Increase of Diversity of Mumps Virus Genotype G SH Variants Circulating Among a Highly Immunized Population: Spain, 2007-2019

MuV caused three epidemic waves in Spain since genotype G emerged in 2005, despite high vaccination coverage. SH gene sequencing according to WHO protocols allowed the identification of seven relevant variants and 88 haplotypes. While the originally imported MuVi/Sheffield.GBR/1.05/-variant prevailed during the first two waves, it was subsequently replaced by other variants originated by either local evolution or importation, according to the additional analysis of hypervariable NCRs. The time of emergence of the MRCA of each MuV variant clade was concordant with the data of the earliest sequence. The analysis of Shannon entropy showed an accumulation of variability on six particular positions as the cause of the increase on the number of circulating SH variants. Consequently, SH gene sequencing needs to be complemented with other more variable markers for mumps surveillance immediately after the emergence of a new genotype, but the subsequent emergence of new SH variants turns it unnecessary.

In utero negativization of Zika virus in a foetus with serious central nervous system abnormalities

We describe a case of a pregnant woman with Zika virus (ZIKV) infection and a foetus with severe brain malformations. ZIKV tested positive in amniotic fluid at 19 weeks but was negative at delivery. The newborn did not meet the case definition of congenital ZIKV syndrome because neither ZIKV RNA nor IgM antibodies were detected; however, prenatal brain lesions were confirmed after birth (Graphical Abstract).

Prevalence of anti-rubella, anti-measles and anti-mumps IgG antibodies in neonates and pregnant women in Catalonia (Spain) in 2013: susceptibility to measles increased from 2003 to 2013

Non-immune neonates and non-immune pregnant women are at risk of developing rubella, measles and mumps infections, including congenital rubella syndrome. We describe the seroepidemiology of measles, mumps and rubella (MMR) in neonates and pregnant women in Catalonia (Spain). Anti-rubella, anti-measles and anti-mumps serum IgG titres were assessed using enzyme-linked immunosorbent assay (ELISA) tests in 353 cord blood samples from neonates of a representative sample of pregnant women obtained in 2013. The prevalence of protective antibody titres in neonates was 96 % for rubella IgG (≥8 IU/ml), 90 % for measles IgG (>300 IU/ml) and 84 % for mumps IgG (>460 EU/ml). Slightly lower prevalences of protective IgG titres, as estimated from the cord blood titres, were found in pregnant women: 95 % for rubella IgG, 89 % for measles IgG and 81 % for mumps IgG. The anti-measles and anti-mumps IgG titres and the prevalences of protective IgG titres against measles and mumps increased significantly (p < 0.001) with maternal age. The prevalence of protective anti-measles IgG titres decreased by 7 % [odds ratio (OR) = 0.15, p < 0.001), the prevalence of protective anti-rubella IgG titres increased by 3 % (OR = 1.80, p < 0.05) and the MMR vaccination coverage (during childhood) in pregnant women increased by 54 % (OR = 2.09, p < 0.001) from 2003 to 2013. We recommend to develop an MMR prevention programme in women of childbearing age based on mass MMR vaccination or MMR screening and vaccination of susceptible women to increase immunity levels against MMR.

Molecular characterization of enteroviruses associated with neurological infections in Spain, 2008

In order to investigate the etiology of viral neurological infections in Spain, a national study was performed in 2008. The results obtained have been published. Enteroviruses were the most frequent cause of the aseptic meningitis and infant febrile syndromes. The present report supplements the previous study with the genotyping of the detected enteroviruses. Typing was by amplification of partial VP1 region and sequencing in 70 (53%) of the 132 available cerebrospinal fluid samples positive for enteroviruses. Twelve different genotypes within the B species were identified. Echovirus 4 was predominant (24%), followed by echovirus 30 (19%), echovirus 9 (17%), and echovirus 6 (14%). In summary, a co-circulation of several enterovirus types associated with meningitis in children under 15 years old was observed. Although infrequently detected, echovirus 4 was the predominant genotype identified due to an aseptic meningitis outbreak which occurred in the Canary Islands in 2008.

