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Background: Psoriasis is one of the chronic and autoimmune skin diseases. It is important to uncover the mechanisms underlying the psoriasis. Transcription factor activator protein (TFAP-2) gamma, also known as AP2-gamma, is a protein encoded by the TFAP2C gene. Immunemediated pathophysiological processes could be linked to psoriasis, but the mechanism is still unclear. Therefore, to date the cause of psoriasis has not been understood completely. Materials and methods: Psoriasis is a complex disease triggered by genetic, immunological, and environmental stimuli. Keratinocytes play an important role in both initiation and maintenance phases of psoriasis. A psoriatic keratinocyte model was established by stimulating high sensitivity of human epidermal keratinocytes (HaCaT) to topoisomerase inhibitor cell lines using the accumulation of M5 cytokines comprising interleukin (IL)-17A, IL-22, oncostatin M, IL-1α, and tumor necrosis factor-α (TNF-α). The TFAP2C and transcriptional enhanced associate domain 4 (TEAD4) genes expression was evaluated by reverse transcription-quantitative polymerase chain reaction. Western blot analysis was used to examine protein expression. Cell viability (quantitative) of keratinocytes, including cytotoxicity, proliferation, and cell activation, was evaluated by the MTT assay. The relative percentage values of interleukin (IL)-17a, interferon gamma, and IL-4+ cells were measured by flow cytometry. Accordingly, chromatin immunoprecipitation and luciferase reporter assays were applied to evaluate the binding affinity of TFAP2C and TEAD4 promoter. Results: Level of the TFAP2C gene was elevated in the lesional skin of psoriasis patients. On the other hand, silencing of the TFAP2C gene suppressed the proliferation and inflammatory response in M5-induced keratinocytes. In addition, inhibition of TFAP2C alleviated imiqui-mod (IMQ)-induced skin injury in mice model. We also observed that suppression of TFAP2C inhibited the activation of T-helper 17 (Th17) and Th1 cells in IMQ-induced mice model. Mechanically, TFAP2C promoted TEAD4 transcriptional activation. Conclusion: TFAP2C exacerbated psoriasis-like inflammation by increasing the activation of Th17 and Th1 cells by regulating TEAD4 transcription. This finding clearly indicated that TFAP2C could be considered a valuable biomarker for the prevention and treatment for psoriasis.

As a continuous antenna, the leaky coaxial cable (LCX) is widely used in wireless communication of closed or semi-closed areas such as the subway, mine, tunnel, etc. Usually, LCX networks are required in coal mines. Its channel characteristics are of great significance to mobile communication and mine safety. This paper presents an effective channel modeling and optimization method that combines the state transition and the particle swarm optimization (PSO) algorithms for the LCX network. First, a channel model can be established with a few parameters based on the state transition method, which can describe the complex transfer function of the LCX network; then, taking the transfer characteristics of the LCX network as the optimization objective, which should be consistent with the measured results. And the established objective function is optimized and designed with the PSO algorithm. Finally, the proposed method is validated by comparing the measured results and the model-based simulations on two test LCX networks. The experimental results show that the absolute error between the proposed model and the measurement model is less than that of other models at any frequency point. The proposed model can accurately obtain all responses between point-to-point channels at one time. It will help to accurately obtain the performance of different LCX networks and help to detect and locate faults in future studies.

