Prevalence of enteroviruses in children with and without hand, foot, and mouth disease in China

Prevalence and phylogenetic analysis of human enteric emerging viruses in porcine stool samples in the Republic of Korea

Emerging infectious diseases (EID) in humans and animals are proving to be a serious health concern. This study investigated the prevalence of emerging or re-emerging human enteric viruses in porcine stools and swabs. Eleven enteric EID viruses were selected as target viruses for the current study and ranked based on their impact on public health and food safety: enterovirus (EV), hepatitis E virus, norovirus GI and GII, sapovirus (SaV), adenovirus (AdV), astrovirus, rotavirus, hepatitis A virus, aichivirus, and bocavirus. Using real-time RT-PCR or real-time PCR, EID viruses were detected in 129 (86.0%) of 150 samples. The most prevalent virus was EV, which was detected in 68.0% of samples, followed by AdV with a detection rate of 38.0%. In following sequencing and phylogenetic analyses, 33.0% (58/176) of the detected viruses were associated with human enteric EID viruses, including AdV-41, coxsackievirus-A2, echovirus-24, and SaV. Our results show that porcine stools frequently contain human enteric viruses, and that few porcine enteric viruses are genetically related to human enteric viruses. These findings suggest that enteric re-emerging or EID viruses could be zoonoses, and that continuous monitoring and further studies are needed to ensure an integrated "One Health" approach that aims to balance and optimize the health of humans, animals, and ecosystems.

Prevalence of recessive infection of pathogens of hand, foot, and mouth disease in healthy people in China: A meta-analysis

BACKGROUND

To analyze the prevalence of latent infection of pathogens of hand, foot, and mouth disease (HFMD) in Chinese healthy population and its influencing factors, so as to provide reference for the prevention and control of HFMD.

METHODS

A systematic literature searching about the incidence of latent infection of HFMD was conducted in Chinese and English databases. The inclusion and exclusion criteria of the retrieved literature were established. The qualified literatures were screened and the data were extracted. The pooled rate and its 95% confidence interval was used to assess the latent infection rate of HFMD pathogens in healthy Chinese population, and subgroup analysis was conducted based on gender and age. All statistical analyses were performed using the STATA version 12.0 software.

RESULTS

A total of 31 literatures were included in this meta-analysis. The recessive infection rate of HFMD pathogens reported in the literature of Chinese healthy people ranged from 4.59% to 44.12%. The results of meta-analysis showed that the latent infection rate of human enteroviruses (HEVs) in healthy Chinese population was 17.5% (14.9-20.1%), among which, the latent infection rates of EV-A71, CV-A16, and other HEVs were 3.3% (2.2-4.4%), 1.7% (1.0-2.5%), and 15.1% (11.1-17.1%), respectively. The latent infection rates of HEVs in healthy men and women in China were 16.7% (12.9-20.4%) and 14.4% (10.8-18.0%), respectively. The latent infection rates of HEVs in the healthy population aged 0 to 5 years and over 5 years were 24.4% (20.4-28.5%) and 9.4% (6.5-12.2%), respectively. Meta regression showed that the factors affecting the latent infection rate of HEVs in Chinese healthy population included sampling period, sampling area, and study population.

CONCLUSION

The latent infection rate of HEVs is high in healthy people in China, but it is mainly caused by other enteroviruses. The latent infection rate of HEVs in male was higher than that of female and was greater in people aged 0 to 5 than that of aged over 5 years. Limited by the quantity and quality of the included studies, more high-quality studies are needed for further verification in the future.

Disseminated cortical and subcortical lesions in neonatal enterovirus 71 encephalitis

Enteroviruses are one of the most important causes of viral encephalitis in the neonatal period. However, the non-specificity of the symptoms presented renders its diagnosis challenging. Intracranial MRI has been reported to be a very useful imaging modality that can detect the characteristic white matter lesions around the periventricular regions. In this study, we report a case of a patient with neonatal encephalitis who presented with normal white blood cell counts in the initial cerebrospinal fluid analysis. A lumbar puncture retap identified pleocytosis, and polymerase chain reaction assays detected enterovirus 71 in the blood and stool samples. Furthermore, MRI revealed atypical disseminated cortical and subcortical white matter lesions on diffusion weighted images, and neuroradiological re-evaluation showed necrotic changes 2 weeks later. This unique case expands our knowledge of the spectrum of neurological disorders due to enterovirus 71 infection in neonatal period.

