Epidemiologic aspects and laboratory features of enterovirus infections in Western Germany, 2000–2005

From 2000 to 2005, a total of 1,096 enterovirus infections were diagnosed either by isolation of virus from cell culture or by RT-PCR (5'non-coding region (NCR)). Typing of viruses (n = 674) was carried out by immunofluorescence with monoclonal antibodies, neutralization test or molecular methods. Seasons with high enterovirus activity were characterized by high prevalence of echovirus 30 (62.2% in 2000, 25.5% in 2001) and echovirus 13 (34.5% in 2001). In contrast, in the 2003 season, which had very low enterovirus activity, these types were rare. During this season, cell culture sensitivity (human colonic carcinoma cells and human embryonic lung fibroblasts (HEL)) was exceptionally low. In order to determine the type of "non-cultivable" enteroviruses, purified RNA from selected stool samples was subjected to direct molecular typing. VP1/2A-specific fragments were amplified by RT-PCR, cloned and sequenced. The predominant virus identified was coxsackie A. Consequently, rhabdomyosarcom cells were introduced into the daily routine, which improved the isolation of enteroviruses. Echovirus 30 was again most commonly isolated during seasons 2004 and 2005 with increasing enterovirus activity. In conclusion, high prevalence of echovirus 30 and 13 is indicative of seasons with high enterovirus activity. The type of circulating enteroviruses may influence isolation of enterovirus from cell culture. RT-PCR (VP1/2A) combined with cloning and sequencing of amplicons is a useful tool for viral typing directly from stool samples. In cases of severe enterovirus infection, virological diagnosis should not solely rely on virus isolation from cell culture.

Evaluation of enterovirus recovery in surface water by different adsorption and elution procedures

The performance of six concentration method combinations and two quantitative analysis techniques were evaluated in terms of enterovirus recovery efficiencies by adjusting the pH and salt concentration of water samples. Of the six concentration method combinations, adsorption on nitrocellulose membranes followed by an acid rinse elution consistently gave the highest recovery efficiencies. In theory, an electropositive membrane should be the most appropriate technique for adsorption of electronegative viruses in pure water. However, it displayed the greatest loss in natural waters. For adsorption and elution procedures, both the electronegative membrane, accompanied by an acid rinse step, and the electropositive membrane, accompanied by a glycine rinse step, provided higher recovery efficiencies. MPN-RT-PCR, a statistically quantitative analysis method, performed more efficiently, in economic terms, but had a similar enterovirus recovery trend to real-time RT-PCR, which is the authoritative quantitative analysis method for nucleic acid.

Enterovirus detection in stool specimen: relevance for poliovirus and enterovirus surveillance

Detection of enterovirus genome by PCR in clinical samples is now extensively used for the diagnostic of enterovirus infections given its rapidity and high sensitivity. In contrast, its use in surveillance programs targeting specific enterovirus serotypes remains less frequent. The most sensitive protocols are those amplifying in the 5'untranslated region (5'UTR). However the possibility to use sequence analysis of the 5'UTR amplicons for serotype identification is not yet well established. In this report, stool samples from polio suspected cases and their healthy contacts were tested. The results of direct detection of enterovirus genome by PCR and serotype identification based on sequence analysis of the PCR products in the 5'UTR were compared to those of standard cell-culture-based protocols. Standard protocols detected enterovirus isolates in 7.4% of cases while 9.8% of samples were positive by PCR. Serotype identification based on sequence analysis of amplicons showed concordant results with serotypes determined on virus isolates by seroneutralisation or sequencing in the VP1 gene in 39% of cases only. These results confirm that the use of PCR amplification from stool samples improves the sensitivity of enterovirus detection but do not recommend the use of sequence analysis of the 5'UTR PCR product to determine enterovirus serotype.