Viral infections of the central nervous system in Spain: a prospective study

The aim of the study was to determine the incidence of viruses causing aseptic meningitis, meningoencephalitis, and encephalitis in Spain. This was a prospective study, in collaboration with 17 Spanish hospitals, including 581 cases (CSF from all and sera from 280): meningitis (340), meningoencephalitis (91), encephalitis (76), febrile syndrome (7), other neurological disorders (32), and 35 cases without clinical information. CSF were assayed by PCR for enterovirus (EV), herpesvirus (herpes simplex [HSV], varicella-zoster [VZV], cytomegalovirus [CMV], Epstein-Barr [EBV], and human herpes virus-6 [HHV-6]), mumps (MV), Toscana virus (TOSV), adenovirus (HAdV), lymphocytic choriomeningitis virus (LCMV), West Nile virus (WNV), and rabies. Serology was undertaken when methodology was available. Amongst meningitis cases, 57.1% were characterized; EV was the most frequent (76.8%), followed by VZV (10.3%) and HSV (3.1%; HSV-1: 1.6%; HSV-2: 1.0%, HSV non-typed: 0.5%). Cases due to CMV, EBV, HHV-6, MV, TOSV, HAdV, and LCMV were also detected. For meningoencephalitis, 40.7% of cases were diagnosed, HSV-1 (43.2%) and VZV (27.0%) being the most frequent agents, while cases associated with HSV-2, EV, CMV, MV, and LCMV were also detected. For encephalitis, 27.6% of cases were caused by HSV-1 (71.4%), VZV (19.1%), or EV (9.5%). Other positive neurological syndromes included cerebellitis (EV and HAdV), seizures (HSV), demyelinating disease (HSV-1 and HHV-6), myelopathy (VZV), and polyradiculoneuritis (HSV). No rabies or WNV cases were identified. EVs are the most frequent cause of meningitis, as is HSV for meningoencephalitis and encephalitis. A significant number of cases (42.9% meningitis, 59.3% meningoencephalitis, 72.4% encephalitis) still have no etiological diagnosis.

Differential diagnosis of hepatitis E virus, cytomegalovirus and Epstein-Barr virus infection in patients with suspected hepatitis E

BACKGROUND

The accuracy of the diagnosis of hepatitis E in the clinical setting relies mainly on the performance of assays for hepatitis E virus (HEV)-specific IgM (anti-HEV IgM) testing in serum.

OBJECTIVES

Identification of factors influencing the specificity of the results obtained with these assays is an important issue in regard to the accuracy of the diagnosis.

STUDY DESIGN

Anti-HEV IgM and HEV RNA were studied in samples from 153 patients with acute hepatitis of unknown aetiology received during a two-year period. Fifteen patients were positive for anti-HEV IgM, and eight of them were also positive for HEV RNA. Investigation of CMV and Epstein-Barr virus (EBV) infection markers among the remaining seven patients, and of HEV infection markers among 18 patients with infectious mononucleosis, was performed.

RESULTS

The results obtained showed that acute infection by CMV or EBV may cause false reactivity for anti-HEV IgM, likely because of polyclonal B-cell stimulation.

CONCLUSIONS

Since infection by these herpesviruses may produce acute hepatitis, such event can cause diagnostic mistakes and should be investigated in patients positive for anti-HEV IgM and negative for HEV RNA.

Eliminating congenital rubella syndrome in Spain: does massive immigration have any influence?

In this short report we highlight the importance of implementing good immunization programs adapted to the epidemiological situation of rubella and congenital rubella syndrome (CRS), discuss the influence of massive immigration and stress the need to improve surveillance and control by implementing comprehensive national surveillance and promoting awareness among primary healthcare workers and midwives to find out any signs and symptoms compatible with rubella in pregnant women who have recently arrived from countries with high susceptibility to rubella infection.

Internationally adopted children: what vaccines should they receive?