Non-polio enteroviruses among healthy children in the Philippines

BACKGROUND

Enteroviruses (EVs) are most commonly associated with either mild or asymptomatic infections, however, the presence of silent carriers in the community has been proven to play a crucial role in the spread of diseases such as hand, foot, and mouth disease (HFMD) that records high incidence in Asia Pacific region. In the Philippines, limited information is available on the etiology and prevalence of enterovirus outside the Acute Flaccid Paralysis (AFP) surveillance, thus, a study to determine the baseline prevalence of Non-Polio Enteroviruses (NPEVs) among healthy Filipino children was conducted.

METHODS

A descriptive, cross-sectional study was performed to determine the prevalence of NPEV among healthy children under 6 years old in the Philippines. Duplicate stool samples were collected from 360 healthy children residing in three major urban cities in the country. Virus isolation and polymerase chain reaction were performed to identify enteroviruses present in the samples. To determine if the results of the study are comparable to the AFP surveillance data, the results of the study were compared to the prevalence and isolation rate among AFP cases of the similar cases collected the same year.

RESULTS

Prevalence of enteroviruses among healthy children was found to be at 24.7%. Comparing the NPEV rates from the study and AFP surveillance of similar age and the same year of collection, there was no significant difference in NPEV case prevalence. The study identified a total of 19 different enterovirus serotypes with majority belonging to species Enterovirus B (EV-B).

CONCLUSION

The study was able to establish a baseline NPEV case prevalence of 24.7% among healthy children aged under 6 years old in three major urban sites in the Philippines. The high isolation of NPEV among healthy children signifies continuous fecal-oral transmission of enteroviruses in the community.

Identification of a new recombinant strain of echovirus 33 from children with hand, foot, and mouth disease complicated by meningitis in Yunnan, China

Background

Hand, foot, and mouth disease (HFMD) is a common childhood disease, which is usually caused by enterovirus A (EV-A) serotypes. Enterovirus A71 (EV-A71) and coxsackievirus A16 (CV-A16) are the main etiologic agents. Multiple serotypes of enterovirus B serotypes (EV-B) have been detected in outbreaks or sporadic cases of HFMD.

Results

During HFMD surveillance in Yunnan, China in 2013, two echovirus 33 (E-33) isolates were recovered in cell culture and typed by molecular methods from the cerebrospinal fluid (CSF) and feces of two sporadic cases of HFMD complicated by meningitis. Sequence analysis indicated that the study isolates, YNK35 and YNA12, formed an independent branch, and belonged to E-33 genotype H. Recombination analysis indicated multiple recombination events in the genomic sequence of isolate YNK35. The recombination mainly occurred in the non-structural coding region of P2 and P3, and involved intra-species recombination of species B.

Conclusion

In this study, the complete sequences of two E-33 isolates were determined. This is the first report of severe HFMD associated with E-33 in Yunnan China, and it enriches the number of full-length genome sequences of E-33 in the GenBank database.

Electronic supplementary material

The online version of this article (10.1186/s12985-019-1164-2) contains supplementary material, which is available to authorized users.

Seroprevalence of antibodies to enterovirus 71 and coxsackievirus A16 among people of various age groups in a northeast province of Thailand

BACKGROUND

Hand, foot and mouth disease (HFMD) is endemic among population of young children in Thailand. The disease is mostly caused by enterovirus 71 (EV71) and coxsackievirus A16 (CA16).

METHODS

This study conducted serosurveillance for neutralizing (NT) antibodies to EV71 subgenotypes B5 and C4a, and to CA16 subgenotypes B1a and B1b, in 579 subjects of various ages using a microneutralization assay in human rhabdomyosarcoma (RD) cells. These test viruses were the major circulating subgenotypes associated with HFMD in Thailand during the study period.