New enteroviruses, EV-93 and EV-94, associated with acute flaccid paralysis in the Democratic Republic of the Congo

Surveillance of acute flaccid paralysis often identifies enteroviruses not typeable by virus neutralization in cell culture. During 2000 and 2001, 186 isolates from 138 children with acute flaccid paralysis in the Democratic Republic of the Congo were sent for typing to the National Reference Centre for Enteroviruses in Lyon, France. The 5' UTR of the viral genome could be amplified by PCR for 158 isolates from 114 patients. Isolates from 89 patients were neutralizable, and contained non-polio enterovirus types. Seventeen children were infected with more than one entero- or adenovirus; another three were co-infected with both these viruses. Serological typing failed with 19 isolates from 13 (9%) patients. The VP1 region of these strains could be amplified by PCR and sequenced, which revealed that five children were infected with CV-A17, EV-70, EV-76, EV-77, or CV-A13. Two patients were doubly infected, one with CV-A24 and E-9, and another with E-27 and EV-81. Isolates from six children contained strains with divergent VP1 region. The amino acid sequences of these complete VP1 regions diverged >or=28% from published types indicating that they represented two new enterovirus types, tentatively designated EV-93 belonging to HEV-B and EV-94 within HEV-D. The latter enterovirus has in parallel been isolated from sewage in Egypt. In conclusion, there was a high frequency of "untypable" enterovirus isolates from cases with acute flaccid paralysis in the Democratic Republic of the Congo. Six of these were shown to represent two enteroviruses not previously described.

[Epidemiology of enterovirus associated with neurologic diseases]

This report describes the results of human enterovirus (HEV) detection and characterization using cell culture, polymerase chain reaction and molecular typing in 2167 samples obtained from acute flaccid paralysis, aseptic meningitis and acute encephalitis patients, from 1991 to 1998 in Argentina. HEV were isolated in 130 out of 666 cases (19.5%) and 36 out of 666 (5.4%). HEV RNA was detected in 28.8% (231/801) and 3.0% (21/700) of the patients with meningitis and encephalitis, respectively. Children with ages ranging from 1 to 9 years accounted for 75.3% of the meningitis cases and from 1 to 4 years for 58% of acute flaccid paralysis patients. Echovirus 4 (E4), E9, E30 and E17 were identified from meningitis outbreaks. Coxsackievirus A2 (CAV2), CBV2, CBV5, E7, E11, E19, E24, E29 and enterovirus 71 were recovered only from sporadic cases. Three different serotypes were identified in encephalitis patients: E4, E7 and E24. A total of 28 different serotypes of non-polio enteroviruses were detected from acute flaccid paralysis cases. The information here presented contributes to improving our knowledge about enteroviruses epidemiology in Argentina and their relationship with different neurological diseases. This study provides valuable data that could be useful to further research.

Identification, phenotypic analysis, and full-length nucleotide sequence of a Dutch Coxsackievirus A20 isolate

Recombination between (human) enteroviruses is a common event in nature. Recently, it has been recognised that this feature has a major impact on the use of the live-attenuated polio vaccine during the end stage of polio eradication. The constraints for successful recombination between (vaccine-derived) polioviruses and human enteroviruses are, however, largely unknown. Here, we describe the identification and characterisation of a HEV-C field strain, isolated from the stool of a 2-year-old Dutch boy. Serotyping indicated that strain 89490 is a variant of strain CAV20a, which is already a variant of the prototype CAV20 strain. Amino acid sequence identity of 94.1% for the entire P1-region, and 92.4% for the major structural protein (VP1) indicates that this strain is indeed related to CAV20. However, virus neutralisation and Western blot analysis failed to show antigenic homology between the prototype CAV20 strain and our field strain. Furthermore, the 89490 field strain, just like the sub-prototype CAV20a, is able to replicate on RD-cells, while the prototype CAV20 and another sub-prototype CAV20b are not. On the basis of the phylogenetic analysis of the P2 and P3 region we expect that strain 89490 can act as recombination partner for the attenuated poliovirus strains of the Oral Polio Vaccine (OPV).

