Enterovirus infection during pregnancy is not a risk factor for celiac disease in the offspring

BACKGROUND

There is a strong genetic influence on the susceptibility to celiac disease but it is also evident that environmental factors play a role in the development of the disease. Diverging studies about adenovirus infection as a possible triggering factor in the pathogenesis have been reported. Our study was undertaken to determine whether enterovirus infection during pregnancy is a risk factor for the development of celiac disease later in childhood.

METHODS

Cord blood from 76 mothers whose children developed celiac disease before 15 years of age were analyzed for IgA, IgG, and IgM antibodies for enteroviruses and Ig-A endomysium antibodies. The control group comprised cord blood from 327 mothers with children without known celiac disease.

RESULTS

There were no significant differences in antibody titers for enterovirus between the two groups. IgA-endomysium antibodies were elevated in 3 of the 76 mothers, whereas none had known celiac disease.

CONCLUSION

This study does not show that enterovirus infection during pregnancy is associated with the development of celiac disease in childhood. Of the mothers whose children developed celiac disease, 4% had Ig-A endomysium antibodies, which may reflect a silent celiac disease.

Enterovirus infection can induce immune responses that cross-react with beta-cell autoantigen tyrosine phosphatase IA-2/IAR

Insulin-dependent (type 1) diabetes is characterized by progressive destruction of insulin-producing beta cells probably by autoreactive T lymphocytes. Viral infections, especially those caused by coxsackieviruses, are postulated to play a role in the pathogenesis of the disease in humans. One mechanism by which viral infections could initiate or accelerate diabetogenic processes is "molecular mimicry," induction of antiviral immune responses cross-reacting with epitopes in the beta-cell autoantigens. Tyrosine phosphatases (IA-2, IAR) represent a major target autoantigen in type 1 diabetes. Both humoral and cellular immune responses are directed to the carboxy-terminal (C-terminal) part of the protein. This region has a 5-amino acid sequence identity, followed by five amino acid similarity with the conservative motif in the VP1-protein of enteroviruses (PALTAVETGA/HT), which is a highly immunogenic B- and T-cell epitope in enterovirus infection-induced immune responses. This observation prompted us to investigate potential humoral cross-reactions between immune responses induced by tyrosine phosphatases and enteroviruses. The reactivities of various peptide- and virus-induced rabbit antisera clearly demonstrated that cross-reactions do exist, and in both directions. Using epitope mapping, we were able to show that several diabetes-linked epitopes in IA-2 were also recognized by CBV-4-induced antisera. Immunization of female NOD-mice with formalin-inactivated purified strain of coxsackievirus B4 (CBV-4-E2) induced an immune response that recognized the IA-2/IAR diabetogenic peptide. The results obtained with human paired sera, collected during enterovirus infection, indicated that enterovirus infection in humans may also occasionally induce a humoral response that cross-reacts with IA-2/IAR.

Neutralizing antibodies to enterovirus 71 in Belém, Brazil

Non-polio enteroviruses (Coxsackievirus A, Coxsackievirus B, Echovirus and EV 68-72) which belong to the enterovirus (EV) genus, Picornaviridae family, may be responsible for acute flaccid paralysis, aseptic meningitis, myocarditis, hepatitis, pleurodinia, neonatal sepsis, hand, foot and mouth disease (HFMD) even though 50-80% of infections are asymptomatic. EV 71 has been responsible for outbreaks and epidemics of HFMD and acute neurologic disease justifying its study in our country. The aim of this study was to detect neutralizing antibodies (NtAb) to EV 71 in individuals up to 15 years of age living in Belém, State of Pará, northern Brazil. Serum samples from 238 patients attending the Virology Sector of Evandro Chagas Institute in Belém, Brazil, were analyzed using microneutralization tests that included RD cells and BrCr strain. Overall 40.8% (97/238) of tested samples had NtAb to EV 71. Regarding the distribution per age group, 85.2% (92/108) of patients aged 0-3 years had no NtAb to this virus and 69.2% of those 12 to 15 years of age were seropositive. These results confirm that EV 71 infection occurs in the city of Belém; and that a high rate of individuals in this study were infected aged 3 years and over and, when aged 15 years nearly 70% had EV 71 NtAb.