It is of paramount importance to know the vaccination status in internationally adopted children, so that they can be correctly immunized. This study ascertains the seroprotection rate for vaccine-preventable diseases and the validity of the immunization cards in 637 adopted children. The absence of the immunization card (13% of children) correlated with a poor global vaccine protection. Children with immunization records (87%) had a better global seroprotection but the information obtained from the card did not accurately predict seroprotection for each particular antigen. The best variable to predict the status of seroprotection was the country of origin. The highest rate of protection was found in children from Eastern Europe and, in descending order, India, Latin America, China and Africa. General recommendations for immunization of internationally adopted children are difficult to establish. Actions for vaccination have to be mainly implemented on the basis of the existence of the immunization card and of the country of origin.

The comparative sero-epidemiology of varicella zoster virus in 11 countries in the European region

The European sero-epidemiology network (ESEN2) aims to standardise serological surveillance of varicella zoster virus (VZV) in 11 participant countries. In each country, serum banks were collected between 1996 and 2003 and tested for VZV antibodies. Assay results were standardised so that international comparisons could be made. Age-specific forces of infection were calculated for three age groups (<5, 5-9 and >or=10 years of age) and used to estimate the base reproduction number (R(0)) and the herd immunity threshold (H). Most VZV infection occurred in childhood, but there was a wide variation in transmissibility, with R(0) ranging from 16.9 in the Netherlands to 3.3 in Italy. Herd immunity thresholds varied from 70% in Italy to 94% in the Netherlands. There are substantial differences in VZV sero-epidemiology within the European region, which will need to be taken into account in designing national policies regarding VZV vaccination.

The European Sero-Epidemiology Network 2: standardization of assay results for hepatitis B virus

The aim of the European Sero-Epidemiology Network 2 was to coordinate and standardize the serological surveillance of vaccine-preventable diseases in Europe. In this study, the standardization of hepatitis B virus (HBV) results is described. The 15 participating national laboratories tested a unique panel of 172 sera established by the Greek reference centre for HBV surface antigen (HBsAg), antibodies to HBsAg (anti-HBs) and/or to the HBV core antigen (anti-HBc) by assay methods of their choice. Country-specific quantitative measurements for anti-HBs and anti-HBc were transformed into common units using standardization equations derived by regressing each country's panel results against the reference centre's results, thus adjusting for interassay and interlaboratory variability. For HBsAg, a qualitative analysis (positive/negative) showed at least 99% agreement with the reference laboratory for all countries. By combining these standardized and qualitative results for the markers mentioned earlier, it was possible to achieve comparable estimates of the proportion of the population susceptible to HBV, vaccinated against HBV, with a past HBV infection, and with a current infection or chronic carrier state. Standardization is a very important tool that allows for international serological comparisons to assess the current vaccination policies and the progress of HBV control in Europe.

A measles outbreak in children under 15 months of age in La Rioja, Spain, 2005-2006

This paper describes a measles outbreak in La Rioja, Spain, which began in December 2005 and mainly affected children under 15 months of age who were not yet immunised with MMR vaccine. The measles cases were detected by the mandatory reporting system, under which laboratories must report every confirmed measles case. Cases were classified in accordance with the National Measles Elimination Plan: suspected and laboratory-confirmed. In the period 14 December 2005 to 19 February 2006, 29 suspected cases of measles were investigated, and 18 were confirmed. The mean incubation period was 13.8 days (range: 9 to 18). Of the 18 confirmed cases, only two were in adults. MMR vaccination was recommended for all household contacts, as well as for children aged 6 to 14 months who attended the daycare centres where the cases had appeared. At these centres, the second dose of MMR was administered ahead of schedule for children under three years of age. It was recommended that the first dose of MMR vaccine be administered ahead of schedule for all children aged 9 to 14 months. During an outbreak of measles, children aged 6 months or older, who have not previously been vaccinated against measles, mumps and rubella, should receive a first dose as soon as possible, and those who have had a first dose should receive a second dose as soon as possible, provided that a minimum of one month has elapsed between the two doses