Assessment of the Utility of Viral Culture of Cerebrospinal Fluid

Nucleic acid amplification testing is the preferred method to detect enteroviruses and Herpesviridae in cerebrospinal fluid, but clinicians still request viral culture. Review of 22,394 viral cultures of cerebrospinal fluid samples found that <0.1% recovered nonenterovirus, non-Herpesviridae species, suggesting that, when nucleic acid amplification testing is performed, viral culture may have no additional benefit.

Microarray-in-a-tube for detection of multiple viruses

Background: The detection of multiple viruses is important for pathogenic diagnosis and disease control. Microarray detection is a good method, but requires complex procedures for multiple virus detection.

Methods: We developed a novel PCR assay, the microarray-in-a-tube system, which integrates multiple PCR processes and DNA microarrays for multiple virus detection. A 5 × 5 oligonucleotide microarray for detecting 4 respiratory tract viruses (severe acute respiratory syndrome–associated coronavirus, influenza A virus, influenza B virus, and enterovirus) with inner controls was arranged on the inner surface of a specially designed Eppendorf cap with a flat, optically transparent window.

Results: We were able to perform all detection processes in the encapsulated system without opening the cap. The 4 viruses were successfully amplified by one-step reverse transcription–PCR in the encapsulated tube. After the PCR process, the microarray-in-a-tube was inverted, and the fluorescence-labeled PCR products were directly hybridized on the microarray. Hybridization signals were obtained with an ordinary fluorescent microscope. The sensitivity of the system for virus detection reached 10² copies/μL. With the help of inner controls, the system provided reliable results without false negatives and false positives.

Conclusions: The microarray-in-a-tube system is a rapid, labor-saving tool for multiple virus detection with several advantages, such as convenience, prevention of cross-contamination of the PCR products, and potential for multiple-gene detection.

Minimal hepatic toxicity of Onyx-015: spatial restriction of coxsackie-adenoviral receptor in normal liver

We administered an adenoviral vector, Onyx-015, into the hepatic artery of patients with metastatic colorectal cancer involving the liver. Thirty-five patients enrolled in this multi-institutional phase I/II trial received up to eight arterial infusions of up to 2 × 10¹² viral particles. Hepatic toxicity was the primary dose-limiting toxicity observed in preclinical models. However, nearly 200 infusions of this adenoviral vector were administered directly into the hepatic artery without significant toxicity. Therefore, we undertook this analysis to determine the impact of repeated adenoviral exposure on hepatic function. Seventeen patients were treated at our institution, providing a detailed data set on the changes in hepatic function following repeated exposure to adenovirus. No changes in hepatic function occurred with the first treatment of Onyx-015 among these patients. Transient increases in transaminase levels occurred in one patient starting with the second infusion and transient increases in bilirubin was observed in two patients starting with the fifth treatment. These changes occurred too early to be explained by viral-mediated lysis of hepatocytes. In addition, viremia was observed starting 3–5 days after the viral infusion in half of the patient, but was not associated with hepatic toxicity. To further understand the basis for the minimal hepatic toxicity of adenoviral vectors, we evaluated the replication of adenovirus in primary hepatocytes and tumor cells in culture and the expression of the coxsackie-adenoviral receptor (CAR) in normal liver and colon cancer metastatic to the liver. We found that adenovirus replicates poorly in primary hepatocytes but replicates efficiently in tumors including tumors derived from hepatocytes. In addition, we found that CAR is localized at junctions between hepatocytes and is inaccessible to hepatic blood flow. CAR is not expressed on tumor vasculature but is expressed on tumor cells. Spatial restriction of CAR to the intercellular space in normal liver and diminished replication of adenovirus in hepatocytes may explain the minimal toxicity observed following repeated hepatic artery infusions with Onyx-015.