Background More than 2 months have passed since the novel coronavirus disease 2019 (COVID-19) first emerged in Wuhan, China. With the migration of people, the epidemic has rapidly spread within China and throughout the world. Due to the severity of the epidemic, undiscovered transmission of COVID-19 deserves further investigation. The aim of our study hypothesized possible modes of SARS-CoV-2 transmission and how the virus may have spread between two family clusters within a residential building in Guangzhou, China. Methods In a cross-sectional study, we monitored and traced confirmed patients and their close contacts from January 11 to February 5, 2020 in Guangzhou, China, including 2 family cluster cases and 61 residents within one residential building. The environmental samples of the building and the throat swabs from the patients and from their related individuals were collected for SARS-CoV-2 and tested with real-time reverse transcriptase polymerase chain reaction (RT-PCR). The relevant information was collected and reported using big data tools. Results There were two notable family cluster cases in Guangzhou, which included 3 confirmed patients (family No.1: patient A, B, C) and 2 confirmed patients (family No.2: patient D, E), respectively. None of patients had contact with other confirmed patients before the onset of symptoms, and only patient A and patient B made a short stop in Wuhan by train. Home environment inspection results showed that the door handle of family No.1 was positive of SARS-CoV-2. The close contacts of the 5 patients all tested negative of SARS-CoV-2 and in good health, and therefore were released after the official medical observation period of 14-days. Finally, according to the traceability investigation through applying big data analysis, we found an epidemiological association between family No.1 and family No.2, in which patient D (family No.2) was infected through touching an elevator button contaminated by snot with virus from patient A (family No.1) on the same day. Conclusions Contaminants with virus from confirmed patients can pollute the environment of public places, and the virus can survive on the surface of objects for a short period of time. Therefore, in addition to the conventional droplet transmission, there is also indirect contact transmission such as snot-oral transmission that plays a crucial role in community spread of the virus.

Despite the rapid development of cloud computing for many years, data security and trusted computing are still the main challenges in current cloud computing applications. In order to solve this problem, many scholars have carried out a lot of research on this, and proposed many models including data integrity test and secure multi-party calculation. However, most of these solutions face problems such as excessive computational complexity or lack of scalability. This paper studies the use of blockchain techniques to improve this situation. Blockchain is a decentralized new distributed computing paradigm. Applying blockchain technology to cloud computing, using the security mechanism of the former to improve the performance of the latter’s secure storage and secure computing is a promising research topic. In this paper, the distributed virtual machine agent model is deployed in the cloud by using mobile agent technology. The virtual machine agent enables multi-tenants to cooperate with each other to ensure data trust verification. The tasks of reliable data storage, monitoring and verification are completed by virtual machine agent mechanism. This is also a necessary condition for building a blockchain integrity protection mechanism. The blockchain-based integrity protection framework is built by the virtual machine proxy model, and the unique hash value corresponding to the file generated by the Merkel hash tree is used to monitor the data change by means of the smart contract on the blockchain, and the data is owned in time. The user issues a warning message for data tampering; in addition, a “block-and-response” mode is used to construct a blockchain-based cloud data integrity verification scheme.

Objectives Avian influenza viruses (AIVs) poise significant risk to human health and the poultry industry. We evaluated the transmission risk along the poultry supply chain. Methods During October 2015 and July 2016, four rounds of cross-sectional surveys were performed to characterize AIV spread in farms, transport vehicles, slaughterhouses, wholesale and retail live poultry markets (LPMs). Poultry cloacal and oral swabs, environmental swabs, bioaerosol samples and human sera were collected. Poultry and environmental samples were tested for AIVs by rRT-PCR, further subtyped by next generation sequencing. Previous human H9N2 infections were identified by hemagglutination inhibition and microneutralization tests. Logistic regression was fitted to compare AIV transmission risk in different settings. Results AIVs was detected in 23.9% (424/1771) of the poultry and environmental samples. AIV detection rates in farms, transport vehicles, wholesale and retail LPMs were 4.5%, 11.1%, 30.3% and 51.2%, respectively. 5.2%, 8.3% and 12.8% of the poultry workers were seropositive in farms, wholesale and retail LPMs, respectively. The regression analysis showed that virus detection and transmission risk to human increased progressively along the poultry supply chain. Conclusions Strengthening control measures at every level along the poultry supply chain, using a one health approach, is crucial to control AIV circulation.

