Seroepidemiology of enterovirus D68 in a healthy population in Beijing, China, between 2012 and 2017: A retrospective study.

To investigate the seroepidemiological features of enterovirus D68 (EV-D68) in the healthy population from 2012 to 2017 in Beijing, China. A retrospective cross-sectional investigation was conducted using serum specimens collected from healthy individuals in Beijing from 2012 to 2017. These samples were tested for neutralization antibodies (NtAbs) against EV-D68. The sera from six EV-D68 infected patients in the acute or convalescent phase were used to determine the protection level of NtAbs against EV-D68. The geometric means of the titers (GMT) of EV-D68 NtAbs in 2012 and 2017 were 92.82 and 242.91, respectively; the seroprevalences of EV-D68 were 89.43% and 98.43%, respectively. The GMT reached its peak in the 11 to 15 age group in 2012, while in 16 to 20 age group in 2017. We also observed that EV-D68 NtAbs titers of six sera from the acute phase were all less than equal to 1:64 and that of three sera from the convalescent phase were all more than 1:64. Anti-EV-D68 NtAbs in the population remained low from 2012 to 2016 but increased significantly in 2017. Although most of the EV-D68 infections remain undetected in Beijing, the risk of a large outbreak of EV-D68 exists and should be taken seriously.

Human Enterovirus C105, China, 2017.

We report a case of enterovirus C105 infection in an 11-year-old girl with lower respiratory tract symptoms that was identified through the Respiratory Virus Surveillance System, which covers 30 sentinel hospitals in all 16 districts of Beijing, China. The presence of this virus strain in China confirmed its geographically wide distribution.

Comparison of the prevalence of respiratory viruses in patients with acute respiratory infections at different hospital settings in North China, 2012-2015.

BACKGROUND: Acute respiratory infections (ARIs) are a great public health challenge globally. The prevalence of respiratory viruses in patients with ARIs attending at different hospital settings is fully undetermined. METHODS: Laboratory-based surveillance for ARIs was conducted at inpatient and outpatient settings of 11 hospitals in North China. The first 2-5 patients with ARIs were recruited in each hospital weekly from 2012 through 2015. The presence of respiratory viruses was screened by PCR assays. The prevalence of respiratory viruses was determined and compared between patients at different hospital settings. RESULTS: A total of 3487 hospitalized cases and 6437 outpatients/Emergency Department (ED) patients were enrolled. The most commonly detected viruses in the hospitalized cases were respiratory syncytial virus (RSV, 33.3%) in children less than two years old, adenoviruses (13.0%) in patients 15-34 years old, and influenza viruses (IFVs, 9.6%) in patients ≥65 years. IFVs were the most common virus in outpatient/ED patients across all age groups (22.7%). After controlling for the confounders caused by other viruses and covariates, adenoviruses (adjusted odds ratio [aOR]: 3.97, 99% confidence interval [99% CI]: 2.19-7.20) and RSV (aOR: 2.04, 99% CI: 1.34-3.11) were independently associated with increased hospitalization in children, as well as adenoviruses in adults (aOR: 2.14, 99% CI: 1.19-3.85). Additionally, co-infection of RSV with IFVs was associated with increased hospitalization in children (aOR: 12.20, 99% CI: 2.65-56.18). CONCLUSIONS: A substantial proportion of ARIs was associated with respiratory viruses in North China. RSV, adenoviruses, and co-infection of RSV and IFVs were more frequent in hospitalized children (or adenoviruses in adults), which might predict the severity of ARIs. Attending clinicians should be more vigilant of these infections.

Respiratory infections associated with enterovirus D68 from 2011 to 2015 in Beijing, China.