Echovirus 7 associated encephalomyelitis

BACKGROUND

Hand, foot, and mouth disease (HFMD) is endemic in Malaysia. In 1997, a large outbreak of enterovirus 71 (EV-71) associated HFMD resulted in 41 deaths due to severe left ventricular dysfunction and central nervous system infection with extensive damage to the medulla and pons. The clinical presentation in all these patients were rapid cardio-respiratory decompensation leading to cardiac arrest. Another large outbreak of HFMD with 55 fatal cases and a similar clinical picture was reported in Taiwan in 1998. In 2000, an outbreak of HFMD resulted in the deaths of three children who had rapid cardio-respiratory decompensation and one child who survived a central nervous system infection.

OBJECTIVES

We set out to study the etiologic agent and mechanism involved in three children who presented to our hospital, two of whom died and one survived a central nervous system infection.

STUDY DESIGN

The clinical course of the disease was described. Throat, rectal swab and cerebrospinal fluid samples were subjected to viral isolation and viral isolates were identified by immunofluorescence, micro-neutralisation using human rhabdomyosarcoma (RD) cells, and reverse transcritpase polymerase chain reaction. Magnetic resonance imaging was performed on two of the patients.

RESULTS

Echovirus 7 was the sole pathogen isolated from three cases of acute encephalomyelitis, two of which were fatal due to severe left ventricular dysfunction resistant to inotropic support. The survivor had residual bulbar palsy, but is considered to have had a good neurological outcome.

CONCLUSION

Echovirus 7 infection associated with encephalomyelitis could be fatal due to indirect involvement of the heart resulting in severe left ventricular dysfunction. In addition one of the children presented with hand, foot, and mouth disease, a syndrome that has not been previously associated with echovirus 7 infection.

[Sero-monitoring of notifiable diseases in wild boar in the Netherlands 1999-2001]

Within the framework of a sero-monitoring system, in operation since 1996. blood samples from wild boar shot during the hunting seasons 1999-2000 and 2000-2001 in The Netherlands were screened for the presence of antibodies against classical swine fever virus (CSFV), swine vesicular disease virus (SVDV), and Anjeszky's disease virus (ADV). The results indicate that CSFV, SVDV, and ADV are uncommon in the wild boar population in the Netherlands. Because of the recent foot-and-mouth disease (FMD) epidemic in the Netherlands in 2001, blood samples (approximately 200 samples) from wild boar shot in the Netherlands during the hunting season 2001/2002 were examined for antibodies against FMD. To date, antibodies against FMD have not been detected.

Detection of Coxsackievirus B 4 antibodies in cases of suspected encephalopathy by microneutralization test

A retrospective study of serum and cerebrospinal fluid (CSF) samples collected from suspected viral encephalitis and encephalopathy cases was carried-out and it included 100 CSF and 89 serum samples from Goa, collected during 1990-1994. These samples which were negative for antibodies to Japanese encephalitis (JE), West Nile (WN), Dengue-2 (DN-2) and herpes viruses, were tested for Coxsackievirus B 4 specific antibodies by 'in vitro' microneutralization technique along with 80 negative control serum samples. Out of 189 specimens (100 CSF and 89 serum), 23 CSF and 41 serum samples were positive for Coxsackievirus B 4 neutralizing antibodies. Antibody profile seemed to be IgG as revealed by mercaptoethanol treatment. The presence of neutralizing antibodies to coxsackievirus B 4 with titres as high as 1:512 in 8 CSF and 19 serum samples seemed to be suggestive of viral meningitis due to Cox B-4 viruses.

Detection of enterovirus viraemia in blood donors

BACKGROUND AND OBJECTIVES

The infrastructure established for screening blood donations for hepatitis C virus has enabled large-scale population testing for other viruses which are potentially transmissible by transfusion of blood components and plasma-derived blood products. We have measured the frequency of viraemia of enteroviruses and parechoviruses in 83 600 Scottish blood donors to allow an initial assessment of their risk to blood safety.

MATERIALS AND METHODS

Plasma samples collected from blood donors over 7 calendar months were tested anonymously in mini-pools of 95 donations, by polymerase chain reaction (PCR) for human enterovirus and parechovirus sequences.

RESULTS

A total of 19 mini-pools, from the 880 that were tested, were PCR-positive for enterovirus RNA, predicting a donor prevalence of 0.023%. Enterovirus sequences were not detected in factor VIII or IX clotting factor concentrates. None of the 230 mini-pools or concentrates contained detectable parechovirus RNA.

CONCLUSIONS

The prevalence of enterovirus viraemia detected in this study predicts that at least 1000 enterovirus-contaminated blood components are transfused per year in the UK. The frequency of transmission and clinical outcome after exposure to enterovirus-contaminated blood components in recipients is unknown.

