A sensitive and quantitative single-tube real-time reverse transcriptase-PCR for detection of enteroviral RNA

Human Rhinovirus as a Cause of Fever in Neonates and Young Infants During the COVID-19 Pandemic, 2020-2022

BACKGROUND

Human rhinovirus (HRV) was predominant and persistent during the coronavirus disease 2019 (COVID-19) pandemic despite nonpharmaceutical interventions. The data whether HRV persistence also occurred in neonates and young infants were very limited.

METHODS

This prospective observational study was conducted in Niigata, Japan, between January 2020 and September 2022. The participants were hospitalized neonates and infants less than 4 months of age with fever. We excluded patients with evidence of bacterial infection or obvious sick contact with influenza or respiratory syncytial virus infection, as confirmed by rapid antigen detection tests. COVID-19 diagnosed by polymerase chain reaction (PCR) or rapid antigen detection tests were also excluded. Parechovirus and enterovirus were examined by PCR using serum and/or cerebrospinal fluid. FilmArray Respiratory Panel v1.7 was conducted on nasopharyngeal swabs. If HRV was positive, the genotype was identified.

RESULTS

We included 72 patients (median age, 54 days; interquartile range, 28.5-79 days), and sepsis was diagnosed in 31 (43.1%) patients. In total, 27 (37.5%) patients had had positive multiplex PCR tests. These patients were more likely to have rhinorrhea ( P  = 0.004), cough ( P  = 0.01), and sick contact ( P  < 0.001) than those who with negative multiplex PCR. HRV was the most frequently detected virus (n = 23, 85.2%), and species A (n = 15, 71.4%) and C (n = 6, 28.6%) were genotyped. No seasonality or monthly predominance of the specific HRV types was observed.

CONCLUSIONS

HRV was an important cause of fever in neonates and young infants during the COVID-19 pandemic, 2020 to 2022.

An outbreak investigation of parechovirus-A3 in a newborn nursery

OBJECTIVE

To investigate parechovirus-A3 (PeV-A3) transmission in a newborn nursery, after encountering 3 neonates with fever and rash.

DESIGN

An observational study.

SETTING

At a newborn nursery at the general hospital in Hyogo, Japan.

PARTICIPANTS

Symptomatic neonates and their family members, and asymptomatic neonates born during the same period.

METHODS

PCR assays for PeV-A and genotyping were used for the investigation of PeV-A3. Preserved umbilical cords were used to identify the route of transmission.

RESULTS

PeV-A3 infection was confirmed in the three symptomatic neonates. The index case had fever and rash, and the 2 neonates treated later became symptomatic and had serum, cerebrospinal fluid, and stool specimens that were positive for PeV-A3 on PCR. The umbilical cord of the index case was positive for PeV-A3 on PCR. The family members of the index case, including the mother, were asymptomatic before delivery. The older sister and cousin of the PeV-A3-infected neonate had positive PCR results. The sequence analysis suggested 2 possible transmission routes: vertical and horizontal transmission in a newborn nursery and/or a family outside the hospital. The incubation period of PeV-A3 infection was estimated to be 1-3 days (maximum, 7 days).

CONCLUSION

Horizontal transmission of PeV-A3 was confirmed in a newborn nursery. Vertical transmission was suggested by the detection of RNA in an umbilical cord sample from the index case. These observations indicate that PeV-A3 can be horizontally transmitted in a newborn nursery and that special caution is required to prevent healthcare-associated transmission of PeV-A3.

Clinical manifestations and outcome of viral acute lower respiratory infection in hospitalised children in Myanmar

Background

Acute lower respiratory infection (ALRI) remains the leading cause of death in children worldwide, and viruses have been the major cause of ALRI. In Myanmar, ALRI is associated with high morbidity and mortality in children, and detailed information on ALRI is currently lacking.

Methods

This prospective study investigated the viral aetiologies, clinical manifestations, and outcomes of ALRI in hospitalised children aged 1 month to 12 years at the Yankin Children Hospital, Yangon, Myanmar from May 2017 to April 2019. The sample size was set to 300 patients for each year. Two nasopharyngeal swabs were obtained for the patients with suspected viral ALRI; one for rapid tests for influenza and respiratory syncytial virus (RSV), and the other for real-time PCR for the 16 ALRI-causing viruses. Pneumococcal colonization rates were also investigated using real-time PCR. Clinical information was extracted from the medical records, and enrolled patients were categorised by age and severity for comparison.

Results

Among the 5463 patients admitted with a diagnosis of ALRI, 570 (10.4%) were enrolled in this study. The median age of the patients was 8 months (interquartile range, 4–15 months). The most common symptoms were cough (93%) and difficulty in breathing (73%), while the most common signs of ALRI were tachypnoea (78%) and chest indrawing (67%). A total of 16 viruses were detected in 502 of 570 patients’ samples (88%), with RSV B (36%) and rhinovirus (28%) being the most commonly detected. Multiple viruses were detected in 221 of 570 samples (37%) collected from 570 patients. Severe ALRI was diagnosed in 107 of 570 patients (19%), and RSV B and human rhinovirus were commonly detected. The mortality rate was 5%; influenza virus A (29%) and RSV B (21%) were commonly detected, and stunting and lack of immunization were frequently observed in such cases. Additionally, 45% (259/570) of the patients had pneumococcal colonization.

Conclusions

Viral ALRI in hospitalised children with a median of 8 months has significant morbidity and mortality rates in Myanmar. RSV and rhinovirus were the most commonly detected from nasopharyngeal swabs, while influenza virus and RSV were the most frequently associated with fatal cases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07342-1.

Development of Novel PCR Assays for Improved Detection of Enterovirus D68

Enterovirus D68 (EV-D68) causes a range of clinical manifestations, including asthma-like illness, severe respiratory disease, and acute flaccid myelitis. EV-D68 has caused worldwide outbreaks since 2014 and is now recognized as a reemerging infection in many countries. EV-D68-specific PCR assays are widely used for the diagnosis of EV-D68 infection; however, assay sensitivity is a concern because of genetic changes in recently circulated EV-D68. To address this, we summarized EV-D68 sequences from previously reported world outbreaks from 2014 through 2020 on GenBank, and found several mutations at the primer and probe binding sites of the existing EV-D68-specific PCR assays. Subsequently, we designed two novel assays corresponding to the recently reported EV-D68 sequences: an EV-D68-specific real-time and seminested PCR. In an analysis of 22 EV-D68 confirmed cases during a recent EV-D68 outbreak in Japan, the new real-time PCR had higher sensitivity than the existing assay (100% versus 45%, P < 0.01) and a lower median C_T value (27.8 versus 32.8, P = 0.005). Sensitivity was higher for the new nonnested PCR (91%) than for the existing seminested PCR assay (50%, P < 0.01). The specificity of the new real-time PCR was 100% using samples from non-EV-D68-infected cases (n = 135). In conclusion, our novel assays had higher sensitivity than the existing assay and might lead to more accurate diagnosis of recently circulating EV-D68. To prepare for future EV-D68 outbreaks, EV-D68-specific assays must be continuously monitored and updated.

Weaning-associated feed deprivation stress causes microbiota disruptions in a novel mucin-containing in vitro model of the piglet colon (MPigut-IVM)

BACKGROUND

Risk factors for the etiology of post-weaning diarrhea, a major problem in swine industry associated with enormous economic losses, remain to be fully elucidated. In concordance with the ethical concerns raised by animal experiments, we developed a new in vitro model of the weaning piglet colon (MPigut-IVM) including a mucin bead compartment to reproduce the mucus surface from the gut to which gut microbes can adhere.