Human rhinoviruses in otitis media with effusion

Frequent viral upper respiratory tract infections (URTI) are considered to be risk factors for otitis media with effusion (OME). Atopy has also been associated with both OME and viral infections. The aim of this study was to evaluate the presence of viruses in middle ear effusions (MEE) in children 2-7 yr old with OME, and to determine risk factors for virus detection in the MEE. MEE samples, collected at the time of myringotomy from 37 children with OME were assessed. Physical examination, skin prick tests and a standardized questionnaire on OME and allergy were also performed. Viral RNA was detected by the use of reverse transcription PCR (RT-PCR). Fifteen samples (40.5%) were positive for rhinovirus (RV). One enterovirus and no other respiratory viruses were detected. Two out of five (40%), 3/7 (43%) and 10/25 (40%) were positive for RV in acute, subacute and chronic cases, respectively. Children with frequent episodes of OM, with early onset of OM (<2 yr old), and a positive family history of allergy had a statistically increased risk of RV detection. The two groups were comparable with respect to all other parameters examined. RV is the predominant virus recovered by RT-PCR in the middle ear cavity of children with asymptomatic OME, especially those with a history of longstanding OME or repeated episodes, or children with a family history of allergy. Interactions between allergy and RV infections are likely to predispose to middle ear disease.

[Gene expression of tumor cells both in vitro and in vivo enhanced by integrin-targeting adenovirus vector]

AIM

To construct an efficient recombinant viral vector for gene therapy.

METHODS

First-generation adenovirus (Ad) vector was modified with the RGD peptide inserted into the fiber. Both in vitro and in vivo experiments of gene expression in different tumor cells with conventional and recombinant vectors were conducted. RT-PCR was used for detecting the expression of coxackievirus and adenovirus receptor and integrin at the surface of Meth-A cells.

RESULTS

Fiber-mutant adenovirus vector showed a notably enhanced gene expression in A2058, B16BL6, OV-HM, and Meth-A tumor cells compared with that of conventional ones. In vivo study carried out using Meth-A tumor-bearing mice also demonstrated that the intra-tumoral injection of recombinant adenovirus induced strong gene expression in these CAR-deficient tumor cells.

CONCLUSION

The recombinant vector can be a promising one for effective cancer gene therapy.

Quantitative detection of hepatitis a virus and enteroviruses near the United States-Mexico border and correlation with levels of fecal indicator bacteria

For decades, untreated sewage flowing northward from Tijuana, Mexico, via the Tijuana River has adversely affected the water quality of the recreational beaches of San Diego, California. We used quantitative reverse transcription-PCR to measure the levels of hepatitis A virus (HAV) and enteroviruses in coastal waters near the United States-Mexico border and compared these levels to those of the conventional fecal indicators, Escherichia coli and enterococci. Over a 2-year period from 2003 to 2005, a total of 20 samples were assayed at two sites during both wet and dry weather: the surfzone at the mouth of the Tijuana River and the surfzone near the pier at Imperial Beach (IB), California (about 2 km north of the mouth of the Tijuana River). HAV and enterovirus were detected in 79 and 93% of the wet-weather samples, respectively. HAV concentrations in these samples ranged from 105 to 30,771 viral particles/liter, and enterovirus levels ranged from 7 to 4,417 viral particles/liter. The concentrations of HAV and enterovirus were below the limit of detection for all dry weather samples collected at IB. Regression analyses showed a significant correlation between the densities of both fecal bacterial indicators and the levels of HAV (R2>0.61, P<0.0001) and enterovirus (R2>0.70, P<0.0001), a finding that supports the use of conventional bacterial indicators to predict the levels of these viruses in recreational marine waters.