Neurological manifestations of enterovirus 71 infection in children during an outbreak of hand, foot, and mouth disease in Western Australia

Enterovirus 71 (EV71) causes epidemics of hand, foot, and mouth disease associated with neurological complications in young children. We report an outbreak of EV71-associated neurological disease that occurred from February through September 1999 in Perth, Western Australia. Fourteen children with culture-proven, EV71-induced neurological disease were identified. Nine patients (64%) developed severe neurological disease; 4 of these patients developed long-term neurological sequelae. Neurological syndromes included aseptic meningitis, Guillain-Barré syndrome, acute transverse myelitis, acute cerebellar ataxia, opso-myoclonus syndrome, benign intracranial hypertension, and a febrile convulsion. Clinical and magnetic resonance imaging data indicated that immunopathology was a major factor in the pathogenesis of neurological disease in this outbreak. This finding is in contrast to reports of previous EV71 epidemics, in which virus-induced damage to gray matter was the most frequent cause of neurological disease.

Expression of capsid [correction of caspid] protein VP1 for use as antigen for the diagnosis of enterovirus 71 infection

To produce enterovirus 71 antigen for diagnostic purposes, the gene encoding the entire capsid protein VP1 was amplified by reverse transcription-polymerase chain reaction (RT-PCR), cloned and expressed in Escherichia coli as a poly-histidine fusion protein. Western blotting experiments with sera from patients with enterovirus 71 infection indicated that immunoglobulin G (IgG) and IgM antibodies bound to a single polypeptide VP1. According to these results, IgM anti-VP1 appeared in sera of patients with a symptomatic enterovirus 71 acute infection, whereas IgG anti-VP1 was present in sera of past infection. This finding suggests that detecting IgG and IgM immune responses against linear epitopes of recombinant VP1 is an effective means of determining the different phases of enterovirus 71 infection. In addition, sera containing coxsackie virus 16 (CA16) antibodies did not cross-react with the recombinant VP1 of enterovirus 71, despite the homology between VP1 proteins of both viruses. Comparison with reference PCR and neutralization assays showed these antibody tests to be appropriate for the serodiagnosis of enterovirus 71 infection.

[Rapid diagnosis of the type of meningitis (bacterial or viral) by the assay of serum procalcitonin]

OBJECTIVE

It has been shown that serum procalcitonin (PCT) can be used to differentiate bacterial from viral meningitis in children in all cases. The aim of this study was to demonstrate the interest of PCT in the management of suspected meningitis in adults.

PATIENTS AND METHODS

We conducted a prospective study including 179 consecutive patients admitted to the emergency department for suspected meningitis. All samples were taken at patient admission. The discriminant potential between bacterial and viral meningitis was studied for cerebrospinal fluid parameters (cytology, protein, glucose, lactate) and serum parameters (C reactive protein, PCT).

RESULTS

Thirty-two patients had bacterial meningitis, 90 had viral meningitis and meningitis was ruled out in 57. Among all studied parameters, the most discriminant for distinguishing between bacterial and viral meningitis in 100% of the cases proved to be serum procalcitonin with a threshold value of 0.93 ng/ml.

CONCLUSION

Serum procalcitonin is an interesting parameter in the emergency department for management of meningitis suspicion in adults.

Enteroviruses and myocardial infarction

BACKGROUND

Several lines of evidence suggest that some microbial infections are involved in the pathogenesis of atherosclerosis. The aim of the studies referred to here was to evaluate the possible role of enteroviral infections as potential risk factors for cardiac events.

METHODS AND RESULTS

The association of enterovirus-specific antibodies and cardiac events was analyzed in 3 large, prospective population studies with the nested case-control design. Stored sera collected at the study baseline were tested for enterovirus group-specific immunoglobulin G antibodies. The study samples from the North Karelia Project, the Helsinki Heart Study, and the Mobile Clinic Health Service were composed of 183, 241, and 276 men with myocardial infarction, respectively, and their matched control patients. In 2 of the 3 studies, male cases without evidence of heart disease at the baseline had significantly higher levels of antibodies to enteroviruses than their matched control patients. High enterovirus antibody level was found to be a definite independent risk factor for future cardiac events. In the North Karelia study the risk was high in men aged 25 to 49 years, whereas in the Mobile Clinic Health Service study the risk was particularly strong in those with low levels of serum cholesterol. No association with high levels of enterovirus antibodies and cardiac events was seen in the Helsinki Heart Study, which consisted of hypercholesteremic men.