RESULTS

Our results indicated that the MPigut-IVM is able to establish a representative piglet archaeal and bacterial colon microbiota in terms of taxonomic composition and function. The MPigut-IVM was consequently used to investigate the potential effects of feed deprivation, a common consequence of weaning in piglets, on the microbiota. The lack of nutrients in the MPigut-IVM led to an increased abundance of Prevotellaceae and Escherichia-Shigella and a decrease in Bacteroidiaceae and confirms previous in vivo findings. On top of a strong increase in redox potential, the feed deprivation stress induced modifications of microbial metabolite production such as a decrease in acetate and an increase in proportional valerate, isovalerate and isobutyrate production.

CONCLUSIONS

The MPigut-IVM is able to simulate luminal and mucosal piglet microbiota and represent an innovative tool for comparative studies to investigate the impact of weaning stressors on piglet microbiota. Besides, weaning-associated feed deprivation in piglets provokes disruptions of MPigut-IVM microbiota composition and functionality and could be implicated in the onset of post-weaning dysbiosis in piglets.

Innate Immune Responses in Serum and Cerebrospinal Fluid From Neonates and Infants Infected With Parechovirus-A3 or Enteroviruses

BACKGROUND

Parechovirus (PeV)-A3 and enteroviruses (EV) are the most common viruses causing sepsis and meningoencephalitis in neonates and young infants. Clinical manifestations of PeV-A3 infection are more severe than those of EV infection, and no pleocytosis with a positive polymerase chain reaction (PCR) result for PeV-A3 in cerebrospinal fluid (CSF) are characteristic findings. We hypothesized that innate immune responses to PeV-A3 and EV are distinct in serum and CSF.

METHODS

We evaluated 22 cytokines/chemokines in serum and CSF from PeV-A3- or EV-infected patients younger than 4 months in Niigata, Japan, from 2015 through 2018. Infection was diagnosed with real-time PCR followed by sequencing. Febrile neonates and infants with sepsis-like syndrome who had negative bacterial culture and viral PCR for both PeV-A and EV were also included (non-PeV-A/EV patients).

RESULTS

Among 192 febrile patients, we evaluated 16 PeV-A3-infected, 15 EV-infected, and 8 non-PeV-A/EV patients. Serum pro-/anti-inflammatory cytokine/chemokine levels were higher in PeV-A3-infected patients than in EV-infected patients (P < .02). Although most cytokine/chemokine were elevated in CSF from EV-infected patients, levels were low or undetectable in PeV-A3-infected and non-PeV-A/EV patients (P < .001).

CONCLUSIONS

Distinct cytokine/chemokine patterns in serum and CSF may explain the different clinical manifestations of PeV-A3-infected and EV-infected neonates and young infants.

Assessment of Full-Scale Indirect Potable Water Reuse in El Port de la Selva, Spain

In 2015, the town of El Port de la Selva in Spain implemented soil-aquifer treatment (SAT) using tertiary treated wastewater effluents to replenish the local potable aquifer. This study evaluated the initial phase of this indirect potable water reuse system including a characterization of hydraulic conditions in the aquifer and monitoring of microbial contaminants and 151 chemicals of emerging concern (CECs). The combined treatment resulted in very low abundances of indicator bacteria, enteric viruses and phages in the monitoring wells after three days of infiltration and a reduction of antibiotic microbial resistance to background levels of local groundwater. After tertiary treatment, 94 CECs were detected in the infiltration basin of which 15 chemicals exceeded drinking water thresholds or health-based monitoring trigger levels. Although SAT provided an effective barrier for many chemicals, 5 CECs were detected above health-based threshold levels in monitoring wells after short hydraulic retention times. However, additional attenuation is expected due to dilution prior to abstraction via downstream drinking water wells and during granular activated carbon (GAC) filtration, which was recently installed to mitigate residual CECs. Overall, the results demonstrate that indirect potable water reuse can be a reliable option for smaller communities, if related risks from microbial and chemical contaminants are adequately addressed by tertiary treatment and subsequent SAT, providing sufficient hydraulic retention times for pathogen decay and CEC removal.

PCR detection rates for serum and cerebrospinal fluid from neonates and young infants infected with human parechovirus 3 and enteroviruses

BACKGROUND

Human parechovirus 3 (HPeV-3) and enteroviruses (EV) are commonly detected viruses in febrile neonates and young infants and are usually diagnosed by PCR. However, in this population, data on detection rates for samples from different anatomical sites are limited.

OBJECTIVES

To determine PCR detection rates for HPeV-3 and EVs in serum and cerebrospinal fluid (CSF) samples from febrile neonates and young infants.

STUDY DESIGN

This prospective study identified viruses in serum and CSF samples collected from febrile neonates and young infants (age <4 months) in Niigata, Japan, during 2014-2018. HPeV-3 or EV infection was defined as a positive quantitative real-time PCR result for the virus in serum or CSF. Genotypes were identified by sequence analyses of the viral protein 1 region.

RESULTS

Among 216 patients, we identified 56 HPeV-3-infected (26 %) and 48 EV-infected patients (22 %). All (56/56; 100 %) HPeV-3-infected patients had a positive PCR result for serum, and 49/56 (88 %) had a positive result for CSF. In EV-infected patients, 40/48 (83 %) were positive for serum, and 34/48 (71 %) were positive for CSF, and 22/48 (46 %) were positive for serum (n = 14) or CSF (n = 8). If only a CSF sample had been obtained, 7 (12 %) HPeV-3 infections and 14 (29 %) EV infections would have been undiagnosed. Detection rates in serum and CSF differed by genotype in EV-infected patients.

CONCLUSIONS

Viral RNA detection rates differed between serum and CSF in HPeV-3- and EV-infected neonates/infants. Combined evaluation of serum and CSF samples is important for accurate viral diagnosis in this population.

First record of West Nile Virus detection inside wild mosquitoes in Khartoum capital of Sudan using PCR

This study aimed to explore the presence of West Nile Virus (WNV) inside four species of mosquitoes: Culex univittatus (Theobald), Culex quinquefasciatus (Say) Aedes vittatus (Bigot) and Aedes vexans (Meigen). Adult wild mosquitoes were collected from different sites: Soba West, Hellat Kuku, Shambat, and Khartoum North Central Live Stock Market (KCLM). Surveys were carried out at Khartoum State during two phases: pre to the rainy season and post to the rainy season. Mosquito specimens were identified using classical keys then preserved at -80 °C freezer for two weeks till the virus examination using polymerase chain reaction (PCR) were carried out. WNV has been detected inside the three species of mosquitoes: A. vexans, C. univittatus, and C. quinquefasciatus. The species were collected from Hellat Kuku, (Shambat and Hellat Kuku), and (Shambat and KCLM) respectively. Two species of mosquitoes were positive for the virus: C. quinquefasciatus and C. univittatus. Positive results for the virus during the first phase of the study; males of C. quinquefasciatus and C. univittatus collected during the second phase of the study were also tested for the existence of the virus and they were positive. For our knowledge this study represents first record of WNV inside wild mosquitoes in Sudan. PCR technique provided reliable information because specific primer-probe sets were used for the detection of the virus. Extra studies are required to incriminate these species of mosquitoes as potential vectors of WNV.