Virological analysis in the diagnosis of sudden children death: A medico-legal approach

Infections are considered to be an important cause of unexpected death in children. It has also been assumed that respiratory viruses are involved in the genesis of sudden infant death syndrome (SIDS). The Spanish National Institute of Toxicology and Forensic Sciences act as the forensic reference centre for Spain. We analyse the experience of this centre in the virological study of 64 cases of sudden children death where viral serology, virological cultures, herpesviruses polymerase chain reaction (PCR) and electron microscopy were performed. According to pathological findings, death could only be attributed to an adenovirus infection in one amygdalitis with upper airways stenosis and asphyxia. Human herpes virus 6 (HHV-6) was detected by PCR in one case with pathological findings characteristic of SIDS. Recent infection by respiratory syncytial virus (RSV), Epstein-Barr virus (EBV) and cytomegalovirus (CMV) were also detected. Meanwhile, 85.9% of the cases yielded negative viral results. Twenty-eight infants were finally categorised as SIDS. Pathological findings of infection were detected in 12 patients despite the negativity of viral analyses. Although viral infection is an uncommon cause of sudden children death, a complete microbiological investigation will help to solve the puzzle of SIDS. Definitive guidelines for microbiological analyses need to be updated whilst new pathogens are discovered or new techniques are implemented in order to clarify unsolved cases.

Yellow fever vaccine-associated viscerotropic disease and death in Spain

Yellow fever vaccine-associated viscerotropic disease (YEL-AVD) is a recently described severe adverse event after yellow fever vaccination, and some cases have been reported in different countries [Anonymous. Effects of yellow fever and vaccination. Lancet 2001;358(9296):1907-9]. Herein we describe a YEL-AVD case in a young woman, who died after vaccination with 17D-204 strain. Clinical, serological and immunochemical analysis as well as virus detection, quantification, sequence analysis and cytokine release, were performed. Further investigations on yellow fever vaccine adverse events, and carefully analysis of the immune response elicited are important tasks for the future.

A measles outbreak in children under 15 months of age in La Rioja, Spain, 2005-2006

This paper describes a measles outbreak in La Rioja, Spain, which began in December 2005 and mainly affected children under 15 months of age who were not yet immunised with MMR vaccine. The measles cases were detected by the mandatory reporting system, under which laboratories must report every confirmed measles case. Cases were classified in accordance with the National Measles Elimination Plan: suspected and laboratory-confirmed. In the period 14 December 2005 to 19 February 2006, 29 suspected cases of measles were investigated, and 18 were confirmed. The mean incubation period was 13.8 days (range: 9 to 18). Of the 18 confirmed cases, only two were in adults. MMR vaccination was recommended for all household contacts, as well as for children aged 6 to 14 months who attended the daycare centres where the cases had appeared. At these centres, the second dose of MMR was administered ahead of schedule for children under three years of age. It was recommended that the first dose of MMR vaccine be administered ahead of schedule for all children aged 9 to 14 months. During an outbreak of measles, children aged 6 months or older, who have not previously been vaccinated against measles, mumps and rubella, should receive a first dose as soon as possible, and those who have had a first dose should receive a second dose as soon as possible, provided that a minimum of one month has elapsed between the two doses.

Molecular identification of mumps virus genotypes from clinical samples: standardized method of analysis

A sensitive nested reverse transcription-PCR assay, targeting a short fragment of the gene encoding the small hydrophobic protein (SH gene), was developed to allow rapid characterization of mumps virus in clinical samples. The sensitivity and specificity of the assay were established using representative genotypes A, B, C, D, E, and F. Mumps virus RNA was characterized directly from cerebrospinal fluid (CSF) samples and in extracts of mumps virus isolates from patients with various clinical syndromes. Direct sequencing of products and subsequent phylogenetic analysis enabled genetic classification. A simple web-based system of sequence analysis was established. The study also allowed characterization of mumps virus strains from Argentina as part of a new subgenotype. This PCR assay for characterization of mumps infections coupled to a web-based analytical program provides a rapid method for identification of known and novel strains.