Background Henoch–Schonlein purpura (HSP) is a systemic small vessel vasculitis that is mainly caused by IgA1‐type immune complex deposition. Advanced oxidation protein products (AOPPs) are specific markers of protein oxidation. Objective To explore the role of AOPPs in the pathogenesis of HSP. Methods There are 51 HSP patients who were divided into four subgroups: (i) skin type – 20 cases; (ii) joint type – 8 cases; (iii) abdominal type – 12 cases; (iv) renal type – 11 cases; and 18 healthy volunteers were enrolled as controls. The serum levels of AOPPs and Gd‐IgA1 were quantified by an HAA‐lectin‐based ELISA. The Cosmc mRNA expression in peripheral B lymphocytes was measured by RT‐PCR. Results 1. Advanced oxidation protein products in different subgroups of HSP patients are all higher than the controls, while the renal‐type subgroup is the highest and the skin‐type subgroup is the lowest. 2. Spearman correlation analysis shows that: (i) AOPPs and Gd‐IgA1 in HSP patients are positively correlated; both of them are positively correlated with the disease severity scores; (ii) AOPPs are negatively correlated with the relative expression value (RQ) of Cosmc mRNA. Conclusion Advanced oxidation protein products play an important role in the pathogenesis of HSP, especially in renal‐type patients.

Nowadays, more and more places need authentication. Face recognition is a mature technology for identity verification research. Recognition accuracy is an important indicator for evaluating authentication algorithms. In order to improve the accuracy of identity verification, advanced face is used. Feature recognition algorithm is an effective way, but it is also an effective algorithm to study the factors affecting facial features. Therefore, many researchers study the recognition results based on the poses of the face, light and other factors. This paper is also a study on the factors affecting face recognition, mainly by studying the influence of the age and gender factors on the identity verification results, and using the deep learning method to classify facial features. The simulation results show that the average recognition rate reaches 83.73%. At the same time, this paper analyzes the effect of age and gender on the classification results. The results show that the recognition effect of middle-aged men in male subjects is lower than that of youth and the elderly. Women have little difference in recognition effect with age. Males have higher recognition rates than women.

Summary: Blink reflex has long been considered closely related to physiological states, from which abundant information on ocular health and activities can be revealed. In this study, a smart glasses wearable has been developed, incorporating a flexible and sensitive pressure sensor, to monitor blink patterns by continuously detecting ocular muscular movements, referred to as blink-sensing glasses. By applying the emerging flexible iontronic sensing (FITS) sensor with the sensitivity of 340 pF/mmHg, the skin pressure variations induced by movements of the orbicularis oculi muscles can be monitored in real time. The blink-sensing glasses can successfully capture blink patterns with a high accuracy of 96.3% and have been used to differentiate the blink features from both dry-eye subjects and healthy controls. This device can be potentially used as a new clinical and research monitoring tool for continuous eye blink analysis, while providing patients with high comfortableness in long-term ambulatory and home settings.

Objectives: This study aimed to compare the risk of infection of children with that of adults and to explore risk factors of infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) by following up close contacts of COVID-19 patients. Method: The retrospective cohort study was performed among close contacts of index cases diagnosed with COVID-19 in Guangzhou, China. Demographic characteristics, clinical symptoms and exposure information were extracted. Logistic regression analysis was employed to explore the risk factors. The restricted cubic spline was conducted to examine to the dose-response relationship between age and SARS-CoV-2 infection. Results: The secondary attack rate (SAR) was 4.4% in 1,344 close contacts. The group of household contacts (17.2%) had the highest SAR. The rare-frequency contact (p < 0.001) and moderate-frequency contact (p < 0.001) were associated with lower risk of infection. Exposure to index cases with dry cough symptoms was associated with infection in close contacts (p = 0.004). Compared with children, adults had a significantly increased risk of infection (p = 0.014). There is a linear positive correlation between age and infection (p = 0.001). Conclusions: Children are probably less susceptible to COVID-19. Close contacts with frequent contact with patients and those exposed to patients with cough symptoms are associated with an increased risk of infection.