Enterovirus D68 (EV-D68) is an emergent viral pathogen associated with mild to severe respiratory infections. In this study, we describe respiratory infections associated with EV-D68 in Beijing over a 4 year period. Total nucleic acid was extracted from 7,945 clinical specimens collected between January 5, 2011 and July 30, 2015 in Beijing and used for detecting EV-D68 and other enteroviruses by real-time PCR. Overall, 555/7,945 (6.99%) specimens were enterovirus positive: 12/7,945 (0.2%) specimens were EV-D68 positive. Of these patients, 11 were pediatric patients and 1 was a 76-year-old man. The main symptoms for the 12 EV-D68 positive patients were fever (10/12, 83.3%) and cough (6/12, 50%). Ten EV-D68 infection cases were identified in autumn or winter season. The phylogenetic relationships of the 12 EV-D68 viral strains with other strains were analyzed based on the sequences of viral protein 1(VP1). The EV-D68 strains from 2011 to 2013 belonged to groups 1 or 3, while all strains in 2014 were clustered into group 1 together with the strains circulating in the USA. In conclusion, EV-D68 played a role in respiratory infections in Beijing during this period. In addition, the most common EV-D68 strain detected was similar to that circulating in the USA in 2014. J. Med. Virol. 88:1529-1534, 2016. © 2016 Wiley Periodicals, Inc.

Retina images classification based on 2D empirical mode decomposition and multifractal analysis.

Diabetic retinopathy is an ocular disease caused by long-term damage to the retina due to high blood sugar levels. Elevated blood sugar can impair the microvasculature in the retina, leading to vascular abnormalities and the formation of abnormal new blood vessels. These changes can manifest in the retina as hemorrhages, leaks, vessel dilation, retinal edema, and retinal detachment. The retinas of individuals with diabetes exhibit different morphologies compared to those without the condition. Most histological images cannot be accurately described using traditional geometric shapes or methods. Therefore, this study aims to evaluate and classify the morphology of retinas with varying degrees of severity using multifractal geometry. In the initial experiments, two-dimensional empirical mode decomposition was employed to extract high-frequency detailed features, and the classification process was based on the most relevant features in the multifractal spectrum associated with disease factors. To eliminate less significant features, the random forest algorithm was utilized. The proposed method achieved an accuracy of 96%, sensitivity of 96%, and specificity of 95%.

Rubella epidemic caused by genotype 1E rubella viruses in Beijing, China, in 2007-2011.

BACKGROUND: A series of different rubella vaccination strategies were implemented to control rubella and prevent congenital rubella virus infection in Beijing, China. The rubella vaccine was available in 1995 in Beijing, and was introduced into the Beijing immunization program (vaccine recipients at their own expense vaccination) in 2000, and was introduced into the National Expanded Program on Immunization (vaccine recipients free vaccination) in 2006. Rubella virological surveillance started in Beijing in 2007. RESULTS: The reported rubella incidence rate has decreased dramatically due to the introduction of the vaccine in Beijing since 1995. However, rubella epidemics occurred regardless in 2001 and 2007. The incidence rate among the floating population has gradually increased since 2002, reaching 2 or more times that in the permanent resident population. The peak age of rubella cases gradually changed from <15 years of age to adults after 2005. Phylogenetic analysis was performed and a phylogenetic tree was constructed based on the World Health Organization standard sequence window for rubella virus isolates. All Beijing rubella virus isolates belong to genotype 1E/cluster1 and were clustered interspersed with viruses from other provinces in China. The effective number of infections indicated by a Bayesian skyline plot remained constant from 2007 to 2011. CONCLUSIONS: The proportion of rubella cases among the floating population has increased significantly in Beijing since 2002, and the disease burden gradually shifted to the older age group (15- to 39-year olds), which has become a major group with rubella infection since 2006. Genotype 1E rubella virus continuously caused a rubella epidemic in Beijing in 2007-2011 and was the predominant virus, and all Beijing genotype 1E viruses belong to cluster 1, which is also widely circulated throughout the country.

[Rapid identification of Beijing measles vaccine virus and wild virus by multiplex real-time fluorescent PCR].