CONCLUSIONS

If a high level of enterovirus group-specific antibodies can be considered as a sign of frequent enterovirus infections in the past, these studies suggest that enterovirus infections increase the risk of myocardial infarction at least in normocholesteremic men.

An epidemic of acute haemorrhagic conjunctivitis caused by enterovirus 70 in Okinawa, Japan, in 1994

BACKGROUND

Although enterovirus 70 (EV70) has been identified as the major aetiological agent of acute haemorrhagic conjunctivities (ACH),no EV70 strain has been isolated by cell culture method since 1988. Therefore, recent clinical and epidemiological characteristics of AHC caused by EV70 have not been clarified.

METHODS

Clinical and serological studies were carried out on patients during the AHC epidemic in Okinawa, Japan, in 1994 in which 7509 cases were reported by national epidemiological surveillance. EV70 was confirmed as the causative agent by reverse-transcription polymerase chain reaction.

RESULTS

The 11-15 years age group contained the highest number of cases (62% of the total). Conjunctival hyperaemia was present in all patients, and subconjunctival haemorrhage, superficial punctate keratitis and preauricular lymphadenopathy were present in 24.0%, 11.7% and 9.3% of AHC cases, respectively. No neurological complication was observed in this epidemic. Out of 31 paired serum samples, 10 pairs showed a fourfold rise in antibody level to EV70. None of the paired serum samples showed a fourfold rise in antibody level to Coxsackie A24 variant virus.

CONCLUSION

These findings demonstrate that the clinical features of AHC observed in this study were milder than those reported previously, in contrast to the high transmission rate during an epidemic. Changes in clinical features of AHC, such as a low incidence of subconjunctival haemorrhage and disappearance of neurological complications, might be due to biological transformation of EV70. It should be noted that EV70 is still an important aetiological agent of explosive epidemics of AHC.

A novel serological technique: polymerase chain reaction enhanced immunoassay. Application to enterovirus IgM diagnosis

The polymerase chain reaction (PCR) method is a sensitive, specific and rapid technique for virus detection. The principles of a PCR enhanced immunoassay (PIA) are described. The method combines solid phase serological techniques with the PCR, providing a versatile and sensitive method for antibody detection. By linking the antigenicity of virus particles with their content of nucleic acid, the method provides new possibilities for virus serology: for example, antibody specificity can be coupled to viral sequence in patients with chronic infections caused by highly variable viruses such as HIV and HCV. An application of the PIA technique is described for the detection of anti-enterovirus IgM. IgM is captured to anti-human IgM-coated microwell plates. The anti-enterovirus IgM is allowed to bind crude enterovirus antigen. Bound virus is heat denatured and the released RNA is used as a template for reverse transcription PCR (RT-PCR) amplification. Amplicons are detected by hybridisation to an affinity labelled probe in a microwell colorimetric assay. In a pilot study, 18 serum specimens from patients with enterovirus infections were examined. Using a mixture of ten crude enterovirus antigens, the frequency of IgM positivity was 6/18 (33%). Titres between 1/500 and 1/100,000 were recorded. Predominantly type-specific antibodies were detected. The results were compared with a procapsid enterovirus radioimmunoassay (RIA). After further optimisation, the PIA has the potential to be a clinically useful assay for the detection of antiviral antibodies.

[Evaluation of the usefulness of the ELISA method for determining the level of enterovirus antibodies in serum and cerebrospinal fluid]

The usefulness of the methods was compared: complement fixation test (CFT), neutralization test (NT) and ELISA IgG and IgM against enteroviruses for the evaluation of specific immune reaction in sera and cerebrospinal fluid (CSF) samples of patients with confirmed enterovirus infections. The criteria were established for the assessment of ELISA results in rapid diagnosis of enterovirus neuroinfections. The criteria accepted by the producer lowered the sensitivity of the method and the possibility of recognition of local synthesis of antibodies in the CNS. The use of serum negative in CFT and negative CSF as reference for the determination made possible using of that kit for rapid diagnosis of neuroinfections. The modified ELISA IgG test makes possible determination of antibodies in CSF and serum, and accepting the generally recognized criteria for local production of antibodies in the CNS the ELISA test makes possible rapid diagnosis of neuroinfections which is not possible by other methods.