RESULTS

We found that the levels of seropositivity against all 4 study viruses were lowest in the age group of 6-11 months, i.e., 5.5% had antibody to both EV71 subgenotypes, while 14.5% and 16.4% had antibody to CA16 subgenotypes B1a and B1b, respectively. The percentages of subjects with antibodies to these 4 viruses gradually increased with age, but were still less than 50% in children younger than 3 years. These laboratory data were consistent with the epidemiological data collected by the Ministry of Public Health which showed repeatedly that the highest number of HFMD cases was in children aged 1 year. Analyses of amino acid sequences of the test viruses showed 97% identity between the two subgenotypes of EV71, and 99% between the two subgenotypes of CA16. Nevertheless, the levels of seropositivity and antibody titer against the two subgenotypes of EV71 and of CA16 were not significantly different.

CONCLUSIONS

This study clearly demonstrated NT antibody activity across EV71-B5 and EV71-C4a subgenotypes, and also across CA16-B1a and CA16-B1b subgenotypes. Moreover, there were no significant differences by gender in the seropositive rates and antibody levels to any of the 4 virus subgenotypes.

Epidemiological and genetic characteristics of EV71 in hand, foot, and mouth disease in Guangxi, southern China, from 2010 to 2015

Hand, foot, and mouth disease (HFMD) is a significant public health challenge in China. Human enterovirus 71 (EV71) is regarded as the predominant causative pathogen of HFMD. Since 2015, two inactivated EV71 vaccines have been approved in mainland China, and because their use could change the HFMD pathogen spectrum, this should now be monitored. However, the epidemiological and genetic trends of EV71 with respect to HFMD in Guangxi, southern China, are still not clear. In this study, we describe the epidemiological and genetic characterization of this virus in clinically-diagnosed HFMD reported from 2010 to 2015 in Guangxi. Data showed that a two-year epidemic cycle, with a predominance of EV71 infections, contributed to HFMD outbreaks in Guangxi. Furthermore, this virus is a major causative agent of severe and fatal HFMD. Interestingly, in Guangxi, EV71-positive rates tended to decrease over time. In particular, EV71-positive rates were found in Fangchenggang city, which reported very few severe and fatal cases over the six-year period. Phylogenetic analysis of the VP1 gene revealed that the major circulating strains belonged exclusively to genotype C, subtype 4a (C4a), and most clustered with strains circulating in southern China. The most interesting finding was that a strain isolated in 2012 clustered with Vietnamese strains isolated from 2011–2012. The data highlight the importance of pathogen surveillance for HFMD in China, especially Guangxi, which is located on the border of China and the Association of Southeast Asian Nations.

Case report: Features of hand, foot and mouth disease in neonates

RATIONALE

Hand, foot and mouth disease (HFMD) is caused by enterovirus. The virus may exist in secretions.

PATIENT CONCERNS

Five neonates had symptoms of fever and maculopapular rashes involving face, trunk, breech, arms, and legs, especially scattering on palms and feet. Blood, oropharyngeal fluid, urine, and cerebrospinal fluid (CSF) samples were collected and detected for further diagnoses with the consent of the infants' parents. Some of them suffered aseptic meningitis.

DIAGNOSES

They were diagnosed as HFMD with CSF enterovirus positive.

INTERVENTIONS

All of them continued breastfeed. Water bag was used during the pyrogenic stage. Antibiotics were administrated at first and withdrawn as soon as possible.

OUTCOMES

None of them developed into brainstem encephalitis or pulmonary edema and they all recovered well.

LESSONS

HFMD is more common in neonates than it has been thought. Enterovirus may exist in neonatal CSF and cause CSF cell to increase similar to purulent meningitis. Medical history, physical examination, and CSF enterovirus detection are important in making correct diagnosis. Unlike bacterial infection, HFMD is a self-limited disease. Once HFMD is determined and bacterial infection is ruled out, antibiotics should be avoided.