Background: The objective of this study was to test the effectiveness of the novel aesculin (AES) eye drops on treating dry eye syndrome (DES), using murine model. Methods: Dry eye was induced in murine eye with the use of an intelligent controlled environmental system (ICES). High-flow air which had been desiccated within the ICES, induced the DES. Treatment included Aesculin eye drops for 14 days. After expiration, corneal fluorescein staining was examined and stained with an endothelial maker created for tracking of lymph: Lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1). Subsequently, real-time PCR and ELISA were completed to quantify secretion of TNF-α，IFN-γ，IL-1β and IL-8 in serum, ocular surface and lacrimal gland. Results: Aesculin eye drops significantly repaired ICES-induced corneal injury in murine models Statistically significant increase in lymph angiogenesis was observed at day 14 of observation. Consequently, DES in treatment group was reduced using aesculin eye drops. aesculin eye drops can significantly inhibit lymphangiogenesis and reduce inflammatory cytokines levels in mice. The percentage of Th1 and Th17 cells were decreased after treating with aesculin eye drops, while the percentage of Treg was increased. Injection of VEGF-C into mice can reduce the efficacy of aesculin eye drops in ICES-induced DES. Conclusion: as treatment group of murine models indicated significant reduction of inflammation in the cornea associated with DES, treatment of DES with aesculin eye drops, should be considered a viable treatment method for DES.

ObjectiveTo explore associations between temperature, humidity and hand, foot and mouth disease (HFMD) incidence in Guangzhou, China from 2013 to 2017.MethodsA distributed lag non-linear model was applied to estimate the effects of daily temperature and humidity on HFMD incidence after adjusting for long-term trends, seasonal trends, and day of the week.ResultsIn total, 353,431 confirmed HFMD cases were reported in Guangzhou over the study period. A bimodal seasonal pattern was observed. High temperatures had acute short-term effects on HFMD incidence that declined quickly over time. The effects of low humidity declined over lag periods, but increased when the humidity surpassed 60.5%. Temperature and humidity were both inversely associated with HFMD incidence during lag days 0 to 3 and with lag periodsConclusionsTemperature and humidity play important roles in HFMD incidence. These data are important for developing public health strategies.

Psoriasis is a common chronic inflammatory disease with the prevalence rate of approximately 1-3 %. Currently, it is generally believed that the pathogenesis of psoriasis is a T-cell immune-mediated skin disease mediated by multiple genes and factors, and the interaction between keratinocytes and T cells. TEA domain family member 4 (TEAD4) is a transcription factor which regulates the expression of downstream genes in Hippo pathway and affects several biological processes, such as regulating cell differentiation and embryonic development. However, few studies have reported the role of TEAD4 in psoriasis and its possible regulatory mechanism. In this study, we found the expression level of TEAD4 in the skin of psoriasis was significantly higher than that of normal skin. In patients with the pathological keratinocytes, TEAD4 can transcriptionally regulate the expression of SERPINB3/4 and affect the secretion of chemokines, and the depletion of SERPINB3/4 inhibited the secretion of chemokines. In addition, the supernatant of keratinocytes of patients can significantly increase the migration ability of T cells, and the supernatant of T cells cultured by the supernatant of keratinocytes of patients can significantly enhance the proliferation ability of keratinocytes. Therefore, our results suggested that TEAD4 is a key regulatory factor in progression of psoriasis, and the crosstalk between keratinocytes and T cells mediated by TEAD4 plays a critical role in the psoriasis pathogenesis.

BackgroundA large number of students at a school in Guangzhou city developed a sudden onset of symptoms of diarrhea and vomiting. To help control the outbreak, we conducted an epidemiological investigation to determine the causative agent, sources, role of transmission and risk factors of the infections.MethodsThe study population consisted of probable and confirmed cases. An active search was conducted for cases among all students, teachers and other school staff members. A case control study was carried out using standardized online questionnaires. Data were obtained regarding demographic characteristics, gastrointestinal symptoms, personal hygiene habits, history of contact with a person who had diarrhea and/or vomiting and dining locations during the past 3 days. Rectal swabs or stool samples of the cases and, food handlers, as well as environmental samples were collected to detect potential intestinal viruses and bacteria. We calculated odds ratios and 95% confidence intervals (CIs).ResultsA total of 157 individuals fit the definition of a probable case, including 46 with laboratory-confirmed norovirus infection between March 8 and March 22, 2018. The proportion of students who had eaten delivery food 3 days before the onset of illness in the case group was 2.69 times that in the control group (95%CI: 1.88–3.85). Intake of take-out food 3 days earlier, and exposure to similar cases 72 h before onset and case in the same dormitory were risk factors. A total of 20 rectal swab samples from students, 10 rectal swabs from food handlers and 2 environmental swab samples from the out-campus restauranttested positive for norovirus (GII, genogroup II strain).ConclusionsWe investigated an outbreak of norovirus infectious diarrhea. Food handling practices carry potential risk of acute gastroenteritis outbreaks owing to a lack of surveillance and supervision. Greater attention should be paid to the monitoring and supervision of food handlers in off campus restaurant to reduce the incidence of norovirus-related acute gastroenteritis associated with delivery food.