Outbreak of severe neurologic involvement associated with Enterovirus 71 infection

Enterovirus 71 has been associated with several outbreaks, as well as sporadic cases, of central nervous system infection and has a worldwide distribution. Seven children with encephalitis and five with aseptic meningitis caused by Enterovirus 71 were seen at Otsu Municipal Hospital during the summer of 1997. The infections were confirmed serologically, although detection of the viral genome in cerebrospinal fluid was unsuccessful. Seven children were diagnosed as having hand-foot-and-mouth syndrome, two were diagnosed as having herpangina, and three patients younger than 12 months old developed no eruptions. The skin or mucosal manifestations of this outbreak demonstrated considerable variation. The Enterovirus 71 strain that caused the outbreak had a strong neurovirulent tendency. Among the patients with encephalitis, symptoms originating from the impairment of diencephalon were seen in four patients, and those originating from cerebellar impairment were seen in two patients. Brain magnetic resonance imaging in one patient revealed an abnormality in the pons. The neurologic manifestations associated with Enterovirus 71 infection may be characterized by involvement of the cerebellum, brainstem, and diencephalon. Enterovirus 71 is one of the pathogenic viruses that cause hand-foot-and-mouth syndrome, as well as a variety of other clinical manifestations. The most important of these is neurologic disease, especially in infants and young children.

[Enterovirus meningoencephalitis in the last 5 years]

The results of the study of Enterovirus as viral meningoencephalitis producing agents, carried out from 1990 to 1994, are described, 546 feces samples, 95 cerebrospinal fluids and 1,058 matched sera were studied and obtained from 1,388 patients clinically diagnosed with this disease. Samples for viral isolation were inoculated into two different cellular systems. The highest number of isolation was found in diploid cells from human fibroblast. Antibody determinations were carried out by a neutralization test (micromethod) with 11 Enterovirus antigens (Echo 4, 6, 9, 11 and 30; and Coxsackie B1, 2, 3, 4, 5 and 6) and in epidemic periods with the isolated virus. During the years under study, 2 epidemic outbreaks took place: on caused by Coxsackie A9 (1990-1991) and the other one by Echo 30 (1994). A greater positivity to Echo 6 and 11 was found among the matched sera.

Onset of type 1 diabetes mellitus in infancy after enterovirus infections

Enterovirus infections may initiate and accelerate the beta-cell damaging process leading to Type 1 (insulin-dependent) diabetes mellitus (Type 1 DM). Recent prospective studies have suggested that this can happen long before overt disease and even in utero. We describe an infant, followed regularly from birth, who progressed to clinical Type 1 DM at the age of 14 months. He had a strong enterovirus exposure exceptionally early in life; the first enterovirus infection occurred before the age of 3 months and the second between the age of 9 and 12 months. The first infection probably occurred at birth, when the child had symptoms of a respiratory infection. This infection was followed by the appearance of beta-cell autoimmunity, and clinical Type 1 DM was diagnosed shortly after the second infection. The child had a low level of maternal enterovirus antibodies and short duration of breast-feeding, both associated with increased risk for enterovirus infections during the fetal period and infancy. This case fits with the current hypothesis that enterovirus infections can induce the process resulting in Type 1 DM, especially when occurring early in life. Furthermore, this demonstrates the feasibility of the present study design, which is applicable also in large-scale birth-cohort studies.

Development of an enterovirus specific PCR method for the quantification of enterovirus genomes in blood of diabetes patients

BACKGROUND

Insulin-dependent diabetes mellitus or type 1 diabetes is a disease with a diverse aetiology. Epidemiological studies examining newly diagnosed, recent onset IDDM patients have suggested a role for viruses in the aetiology of IDDM (Yoon, 1995, Diabetes/Metabolism Reviews 11, 83-107). Important candidates are the enteroviruses, in particular coxsackieviruses B3 and B4. The latter can cause diabetes in animals (Clements et al., 1995, Lancet 346, 221-223).

OBJECTIVES

We have developed a quantitative PCR method for the detection of enterovirus genomes in biological samples. The quantitative PCR will be used to screen for enteroviruses in blood of diabetes patients and their relatives by testing a Blood Diabetes Register.

STUDY DESIGN

A substantial amount of data has been collected on enterovirus induced IDDM, our study is original in so far as it will be: (1) a quantitative study, not only the presence of viral genome sequences in blood will be determined, but also their concentrations (viral load); and (2) a longitudinal study, samples are and will be collected as a function of time. Positive PCR samples will be quantified using the standard addition method.

RESULTS

The test is specific for enteroviruses, since all enteroviruses were detected with equal sensitivity. Viruses belonging to other picornavirus genera scored negative (even up to 3 x 10(6) genome copies). An equal detection limit of 10 genome copies was found for all enteroviruses.