OBJECTIVE: To identify wild measles virus and vaccine virus by detection nucleic acid of clinical samples from measles patients with immunization history circulating in Beijing through multiplex real-time fluorescent PCR technology. METHODS: From July 2011 to February 2012, 10 throat swabs and 15 urine specimens were collected from 16 suspected measles patients who were 8 - 9 months old infants with immunization history in Beijing. The specificity of multiplex real-time fluorescent PCR was firstly tested by measles vaccine virus, wild virus and other respiratory virus. Then the vaccine virus and wild virus were titrated and diluted to test the sensitivity of the PCR method. The result was then compared with it analyzed by PCR-RFLP method. Meanwhile, the clinical sample of the measles patients were tested and confirmed by sequencing method. RESULTS: The primer-probe sets of Fam, Joe and Cy5 showed great specificity of measles virus, and could distinguish the measles vaccine virus and wild virus well. The sensitivity of this method to detect measles vaccine virus reached 0.1 CCID(50)/0.1 ml; and the sensitivity to wild virus reached 0.006 CCID(50)/0.1 ml; which were both higher than the sensitivity of PCR-RFLP method. Out of the 16 measles patients with vaccination history, 3 were negative and the other 13 all belonged to measles virus genotype A, and were confirmed to be vaccine virus by sequencing method. CONCLUSION: Multiplex real-time PCR method is accurate, rapid and sensitive to identify measles vaccine virus and wild virus. The method could greatly help us to find measles patients and to identify the vaccine-related cases.

Seroepidemiology of pertussis in China: A population-based, cross-sectional study.

BACKGROUND: Despite high pertussis vaccination coverage and significant decrease of pertussis since the adoption of the Expanded Programme on Immunization (1978), increased pertussis incidence has been reported in China from 2013 to 2017. This study aimed at evaluating the immune response to pertussis among vaccinated children and beyond in China. METHODS: The study recruited 2 144 healthy subjects. Serum IgG antibodies against pertussis toxin (anti-PT IgG) were measured by ELISA. Anti-PT IgG concentration (GMC), seropositivity rate (GMC ≥ 40 IU/ml), and recent infection rate (GMC > 100 IU/ml) were calculated. Participants ≤ 2 years-old were further stratified by vaccination schedule intervals and participants ≤ 6 years-old by vaccine used (Domestic DTaP or DTaP-IPV//PRP ~ T (Pentaxim, SP)). RESULTS: Among 0-6-year-olds, the anti-PT IgG GMC was 5.99 IU/ml (95%CI 5.39-6.67). The GMC increased in accordance with the primary vaccination series (4-6 months) and the toddler booster (18-23 months), and continuously declined thereafter to its nadir at 6 years-old [3.72 IU/ml (95%CI 2.91-4.77)]. GMCs were markedly higher in those vaccinated with DTaP-IPV/PRP ~ T compared to DTaP. In individuals > 6 years-old, the GMC was 5.67 IU/ml (95%CI 5.36-6.00), the seropositivity rate was 6.7% (95%CI 5.5-7.9) and the recent infection rate was 1.2% (95%CI 0.7-1.7). The seropositivity rates increased from 6 years-old and peaked at 9 years-old (10.3% [95%CI 0.7-19.8]). CONCLUSIONS: Vaccination against pertussis increases anti-PT IgG, but wanes over time. The sero-estimated infection rates increase from school age and peak at about 9 years-old. These results support the addition of a booster of pertussis vaccine at preschool age.

Response of water quality to land use in hydrologic response unit and riparian buffer along the Dan River, China.

Land uses determine water quality within riparian environments to a certain extent and directly affect human health via drinking water. The main objective of this paper is to investigate the influences of land use, both in hydrologic response units (HRUs) and 200-m-wide buffer areas, on surface water quality. The variations and interrelationships between water physicochemical properties and land uses were assessed for better management of water environment. Nitrogen was the dominant nutrient and was significantly correlated with other water quality parameters. In the HRUs and buffer areas, the dominant landscape was grassland and farmland, respectively. Total organic carbon (TOC) and dissolved oxygen (DO) had negative correlation with land use factors; nitrate nitrogen, total nitrogen, total phosphorus, electrical conductivity, and temperature, in contrast, were positively correlated with them. Industrial and residential land was the critical land use for the aquatic environment in the Dan River, indicating that point pollution should receive more attention. Vegetation area had strong regression relationships with TOC and DO. Furthermore, more specific types of land use (subcategory classification) had a greater role in water quality. The land use in buffers can act on the water body more directly and effectively.

[Herd immunity against new influenza A (H1N1) in pre-vaccinated residents aged over 5 years in Beijing].