Molecular typing of enteroviruses associated with viral meningitis in Cyprus, 2000-2002

Human enteroviruses are responsible for a wide spectrum of clinical diseases affecting many different organ systems. Although infection is usually asymptomatic, infections of the central nervous system manifested as meningitis or encephalitis can pose a serious public health problem, especially during outbreaks. In this study, samples from 218 patients diagnosed with enteroviral meningitis between January 2000 and December 2002 were analysed in order to assess the epidemiology of human enteroviruses as a cause of viral meningitis in Cyprus. A new typing strategy, based on partial sequencing of the 5' non-coding region (5'NCR), prediction of type, and selection of type-specific primers for sensitive VP1 PCR amplification, was developed. As clustering in the 5'NCR was concordant with clustering in the VP1 region, quick and reliable typing by VP1 sequencing was achieved without virus isolation in cell culture. The most frequent enterovirus serotypes identified were Human echovirus 30 (55.5%), Human echovirus 13 (15.1%), Human echovirus 6 (13.8%) and Human echovirus 9 (8.3%). Human coxsackieviruses B2, B1 and B5, Human echovirus 4, Human enterovirus 71 and Human coxsackievirus A6 represented rather rare serotypes. This is the first molecular epidemiological study of enterovirus meningitis in Cyprus. Serotype distribution corresponded basically with observations in other European countries, suggesting the spread of enteroviruses by tourism.

Detection of human enteric viruses in shellfish collected in Tunisia

AIMS

The aim of this study was to detect the main pathogenic human RNA enteric viruses able to persist in the environment such as astrovirus, enterovirus, norovirus and hepatitis A virus (HAV) in shellfish collected from two locations in northern Tunisia.

METHODS AND RESULTS

Viruses were eluted from digestive tissues and concentrated by polyethylene glycol precipitation before nucleic acid extraction and purification. After checking for inhibitors, all viruses were detected by reverse transcription-polymerase chain reaction (RT-PCR) and confirmed by hybridization. Overall, 83% of the samples were found positive for at least one virus. Astrovirus was detected in 61% of the samples, norovirus in 35% and HAV in 26%. Surprisingly, only one sample was found positive for enterovirus.

CONCLUSIONS

The mean number of positive samples found in this study is in accordance with the data found in the literature, indicating that no real difference exists in this respect among countries studied. A notable exception is HAV, which reflects the epidemiological status of the population.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study highlights the interest to analyse shellfish samples from different production areas. These data will be helpful to understand virus circulation and to improve shellfish safety. The results, which confirm contamination, necessitate the development of appropriate studies and monitoring in all shellfish-producing countries.

An aged host promotes the evolution of avirulent coxsackievirus into a virulent strain

The emergence of new, more pathogenic viruses necessitates elucidation of factors that promote viral evolution. Aging, a potential factor, is associated with increased susceptibility to viral infections. We used the enterovirus coxsackievirus B3 (CVB3) to investigate the effects of host age on pathogenicity and viral gene sequence. Old mice infected with a normally amyocarditic strain of CVB3, CVB3/0, had significantly higher mean heart viral titers compared with CVB3/0-infected adult mice. To determine whether a change in the CVB3/0 viral population could contribute to the higher titers observed in the old infected mice, CVB3/0 was passed once through an old or adult host and the changes in pathogenicity and viral genome were examined after subsequent infection of old or adult mice. Adult mice infected with CVB3/0 that was passed through an old host (CVB3/0(Old)) exhibited significantly higher heart viral titers, pathology, and weight loss than adult mice infected with either stock CVB3/0 or CVB3/0 passed through an adult host (CVB3/0(Adult)). Sequence analysis of virus isolated from CVB3/0(Old)-infected mice revealed 13 specific and reproducible nucleotide changes. These changes result in a sequence that matches the virulent CVB3/20 strain and are associated with promoting cardiovirulence. In contrast, we observed only one nucleotide change, low heart viral titers, and no heart and liver pathology in adult mice infected with CVB3/0(Adult). These results demonstrate that the aged host promotes rapid selection of a pathogenic variant of CVB3 from an avirulent strain and introduces a host-virus paradigm for studies of viral infection in the aged.