Highlights • We reported a 3-month-old infant who was confirmed as COVID-19 patient with pneumonia. Infant patient with COVID-19 has relatively mild symptoms. • Infants may have different immune responses compare to adults, IL-17A, IL-17 F and TNF-α could be involved in the immune response of COVID-19. • SARS-COV-2 may shed through the gastrointestinal tract and convalescent carrier among infant patients may exist., This study aims to explore the clinical and epidemiological characteristics of infant patients with coronavirus disease-2019 (COVID-19) infection. Clinical and epidemiological data of a 3-month-old patient with COVID-19 were collected, including general status, clinical results, laboratory tests, imaging characteristics, and epidemiological reports. The infant had no fever but had mild respiratory symptoms. The major laboratory results included normal white blood cell counts and lymphocytopenia, notably with elevated interleukin (IL-)-17A, IL-17 F, and tumor necrosis factor (TNF-)-α. The main manifestation of his chest computed tomography scan was pulmonary patchy shadows. All throat swabs and urine of the infant detected via Real-time Quantitative Polymerase Chain Reaction (RT-PCR) were negative, but his anal swab continued to test positive up to 40 days after onset of illness. Our study indicated that infants infected with COVID-19 may have relatively mild symptoms or clinical signs, IL-17A, IL-17 F, and TNF-α could be involved in the immune response of COVID-19. In addition, severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) may shed through the gastrointestinal tract and convalescent carriers may exist among infant patients. We cannot rule out the possibility that infants may acquire infection from breastfeeding. Intensive care and nutrition support are recommended for infant patients with mild symptoms.

Hand, foot and mouth disease (HFMD) primarily affects children younger than 5 years of age. Recently, HFMD has ranked as the top notifiable infectious disease in China. In December 2015, China approved two novel inactivated enterovirus 71 vaccines (EV71 vaccines) for HFMD. Parents’ acceptance is often essential for vaccination program success. The goal of this study was to identify willingness and influential factors to vaccinate among parents of kindergarteners in Guangzhou, China. A cross-sectional survey of face-to-face interviews was conducted from March to July 2016. Fifty-five kindergartens were randomly selected from 11 districts of Guangzhou. An anonymous self-designed questionnaire was used to investigate awareness, knowledge and attitude towards HFMD and EV71 vaccines. A total of 868 parents participated in the survey. Mean(±standard deviation) knowledge score of HFMD was 6.32(±1.70). Approximately 32.03% of parents had heard of the EV71 vaccines with 22.58% receiving information before this study. Nearly 44.24% of parents showed willingness to vaccinate their children. Previously receiving EV71 vaccine-related information [adjusted odds ratio (aOR) = 1.48, 95% confidence interval (CI): 1.04–2.11], no fear of adverse effects (aOR = 4.25, 95%CI: 2.77–6.53), perceived susceptibility of children to HFMD (aOR = 2.15, 95%CI: 1.42–3.25) and children not previously diagnosed with HFMD (aOR = 1.56, 95%CI: 1.07–2.27) were positively associated with EV71 vaccination acceptability. However, parental education background (aOR = 0.54, 95%CI: 0.37–0.80) was negatively correlated with vaccination acceptability. Our study provides baseline information for future vaccination campaigns to help improve the EV71 vaccine uptake rate. Special efforts are urgently needed to improve the awareness and knowledge of EV71 vaccines in China.