CONCLUSIONS

The developed method will permit us to generate quantitative and longitudinal data of enterovirus genomes in blood of diabetes patients and their relatives, which might help in the elucidation of the relationship between enteroviruses and IDDM.

Comparison of use of cerebrospinal fluid, serum, and throat swab specimens in diagnosis of enteroviral acute neurological infection by a rapid RNA detection PCR assay

A PCR assay for detection of enterovirus RNA in multiple specimen types from patients with neurological infections was evaluated. Combined PCR assay of cerebrospinal fluid and serum (systemic specimens) was more sensitive than assaying either specimen alone in children but not in adults. Compared with PCR in systemic specimens, detection of enterovirus RNA in throat swabs showed a sensitivity of 62.5% and a specificity of 75.6%.

[Viral meningoencephalitis caused by enterovirus in Cuba from 1990-1995]

The results of a study on enterovirus as causal agents of viral meningoencephalitis from 1990 to 1995 are described. From the 1458 samples of patients studied, 586 were from feces, 108 from cerebrospinal fluid and 1095 were paired sera. The samples for viral isolation were inoculated in two different cellular systems. A total of 225 samples (32.42%) were found to be positive; the highest number of isolations (n = 217) was found in feces and in diploid human lung fibroblast cells (PHuE-1). Antibody determination were carried out using neutralization by micromethod test with 10 enterovirus antigens (Echovirus 4, 6, 9, 11 and Coxsackievirus B1-6). The isolated virus was also used as antigen during epidemic periods. There were 3 epidemic outbreaks: Coxsackievirus A9 (1990-1991), Echovirus 30 (1994), and Coxsackievirus B5 (1995). Coxsackievirus A9 and Echovirus 30 have been related to viral meningoencephalitis epidemics in Cuba since 1970. In paired sera 66.84% were positive, Echovirus 6 and 11 exhibited higher positivity. When positive results by isolation and serology were considered together, more than 80% of the studied cases were associated to enterovirus infection. These results show the importance of enteroviruses as cause of viral meningoencephalitis in our country.

Sensitivity and specificity of mu-capture ELISA for detection of enterovirus IgM

The sensitivity and specificity of an in-house mu-capture enzyme linked immunosorbent assay (ELISA) for enterovirus IgM in routine use was determined by analysing the results of 77 serum samples from 55 enterovirus culture-positive patients with aseptic meningitis and single serum samples from 140 patients with other infections. In addition, sera from 10 laboratory staff pre- and post-polio virus vaccination and 20 rheumatoid factor positive sera were tested for specificity. On testing the first serum specimen received, only 21 of 55 patients (38%) with aseptic meningitis yielded a positive result, rising to 33 of 55 (60%) on testing a second sample, where available. Out of 14 patients from whom multiple serum samples were tested and negative results obtained with the first serum, 12 were positive with the second sample (86%). Only patients with acute hepatitis A produced a significant number of false positives by the enterovirus ELISA (12 out of 20), but the reverse was not true: patients with enterovirus IgM did not produce false positive results in tests for hepatitis A IgM. Excluding samples positive for hepatitis A IgM, the number of non-enterovirus infections correctly reported as negative was 118 out of 120--a specificity of 98%. This test is probably the most useful serological test available at present for diagnosing recent enterovirus infection, although the limited sensitivity needs to be borne in mind.

Diagnosis of neonatal enterovirus infection by polymerase chain reaction

A 5-hour colorimetric polymerase chain reaction (PCR) assay was more sensitive than viral culture in identifying viral infection in initial serum (13/16 vs 5/16; p = 0.008) and urine (10/16 vs 5/16; p = 0.2) specimens from 16 enterovirus-infected newborn infants, and remained more sensitive throughout their illnesses. Combined sensitivity of serum and urine PCR was 14 of 16 (88%). Results of all acute-phase PCR assays of serum and urine from four neonates with cultures negative for enterovirus were also negative. PCR assay of serum and urine facilitates rapid, accurate diagnosis of neonatal enterovirus infections.

Encephalomyocarditis (EMC) virus-induced myocarditis by different virus variants and mouse strains

The mode of occurrence of encephalomyocarditis (EMC) virus-induced myocarditis in mice was pathologically and virologically investigated using 2 virus variants (highly diabetogenic EMC-D and non-diabetogenic EMC-B) and 2 mouse strains (diabetes-susceptible BALB/c and diabetes-resistant C57BL/6). Mice were inoculated with 10(5) PFU/head of the virus intraperitoneally and observed up to 7 days post inoculation (7DPI). As compared with EMC-B-infected BALB/c and EMC-D-infected C57BL/6 mice, EMC-D-infected BALB/c mice developed marked myocarditis and exhibited a heart virus titer of more than 100 times above that of the others after 4DPI. Electron microscopically, small aggregations of virus-like particles, with 20-25 nm in diameter, were found in the cytoplasm of degenerated cardiomyocytes showing mitochondrial and myofibrillar degeneration in EMC-D-infected BALB/c mice.