Prevalence of enteroviruses in healthy populations and excretion of pathogens in patients with hand, foot, and mouth disease in a highly endemic area of southwest China

Etiological carriers and the excretion of the pathogens causing hand, foot, and mouth disease (HFMD) in healthy persons, patients, and asymptomatic persons infected with HFMD as ongoing infection sources may play an important role in perpetuating and spreading epidemics of HFMD. The aims of this study were to determine the carrier status of EV-A71 and CV-A16 in healthy populations, as well as the duration of EV-A71 and CV-A16 shedding in the stools of HFMD patients in an epidemic area of southwest China. A cross-sectional study and a follow-up study were conducted in three HFMD endemic counties of Yunnan Province. Six hundred sixty-seven healthy subjects were recruited to participate in the cross-sectional study, and two stool specimens were collected from each subject. Among the healthy subjects, 90 (13.5%) tested positive for viral isolation, but neither EV-A71 nor CV-A16 was detected in healthy individuals. Of the 150 patients with probable HFMD, 55.3% (83/150) tested positive for viral isolation with presented serotypes such as EV-A71 (51.81%, 43/83), CV-A16 (32.53%, 27/83), other EVs (13.25%, 11/83), and mixed EV-A71 and CV-A16 (2.41%, 2/83). The longest duration of EV-A71 and CV-A16 shedding in stool specimens from patients with HFMD was >46 days after onset. The positive rate of EV-A71 in the stool specimens of confirmed patients dropped to 50% by the end of the third week, and the same occurred with CV-A16 by the end of approximately the seventh week after onset. Although carriers of major causative agents of HFMD in healthy populations are fewer in number, the prolonged shedding of pathogens in patients with HFMD may serve as an important factor in perpetuating and spreading HFMD epidemics.

Causes and outcomes of sepsis in southeast Asia: a multinational multicentre cross-sectional study

BACKGROUND

Improved understanding of pathogens that cause sepsis would aid management and antimicrobial selection. In this study, we aimed to identify the causative pathogens of sepsis in southeast Asia.

METHODS

In this multinational multicentre cross-sectional study of community-acquired sepsis and severe sepsis, we prospectively recruited children (age ≥30 days and <18 years) and adults (age ≥18 years) at 13 public hospitals in Indonesia (n=3), Thailand (n=4), and Vietnam (n=6). Hospitalised patients with suspected or documented community-acquired infection, with at least three diagnostic criteria for sepsis according to the Surviving Sepsis Campaign 2012, and within 24 h of admission were enrolled. Blood from every patient, and nasopharyngeal swab, urine, stool, and cerebrospinal fluid, if indicated, were collected for reference diagnostic tests to identify causative pathogens. We report causative pathogens of sepsis and 28-day mortality. We also estimate mortality associated with enrolment with severe sepsis. This study was registered with ClinicalTrials.gov, number NCT02157259.

FINDINGS

From Dec 16, 2013, to Dec 14, 2015, 4736 patients were screened and 1578 patients (763 children and 815 adults) were enrolled. Dengue viruses (n=122 [8%]), Leptospira spp (n=95 [6%]), rickettsial pathogens (n=96 [6%]), Escherichia coli (n=76 [5%]), and influenza viruses (n=65 [4%]) were commonly identified in both age groups; whereas Plasmodium spp (n=12 [1%]) and Salmonella enterica serovar Typhi (n=3 [0·2%]) were rarely observed. Emerging pathogens identified included hantaviruses (n=28 [2%]), non-typhoidal Salmonella spp (n=21 [1%]), Streptococcus suis (n=18 [1%]), Acinetobacter spp (n=12 [1%]), and Burkholderia pseudomallei (n=5 [<1%]). 28-day mortality occurred in 14 (2%) of 731 children with known statuses and 108 (13%) of 804 adults. Severe sepsis was identified on enrolment in 194 (28%) of 731 children and 546 (68%) of 804 adults, and was associated with increased mortality (adjusted odds ratio 5·3, 95% CI 2·7-10·4; p<0·001).

INTERPRETATION

Sepsis in southeast Asia is caused by a wide range of known and emerging pathogens, and is associated with substantial mortality.

FUNDING

National Cancer Institute, National Institute of Allergy and Infectious Diseases, National Institutes of Health, USA, and Wellcome Trust, UK.

Seroprevalence of Common Viral Diseases: A Hospital Based Study from Amritsar, India

INTRODUCTION

There is a paucity of published data on epidemiology of the viral infections in Punjab, India. The Viral Research and Diagnostic Laboratory (VRDL) located at Government Medical College (GMC), Amritsar conducts the initial diagnosis of common viruses circulating in the region.

