Genomic epidemiology of dengue in Shantou, China, 2019

ObjectivesDengue has been endemic in Southeast Asian countries for decades. There are few reports tracing the dynamics of dengue in real time. In this study, we generated hundreds of pathogen genomes to understand the genomic epidemiology of an outbreak in a hyper-endemic area of dengue.MethodsWe leveraged whole-genome short-read sequencing (PE150) to generate genomes of the dengue virus and investigated the genomic epidemiology of a dengue virus transmission in a mesoscale outbreak in Shantou, China, in 2019.ResultsThe outbreak was sustained from July to December 2019. The total accumulated number of laboratory-confirmed cases was 944. No gender bias or fatalities were recorded. Cambodia and Singapore were the main sources of imported dengue cases (74.07%, n = 20). A total of 284 dengue virus strains were isolated, including 259 DENV-1, 24 DENV-2, and 1 DENV-3 isolates. We generated the entire genome of 252 DENV isolates (229 DENV-1, 22 DENV-2, and 1 DENV-3), which represented 26.7% of the total cases. Combined epidemiological and phylogenetic analyses indicated multiple independent introductions. The internal transmission evaluations and transmission network reconstruction supported the inference of phylodynamic analysis, with high Bayes factor support in BSSVS analysis. Two expansion founders and transmission chains were detected in CCH and LG of Shantou.ConclusionsWe observed the instant effects of genomic epidemiology in monitoring the dynamics of DENV and highlighted its prospects for real-time tracing of outbreaks of other novel agents in the future

Metal(II) Coordination Polymers from Tetracarboxylate Linkers: Synthesis, Structures, and Catalytic Cyanosilylation of Benzaldehydes

Three 2D coordination polymers, [Cu2(µ4-dpa)(bipy)2(H2O)]n∙6nH2O (1), [Mn2(µ6-dpa)(bipy)2]n (2), and [Zn2(µ4-dpa)(bipy)2(H2O)2]n·2nH2O (3), were prepared by a hydrothermal method using metal(II) chloride salts, 3-(2′,4′-dicarboxylphenoxy)phthalic acid (H4dpa) as a linker, as well as 2,2′-bipyridine (bipy) as a crystallization mediator. Compounds 1–3 were obtained as crystalline solids and fully characterized. The structures of 1–3 were established by single-crystal X-ray diffraction, revealing 2D metal-organic networks of sql, 3,6L66, and hcb topological types. Thermal stability and catalytic behavior of 1–3 were also studied. In particular, zinc(II) coordination polymer 3 functions as a highly active and recoverable heterogeneous catalyst in the mild cyanosilylation of benzaldehydes with trimethylsilyl cyanide to give cyanohydrin derivatives. The influence of various parameters was investigated, including a time of reaction, a loading of catalyst and its recycling, an effect of solvent type, and a substrate scope. As a result, up to 93% product yields were attained in a catalyst recoverable and reusable system when exploring 4-nitrobenzaldehyde as a model substrate. This study contributes to widening the types of multifunctional polycarboxylic acid linkers for the design of novel coordination polymers with notable applications in heterogeneous catalysis

Hepatitis E virus serosurvey among pet dogs and cats in several developed cities in China.

Infection by Hepatitis E virus (HEV), as a zoonotic disease virus, is well studied in pigs in China, but few studies in pets have been performed. This study was designed to characterize the prevalence of HEV infection among pet dogs and cats in major metropolitan areas of China. We conducted a seroepidemiological survey from 2012 to 2013 in 5 developed cities, Beijing, Shanghai, Canton, Shenzhen and Macao, by enzyme-linked immunosorbent assay (ELISA). The overall HEV seroprevalence in 658 dog and 191 cat serum samples was 21.12% and 6.28%, respectively. The analysis in dogs suggested that there were significant differences among cities, and the positive rate of HEV-specific antibody in all cities ranged from 6.06% (Shenzhen) to 29.34% (Beijing). Older pet cats have a high risk (OR, 10.25) for HEV seropositivity, but no strong relationship was observed between different genders and age groups. Additionally, it was revealed that stray dogs, omnivorous pet dogs and pet cats who share food, such as kitchen residue, with the general population would have a higher risk for HEV seropositivity. The odds ratios for these groups are 2.40, 2.83 and 5.39, respectively, compared with pet dogs and cats fed on commercial food. In this study, we first report that HEV is prevalent in pet dogs and cats in several large cities in China. Swill and kitchen residue may be a potential risk for HEV transmission from human to pets. As the sample size was relatively small in this study and may not be fully representative of China, further investigation is required to confirm the conclusions

The anti-HEV rates of the population in Guangdong province, China, according to age, gender, and pig-exposure status.

<p>a: OR, odds ratio; b: 95%CI, 95%confidence interval; c: X², Chi-Square Test; d: ref, reference; UF, urban female; UM, urban male; FF, swine farm female; FM, swine farm male; **, significant difference; *, different.</p

The estimated seroprevalence of the hepatitis E virus in Guangdong Province.

<p>The best fit trendline for the positive rate data was selected based on the R-squared value of the curves drawn using the Microsoft Office Excel 2007 program (Microsoft, Redmond, WA). 1. Overall gender-specific seroprevalence; 2. Gender-specific seroprevalence of swine farm; 3. Gender-specific seroprevalence of the general population; 4. Overall population-specific seroprevalence; 5. Population-specific seroprevalence of females; 6. Population-specific seroprevalence of males.</p

A phylogenetic tree based on the full nucleotide sequence of HEV.

<p>Total RNA positive bile samples are 48, from 9 different districts in Guangdong. We have chosen at least one sample from each district by random sampling. The amplification products of ORF2 (509 nucleotides, primer sequences were HEV-INF and HEV-INR as described above) from 10 positive bile samples were sequenced and compared. The nucleotide sequence identity among the 10 swine HEV isolates obtained from pigs from different farms in three years ranged between 94.3 and 99.8%. Phylogenetic trees were constructed by the neighbor-joining method based on the partial nucleotide sequence of the ORF2 region (509 nucleotides). The bootstrap values (expressed as percentages) were determined on 1000 re-samplings of the data sets. △were the isolates in this study.</p

The prevalence of HEV RNA in pig bile samples collected from the Pearl River Delta. ^b

b<p>Pig bile samples have been collected from 9 districts of the Pearl River Delta since 2011.</p

The prevalence of antibodies against HEV among pigs in 2011–2013, Guangdong Province, China.

<p>a: OR, odds ratio;</p><p>b: 95%CI, 95%confidence interval;</p><p>c: X², Chi-Square Test;</p><p>d: ref, reference.</p

Fourfold plot for odds ratio (OR).

<p>Univariate analysis results are presented in the Fourfold plot diagram. Fourfold display for seropositive data of sows: Evidence for pig herds bias or multiparity bias? The area of eachshaded quadrant shows the frequency, standardized to equate the margins for different herds and seropositive. Circular arcs show the limits of a 95% confidence interval for the odds ratio. 1. Compared with nursery pigs, the OR of growing pigs was 3.51(95%CI, 1.95–6.33; p<0.0001); 2. Compared with nursery pigs, the OR of sows was 5.04(95%CI, 3.27–7.77; p<0.0001); 3. Compared with nursery pigs, the OR of boars was 21.56(95%CI, 9.47–49.10; p<0.0001); 4. Compared with pre-farrowing sows, the OR of multiparous sows was 2.46(95%CI, 1.45–4.18; p<0.01).</p