[Nephropathia caused by hantavirus puumala: a case report]

We present a patient from Germany with Hantavirus infection, admitted in the Emergency room of our hospital, with fever, thrombocytopenia, acute renal failure, oliguria, mild proteinuria and hematuria. Percutaneous renal biopsy revealed an acute interstitial nephritis without medulla haemorrhages. The virus infection confirmation was made by detection of IgM against Hantavirus Puumala. This infection should be considered in patients with thrombocytopenia, fever and acute renal failure, over all if they are from North and Central Europe.

Evaluation of an automated complement-fixation test (Seramat) for diagnosis of acute respiratory infections caused by viruses and atypical bacteria

The complement-fixation test (CFT) permits low-cost screening of serum samples for different agents within a single assay, and is a useful tool for the serological diagnosis of acute respiratory infections. This study evaluated the automated Seramat CFT system with 160 paired serum samples taken from 80 patients with acute respiratory infection in comparison with in-house CFTs against a panel of agents, including influenza A and B, adenovirus, respiratory syncitial virus, cytomegalovirus, Mycoplasma pneumoniae, Coxiella burnetti and Chlamydia spp., and in comparison with indirect immunofluorescence (IIF) against Legionella pneumophila. Overall, the Seramat system identified 75 (88.2%) of the 85 seroconversions recognised by in-house CFTs or IIF. In comparison to the in-house CFTs, the correlation was 89.2% (66/74). For L. pneumophila, the Seramat system detected nine (81.8%) of the 11 cases diagnosed by IIF. The Seramat system also identified eight additional seroconversions that were not detected by the in-house assays; none of these seroconversions was detected by the in-house assay on retesting. The Seramat system represents a significant technical improvement that may enable many clinical laboratories to use the CFT as a routine diagnostic tool.

Evaluation of the measles, mumps and rubella immunisation programme in Spain by using a sero-epidemiological survey

In Spain, measles, mumps and rubella vaccination was introduced in 1981, with one dose at the age of 15 months and another at the age of 11 years being administered since 1995. Reported disease incidence was less than one case per 100,000 people for measles and rubella, and 23 cases per 100,000 people for mumps. A seroepidemiological survey was undertaken to estimate the frequency of susceptible individuals by age and environment; and vaccination coverage and efficacy of the vaccines administered. A population-based cross-sectional study was then conducted, covering the population aged 2-39 years, residing in Spain (excluding Catalonia). The sample was stratified by age and rural/ urban environment and informed consent obtained to take blood specimens from subjects attending blood-extraction centres. The final sample totalled 3,932 persons. IgG antibodies were detected by an enzyme-linked immunosorbent assay. Estimated vaccination coverage was 96% for children aged 2-5 years; vaccine efficacies were 96.7% for measles, 97.2% for rubella and 79.3% for mumps. Immunity was the lowest in the 6-9 year age group for measles (90.8%) and in males aged between 15 and 24 years for rubella (86 and 89.8%, respectively). In the case of mumps, this proved the lowest in the 2-5 year age group (76.7%) and in those autonomous regions in which only the Rubini strain had been administered. The incidence of measles has enabled the National Measles Elimination Plan to be implemented by which the elimination of congenital rubella syndrome could now be initiated. A possible explanation for the higher susceptibility observed for mumps might lie in the Rubini strain's low efficacy.

Is there a change in cytomegalovirus seroepidemiology in Spain?