Rotavirus is the most common cause of severe diarrhea in children under 5 y old in the world. The study aims to explore the relationship between rotavirus vaccination and infection in the outbreak of rotavirus gastroenteritis in a childcare center. Earlier immunization and high vaccination rate should be encouraged.

Background Infectious diarrhea (ID) has exerted a severe disease burden on the world. The seasonal ID patterns suggest that meteorological factors (MFs) may influence ID incidence. The aim of this study was to evaluate the effect of MFs on ID, and to provide scientific evidence to the relevant health authorities for disease control and prevention. Methods Data from ID cases and daily MFs (including mean temperature, diurnal temperature range, relative humidity, precipitation, atmospheric pressure, and wind velocity) in Guangzhou, Southern China from 2006 to 2017 were collected. Using a distributed lag non-linear model approach, we assessed the relationship between MFs and ID incidence. Results Compared with the lowest ID risk values, low mean temperature, relative humidity, and precipitation were associated with an increased risk for ID, while higher diurnal temperature range and atmospheric pressure were also associated with increased risk. Maximum atmospheric pressure and minimum relative humidity had larger cumulative effects within 21 lag days, yielding relative risks of 133.11 (95% CI: 61.29–289.09) and 18.17 (14.42–22.89), respectively. The cumulative effect within 21 lag days of minimum temperature was higher than that from maximum temperature in all sub-populations. The cumulative effects of minimum temperature for men, teenagers, and young adults (10–29 years) were higher than those for other populations. Conclusions MFs should be considered when developing prevention and surveillance programs for ID. Special attention should be paid to vulnerable populations, such as teenagers and young adults.

With the rapid development of computer technology and electronics industry, computer processing capability and image processing technology have been greatly improved, making robots based on computer processing and image processing have entered a new development in the field of navigation path recognition research. As an indispensable carrier for intelligent manufacturing and industrial development, robots are expanding their applications. The key to the successful execution of the mobile robot is to move according to the planned path and to avoid obstacles autonomously. These two points depend on the validity and accuracy of navigation path identification. At present, research on mobile robot navigation path recognition mainly uses visual navigation as the main method, which uses visual sensors to simulate human eye functions, obtains relevant information from external environment images, and processes them to realize related functions that the system needs to complete. The two major problems in visual navigation are poor recognition ability and insufficient ability to resist light source interference. The main purpose of this paper is to improve the recognition ability of mobile robot navigation path and the ability to resist light source interference. It mainly uses the [Formula: see text]-means algorithm for visual navigation research. By simulating the acquired image and the selected color space, the results show that the average time taken to complete a path identification method is 152[Formula: see text]ms. Under different illumination environments, the information extraction rate of mobile robot navigation path can reach 90%, and the effect of strong light on navigation path recognition is effectively reduced under strong illumination environment. The results show that the recognition of the visual navigation path of a mobile robot using the [Formula: see text]-means algorithm is more precise than the conventional method, and it takes less time to better meet the timeliness requirements of mobile robots.

With the increase in the total population of the society and the continuous increase in the number of trips, the traffic pressures faced by people are increasing. With the development and advancement of computer technology, the emergence of intelligent transportation provides a better way to solve the problem of effectively alleviating traffic pressure and reducing the incidence of traffic accidents. In recent years, intelligent traffic monitoring system, as one of the important branches in the field of intelligent transportation, has also received more and more attention. Among them, video-based moving target recognition technology involves theoretical knowledge in various fields such as artificial intelligence, image processing, pattern recognition and computer vision. It is an important means to realize “safe city” and “smart city” and a key technology for intelligent monitoring. Therefore, the research on human motion target recognition algorithm in complex traffic environment has important theoretical and practical value. In the field of intelligent traffic monitoring, the moving target detection and recognition effect of video images will have certain influence on the classification and behavior understanding of subsequent moving targets. In this paper, the commonly used moving target detection methods are studied first, and the convergence problem of the traditional Adaboost algorithm is improved. An Adaboost algorithm based on adaptive weight update is proposed, and then the support vector machine (SVM) is used. The algorithm identifies the detected moving target. Finally, through simulation experiments on the acquired video images, the results show that the proposed human motion target recognition algorithm based on adaptive weight update Adaboost and SVM has good feasibility and rationality.