Novel scoring system for differentiating parechovirus-A3 and enterovirus infection in neonates and young infants

BACKGROUND

Parechovirus-A3 (PeV-A3) and the enteroviruses (EVs) are the most common viral pathogens responsible for sepsis and meningoencephalitis in neonates and young infants; however, differences in the clinical presentations of two infections are not well described.

OBJECTIVES

To describe the clinical presentations of PeV-A3- and EVs-related diseases and develop a novel scoring system to differentiate two diseases.

STUDY DESIGN

This prospective study used real-time PCR and genetic sequencing to evaluate viral etiologies of febrile neonates and infants <4 months with suspected sepsis or meningoencephalitis in Niigata area, Japan, in 2014-2016. The clinical manifestations of PeV-A3- and EVs-infected patients were compared, and a novel scoring system was developed after identifying the most distinguishable clinical findings, followed by the external cohort validation.

RESULTS

In 210 patients evaluated, we identified 56 PeV-A3-infected (27%) and 43 EVs-infected (20%) patients. The following clinical manifestations were significant in PeV-A3-infected patients, as compared with EVs-infected patients; a higher body temperature (38.9°C vs. 38.5°C, P < .01) and heart rate (181/min vs. 168/min, P = .01), cold extremities (72% vs. 34%, P < .01) and skin mottling (65% vs. 23%, P < .01), lower white blood cell count (5,200/μL vs. 8,900/μL, P < .01) and incidence of cerebrospinal fluid (CSF) pleocytosis (2% vs. 63%, P < .01). Using some of these significant findings, the scoring system successfully distinguished the diseases (accuracy: 86% and 83% for the derivative and external validation cohorts, respectively).

CONCLUSIONS

We found significant clinical manifestations in PeV-A3-infected patients compared to EVs-infected patients. The scoring system may be helpful to distinguish two infections, especially at onset of outbreak.

Detection of viral DNA of myxoma virus using a validated PCR method with an internal amplification control

Recognition of myxomatosis is usually based on clinical symptoms, but amyxomatous cases of the disease require the use of laboratory methods. Nowadays PCR assays are routinely employed for detection of MYXV DNA, but none of them have had their diagnostic usefulness conclusively confirmed through validation. The aim of the study was the development and validation of a PCR with an internal amplification control (IAC) for intravital and postmortem detection of viral DNA of myxoma virus. To avoid false negative results a chimeric internal amplification control (IAC) was prepared and incorporated into the PCR and amplified by the same primer set as the target DNA (M071L). The optimal concentration of particular ingredients in the PCR mixture (including IAC concentration and volume of DNA sample) was determined. To minimize the risk of amplicon carry-over contamination, uracil N-glycosylase was added to the reaction. Before proper validation the robustness of the IAC-PCR was verified. Validation of the method encompassed the following parameters: the analytical and diagnostic specificity (ASp, DSp) and sensitivity (ASe, DSe) of the assay, repeatability, and intra-laboratory reproducibility. The assay LOD was established at 2 TCIU of the virus particles/0.2 ml tissue homogenate with a 100% capacity to detect different MYXV strains (ASp). The method was characterized by good DSp of 0.955 (0.839-0.999 CI) and DSe of 0.976 (0.914-1.00 CI). In addition, it was repeatable and reproducible and confirmed its suitability for the detection of MYXV in clinical material. The IAC-PCR developed meets OIE validation requirements for virological methods and can be used in diagnostic or epidemiological studies of rabbit myxomatosis.

Prevalence and identification of arthropod-transmitted viruses in Kassala state, Eastern Sudan

Vector-borne diseases are responsible for more than 20% of the infectious diseases worldwide. The prevalence of arboviruses transmit diseases to humans in Sudan has not been investigated. Mosquito-borne viral diseases increase globally incidence, including the Sudan. Frequent unknown fever outbreaks have been reported in eastern region, Sudan. However, diagnosis was based exclusively on clinical signs and symptoms without confirmatory laboratory investigations. However, for accurate detection of these viruses in outbreaks, molecular technique is considered. The objective of this study was to determine the prevalence of six arboviruses in the Kassala state of east Sudan during unknown fever outbreak. A cross sectional hospital-based study was conducted in the Kassala, Teaching Hospital. Blood samples from 119 patients suffering from unknown fever were used for screening of six arboviruses, hepatitis E virus and malarial using molecular techniques and serology.  The overall arboviruses seroprevelance was 61.3% (73/119). The highest positivity rate was 73.1% (52/73) chikungunya virus; 29 males and 20 females patients were chikungunya positive. Other arboviruses were circulating in low rate 20.5% (15/73), and 6.8% (5/73) for sindbis and rift valley fever viruses respectively. Hepatitis E virus was negative in all cases and malaria positivity rate 13.4% (16/119). The prevalence of arboviruses among unknown fever patients present to Kassala teaching hospital of eastern region in Sudan is significantly high (61.3%). The chikungunya virus is the predominant causative agent of arboviruses. Molecular techniques such as PCR are important for accurate and rapid diagnosis of this viral outbreak.

Estandarización del protocolo para la detección de las fusiones TMPRSS2:ERG y de la expresión de los genes EZH2, SPINK-1 y NKX3.1 en cáncer de próstata (CaP)

En la actualidad no existe una herramienta que permita diferenciar pacientes con cáncer de próstata (CaP) de mal pronóstico de aquellos con enfermedad indolente que sólo requieren un seguimiento controlado de la enfermedad. Debido a la coexistencia de diferentes focos premalignos y malignos en el CaP, el entendimiento sobre el proceso de carcinogénesis requiere de un mejor conocimiento. Actualmente, la heterogeneidad morfológica en CaP es evaluada con la puntuación de Gleason, la cual está fuertemente relacionada con el pronóstico de la enfermedad, sin embargo, esto es insuficiente por lo que se trabaja actualmente en identificación de alteraciones moleculares que permitan identificar subtipos que puedan establecer de manera más precisa el pronóstico del paciente. Este estudio preliminar buscó la estandarización del método de cuantificación en muestras prostáticas de FFPE de la expresión de los transcritos de posibles biomarcadores, como los oncogenes SPINK-1 y EZH2, el supresor tumoral NKX3.1, en conjunto con la determinación de la presencia/ausencia del gen de fusión TMPRSS2:ERG, ya que estos transcritos se encuentran involucrados en aparentes eventos excluyentes de la evolución natural del CaP, que apoyan la posibilidad de una clasificación molecular para esta enfermedad.

Role of Maternal Antibodies in Infants with Severe Diseases Related to Human Parechovirus Type 3

Maternal antibodies may protect infants from severe illness caused by this pathogen.

Human parechovirus type 3 (HPeV3) is an emerging pathogen that causes sepsis and meningoencephalitis in young infants. To test the hypothesis that maternal antibodies can protect this population, we measured neutralizing antibody titers (NATs) to HPeV3 and other genotypes (HPeV1 and HPeV6) in 175 cord blood samples in Japan. The seropositivity rate (>1:32) for HPeV3 was 61%, similar to that for the other genotypes, but decreased significantly as maternal age increased (p<0.001). Furthermore, during the 2014 HPeV3 epidemic, prospective measurement of NATs to HPeV3 in 45 patients with severe diseases caused by HPeV3 infection showed low NATs (<1:16) at onset and persistently high NATs (>1:512) until age 6 months. All intravenous immunoglobulin samples tested elicited high NATs to HPeV3. Our findings indicate that maternal antibodies to HPeV3 may help protect young infants from severe diseases related to HPeV3 and that antibody supplementation may benefit these patients.