The changing spectrum of neonatal meningitis over a fifteen-year period

One hundred seventy-seven cases of neonatal meningitis treated at the University of Texas Medical Branch at Galveston over a 15-year period (1974-1988) were reviewed. Over this period, the incidence of bacterial meningitis decreased, the incidence of aseptic meningitis remained stable, and the diagnosis of enteroviral meningitis increased in frequency. During 1984-1988, enterovirus was the most common cause of meningitis in neonates older than seven days and accounted for one third of all cases of neonatal meningitis. Half of all neonates with bacterial meningitis had negative blood cultures. We recommend that 1) diagnostic lumbar puncture remain part of the routine assessment of the neonate with suspected sepsis, and 2) CSF be cultured for enterovirus as well as for bacteria when a neonate older than seven days presents with suspected sepsis.

Intrathecal synthesis of virus-specific oligoclonal antibodies in patients with enterovirus infection of the central nervous system

Cerebrospinal fluid (CSF) and serum samples from six patients with enterovirus infections were investigated by isoelectric focusing (IEF) and affinity-mediated immunoblot AMI) for the clonal distribution of entervirus-specific antibodies. In two patients with either acute meningitis or encephalitis and in one patient with a relapse of multiple sclerosis, oligoclonal IgG bands specific for enteroviruses were found predominantly in the CSF, revealing intrathecal synthesis of these antibodies. In three other patients with neurological symptoms probably unrelated to a current enterovirus infection, IEF and AMI disclosed nearly identical patterns of coxsackievirus-B-specific oligoclonal bands in the CSF and serum, indicating diffusion of these antibodies from the serum into the CSF. Although the number of patients in this study is small, the results suggest that intrathecally synthesized enterovirus-specific antibodies may be used as a means of identifying an enterovirus infection of the CNS.

Viral myocarditis: immunopathogenesis and the effect of immunosuppressive treatment in a murine model

Serial changes in lymphocyte subset were investigated in an animal model of encephalomyocarditis (EMC) virus myocarditis in mice. The lymphocyte subset in the peripheral blood was measured by flow cytometry and, T cell subset in the myocardium was stained by labeled avidin-biotin technique. Helper-inducer T cells (Lyt 1 cells) decreased significantly on day 7, but there was no change in cytotoxic-suppressor T cells in the peripheral blood. During the acute stage a significant number of T cells (Thy 1.2 cells) were seen in the heart with helper-inducer T cells predominating. The effect of prednisolone and cyclosporine on viral myocarditis was studied in our experimental model. Prednisolone or cyclosporine given in the early stage aggravated the course, and they did not have beneficial effects during the early recovery period.

Histopathology of BALB/c mice infected with the D variant of encephalomyocarditis virus

BALB/c mice infected with 10(5) pfu of the D variant of encephalomyocarditis virus were examined histopathologically during the subacute stage of infection. Main pathologic changes were observed in the brain, heart (massive myocardial necrosis with subsequent organization (i.e., replacement of necrotic myocardium by connective tissue) and congestion and dilatation of the right ventricle) and pancreas (moderate degranulation of beta-cells resulting in elevation of blood glucose level). The brain lesions were found most frequently in the pyramidal layer of the hippocampus and the granular layer of the cerebellum and were characterized by degeneration of neurons containing virus antigens. Perivascular mononuclear cell infiltration, spreading to the adjacent brain tissue, and thrombosis in small vessels were also frequently seen. Focal loss of neurons and gliosis developed later in these lesions.

Cerebrospinal fluid findings in infants with nonpolio enteroviral meningitis

We studied 25 infants aged less than 9 months who were diagnosed as having nonpolio enteroviral meningitis (EM) confirmed by virus isolation from cerebrospinal fluid (CSF). CSF protein, glucose and cellular content in these infants was compared with that of 125 age-matched febrile infants without cerebromeningeal illness. In order to control for changes occurring in the CSF during the first 2 months of life, the studied infants and the control subjects were stratified into 2-week age-groups and were compared. All but three of the infants with EM had increased CSF leukocyte count, and 10 infants showed domination of the polymorphonuclear leukocytes in the CSF. Only two had increased CSF protein levels, and low CSF/blood glucose ratios were found in all but two cases. None of the infants with EM had increased values of CSF protein concomitant with decreased CSF/blood glucose ratio. CSF in EM is characterized by increased white blood cell count in contrast with normal or near-normal CSF protein and glucose levels. In some infants, enterovirus isolation may be the only evidence of EM.