The aim of this paper is to compare the seroprevalence of cytomegalovirus (CMV) in women in the Autonomous Region of Madrid (ARM) obtained in two different years (1993 and 1999), according to age and seroprevalence of a virus transmitted by the faecal-oral route (hepatitis A virus, HAV) and another virus of respiratory transmission (varicella zoster virus, VZV). A total of 1813 serum samples were studied, taken from females aged 2-40 in two different serosurveys which were representative of the general population in the ARM. Of these, 933 were taken in 1993, and 880 in 1999. In each survey the samples were distributed over six groups, according to age group (2-5, 6-10, 11-15, 16-20, 21-30 and 31-40 years). CMV- and VZV-specific IgG was tested by indirect ELISA (Dade-Behring, Germany); and HAV-IgG by ImX (Abbott, USA) in the 1993 samples, or by Vidas (BioMérieux, France) in the case of those taken in 1999. A significant age-related rise in CMV seroprevalence was observed in both serosurveys. The seroprevalence obtained was lower in all age groups in 1999 than in 1993. The differences were statistically significant in two age groups: 6-10 years old (43.7 vs. 56.7%) and 31-40 years old (79.1 vs. 90.3%). In the younger age groups concurrent seroprevalence of CMV and VZV was significant lower in 1999. In older age groups a significant decrease in concurrent seroprevalence of both CMV and HAV was also seen. Agreement between serological results for CMV-HAV, CMV-VZV and HAV-VVZ during the two time periods and in every age group was poor or fair (kappa index < or = 0.2 or between 0.21 and 0.4) in all age groups. To conclude, a change in CMV epidemiology seems to be taking place in Madrid. The increase in the proportion of CMV seronegative women of childbearing age may have some impact on the incidence of congenital diseases related to vertical transmission of CMV. Apparently, such a change, among children, could be related to a lower close contact transmission rate (as in VZV), and among adults to improvements in standards of public health (as in HAV). However, due to the poor or fair agreement between serological results for CMV-HAV, CMV-VZV and HAV-VVZ, other independent factors may affect the fall in CMV seroprevalence.

Seroprevalence of HIV and HTLV in a representative sample of the Spanish population

HIV and HTLV seroprevalence was determined by means of unlinked anonymous testing of 2144 sera, originally obtained from primary care patients by representative sampling of the Spanish population aged 15-39 years in 1996. HIV-1 seroprevalence was 4.3 per 1000 population in the 15-39 years age group [95% confidence interval (CI), 1.5-10.7] and 5.6 per 1000 (95% CI, 1.8-15.3) in the 20-39 years age group. Seroprevalence proved higher in males and urban residents. No antibodies to HIV-2 and HTLV-I were detected in any of the sera studied. However, presence of antibodies to HTLV-II was confirmed in one serum sample, while HTLV seroreactivity, though detected in another, could not be typed. The two HTLV-positive results equated to a seroprevalence of 1.9 per 1000 in the 20-39 years age group (95% CI, 0.3-8.6). HIV-I seroprevalence was consistent with previous estimates yielded by back-calculation. The level of HTLV seroprevalence found suggests endemicity.

Persistent human herpesvirus 8 viremia before Kaposi's sarcoma development in a liver transplant recipient

HHV8 DNA has been detected in essentially all Kaposi's sarcoma (KS) lesions investigated, including those associated with transplantation. However, the possibility of human herpesvirus 8 (HHV8) detection in serum before appearing in the tumor is unknown. We therefore studied the natural history of HHV8 infection in a liver transplant recipient who developed KS 9 months after receiving the hepatic allograft. The presence of HHV8 DNA was retrospectively analyzed by using polymerase chain reaction in frozen stored follow-up serum specimens and KS tissues (skin and lymph node biopsies). Although KS was diagnosed the day +279 posttransplant by histopathological examination of KS tissues, retrospective analysis showed that HHV8 DNA was present in all successive serum specimens taken from the day +119 onward. Accordingly, asymptomatic and persistent HHV8 viremia may precede the appearance of typical KS lesions. Monitoring transplant recipients for HHV8 could be useful for developing therapeutic and prophylactic strategies.

[Seroepidemiologic study of cytomegalovirus in childbearing age women in the community of Madrid]

BACKGROUND

The determination of seroprevalence against cytomegalovirus in women from the Autonomous Region of Madrid (Spain), and the study of risk factors associated with the infection.