A Novel High-Throughput Method for Molecular Detection of Human Pathogenic Viruses Using a Nanofluidic Real-Time PCR System

Human enteric viruses are recognized as the main causes of food- and waterborne diseases worldwide. Sensitive and quantitative detection of human enteric viruses is typically achieved through quantitative RT-PCR (RT-qPCR). A nanofluidic real-time PCR system was used to develop novel high-throughput methods for qualitative molecular detection (RT-qPCR array) and quantification of human pathogenic viruses by digital RT-PCR (RT-dPCR). The performance of high-throughput PCR methods was investigated for detecting 19 human pathogenic viruses and two main process controls used in food virology. The conventional real-time PCR system was compared to the RT-dPCR and RT-qPCR array. Based on the number of genome copies calculated by spectrophotometry, sensitivity was found to be slightly better with RT-qPCR than with RT-dPCR for 14 viruses by a factor range of from 0.3 to 1.6 log₁₀. Conversely, sensitivity was better with RT-dPCR than with RT-qPCR for seven viruses by a factor range of from 0.10 to 1.40 log₁₀. Interestingly, the number of genome copies determined by RT-dPCR was always from 1 to 2 log₁₀ lower than the expected copy number calculated by RT-qPCR standard curve. The sensitivity of the RT-qPCR and RT-qPCR array assays was found to be similar for two viruses, and better with RT-qPCR than with RT-qPCR array for eighteen viruses by a factor range of from 0.7 to 3.0 log₁₀. Conversely, sensitivity was only 0.30 log₁₀ better with the RT-qPCR array than with conventional RT-qPCR assays for norovirus GIV detection. Finally, the RT-qPCR array and RT-dPCR assays were successfully used together to screen clinical samples and quantify pathogenic viruses. Additionally, this method made it possible to identify co-infection in clinical samples. In conclusion, given the rapidity and potential for large numbers of viral targets, this nanofluidic RT-qPCR assay should have a major impact on human pathogenic virus surveillance and outbreak investigations and is likely to be of benefit to public health.

Clinical utility of serum samples for human parechovirus type 3 infection in neonates and young infants: The 2014 epidemic in Japan

During the 2014 human parechovirus type 3 (HPeV3) epidemic in Niigata, Japan, this prospective observational study identified HPeV3 from 43/85 (51%) febrile young infants <4 months using PCR analysis of serum (n = 42) and/or cerebrospinal fluid (CSF) (n = 32) and genetic sequencing of the VP1 region of HPeV3. HPeV3-infected patients (median age, 32 days; range, 4-113 days) were diagnosed as having sepsis (79%), sepsis-like syndrome (19%), or encephalitis with septic shock (2%). Other than fever, mottled skin (67%) was significantly more frequent in HPeV3-infected patients than other virus-infected patients (P = 0.005). The rate of HPeV3 RNA detection in CSF without pleocytosis was high (88%; 28/32). Among the 32 patients whose serum and CSF samples were available, all patients were positive for serum PCR; however, 4 (12%) patients were negative for CSF PCR. Serum HPeV3 RNA level on admission was associated with younger age (P = 0.002), bad temper (P = 0.041), and grunting (P = 0.008). Among 6 patients with sequential data on serum HPeV3 RNA level, levels decreased rapidly without specific therapy. In conclusion, serum samples at disease onset are the most useful compared to CSF in detection of HPeV RNA and serum HPeV3 RNA level on admission was associated with important clinical manifestations in HPeV3-infected patients.

Effectiveness of the 2012/13 trivalent live and inactivated influenza vaccines in children and adolescents in Saxony-Anhalt, Germany: a test-negative case-control study

A live attenuated influenza vaccine has been available in Germany since the influenza season 2012/13, which is approved for children aged 2-17 years. Using data from our laboratory-based surveillance system, we described the circulation of influenza and non-influenza respiratory viruses during the influenza season 2012/13 in Saxony-Anhalt. We estimated the effectiveness of live and inactivated trivalent influenza vaccines in preventing laboratory-confirmed cases among children and adolescents. From week 40/2012 to 19/2013, sentinel paediatricians systematically swabbed acute respiratory illness patients for testing of influenza and 5 non-influenza viruses by PCR. We compared influenza cases and influenza-negative controls. Among children aged 2-17 years, we calculated overall and vaccine type-specific effectiveness against laboratory-confirmed influenza, stratified by age group (2-6; 7-17 years). We used multivariable logistic regression to adjust estimates for age group, sex and month of illness. Out of 1,307 specimens, 647 (35%) were positive for influenza viruses and 189 (15%) for at least one of the tested non-influenza viruses. For vaccine effectiveness estimation, we included 834 patients (mean age 7.3 years, 53% males) in our analysis. Of 347 (42%) influenza-positive specimens, 61 (18%) were positive for A(H1N1)pdm09, 112 (32%) for A(H3N2) and 174 (50%) for influenza B virus. The adjusted overall vaccine effectiveness including both age groups was 38% (95% CI: 0.8-61%). The adjusted effectiveness for inactivated vaccines was 37% (95% CI: -35-70%) and for live vaccines 84% (95% CI: 45-95%). Effectiveness for the live vaccine was higher in 2-6 year-old children (90%, 95% CI: 20-99%) than in children aged 7-17 years (74%, 95% CI: -32-95%). Our study of the strong influenza season in 2012/13 suggests a high preventive effect of live attenuated influenza vaccine especially among young children, which could not be reached by inactivated vaccines. We recommend the use of live attenuated influenza vaccines in children unless there are contraindications.

The presence of enterovirus, adenovirus, and parvovirus B19 in myocardial tissue samples from autopsies: an evaluation of their frequencies in deceased individuals with myocarditis and in non-inflamed control hearts

PURPOSE

Multiple viruses have been detected in cardiac tissue, but their role in causing myocarditis remains controversial. Viral diagnostics are increasingly used in forensic medicine, but the interpretation of the results can sometimes be challenging. In this study, we examined the prevalence of adenovirus, enterovirus, and parvovirus B19 (PVB) in myocardial autopsy samples from myocarditis related deaths and in non-inflamed control hearts in an effort to clarify their significance as the causes of myocarditis in a forensic material.

METHODS

We collected all autopsy cases diagnosed with myocarditis from 1992 to 2010. Eighty-four suicidal deaths with morphologically normal hearts served as controls. Polymerase chain reaction was used for the detection of the viral genomes (adenovirus, enterovirus, and PVB) in myocardial tissue specimens. The distinction between acute and persistent PVB infection was made by the serological determination of PVB-specific immunoglobulins M and G.

RESULTS

PVB was detected in 33 of 112 (29 %) myocarditis cases and 37 of 84 (44 %) control cases. All of the samples were negative for the presence of adenovirus and enterovirus. Serological evidence of an acute PVB infection, determined by the presence of immunoglobulin M, was only present in one case. In the remaining cases, PVB was considered to be a bystander with no or limited association to myocardial inflammation.

CONCLUSION

In this study, adenovirus, enterovirus, and PVB were found to be rare causes of myocarditis. The detection of PVB in myocardial autopsy samples most likely represents a persistent infection with no or limited association with myocardial inflammation. The forensic investigation of myocardial inflammation demands a thorough examination, including special attention to non-viral causes and requires a multidisciplinary approach.