AIM

To report the seroprevalence of various viral diseases in Amritsar and neighboring districts of Punjab along with the demographic and geographical data of the patients.

MATERIALS AND METHODS

Whole blood sera samples from a total of 5781 patients suspected of various viral diseases (chikungunya, dengue, hepatitis A, hepatitis B, hepatitis C, hepatitis E, herpes simplex-1 or herpes simplex-2) were received at VRDL, GMC, Amritsar from January 2015 to April 2016 and a cross sectional study was conducted. The diagnosis was based on serological assays.

RESULTS

Out of total 5781 suspected cases, 1790 were diagnosed with antibodies for atleast one of the tested viral diseases. Dengue virus was the highest occurring viral disease (56.77%). Male patients infected with viruses outnumbered female cases, except for hepatitis E and herpes simplex-1. The 21-40 years age group appeared to be the most susceptible age group for nearly all studied viral infections. Among the total nine reported outbreak investigations, largest encompassed 1335 dengue cases from Amritsar district.

CONCLUSION

VRDL established in GMC, Amritsar has become instrumental in detection of emerging and re-emerging viral diseases including outbreak investigation of communicable diseases. Timely action with the help of adequate information and capacity to diagnose the viruses might help in saving numerous lives.

Coxsackievirus A16 induced neurological disorders in young gerbils which could serve as a new animal model for vaccine evaluation

Coxsackievirus A16 (CA16) is one of the major pathogens associated with human hand, foot, and mouth disease (HFMD) in the Asia-pacific region. Although CA16 infections are generally mild, severe neurological manifestations or even death has been reported. Studies on CA16 pathogenesis and vaccine development are severely hampered because the small animal models that are currently available show major limitations. In this study, gerbils (Meriones unguiculatus) were investigated for their suitability as an animal model to study CA16 pathogenesis and vaccine development. Our results showed that gerbils up to the age of 21 days were fully susceptible to CA16 and all died within five days post-infection. CA16 showed a tropism towards the skeletal muscle, spinal cord and brainstem of gerbils, and severe lesions, including necrosis, were observed. In addition, an inactivated CA16 whole-virus vaccine administrated to gerbils was able to provide full protection to the gerbils against lethal doses of CA16 strains. These results demonstrate that gerbils are a suitable animal model to study CA16 infection and vaccine development.

QMRAcatch: Human-Associated Fecal Pollution and Infection Risk Modeling for a River/Floodplain Environment

Protection of drinking water resources requires addressing all relevant fecal pollution sources in the considered catchment. A freely available simulation tool, QMRAcatch, was recently developed to simulate concentrations of fecal indicators, a genetic microbial source tracking (MST) marker, and intestinal pathogens in water resources and to conduct a quantitative microbial risk assessment (QMRA). At the same time, QMRAcatch was successfully applied to a region of the Danube River in Austria, focusing on municipal wastewater emissions. Herein, we describe extension of its application to a Danube River floodplain, keeping the focus on fecal sources of human origin. QMRAcatch was calibrated to match measured human-associated MST marker concentrations for a dry year and a wet year. Appropriate performance characteristics of the human-associated MST assay were proven by simulating correct and false-positive marker concentrations, as determined in human and animal feces. With the calibrated tool, simulated and measured enterovirus concentrations in the rivers were compared. Finally, the calibrated tool allowed demonstrating that 4.5 log enterovirus and 6.6 log norovirus reductions must be achieved to convert current surface water to safe drinking water that complies with a health-based target of 10 infections person yr. Simulations of the low- and high-pollution scenarios showed that the required viral reductions ranged from 0 to 8 log. This study has implications for water managers with interests in assessing robust catchment protection measures and water treatment criteria by considering the fate of fecal pollution from its sources to the point of abstraction.