Asymptomatic circulation of HEV71 in Norway

Widespread circulation of human enterovirus 71 was discovered in a prospective study of fecal samples obtained from healthy Norwegian children. Molecular characterization of the virus determined that it belonged to genotype C1. Complete sequencing of this strain, HEV71 804/NO/03, revealed differences in the 5'UTR and polymerase with respect to more pathogenic genotypes that may explain its reduced neurovirulence.

Rapid one-step quantitative reverse transcriptase PCR assay with competitive internal positive control for detection of enteroviruses in environmental samples

Human enteroviruses can serve as a more accurate indicator of human fecal contamination than conventional bacteriological fecal indicators. We describe here a quantitative reverse transcriptase PCR (qRT-PCR) assay specifically tailored to detect these viruses in environmental waters. The assay included a competitive internal positive control (CIPC) that allowed the inhibition of qRT-PCRs to be quantitatively assessed. Coamplification of the CIPC with enteroviral genetic material did not affect the sensitivity, specificity, or reproducibility of the enteroviral qRT-PCR assay. The assay is rapid (less than 5 h from sample to result), has a wide dynamic range (>3 logs), and is capable of detecting as few as 25 enteroviral genomes with an average amplification efficiency of 0.91. In samples with low or moderate inhibition, the delay in CIPC amplification was used to adjust enterovirus qRT-PCR concentrations to account for losses due to inhibition. Samples exhibiting significant inhibition were not corrected but instead diluted twofold and immediately assayed again. Using significantly inhibited samples, it was found that dilution relieved inhibition in 93% (25 of 27) of the samples. In addition, 15% (4 of 27) of these previously negative samples contained enteroviral genomes. The high-throughput format of the assay compared to conventional culture-based methods offers a fast, reliable, and specific method for detecting enteroviruses in environmental water samples. The ability of the assay to identify false negatives and provide improved quantitative assessments of enterovirus concentrations will facilitate the tracking of human fecal contamination and the assessment of potential public health risk due to enteroviruses in recreational and shellfish harvesting waters.

Phylogenetic evidence for inter-typic recombination in the emergence of human enterovirus 71 subgenotypes

Background

Human enterovirus 71 (EV-71) is a common causative agent of hand, foot and mouth disease (HFMD). In recent years, the virus has caused several outbreaks with high numbers of deaths and severe neurological complications. Several new EV-71 subgenotypes were identified from these outbreaks. The mechanisms that contributed to the emergence of these subgenotypes are unknown.

Results

Six EV-71 isolates from an outbreak in Malaysia, in 1997, were sequenced completely. These isolates were identified as EV-71 subgenotypes, B3, B4 and C2. A phylogenetic tree that correlated well with the present enterovirus classification scheme was established using these full genome sequences and all other available full genome sequences of EV-71 and human enterovirus A (HEV-A). Using the 5' UTR, P2 and P3 genomic regions, however, isolates of EV-71 subgenotypes B3 and C4 segregated away from other EV-71 subgenotypes into a cluster together with coxsackievirus A16 (CV-A16/G10) and EV-71 subgenotype C2 clustered with CV-A8. Results from the similarity plot analyses supported the clustering of these isolates with other HEV-A. In contrast, at the same genomic regions, a CV-A16 isolate, Tainan5079, clustered with EV-71. This suggests that amongst EV-71 and CV-A16, only the structural genes were conserved. The 3' end of the virus genome varied and consisted of sequences highly similar to various HEV-A viruses. Numerous recombination crossover breakpoints were identified within the non-structural genes of some of these newer EV-71 subgenotypes.

Conclusion

Phylogenetic evidence obtained from analyses of the full genome sequence supports the possible occurrence of inter-typic recombination involving EV-71 and various HEV-A, including CV-A16, the most common causal agent of HFMD. It is suggested that these recombination events played important roles in the emergence of the various EV-71 subgenotypes.