MATERIAL AND METHOD

Cytomegalovirus specific IgG was studied in serum samples from the women included in the 2nd Serosurvey of the Autonomous Region of Madrid.

RESULTS

Seroprevalence was 75.6%, ranging from 60.6% (age group 15-24 yr) to 94.6% (36-45), being significantly higher in mothers and in those living in stacking conditions, and significantly lower in women with university studies.

CONCLUSIONS

Cytomegalovirus infection is frequent in childbearing women from Madrid, more than 30% of them could be infected.

Q fever in pregnancy: case report after a 2-year follow-up

We report an acute Q fever case, a febrile syndrome, in the 14th week of pregnancy. Placental infection was documented by Coxiella burnetii culture. Newborn infection was ruled out on the basis of the absence of serological evidence after 2 years and on clinical normality. Serological diagnosis is reviewed here, as maternal serology was suggestive of chronic Q fever. The clinical progress, following extended observation, was consistent with acute infection. A QpDV plasmid, already described as being common to acute and chronic European cases, was detected.

[Laboratory diagnosis of subacute and acute encephalitis probably of viral origin: seven years of experience]

The results obtained in the laboratory diagnosis of 609 cases of acute or subacute encephalitis, studied during a period of time of even years, is briefly presented. Diagnostic methods included virus isolation from stools and cerebrospinal fluid (CSF); specific serology in serum; detection of intrathecal production of IgG antibody; and, in the last two years, detection of viral genome sequences in CSF by the polymerase chain reaction. Significant results were obtained in 196 cases (32.2%) and the alfa-herpesviruses were responsible for a major part of them (77.5%). Furthermore, 18 cases were likely to respond to dual infection by both herpes simplex and varicella-zoster viruses. Epstein-Barr virus and Human herpesvirus 6 were found in CSF from three immunocompetent patients. Besides the current vaccination program, measles virus is still responsible for an important part (22/196, 11.2%) of cases of viral encephalitis.

[Detection of low-avidity IgG antibodies in the diagnosis of primary acute infection by hepatitis C virus]

BACKGROUND

Differential diagnosis of the acute primary infection by hepatitis C virus (HCV) from reactivations and reinfections presents specific problems, especially among patients with impaired humoral immunity. the IgG avidity assay might contribute to resolve these problems.

METHODS

A simple modification of a commercial enzyme immunoassay, allowing evaluation of the avidity of IgG antibody to HCV, was developed and evaluated on a part of 37 serum samples from 14 patients with acute primary infection or reinfection by HCV and 12 samples from 12 seropositive patients lacking evidence of acute infection Eight of the former 14 had impaired ability for antibody response.

RESULTS

The method rendered high percentages of reduction of the antibody signal in samples from acute primary infections taken within two months from onset and significantly lower percentages in samples from reinfections or patients without evidence of acute infection (mean value: 90 degrees C Vs 43% and 25%, respectively. The mean duration of the low-avidity IgG antibody was around six months, but showed wide variations depending on the patient.

CONCLUSIONS

Detection of low-avidity IgG antibody to HCV is easy to perform and may help the study of the HCV infection in some patients. Every method should, however, be carefully validated before using with diagnostic purposes.

[Myelitis associated with varicella-zoster virus in the absence of cutaneous zoster]

INTRODUCTION

The spectrum of neurological complications associated with the infection by varicella-zoster virus (VVZ) is very broad. The diagnosis, usually based on clinical findings and their temporal relationship with cutaneous herpes zoster should be confirmed by serological and/or virological techniques. However, there are an increasing number of cases compatible with this diagnosis in the absence of a skin rash.