Hepatitis E virus: An ancient hidden enemy in Latin America

Hepatitis E virus (HEV) infection is a common cause of acute clinical hepatitis worldwide. HEV is an RNA-containing virus and the only member of the genus Hepevirus in the family Hepeviridae. Human HEV is classified into four genotypes widely distributed across the world. The virus is mainly transmitted via the fecal-oral route, and water-borne epidemics have become characteristic of hepatitis E in developing countries, including those in Latin America. The zoonotic potential of HEV is broadly recognized. Thus, there is an urgent need to re-evaluate virus transmission scenarios and to enforce epidemiological surveillance systems. Additionally, it is known that HEV infections, initially defined as self-limiting, can also take chronic courses in immunocompromised patients. Moreover, we recently reported a high seroprevalence of HEV in samples from cirrhotic patients with no other etiological agents present, suggesting the potential role of HEV in the development of chronic liver illness. In this review, HEV genomic variability, transmission, chronic infectious course, zoonotic potential and treatment are discussed. Focus is placed on the impact of HEV infection in Latin America, to support the development of specific control strategies and the handling of this important and typically imperceptible viral infection.

Epidemiological Research on Hand, Foot, and Mouth Disease in Mainland China

Hand, foot, and mouth disease (HFMD), which has led to millions of attacks and several outbreaks across the world and become more predominant in Asia-Pacific Region, especially in Mainland China, is caused by several Human Enteroviruses including new enterovirus, coxsakievirus and echovirus. In recent years, much research has focused on the epidemiological characteristics of HFMD. In this article, multiple characteristics of HFMD such as basic epidemiology, etiology and molecular epidemiology; influencing factors; detection; and surveillance are reviewed, as these can be help protect high risks groups, prevalence prediction and policy making for disease prevention.

Epidemiologic and etiologic characteristics of hand, foot, and mouth disease in Chongqing, China between 2010 and 2013

Hand, foot, and mouth disease (HFMD) has become very common in children, with widespread occurrence across China. The aim of this study was to investigate the epidemiologic and etiologic characteristics of HFMD, including etiologic variations in Chongqing, China. An epidemiologic investigation was based on 3,472 patients who presented with HFMD manifestations and were admitted at the Children's Hospital of Chongqing Medical University between 2010 and 2013. Fecal specimens from 830 patients were analyzed by nested RT-PCR to identify the enterovirus pathogens, and the molecular characterization of HFMD was illustrated by phylogenetic tree analysis. The results of this study indicate that the peak of the HFMD epidemic in Chongqing between 2010 and 2013 occurred between April and July each year. The median age of onset was 2.24 years old, and children under the age of five accounted for 96.4% of all the HFMD cases; the male-to-female ratio was 1.89:1. Enterovirus 71 accounted for a major proportion of the isolated strains every year, including the majority (74%) of severe cases. However, the proportion of Coxsackie A (CV-A) 6 infections increased from 2.11% in 2010 to 16.36% in 2013, while the proportion of CV-A16 infections decreased from 31.23% in 2010 to 4.67% in 2013. Molecular epidemiologic study showed that all enterovirus 71 strains belonged to subgenotype C4a, whereas all CV-A16 strains belonged to genotype B1, including subgenotype B1a and subgenotype B1b.

The Fecal Virome of Children with Hand, Foot, and Mouth Disease that Tested PCR Negative for Pathogenic Enteroviruses

Hand, foot, and mouth disease (HFMD) affects infant and young children. A viral metagenomic approach was used to identify the eukaryotic viruses in fecal samples from 29 Thai children with clinical diagnosis of HFMD collected during the 2012 outbreak. These children had previously tested negative by PCR for enterovirus 71 and coxsackievirus A16 and A6. Deep sequencing revealed nine virus families: Picornaviridae, Astroviridae, Parvoviridae, Caliciviridae, Paramyxoviridae, Adenoviridae, Reoviridae, Picobirnaviridae, and Polyomaviridae. The highest number of viral sequences belonged to human rhinovirus C, astrovirus-MLB2, and coxsackievirus A21. Our study provides an overview of virus community and highlights a broad diversity of viruses found in feces from children with HFMD.