Clinicopathologic analysis of coxsackievirus a6 new variant induced widespread mucocutaneous bullous reactions mimicking severe cutaneous adverse reactions

BACKGROUND

The cutaneous manifestations of human enterovirus (HEV) infection are usually limited, such as hand-foot-mouth disease. By comparison, Stevens-Johnson syndrome (SJS) is a life-threatening severe cutaneous adverse reaction (SCAR), mainly caused by drugs. During the HEV outbreaks in 2010-2012 in Taiwan, we identified 21 patients who developed widespread blistering mucocutaneous reactions without any suspected drug causality.

METHODS

We screened possible pathogen(s) for detecting human herpes virus (HHV1-HHV7), HEV, or Mycoplasma pneumoniae infections using throat swab virus cultures, real-time PCR, DNA sequencing, immunochemistry and electron microscopy analyses.

RESULTS

Coxsackievirus A6 (CVA6) DNA was identified in the blistering skin lesions in 6 of 21 patients. Cytotoxic T lymphocytes and natural killer cells expressing granulysin predominantly infiltrated into the skin lesions, sharing the histopathological features with SJS. Intact CVA6 viral particles were identified in the blister fluids and skin lesions by electron microscopy. The phylogenetic analysis of the viral genome showed the CVA6 DNA sequence sharing higher similarity (97.6%-98.1%) to CVA6 strains reported from Finland at 2008.

CONCLUSIONS

This study identifies a new variant of CVA6 as the causative agent for severe mucocutaneous blistering reactions mimicking SCAR. An awareness of this unusual presentation of HEV infection is needed in the epidemic area.

The flame-retardant BDE-99 dose-dependently affects viral replication in CVB3-infected mice

The flame retardant component 2,2',4,4',5-penta-BDE (BDE-99) is found in the environment and in human tissues and fluids. In mice the common human coxsackievirus B3 (CVB3) infection has been shown to change the tissue distribution of BDE-99. We now investigate how CVB3 infection in mice affects liver uptake of (14)C at two doses of radiolabelled BDE-99, and whether increased tissue levels are related to changed virus replication and gene expression of the proinflammatory chemokine monocyte chemoattractant protein-1 (MCP-1). Mice were infected on day 0, orally treated either with 200μg or 20mg (14)C-BDE-99/kgbw on day 1, and euthanised on day 3. Serum and liver levels of (14)C-BDE-99, as well as virus levels and gene expressions of MCP-1 in the liver, were measured. In non-infected mice, there was a dose-dependent uptake of BDE-99 in both liver and serum, and in infected animals the liver BDE-99 levels was further increased. When comparing infected mice exposed to the two BDE-99 doses, the higher BDE dose resulted in increased virus amounts in the liver, and decreased infection-induced expression of MCP-1. Consequently, a high enough dose/tissue concentration of BDE-99 may result in a disturbed mobilisation of immune cells into infected tissues that could explain higher virus titres and a possibly altered clinical course of the disease. Moreover, the fact that CVB3 infection increased the BDE-99 levels in liver but not in serum may impair the risk assessment of polybrominated diphenyl ethers (PBDEs) in subclinical and clinically infected individuals, as serum levels is the common marker of exposure.

Probable transmission of coxsackie B3 virus from human to chimpanzee, Denmark

In 2010, a chimpanzee died at Copenhagen Zoo following an outbreak of respiratory disease among chimpanzees in the zoo. Identification of coxsackie B3 virus, a common human pathogen, as the causative agent, and its severe manifestation, raise questions about pathogenicity and transmissibility among humans and other primates.

Development of a highly sensitive real-time one step RT-PCR combined complementary locked primer technology and conjugated minor groove binder probe

Background

Enterovirus (EV) infections are commonly associated with encephalitis and meningitis. Detection of enteroviral RNA in clinical specimens has been demonstrated to improve the management of patients, by ruling out other causes of disease.

Method

To develop a sensitive and reliable assay for routine laboratory diagnosis, we developed a real-time one step reverse transcription polymerase chain reaction (RT-PCR) assay with minor groove binder probes and primers modified with complementary locked primer technology (TMC-PCR). We checked the sensitivity of the developed assay by comparing it to a previously published TaqMan probe real-time one-step RT-PCR (TTN-PCR) procedure using enteroviral isolates, Enterovirus Proficiency panels from Quality Control on Molecular Diagnostics (QCMD-2007), and clinical specimens from patients with suspected EV infections.

Results

One hundred clinical specimens from 158 suspected viral meningitis cases were determined to be positive by the TMC-PCR assay (63.29%), whereas only 60 were found to be positive by the TTN-PCR assay (37.97%). The positive and negative agreements between the TMC-PCR and TTN-PCR assays were 100% and 59.2%, respectively.

Conclusion

This data suggest that the TMC-PCR assay may be suitable for routine diagnostic screening from patient suspected EV infection.

Arsenic trioxide influences viral replication in target organs of coxsackievirus B3-infected mice

New antiviral agents are urgently needed. Based on in vitro studies, arsenic trioxide (As₂O₃) seems to affect viral replication, although this has been studied only marginally in vivo. In this study the replication of coxsackievirus B3 (CVB3) was studied in Balb/c mice administered 1 mg As₂O₃/kg bw once daily during 7 days of infection and in Vero cells exposed for 3 or 5 days to 0.4, 2 or 4 μM As₂O₃. Viral RNA was measured by reverse transcription PCR (RT-PCR) (in vitro and in vivo) and arsenic concentration was measured by inductively coupled plasma-mass spectrometry (ICP-MS) (in vivo). In vivo, As₂O₃ decreased viral RNA in the brain on days 3 (by 81%; p < 0.05) and 7 (by 97%; p < 0.01) and in the pancreas on day 7 (by 75%; p < 0.05), two of the target organs of this infection. The results were confirmed in vitro, where As₂O₃ dose-dependently reduced viral RNA, with the effect being more pronounced in the surrounding culture medium than inside the infected cells, indicating an impaired virion release. Thus, As₂O₃ reduced CVB3 replication both in vitro and in vivo, indicating that As₂O₃ is a viable option in the pursuit of new therapeutic agents against viral infections.

Development of an RNA extraction protocol for detection of waterborne viruses by reverse transcriptase quantitative PCR (RT-qPCR)

RNA extraction from environmental samples yields frequently an RNA preparation containing inhibitors of molecular reactions. Commercial RNA extraction kits commonly permit extraction of only 0.1-0.2 ml sample volume. An RNA extraction buffer (RNAX buffer) was formulated for the extraction of viral RNA from 4.0 ml using a silica column based protocol. To evaluate the RNAX buffer based protocol, we used hepatitis A virus (HAV) and coxsackievirus B3 (CVB3) to monitor the RNA extraction efficiency from environmental samples. For evaluation of viral RNA recovery from water concentrates which were prepared from river and pond water by PEG concentration, serial ten fold dilutions of two waterborne viruses were added to the water concentrates for evaluation by quantitative detection. Quantitative recovery of HAV and CVB3 was determined by reverse transcriptase quantitative real-time PCR (RT-qPCR). The extracted RNA was compatible with RT-qPCR and sensitivity of detection of 0.8PFU per reaction was found with RNAX buffer and the developed protocol. This level of sensitivity was obtained using viral RNA extracted from 4.0 ml of an inoculated water sample concentrate. The RNAX buffer developed in this study could be applicable to the detection of other pathogens in water and food.