OBJECTIVE: To explore the herd immunity against influenza A (H1N1) in pre-vaccinated residents aged over 5 years, and therefore to provide data for vaccination policies in high risk populations. METHODS: From October to December 2009, Beijing CDC conducted a serum survey of the novel influenza A (H1N1) in the local residents, stratified in 10 age groups between 5 years to over 60 years, without H1N1 vaccination history and disease history. Hemagglutination inhibition (HI) assays were performed at Beijing CDC. Statistical significance was determined with geometric mean titer (GMT). RESULTS: 3499 serum samples were tested for HI antibody. The average level of HI antibody was 1:8.03, and 11.06% (387/3499) were sero-positive (HI antibody level ≥ 1:40). In the group aged from 5 to 19 years, the level of HI antibody and the sero-positive rate were higher (HI antibody > 1:8.9, sero-positive rate > 12%). CONCLUSIONS: The antibody levels in different groups were affected by age specific morbidity, and the higher antibody level of the school-age group was correlated with higher disease intensity in this population. The data showed that the herd immunity in Beijing was under the optimal level, but influenza A (H1N1) would probably become prevalent in the short coming future.

Reducing Nitrogen and Phosphorus Losses from Different Crop Types in the Water Source Area of the Danjiang River, China.

Nitrogen and phosphorus are essential for plant growth and are the primary limiting nutrient elements. The loss of nitrogen and phosphorus in agricultural systems can cause the eutrophication of natural water bodies. In this paper, a field simulated rainfall experiment was conducted in a typical small watershed of the Danjiang River to study the nutrient loss process of nitrogen and phosphorus in slope croplands subjected to different crops and tillage measures. The characteristics of the runoff process and nutrient migration of different slope treatments were studied, which were the bare-land (BL, as the control), peanut monoculture (PL), corn monoculture (CL), bare land (upper slope) mixed with peanut monoculture (lower slope) (BP), corn and peanut intercropping (TCP), corn and soybean intercropping (TCS), downslope ridge cultivation (BS) slope, and straw-mulched (SC), respectively. The results showed that the runoff of CL, SC, TCS, BS, BP, PL and TCP slope types were 93%, 75%, 51%, 39%, 28%, 12%, and 6% of the those of the bare land, respectively. The total nitrogen concentration in runoff on different slope types decreased in the order of BP > PL > BS > SC > TCP > BL > CL > TCS. The BL was characterized with the highest NRL-TN (the loss of total nitrogen per unit area), with the value of 1.188 kg/hm2, while those of the TCP is the smallest with the value of 0.073 kg/hm2. The total phosphorus concentration in runoff decreasd in the order of BS > BP > PL > BL > TCP > SC > CL > TCS. The PRL-TP (the loss of total phosphorus per unit area) of BL is the largest (0.016 kg/hm2), while those of TCP is the smallest (0.001 kg/hm2). These indicate that the loss of nitrogen is much higer than that of phosphorus. The loss of nitrogen in runoff is dominated by nitrate nitrogen, which accounts for 54.4%-78.9% of TN. Slope croplands in the water source area should adopt the tillage measures of TCP and PL.These measures can reduce 85% of the runoff of nitrogen and phosphorus compared to the bare land. The results may assist in agricultural non-point source pollution control and help promote improved management of the water environment in the Danjiang River's water source area.

Spatial Distribution Characteristics and Pollution Evaluation of Soil Iron in the Middle Hanjiang River.