Characterisation of two enteroviruses isolated from Australian brushtail possums (Trichosurus vulpecula) in New Zealand

Two enteroviruses, designated W1 and W6, were isolated from intestinal contents of Australian brushtail possums (Trichosurus vulpecula) in New Zealand. The genomic sequences of W1 and W6 were 7390 and 7391 nucleotides (nt), respectively. Genetically, possum isolates W1 and W6 were related to bovine enterovirus serotype 2 (BEV-2) strains, especially to the strain PS87/Belfast, based on the capsid protein sequence. However, W1 and W6 formed a clade that was distinct from PS87Belfast based on nucleotide sequences of the 3' and 5'-non-translated region and in the amino acid sequences of 2A, 3C and 3D. Possum isolates W1 and W6 grew more readily in possum kidney cells than in Madin-Darby bovine kidney (MDBK) cells, suggesting that co-evolution of W1 and W6 with possums has made them more adapted to possum cells.

Combining multiplex reverse transcription-PCR and a diagnostic microarray to detect and differentiate enterovirus 71 and coxsackievirus A16

Cluster A enteroviruses, including enterovirus 71 (EV71) and coxsackievirus A16 (CA16), are known to cause hand-foot-and-mouth disease (HFMD). Despite the close genetic relationship between these two viruses, EV71 is generally known to be a more perpetuating pathogen involved in severe clinical manifestations and deaths. While the serotyping of enteroviruses is mostly done by conventional immunological methods, many clinical isolates remain unclassifiable due to the limited number of antibodies against enterovirus surface proteins. Array-based assays are able to detect several serotypes with high accuracy. We combined an enterovirus microarray with multiplex reverse transcription-PCR to try to develop a method of sensitively and accurately detecting and differentiating EV71 and CA16. In an effort to design serotype-specific probes for detection of the virus, we first did an elaborate bioinformatic analysis of the sequence database derived from different enterovirus serotypes. We then constructed a microarray using 60-mer degenerate oligonucleotide probes covalently bound to array slides. Using this enterovirus microarray to study 144 clinical specimens from patients infected with HFMD or suspected to have HFMD, we found that it had a diagnostic accuracy of 92.0% for EV71 and 95.8% for CA16. Diagnostic accuracy for other enteroviruses (non-EV71 or -CA16) was 92.0%. All specimens were analyzed in parallel by real-time PCR and subsequently confirmed by neutralization tests. This highly sensitive array-based assay may become a useful alternative in clinical diagnostics of EV71 and CA16.

Genetic diversity of enterovirus 71 associated with hand, foot and mouth disease epidemics in Japan from 1983 to 2003

BACKGROUND

Enterovirus 71 (EV71) is one of the major etiologic agents of hand, foot and mouth disease (HFMD). The surveillance data indicate that EV71 infection follows an epidemic mode of transmission, causing large outbreaks and then becoming quiescent for a few years.

METHODS

We investigated the genetic diversity of a total of 121 EV71 strains isolated from patients with HFMD in Fukushima, Japan, from 1983 to 2003 and compared their genetic relation with the 164 EV71 strains isolated in the world using phylogenetic analysis based on the VP4 sequence.

RESULTS

We observed EV71-related HFMD outbreaks in Fukushima in 1984, 1987, 1990, 1993, 1997, 2000 and 2003. Phylogenetic reconstruction of EV71 strains isolated in Fukushima demonstrated 8 genetically distinct clusters, including 6 subgroups previously designated as B-1, B-2 and 3, B-4, C-1, C-2, and C-3 and 2 subgroups newly designated as B-5 and C-4. Additional 2 indistinct clusters belonged to genogroup C and were named C-U1 and C-U2. Of those subgroups, B-1, C-U1, C-U2, C-2, B4, and C-4 and B-5 dominantly related to epidemics that occurred in the years 1984, 1987 and 1990, 1993, 1997, 2000 and 2003, respectively. EV71 strains derived from each outbreak in Fukushima formed a single cluster with those isolated during almost the same time period in other area of Japan and in other countries.

CONCLUSIONS

Our results suggested that the repeated EV71 outbreaks might be the result of the worldwide transmission of the newly introduced genetically divergent EV71 strains.