A rapid and efficient method for studies of virus interaction at the host cell surface using enteroviruses and real-time PCR

Background

Measuring virus attachment to host cells is of great importance when trying to identify novel receptors. The presence of a usable receptor is a major determinant of viral host range and cell tropism. Furthermore, identification of appropriate receptors is central for the understanding of viral pathogenesis and gives possibilities to develop antiviral drugs. Attachment is presently measured using radiolabeled and subsequently gradient purified viruses. Traditional methods are expensive and time-consuming and not all viruses are stable during a purification procedure; hence there is room for improvement. Real-time PCR (RT-PCR) has become the standard method to detect and quantify virus infections, including enteroviruses, in clinical samples. For instance, primers directed to the highly conserved 5' untranslated region (5'UTR) of the enterovirus genome enable detection of a wide spectrum of enteroviruses. Here, we evaluate the capacity of the RT-PCR technology to study enterovirus host cell interactions at the cell surface and compare this novel implementation with an established assay using radiolabeled viruses.

Results

Both purified and crude viral extracts of CVB5 generated comparable results in attachment studies when analyzed with RT-PCR. In addition, receptor binding studies regarding viruses with coxsackie- and adenovirus receptor (CAR) and/or decay accelerating factor (DAF) affinity, further demonstrated the possibility to use RT-PCR to measure virus attachment to host cells. Furthermore, the RT-PCR technology and crude viral extracts was used to study attachment with low multiplicity of infection (0.05 × 10^-4TCID₅₀/cell) and low cell numbers (250), which implies the range of potential implementations of the presented technique.

Conclusion

We have implemented the well-established RT-PCR technique to measure viral attachment to host cells with high accuracy and reproducibility, at low cost and with less effort than traditional methods. Furthermore, replacing traditional methods with RT-PCR offers the opportunity to use crude virus containing extracts to investigate attachment, which could be considered as a step towards viral attachment studies in a more natural state.

Broadly targeted triplex real-time PCR detection of influenza A, B and C viruses based on the nucleoprotein gene and a novel "MegaBeacon" probe strategy

A PCR assay that covers animal and human influenza A, B and C viruses, i.e., most of Orthomyxoviridae, is needed. Influenza types are distinguished based on differences in the nucleoprotein (NP) present in the virus. Conserved NP regions were therefore used to design a TaqMan-based triplex reverse transcription real-time PCR method. Variability of influenza A within the probe target region mandated the development of a novel molecular beacon, the "Mega" molecular beacon (MegaBeacon; MegB), for the detection of influenza A with this method. MegaBeacon is a mismatch-tolerant molecular beacon that is also a TaqMan probe. The triplex method (3QPCR-MegB) was evaluated with influenza A isolates covering 18 HxNx combinations, two influenza B isolates, and five Japanese influenza C isolates, as well as influenza A, B and C synthetic DNA targets. One to ten viral RNA and cDNA genome equivalents were detected per PCR reaction for influenza A, B and C. Seventy-one human nasopharyngeal aspirates from respiratory infections yielded 30 influenza A, 11 influenza B and 0 influenza C with 3QPCR-MegB, where immunofluorescence (IF) found 28 influenza A and 10 influenza B. 3QPCR-MegB was more mismatch-tolerant than a variant PCR with an influenza A TaqMan probe (3QPCR) and is a sensitive and rational method to detect influenza viruses of animal and human origin. MegaBeacon probes hold promise for variable target nucleic acids.

Real-time polymerase chain reaction as a rapid and efficient alternative to estimation of picornavirus titers by tissue culture infectious dose 50% or plaque forming units

Quantification of viral infectious units is traditionally measured by methods based on forming plaques in semisolid media (PFU) or endpoint dilution of a virus-containing solution (TCID50), methods that are laborious, time-consuming and take on average 3-7 days to carry out. Quantitative real-time PCR is an established method to quantify nucleic acids at high accuracy and reproducibility, routinely used for virus detection and identification. In the present study, a procedure was developed using a two-step real-time PCR and the SYBR Green detection method to study whether there are correlations between TCID50/ml, PFU/ml and Ct values generated by real-time PCR enabling rapid and efficient calculation of titer equivalents when working with viruses in the research laboratory. In addition, an external standard with known concentrations was included using in vitro transcribed viral RNA, thus allowing the calculation of the amount of RNA copies needed for various applications (i.e. per plaque or TCID50).The results show that there is a correlation between the three quantification methods covering a wide range of concentration of viruses. Furthermore, a general regression line between TCID50 and Ct values was obtained for all viruses included in the study, which enabled recording titer equivalents using real-time PCR. Finally, by including an external standard, the amount of RNA genomes generating one TCID50 or PFU for each enterovirus serotype included was determined.

Viral RNA kinetics is associated with changes in trace elements in target organs of Coxsackie virus B3 infection

Trace elements are pivotal for the host defense, as well as potentially important for viral replication and virulence. Studies of sequential changes in viral replication in target organs of infection are sparse and a possible association with changes in specific trace elements is unknown. In this study Balb/c mice were infected with Coxsackie virus B3 (CVB3). Results indicated that sequential changes in viral replication (RT-PCR) were related to changes in trace element (arsenic, copper, iron, selenium and zinc) concentrations (as determined by ICP-MS) on days 3, 5 and 7 of the infection in serum, heart, lung, liver, pancreas, kidney, spleen, intestine and brain. After an initial viral peak on day 3, viral load drastically decreased in all organs, i.e. by >99% (serum), 97% (lung), 98% (liver), 60% (pancreas), 95% (kidney) and 93% (spleen), except in the heart, intestine and brain in which viral load increased after day 3. Selenium decreased in all organs except the heart while arsenic decreased in all organs except the kidney, spleen and brain. Moreover, selenium was negatively correlated to viral load in serum, liver, pancreas and intestine. To conclude, these findings give evidence that trace elements are directly involved in the replication of CVB3.

Polybrominated diphenyl ether exposure suppresses cytokines important in the defence to coxsackievirus B3 infection in mice

Environmental pollutants can adversely affect the immune system. The host defence during infection depends on cytokine signalling and proper function of immune cells. However, no studies have addressed how polybrominated diphenyl ethers (PBDEs) affect cytokine responses. We investigated the combined effects in Balb/c mice of human coxsackievirus B3 (CVB3) infection and exposure to PBDEs (BDE-99 or Bromkal mixture) on 21 serum cytokines. The mice were infected (i.p.) on day 0, orally treated with BDE-99 or Bromkal on day 1 (20mg/kg bw) and put to death on day 3. CVB3 was quantitatively measured in the liver and pancreas by RT-PCR. The Luminex 200 multi-analyte system was used for cytokine analysis. High numbers of viral copies were found in the liver and pancreas. Infection increased TNF-alpha, IL-6, MCP-1, IL-12p40, KC and RANTES levels. Notably, PBDE-exposure resulted in a marked decrease, or even lack, of IL-13, MIP-1beta, RANTES, IFN-gamma and KC levels in non-infected mice. However, the effects of PBDE-exposure on cytokines did not affect viral replication during early CVB3 infection. In conclusion, PBDEs causes a selective block in immune signalling pathways but the consequences of this need to be further studied in different host resistance models of infection.