Analyzing the key design for Aerial Passenger Device, 3DMAX is applied for creating models which is the key technology and corresponding safety protection device. Combined with Quest3D engine for setting, such as roadway and safety devices are displayed in virtual. Finally Aerial Passenger Device is in the virtual scene. Then simulation results examine the Aerial Passenger Device's rationality and safety reducing the cycle of system optimization and technology improvement.

Background Hand, foot and mouth disease (HFMD) is usually caused by Enterovirus 71(EV71), and Coxsackievirus A16 (CV-A16) in Guangzhou, the biggest city of South China. However, Coxsackievirus A6 (CV-A6) were observed increased dramatically from 2010–2012. Methods In order to understand and to describe the epidemiologic and genetic characteristics of CV-A6, specimens of 5482 suspected HFMD cases were collected and examined by real-time fluorescence PCR. All samples positive for enteroviruses were analyzed by descriptive statistics. Phylogenetic analysis of CV-A6 based on the VP1 sequences was performed to investigate molecular and evolutionary characteristics. Results Coxsackievirus A6 increased dramatically from 9.04% in 2010 to 23.21% in 2012 and became one of the main causative agents of HFMD in Guangzhou. CV-A6 attack rates were highest in one to two year olds (33.14%). Typical clinic symptoms of CV-A6 HFMD include fever (589/720, 81.81%), maculopopular rash and vesicular exanthema around the perioral area (408/720, 56.66%), intraoral (545/720, 75.69%), the buttock (395/720, 54.86%), the trunk (244/720, 33.89%), the knee (188/720, 26.11%), and the dorsal aspects of hands (437/720, 60.69%). Phylogenetic analysis showed the CV-A6 isolates in this study belonged to Cluster A1 and were similar to those found in Shanghai in 2011 and 2012 (JX495148, KC414735), Shenzhen in 2011 (JX473394), Japan in 2011 (AB649243, AB649246), France in 2010(HE572928), Thailand in 2012(JX556564) and Israel in 2012 and 2013(.KF991010, KF991012). Electronic supplementary material The online version of this article (doi:10.1186/1743-422X-11-157) contains supplementary material, which is available to authorized users.

To investigate the characteristics and dynamic changes of serum neutralizing antibody response in patients with primary infection of dengue virus type 1 (DENV-1).Serum samples were obtained from the same patients with primary infection of DENV-1 within 2 weeks after symptom onset in 2006 and in 2010. A group-specific DENV NS1 capture ELISA-based micro-neutralizing test (ELISA-MNT) capable of detecting neutralizing antibodies against all the 4 serotypes of DENV was used to test the neutralizing antibody titers against DENV in the serum samples. The neutralizing antibody titers against a standard strain and 2 clinically isolated strains of DENV-1 were detected in serum samples collected in 2010.Cross-reactive neutralizing antibody response against all the 4 serotypes of DENV was found in both of the serum samples collected in 2006 and 2010, but the samples collected in 2006 showed stronger cross-reactive neutralizing antibody responses. The neutralizing antibody against DENV-2, rather than the anticipated DENV-1 antibody, had the highest titer in the samples collected in 2006, whereas the antibody against homologous DENV-1 had the highest titer in the samples obtained in 2010. The neutralizing antibody titers against the homologous DENV-1 was significantly higher in samples collected in 2010 (U=86.500, P=0.000), which also demonstrated significantly different neutralizing antibody titers against the 3 different strains of DENV-1 (Χ(2)=12.123, P=0.002).The production of cross-reactive neutralizing antibodies between the 4 serotypes of DENV is a characteristic of DENV infection, particularly during early infection, but only the homologous neutralizing antibody increases obviously over time. The titers of the neutralizing antibodies against different strains, even of the same serotype, may differ distinctly.