions, population and time during 2009-2013. RESULTS: 11.6% of the 34 031 diarrheal cases under surveillance were found with norovirus. Age group of 6-23 month-old children and that of people over 45 years old were found with the highest positive percentage, 13.7% and 12.4% respectively. Positive percentage of norovirus peaks in autumn and winter in a year; it peaks in mid-temperate zones (10.7%) and warm-temperate zones (11.6%) in winter. It peaks in sub-tropical zones in autumn (14.3%). The most prevalent genogroups detected were norovirus G II, accounting for 89.9% of identified strains. CONCLUSION: Norovirus affects all ages and was most prevalent in children and the elderly among diarrhea outpatients. Norovirus' positive percentage showed strong seasonal pattern, and peaks at different times of a year in different climate zones of China. Since no effective preventive measures existed, further study on norovirus epidemiology and intervention strategies should be conducted in future.

Etiology of diarrhea among children under the age five in China: Results from a five-year surveillance.

OBJECTIVES: Diarrhea is a leading cause of morbidity and mortality for children, although sparse data is available on the etiology of diarrhea in China. This study was conducted to determine main causes that underlie childhood diarrhea and related diseases. METHOD: Surveillance data for diarrhea was collected from 213 participating hospitals between 2009 and 2013. These stool specimens, from children aged 0-59 months, were then analyzed for a panel of etiological agents consisting of 5 viruses, 8 bacteria and 3 protozoa. The proportion of children who tested positive for each pathogen was calculated and seasonal patterns for major organisms were determined. RESULTS: Pathogens were identified in 44.6% of the 32,189 samples from children with diarrhea. The most commonly detected pathogens were rotavirus (29.7% of cases), norovirus (11.8%), Diarrheagenic Escherichia coli (DEC; 5.0%), adenovirus (4.8%), non-typhoidal Salmonella (NTS; 4.3%), and Shigella spp. (3.6%). A strong seasonal pattern was observed for these organisms, including rotavirus (winter), norovirus (autumn), and DEC, NTS, and Shigella (summer). CONCLUSION: A wide range of enteropathogens were detected in this five-year surveillance study; rotavirus and norovirus were most common among children under the age five. These findings should serve as robust evidence for public health entities when planning and developing national intervention programs in China.

Enzymatic activity enhancement of non-covalent modified superoxide dismutase and molecular docking analysis.

The enzyme activity of superoxide dismutase was improved in the pyrogallol autoxidation system by about 27%, after interaction between hydroxypropyl-ß-cyclo-dextrin and superoxide dismutase. Fluorescence spectrometry was used to study the interaction between hydroxypropyl-ß-cyclodextrin and superoxide dismutase at different temperatures. By doing this, it can be found that these interactions increase fluorescence sensitivity. In the meantime, the synchronous fluorescence intensity revealed the interaction sites to be close to the tryptophan (Trp) and tyrosine (Tyr) residues of superoxide dismutase. Furthermore, molecular docking was applied to explore the binding mode between the ligands and the receptor. This suggested that HP-ß-CD interacted with the B ring, G ring and the O ring and revealed that the lysine (Lys) residues enter the nanocavity. It was concluded that the HP-ß-CD caused specific conformational changes in SOD by non-covalent modification.