Novel role for integrin-linked kinase in modulation of coxsackievirus B3 replication and virus-induced cardiomyocyte injury

Viral myocarditis is a major cause of sudden cardiac death in children and young adults. Among viruses, coxsackievirus B3 (CVB3) is the most common agent for myocarditis. Recently, more consideration has been given to the role of signaling pathways in pathogenesis of enteroviral myocarditis, providing new platform for identifying a new potential therapeutic target for this, so far, incurable disease. Previously, we reported on the role of the protein kinase-B/Akt in CVB3 replication and virus-induced cell injury. Here, we report on regulation of virus-induced Akt activation by the integrin-linked kinase in infected mouse cardiomyocytes and HeLa cells. This study also presents the first observation that inhibition of ILK in CVB3-infected cells significantly improves the viability of infected cells, while blocking viral replication and virus release. Complementary experiments using a constitutively active form of Akt1 revealed that the observed protective effect of ILK inhibition is dependent on the associated downregulation of virus-induced Akt activation. To our knowledge, this is the first report of such beneficial effects of ILK inhibition in a viral infection model and conveys new insights in our efforts to characterize a novel therapeutic target for treatment of enteroviral myocarditis.

Sentinel surveillance for human enterovirus 71 in Sarawak, Malaysia: lessons from the first 7 years

Background

A major outbreak of human enterovirus 71-associated hand, foot and mouth disease in Sarawak in 1997 marked the beginning of a series of outbreaks in the Asia Pacific region. Some of these outbreaks had unusually high numbers of fatalities and this generated much fear and anxiety in the region.

Methods

We established a sentinel surveillance programme for hand, foot and mouth disease in Sarawak, Malaysia, in March 1998, and the observations of the first 7 years are described here. Virus isolation, serotyping and genotyping were performed on throat, rectal, vesicle and other swabs.

Results

During this period Sarawak had two outbreaks of human enterovirus 71, in 2000 and 2003. The predominant strains circulating in the outbreaks of 1997, 2000 and 2003 were all from genogroup B, but the strains isolated during each outbreak were genetically distinct from each other. Human enterovirus 71 outbreaks occurred in a cyclical pattern every three years and Coxsackievirus A16 co-circulated with human enterovirus 71. Although vesicles were most likely to yield an isolate, this sample was not generally available from most cases and obtaining throat swabs was thus found to be the most efficient way to obtain virological information.

Conclusion

Knowledge of the epidemiology of human enterovirus 71 transmission will allow public health personnel to predict when outbreaks might occur and to plan interventions in an effective manner in order to reduce the burden of disease.

Quantitation of hepatitis A virus and enterovirus levels in the lagoon canals and Lido beach of Venice, Italy, using real-time RT-PCR

In order to assess the microbial water quality of the lagoon canals of Venice, Italy and nearby beach on Lido island, a study was conducted using real-time RT-PCR to enumerate levels of hepatitis A virus (HAV) and enteroviruses in these marine waters over a 3-year period from 2003 to 2005. A total of 17 sites (9 lagoon canal and 8 beach sites) were assayed. For the canals of the Venice Lagoon, 78% were positive for both HAV and enteroviruses, with levels ranging from 75 to 730 and 3 to 1,614 genome copies/L, respectively. At Lido beach, HAV was never detected, but enteroviruses were detected in all Lido beach samples at levels ranging from 2 to 71 genome copies/L. There was a statistically significant correlation between thermotolerant coliform densities and HAV levels (p=0.0002), but the relationship between thermotolerant coliform densities and enterovirus levels was not significant (p>0.05). Despite the fact that enteroviruses were detected at low levels in the surfzone at Lido beach, the risk for enteroviral infection (calculated using the beta-Poisson model) for recreational exposure from swimming, was in the range of 1.9 x 10(-3) - 6.1 x 10(-2), yielding a disease risk at or below the level (5% for gastroenteritis) deemed acceptable by European Guide standards.