Soil iron has an important impact on the ecological environment and on crop growth. This study selected a typical small watershed basin in the middle reaches of the Han River (Yujiehe) at Ankang City and used geostatistical methods and kriging interpolation to analyze the spatial distribution and structure of soil iron content for different land uses and at different depths, using the single-factor pollution evaluation to evaluate the pollution degree of soil iron. The results showed that soil iron in the Yujie River basin decreased with increasing soil depth, with contents of 8.80 mg/kg, 5.52 mg/kg, and 4.92 mg/kg at depths A1 (0-20 cm), A2 (20-40 cm), and A3 (40-60 cm). According to the classification index of effective trace elements in soil, the average contents of soil iron at these three depths were between 4.5 and 10 mg/kg, which are all considered moderate values. The coefficients of variation of soil iron at the three soil depths were 59%, 75%, and 83%, all of which showed moderate spatial variability, and the coefficient of variation increased gradually with soil depth. With semi-variance calculated at the three soil depths, soil iron optimal theoretical models were all exponential models with nugget coefficients of 9.52%, 47.76%, and 33.93%, indicating that spatial correlation was very strong in the A1 layer and moderate in the A2 and A3 layers. The spatial distribution of soil iron showed some variation in the study area, and the soil content was higher in the midwestern part in the A1 and A2 layers; however, in the A3 layer, the higher content was in the center and lower content was in the southern region. Correlations were significant between soil iron content on the one hand and land-use type and topographic factors on the other. The pollution indices of soil iron at the three soil depths under different land uses were all greater than 1.0, with the A1 layer in farmland being the worst, at 3.34. In the study area, using the background value of soil iron as an evaluation standard, the soil iron content of more than 65% of the Yujiehe region exceeded this standard.

Upsurge of Enterovirus D68 and Circulation of the New Subclade D3 and Subclade B3 in Beijing, China, 2016.

We conducted a surveillance among acute respiratory tract infection (ARTI) cases to define the epidemiology, clinical characteristics and genetic variations of enterovirus D68 (EV-D68) in Beijing, China from 2015 to 2017. Nasopharyngeal swabs and sputum were collected from 30 sentinel hospitals in Beijing and subjected to EV and EV-D68 detection by real-time PCR. The VP1 gene region and complete genome sequences of EV-D68 positive cases were analyzed. Of 21816 ARTI cases, 619 (2.84%) were EV positive and 42 cases were EV-D68 positive. The detection rates of EV-D68 were 0 (0/6644) in 2015, 0.53% (40/7522) in 2016 and 0.03% (2/7650) in 2017, respectively. Two peaks of EV-D68 infections occurred in late summer and early-winter. Ten cases (23.81%) with upper respiratory tract infection and 32 cases (76.19%) presented with pneumonia, including 3 cases with severe pneumonia. The phylogenetic analysis suggested 15 subclade D3 strains and 27 subclade B3 strains of EV-D68 were circulated in China from 2016 to 2017. A total of 52 amino acid polymorphisms were identified between subclades D1 and D3. These data suggest an upsurge of EV-D68 occurred in Beijing in 2016, the new subclade D3 emerged in 2016 and co-circulated with subclade B3 between 2016 and 2017.

Distribution of the atypical pathogens of community-acquired pneumonia to disease severity.

BACKGROUND: To investigate the epidemiological characteristics of 11 atypical pathogens of community-acquired pneumonia (CAP) among Chinese, and to determine whether or not there is an association between these pathogens and the severity of illness. METHODS: We conducted a surveillance study for CAP in 30 hospitals of Beijing. Epidemiological data and clinical specimens were systematically collected from enrolled CAP patients. The detection for 11 atypical pathogens [9 respiratory viruses, Mycoplasma pneumoniae (MP) and Chlamydophila pneumoniae (CP)] was performed. Risk factors of severe CAP and death in Hospital were evaluated. RESULTS: A total of 6,008 CAP patients [including 1,071 severe CAP (SCAP)] were enrolled. The overall detection rate of the 11 atypical pathogens was 42.4% among 1,925 child CAP (39.9% among 274 child SCAP), and 25.8% among 4,083 adult CAP (22.8% among 797 adult SCAP). The most frequent atypical pathogen among child SCAP was parainfluenza virus (10.2%) followed by respiratory syncytial virus (RSV) (8.4%). However, the most frequent atypical pathogen among adult SCAP was influenza virus (8.9%) followed by parainfluenza virus (3.8%). Multivariate analyses showed that the important predictors for SCAP were an age ≤9 years, an age ≥65 years and co-existing diseases. These factors, except an age ≤9 years, were also predictors of death in Hospital. None of these 11 atypical pathogens was included as the risk factors of SCAP or death in Hospital. CONCLUSIONS: Although these 11 atypical pathogens were the common causes of CAP (including SCAP) among Chinese, they were not observed to increase risks for SCAP or death in Hospital.