Tissue uptake of mercury is changed during the course of a common viral infection in mice

Mercury (Hg) has been shown to have immunotoxic effects and to influence the severity of infection. However, the impact of infection on the normal Hg homeostasis in different target organs involved in the disease process has not been studied. In this study, Hg was measured through inductively coupled plasma-mass spectrometry (ICP-MS) in the intestine, serum, liver, and brain on days 3, 6, and 9 of coxsackievirus B3 (CVB3) infection in female Balb/c mice. The severity of the infection was assessed from clinical signs of disease and the number of virus particles in infected organs. CVB3 and gene expression of metallothionein 1 (MT1) was measured by reverse transcription-polymerase chain reaction (RT-PCR). Gene expression of MT1 increased and peaked on day 3 in the brain (93%, p<0.01) and liver (19-fold, p<0.01) and on day 6 in the intestine (seven-fold, p<0.01). This peak in MT1 in the liver and brain corresponded to the peak in virus numbers in these tissues. Hg in the intestine and serum tended to decrease on all days of infection. The maximum decrease, in comparison with non-infected mice, occurred in the intestine (78%, p<0.001) on day 9 and in serum (50%, p<0.05) on day 6. However, in the brain, Hg increased by 52% (p<0.05) on day 6. Hg went unchanged in the liver. An infection-induced increase of Hg in the brain but unchanged level in the liver may be due to the peak of virus replication and an associated infection-induced expression of MT1. Moreover, the decrease of Hg in serum and the intestine but a concomitant intestinal increase in MT1 on day 6 may reflect a flux and increased retention of Hg to infected organs such as the brain. The pathophysiological interpretation of these preliminary findings requires further research.

Gastrointestinal uptake of trace elements are changed during the course of a common human viral (Coxsackievirus B3) infection in mice

Most infectious diseases are accompanied by a change in levels of several trace elements in the blood. However, it is not known whether changes in the gastrointestinal uptake of trace elements contribute to this event. Coxsackievirus B3 (CVB3), adapted to Balb/c mice, was used to study whether infection induces gene expression of metallothionein (MT1) and divalent-metal transporter 1 (DMT1) in the intestine and liver and hepcidin in the liver, as well as whether trace elements in these tissues are changed accordingly. Quantitative expression of CVB3, MT1, DMT1 and hepcidin was measured by real-time RT-PCR and six trace elements by ICP-MS on days 3, 6 and 9 of the infection. The copper/zinc (Cu/Zn) ratio in serum increased as a response to the infection. High concentrations of virus were found in the intestine and liver on day 3 and in the intestine on day 6. MT1 in the intestine and liver increased on days 3 and 6. The increase of MT1 in the liver correlated positively with Cu and Zn. Hepcidin in the liver showed a non-significant increase on days 3 and 6 of the infection, whereas DMT1 in the intestine decreased on day 9. Accordingly, iron (Fe) in the liver increased progressively during the disease, whereas in the intestine DMT1 was negatively correlated to Fe. Arsenic (As), cadmium (Cd) and mercury (Hg) were found to decrease to various degrees in the intestine, serum and liver. Thus, enteroviral infections, and possibly many other infections, may cause a change in the gastrointestinal uptake of both non-essential and essential trace elements.

Recent enterovirus infection in type 1 diabetes: evidence with a novel IgM method

Enterovirus (EV) infection has been associated with Type 1 (T1D) diabetes and on a few occasions virus could be isolated at onset of the disease. Using two such isolates as antigens in a quantitative PCR enhanced immunoassay (T1D-EV-QPIA) we have measured IgM antibodies against such potentially diabetogenic viruses in serum from 33 newly diagnosed T1D children, 24 siblings, and 27 healthy children. Sera were also analysed with regard to autoantibodies against GAD65, the cytokine TNF-alpha and the chemokine IP-10. EV-RNA detection was performed on peripheral blood mononuclear cells (PBMC). IgM antibodies against this "new" EV antigen were more frequent in serum from T1D children than in serum from siblings and/or controls (P < 0.001). EV-RNA was detected more frequently in PBMC from T1D children than in healthy control children (P < 0.001) and also compared to the siblings (P < 0.003). The cytokine TNF-alpha was less frequently detected in serum from the T1D children compared with serum from siblings and/controls (P < 0.001). A positive correlation was found between the results obtained with the T1D-EV-QPIA and the EV-PCR (P < 0.001). These findings are in line with earlier findings of an increased frequency of enteroviral infections in newly diagnosed T1D patients. In addition, we found that T1D children at onset of the disease had lower frequencies of the chemokine TNF-alpha in their serum than age- and sex-matched controls had, suggesting an impaired immune response.

Description and validation of a novel real-time RT-PCR enterovirus assay

BACKGROUND

Enteroviruses are a leading cause of aseptic meningitis in adult and pediatric populations. We describe the development of a real-time RT-PCR assay that amplifies a small target in the 5' nontranslated region upstream of the classical Rotbart enterovirus amplicon. The assay includes an RNA internal control and incorporates modified nucleotide chemistry.

METHODS

We evaluated the performance characteristics of this design and performed blinded parallel testing on clinical samples, comparing the results with a commercially available RT-PCR assay (Pan-Enterovirus OligoDetect kit) that uses an enzyme immunoassay-like plate end detection.

RESULTS

We tested 778 samples and found 14 discrepant samples between the 2 assays. Of these, the real-time assay detected 6 samples that were negative by the OligoDetect kit, 5 of which were confirmed as positive by sequence analysis using an alternative primer set. Eight discrepant samples were positive by the OligoDetect kit and real-time negative, with 6 confirmed by sequencing. Overall, detection rates of 97% and 96% were obtained for the OligoDetect kit and real-time assays, respectively. Sequence analysis revealed the presence of a number of single nucleotide polymorphisms in the targeted region. The comparative sensitivities of the 2 assays were equivalent, with the limit of detection for the real-time assay determined to be approximately 430 copies per milliliter in cerebrospinal fluid.

CONCLUSIONS

This novel real-time enterovirus assay is a sensitive and suitable assay for routine clinical testing. The presence of single nucleotide polymorphisms can affect real-time PCR assays.

Coxsackievirus B3 infection affects metal-binding/transporting proteins and trace elements in the pancreas in mice

OBJECTIVE

The trigger of juvenile diabetes has been suggested to be an interaction between a virus and trace elements, where enteroviruses, including coxsackievirus B3 (CVB3), have been discussed as potential initiators. The aim of this study was to investigate the effects in the pancreas on gene expressions of metallothionein 1 (MT1), divalent metal transporter 1 (DMT1), and zinc transporter 5 (ZnT-5) and concomitant changes in iron (Fe), copper (Cu), and zinc (Zn) in serum and pancreas of Balb/c mice on days 3, 6, and 9 of CVB3 infection.

METHODS

Trace elements were measured through inductively coupled plasma-mass spectrometry, and CVB3, MT1, DMT1, and ZnT-5 were measured by reverse transcription-polymerase chain reaction.

RESULTS

Virus was found in the pancreas on all days, with a peak on day 3. Infection tended to increase Fe in both serum and the pancreas. The Cu/Zn ratio in the pancreas increased early in the infection because of a great decrease in Zn. In serum, the Cu/Zn ratio was not increased until day 9 of the disease. In the pancreas, MT1 decreased, whereas DMT1 tended to increase on day 6, and ZnT-5 increased progressively during the course of the disease.