Characterization of the enterovirus 71 P1 polyprotein expressed in Pichia pastor as a candidate vaccine

Human enterovirus 71 (EV71) plays an important role in hand, foot, and mouth disease (HFMD), which recently caused the death of hundreds of children in the Asia-Pacific region. However, there are no specific treatments available for EV71 infections; thus, a safe and effective vaccine is needed urgently. In this study, we developed an effective and economical method for producing EV71 polyprotein (P1 protein) in Pichia pastoris. Furthermore, we evaluated the potential of P1 protein as a candidate vaccine against EV71 virus. The data revealed that P1 protein induced persistent high cross-neutralization antibodies for different EV71 subtypes, and elicited significant splenocyte proliferation. The high levels of interleukin-10(IL-10) and interferon-gamma (IFN-γ) showed that P1 protein induced Th1 and Th2 immune responses. Interestingly, vaccinating female mice with the P1 protein conferred cross-protection against different EV71 subtypes to their neonatal offspring.Compared with heat-inactivated EV71, the P1 protein elicited improved humoral and cellular immune responses and showed good cross-protection with different EV71 subtypes. Therefore, the EV71-P1 protein produced by P. pastoris is a promising candidate vaccine against EV71.

Is a multivalent hand, foot, and mouth disease vaccine feasible?

Enterovirus A infections are the primary cause of hand, foot and mouth disease (HFMD) in infants and young children. Although enterovirus 71 (EV-A71) and coxsackievirus A16 (CV-A16) are the predominant causes of HFMD epidemics worldwide, EV-A71 has emerged as a major neurovirulent virus responsible for severe neurological complications and fatal outcomes. HFMD is a serious health threat and economic burden across the Asia-Pacific region. Inactivated EV-A71 vaccines have elicited protection against EV-A71 but not against CV-A16 infections in large efficacy trials. The current development of a bivalent inactivated EV-A71/CV-A16 vaccine is the next step toward that of multivalent HFMD vaccines. These vaccines should ultimately include other prevalent pathogenic coxsackieviruses A (CV-A6 and CV-A10), coxsackieviruses B (B3 and B5) and echovirus 30 that often co-circulate during HFMD epidemics and can cause severe HFMD, aseptic meningitis and acute viral myocarditis. The prospect and challenges for the development of such multivalent vaccines are discussed.

Control selection methods in recent case-control studies conducted as part of infectious disease outbreaks

Successful investigation of national outbreaks of communicable disease relies on rapid identification of the source. Case-control methodologies are commonly used to achieve this. We assessed control selection methods used in recently published case-control studies for methodological and resource issues to determine if a standard approach could be identified. Neighbourhood controls were the most frequently used method in 53 studies of a range of different sizes, infections and settings. The most commonly used method of data collection was face to face interview. Control selection issues were identified in four areas: method of identification of controls, appropriateness of controls, ease of recruitment of controls, and resource requirements. Potential biases arising from the method of control selection were identified in half of the studies assessed. There is a need to develop new ways of selecting controls in a rapid, random and representative manner to improve the accuracy and timeliness of epidemiological investigations and maximise the effectiveness of public health interventions. Innovative methods such as prior recruitment of controls could improve timeliness and representativeness of control selection.

Coxsackievirus A16 infection induces neural cell and non-neural cell apoptosis in vitro

Coxsackievirus A16 (CA16) is one of the main causative pathogens of hand, foot and mouth disease (HFMD). Viral replication typically results in host cell apoptosis. Although CA16 infection has been reported to induce apoptosis in the human rhabdomyosarcoma (RD) cell line, it remains unclear whether CA16 induces apoptosis in diverse cell types, especially neural cells which have important clinical significance. In the current study, CA16 infection was found to induce similar apoptotic responses in both neural cells and non-neural cells in vitro, including nuclear fragmentation, DNA fragmentation and phosphatidylserine translocation. CA16 generally is not known to lead to serious neurological symptoms in vivo. In order to further clarify the correlation between clinical symptoms and cell apoptosis, two CA16 strains from patients with different clinical features were investigated. The results showed that both CA16 strains with or without neurological symptoms in infected patients led to neural and muscle cell apoptosis. Furthermore, mechanistic studies showed that CA16 infection induced apoptosis through the same mechanism in both neural and non-neural cells, namely via activation of both the mitochondrial (intrinsic) pathway-related caspase 9 protein and the Fas death receptor (extrinsic) pathway-related caspase 8 protein. Understanding the mechanisms by which CA16 infection induces apoptosis in both neural and non-neural cells will facilitate a better understanding of CA16 pathogenesis.