The molecular characterization of serogroup C Neisseria meningitidis strains circulating in Beijing.

The aim of this study was to characterize the molecular features of serogroup C Neisseria meningitidis strains circulating in Beijing, China. Twenty out of 23 strains belonged to ST 4821. The causative serosubtype for meningococcal meningitis was P1.12-1,16-8. All of the strains expressed class 3 PorB protein. Among the five pulsed-field gel electrophoresis patterns observed, pattern III predominated.

Laboratory confirmation of a suspicious meningococcal meningitis death case.

A suspicious meningococcal meningitis death case was reported to the Beijing CDC. The blood specimen was analyzed via multi-PCR and MLST. 6 isolates from close contacts were analyzed via PFGE and MLST. According to the results of the above analyses, the cause of this case was identified as a serogroup A Neisseria meningitidis, which, in terms of sequence typing, belonged the ST7 group.

Cloning and biochemical properties of CDPK gene OsCDPK14 from rice.

A rice CDPK gene, OsCDPK14 (AY144497), was cloned from developing caryopses of rice (Oryza sativa cv. Zhonghua 15). Its cDNA sequence (1922 bp) contains an ORF encoding a 514 amino acids protein (56.7kD, pl 5.18). OsCDPK14 shows the typical structural features of the CDPK family, including a conserved catalytic Ser/Thr kinase domain, an autoinhibitory domain and a CaM-like domain with four putative Ca2+-binding EF hands. Subcellular targeting indicated that OsCDPK14 was located in the cytoplasm, probably due to the absence of myristoylation and palmitoylation motifs. OsCDPK14 was expressed in Escherichia coli and purified from bacterial extracts. The recombinant protein was shown to be a functional protein kinase using Syntide-2, a synthetic peptide. Kinase activity was shown to be Ca2+-dependent, and this activation was strongly enhanced by Mn2+ and inhibited by W7 in vitro. These results provide significant insights into the regulation and biochemical properties of OsCDPK14, suggesting OsCDPK14 may be a signal factor of cytoplasm in rice plant.

Seroepidemiology of diphtheria and pertussis in Beijing, China: A cross-sectional study.

The aim of this study was to assess the level of humoral immunity against diphtheria and pertussis by measuring IgG to diphtheria toxoid (DT) and pertussis toxin (PT) in general population of Beijing. A total of 2147 subjects aged 0-74 y were selected with a random sample of resident population in Beijing. The information of socio-demographic characteristics, vaccination history, disease history of diphtheria and pertussis were collected for each subject by questionnaire. Serum samples were tested for IgG antibodies to DT and PT by using commercial ELISA kits. The overall positivity rate of anti-DT IgG was 66.28% with the mean concentration of 2.169 IU/ml. Age stratified data showed that the highest positivity rate of 97.63% was observed in 1-4 y and the rates decreased with age. The positivity rates were only around 50% or below since 25 y old. The positivity rate of anti-PT IgG was 12.34% with the mean concentration of 15.163 IU/ml. The highest level of positivity rate (22.23%) and antibody level (23.101 IU/ml) was seen in <1 year old. In subjects older than 10 y old, the anti-PT IgG positivity rate was 10.19%-13.51% and concentration was 13.295 IU/ml -16.353 IU/ml, with no significant differences between these groups (χ2 = 1.664, P = 0.948; F = 0.369, P = 0.899). The subjects with anti-PT IgG ≥ 100 IU/ml were observed in nearly all the groups older than 5 y except for 10-14 age group. The estimated incidences of pertussis infection were higher than 6000/100000 in these age groups. A sharp increase of immunity level of diphtheria was observed at 1 y and 6 y respectively, which was consistent with the current immunization schedule. But there was no significant increase of immunity to pertussis observed after booster immunization at 18-24 months, but the proportions of undetectable were lowest in <1, 1, 2 years in children <14 years. As shown in the present study, the adult population was generally lack of protective antibody against diphtheria and all the age groups showed a low immunity to pertussis indicating the potential risk of transmission and outbreaks of the 2 diseases in Beijing.