CONCLUSIONS

Virus-induced changes in trace elements, MT1, DMT1, and ZnT-5 in the pancreas may reflect early stages of the development of pancreatitis and prestages of diabetic disease.

Virus induces metal-binding proteins and changed trace element balance in the brain during the course of a common human infection (coxsackievirus B3) in mice

Autopsy of the brain has shown a change in trace element balance in some virus-infected individuals, but it is not known whether this event was a result of the infection. In the present study coxsackievirus B3 (CVB3) adapted to Balb/c mice was used to study whether infection induces gene expression of the metal-binding/transporting proteins metallothionein (MT1 and MT3) and divalent-metal transporter 1 (DMT1) and whether it changes the balance of trace elements in the brain. Virus and MT1, MT3, and DMT1 were quantitatively measured by RT-PCR on days 3, 6 and 9 of the infection. Trace elements (13) were measured in serum and the brain by ICP-MS. High numbers of virus were found in the brain on days 3 and 6, but virus counts were decreased and present only in 50% of the mice on day 9. Gene expression of MT1 tended to increase on all days, whereas that of MT3 only showed a minor and not significant increase on day 3. No clear effect was observed in the expression of DMT1. The increase of MT3 was correlated to the brain concentration of Cu. The Cu/Zn ratio in serum increased as a response to the infection. There was a similar decrease in Cd in serum and the brain. On day 6 of the infection, Hg increased in the brain (p<0.05) and was positively correlated to a concomitant decrease (p<0.05) in serum. Virus numbers in the brain were on day 6 positively correlated (p<0.05) to As concentrations. Enteroviral infections may therefore be an underlying factor regarding the changes in essential as well as potentially toxic trace elements in the brain.

Aseptic meningitis

PURPOSE OF REVIEW

To highlight some of the recent key epidemiologic and clinical diagnostic dilemmas of aseptic meningitis and to evaluate some tests that may help distinguish aseptic compared with bacterial meningitis.

RECENT FINDINGS

Enteroviruses remain the most common cause of aseptic meningitis. Certain enteroviruses (e.g. coxsackie B5, echovirus 6, 9 and 30) are more likely to cause meningitis outbreaks, while others (coxsackie A9, B3 and B4) are mostly endemic. Nucleic acid tests are more sensitive than cultures in diagnosing enteroviral infections. In centers where the turnaround time for these tests is less than 24 h, there can be substantial cost savings and avoidance of unnecessary treatment of aseptic meningitis with antibiotics. Serum and stool specimens are important adjunct samples for diagnosing enteroviral infections in children. Cerebrospinal fluid protein (> or = 0.5 g/l) and serum procalcitonin (> or = 0.5 ng/ml) appear to be useful laboratory markers for distinguishing between bacterial and aseptic meningitis in children aged 28 days to 16 years, but they have relatively low sensitivity and specificity.

SUMMARY

Enteroviruses are the major causes of aseptic meningitis. The major focus of diagnosis remains ruling out bacterial infection or confirming enteroviral etiology of infection. Properly implemented nucleic acid tests have the potential to reduce cost and unnecessary treatment.

Sequential trace element changes in serum and blood during a common viral infection in mice

When trace elements are used as diagnostic tools during disease, it is important to know whether the balance is changed in free or bound elements. Although acute infections are associated with changed trace element balance in serum/plasma, it is not known whether changes occur concomitantly in serum and blood. In the present study the human coxsackievirus B3 (CB3), here adapted to Balb/c mice, was used to study whether infection alters the normal physiological trace element balance in blood and serum. Virus was quantitatively measured in two target organs (pancreas and liver) of this infection by reverse transcription polymerase chain reaction (RT-PCR), showing high concentrations of virus proving ongoing infection. Concentrations of 14 elements were measured in whole blood and serum using inductively coupled plasma mass spectrometry (ICP-MS) on days 3, 6 and 9 of the infection. Free and total thyroxine were measured in serum to prove metabolic changes associated with the infection. The thyroxine decreased, while iron and the Cu/Zn ratio in serum increased as a response to the infection. No clear changes in these elements were observed in blood. Cd and Hg tended to decrease in serum but to increase in blood, indicating accumulation in blood cells. Moreover, Al showed a similar decreasing trend in both serum and blood. A correlation between serum and blood levels was observed at different time points of the disease for 9 of the elements. However, As was the only element indicating correlations between serum and blood during the entire course of the disease.

Assessment of the quantitative real-time polymerase chain reaction using a cDNA standard for human group A rotavirus

Nucleic acid amplification techniques are used frequently for rapid diagnosis of viral diseases. In this study, a real-time polymerase chain reaction protocol that uses primers specific for the viral VP4 gene and the commercial SYBR Green reagent were evaluated for the quantitative measurement of human rotavirus (HRV) RNA in human stool specimens. SYBR Green I detection involved analysis of the melting temperature of the PCR product and measurement of fluorescence at the optimum temperature. The assay resulted in a sensitive and reproducible detection of targets ranging from low (<10(2)rotavirus cDNA copies/reaction) to high numbers (>10(6)rotavirus cDNA copies/reaction). No cross-reaction was found with crude cell culture stocks of coxsackievirus, echovirus, poliovirus, hepatitis A virus and adenovirus. Analysis with the HRV cDNA standard demonstrated high reproducibility with a coefficient of variation (CV) of 0.2-0.9%. Daily performance among three different laboratories showed a CV no greater than 8%, indicating an intermediate level of variation. These results demonstrate the feasibility of this method for quantitative analysis of human rotavirus in clinical samples.

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.

Detection and monitoring of virus infections by real-time PCR

The employment of polymerase chain reaction (PCR) techniques for virus detection and quantification offers the advantages of high sensitivity and reproducibility, combined with an extremely broad dynamic range. A number of qualitative and quantitative PCR virus assays have been described, but commercial PCR kits are available for quantitative analysis of a limited number of clinically important viruses only. In addition to permitting the assessment of viral load at a given time point, quantitative PCR tests offer the possibility of determining the dynamics of virus proliferation, monitoring of the response to treatment and, in viruses displaying persistence in defined cell types, distinction between latent and active infection. Moreover, from a technical point of view, the employment of sequential quantitative PCR assays in virus monitoring helps identifying false positive results caused by inadvertent contamination of samples with traces of viral nucleic acids or PCR products. In this review, we provide a survey of the current state-of-the-art in the application of the real-time PCR technology to virus analysis. Advantages and limitations of the RQ-PCR methodology, and quality control issues related to standardization and validation of diagnostic assays are discussed.

Experience from the development of a diagnostic single tube real-time PCR for human caliciviruses, Norovirus genogroups I and II

Detection of caliciviruses requires high mutation tolerance and throughput. The development of a rational simple, single tube reverse transcription-real-time quantitative PCR (QPCR) technique for human noroviruses (NV) is reported here. A dual-probe, triple-primer system (NM system) was used for simultaneous detection and preliminary differentiation of NV genogroups in fecal samples. The design was based on a comprehensive analysis of all 1140 NV sequences available in GenBank. A touch-down amplification protocol improved the frequency of detection. The final QPCR was evaluated with 71 fecal samples from outbreak and sporadic cases in Sweden (1997-2004), all calicivirus-positive by electron microscopy. Up to 56 (79 %) were positive. The method is more rational than NV detection methods described previously, and should be a developmental basis for large-scale routine methods for detection of NV.