Enhancement of viral pathogenesis in mice maintained in an antiorthostatic suspension model: coordination with effects on interferon production

Both rodents and men returning from spaceflight and the attendent microgravity or weightlessness conditions have exhibited alterations in immune responses and, in particular, interferon production. We have utilized a model for antiorthostatic (20 degrees head-down tilt). hypokinetic, hypodynamic suspension of mice that simulates some aspects of weightlessness. Female Swiss/Webster mice that are normally resistant to infection with the D variant of encephalomyocarditis virus showed a marked increase in susceptibility to infection when suspended. This correlated with a drop in interferon production. Control, orthostatically suspended mice (no head-down tilt) showed no increase in susceptibility to the virus. These data suggest that maintenance of mice in the antiorthostatic suspension model for simulating some aspects of weightlessness yielded increased susceptibility to virus infection that was coincident with inhibited interferon production.

Effect of encephalomyocarditis (EMC) virus on murine foetal and placental growth monitored by quantification of maternal plasma levels of pregnancy-associated murine protein-2 and alpha-fetoprotein

The present study demonstrates that pregnant mice seem to be more sensitive to encephalomyocarditis (EMC) infection than non-pregnant mice, and the infection results in significantly increased maternal plasma levels of insulin and pregnancy-associated murine protein-2 (PAMP-2), of placental origin, and alpha-fetoprotein (AFP), of foetal origin. Maternal plasma levels of PAMP-2 and AFP are correlated with placental and foetal growth respectively. This indicates that the EMC infection and the increased peripheral insulin levels lead to increased growth of the foetoplacental unit.

Neutralizing antibody and interferon-alpha in cerebrospinal fluids and sera of acute aseptic meningitis

Cerebrospinal fluids (CSFs) and sera from 20 patients with echovirus 30 (E 30) meningitis, 4 patients with enterovirus 71 (EV 71) meningitis, and 5 patients with acute aseptic meningitis (AM) of unknown etiology were investigated at the acute and the convalescent phases of the disease to elucidate the roles of neutralizing antibody (NT) and interferon-alpha (IFN-alpha) in the central nervous system (CNS) in cases of AM in humans. Viruses were isolated from the CSFs at the acute phase of AM, but not at the convalescent phase. There was a fourfold or greater rise in NT titer between paired sera to E 30 or EV 71 but only a slight rise between paired CSFs. IFN-alpha was detected in the CSFs ranging from less than 10 to 25.5 IU/ml but not in the sera, and the IFN-alpha level in the CSF was significantly higher in the acute phase than in the convalescent phase. These results suggest that in cases of acute enteroviral infections in the CNS, NT plays only a small role in the recovery from AM, and IFN-alpha plays a direct or indirect role in curbing the local spread of the virus and eliminating the virus from the CNS at the acute phase of AM.

Effect of experimental duck virus hepatitis infection on some biochemical constituents and enzymes in the serum of white Pekin ducklings

Experimental duck virus hepatitis infection of 11-day-old white Pekin ducklings having specific maternal antibodies revealed significant changes in some biochemical constituents and enzymes of the serum during the 3 weeks following exposure. These changes included a marked decrease in the total proteins and the albumin fraction, together with a significant elevation in levels of alkaline phosphatase, glutamic pyruvic transaminase, bilirubin, and creatinine. Most of these changes were attributed primarily to a deranged liver function associated with duck virus hepatitis infection.

A comparison of the prophylactic and therapeutic effects of poly I:C and endotoxin in mice infected with Mengo virus

We have compared the protective effect in AKR mice of poly I:C and bacterial endotoxins against lethal doses of Mengo virus. Administered intravenously or intraperitoneally, both interferon inducers protected mice to about the same extent from virus challenges of 2-3 LD50's. Endotoxin, however, was unable to protect the mice effectively against higher challenge doses of virus. Evidence is presented that the level of protection afforded by both inducers is related to the level of circulating interferon produced. We have also shown that a single intravenous dose of poly I:C results in the appearance of two distinct bursts of interferon activity, with maxima at about 2 h and 9 h post injection. Endotoxin, on the other hand, produced only one peak of activity, at 2 h post injection.