CLINICAL CASE

We describe the case of a previously healthy woman of 27 who developed a neurological condition of subacute-chronic course, not preceded by a skin rash and compatible with the diagnosis of myelitis. She had had varicella at the age of 13. The MR of the medulla showed two hyperintense lesions in potentiated sequences in T2 at the level of the cervical medulla (segments C3-C4 and C6). Studies made to rule out other causes of myelopathy were normal or negative. After the first lumbar puncture there was an increase in the number of cells seen (up to 50/mm3) mainly mononuclear with oligoclonal bands, raised tibling index, antibodies (ab) IgG to VVZ and the indexes showing specificity to these abs and their intrathecal production were positive. Treatment with acyclovir produced no change in either her clinical condition or in the cerebrospinal fluid findings.

CONCLUSION

One should consider the possibility of the association with VVZ in patients of any age, whether immunodeficient or not, who present any neurological syndrome for which no other aetiology has been found, whether or not it is preceded by a typical skin rash. The improvement of serological and virological methods permits precise diagnosis of the disorder.

Detection of both herpes simplex and varicella-zoster viruses in cerebrospinal fluid from patients with encephalitis

Cerebrospinal fluid (CSF) samples from 46 patients with encephalitis were studied for the presence of herpes simplex virus (HSV) types 1 and 2 and/or varicella zoster virus (VZV)-specific DNA sequences by the polymerase chain reaction (PCR) assay. Patients were studied because of detection of intrathecal production of IgG antibody to HSV alone (10 patients, Group A) or to both HSV and VZV (11 patients, Group B) or because of the presence of specific anti-HSV IgG in CSF without evidence of intrathecal antibody production (25 patients, Group C). CSF samples taken between days 1 and 10 from onset of encephalitis were available from all patients, and follow-up samples (taken after 10 days from onset) were obtained from some of them. Positive PCR results were obtained in a total of 13 patients. Four patients (three from Group A and one from Group B) gave amplification of HSV type 1 DNA alone, two patients (both from Group B) showed amplification of VZV DNA alone, and seven patients (all from Group B) gave dual amplification of both HSV type 1 and VZV DNA sequences in CSF. All CSF samples from patients in Group C were negative by PCR. Ten patients with CSF samples positive by PCR lacked a prior history of herpetic cutaneous lesions. In seven patients, serum antibody tests (specific IgM detection and specific IgG avidity assays) identified both primary and recurrent infections. The results suggest that the dual presence of IgG antibody to both HSV and VZV in CSF from patients with encephalitis may reflect in some cases a dual infection of the central nervous system caused by both agents.

Application of fluoroimmunoassay to the identification of low avidity specific IgG against pathogenic human viruses and Toxoplasma gondii

BACKGROUND

Serological diagnosis of primary viral infections is usually made by detection of specific IgM. In some cases, false positive results (mainly due to crossreactions between closely related viruses) can be obtained. Moreover, some primary infections occur without specific IgM response. Thus, alternative serological approaches are required for diagnosis. Detection of low avidity, specific IgG has been applied as a useful serological marker for diagnosing infections caused by several viruses and Toxoplasma gondii.

OBJECTIVE

The standardization and application of specific IgG avidity assays using a semiautomated solid phase immunoassay (fluoroimmunoassay (FIA)) on the basis of the urea elution principle, for the characterization of low avidity specific IgG against rubella virus, herpes simplex virus (HSV), varicella-zoster virus (VZV), cytomegalovirus (CMV) and T. gondii.

STUDY DESIGN

The method consists of two simultaneous determinations, one as recommended by the manufacturer and the other including a washing step with 8 M urea after the antigen-antibody reaction. A reduction in titer higher than, or equal to, 50% was considered indicative for presence of low avidity specific IgG.

RESULTS

When applied to the diagnosis of infections, this method showed sensitivity ranging from 81% to 100%, and absolute specificity. The detection of low avidity specific IgG allowed the differentiation between primary and recurrent infections caused by VZV. Furthermore, it helped in the identification of CMV as the etiological agent of congenital infection in the absence of specific IgM response, as well as in the elucidation of crossreactivity between antigenically related viruses, i.e., VZV and HSV, and Epstein-Barr virus and CMV.

CONCLUSION

FIA can be used for the characterization of the avidity of specific IgG antibody as a diagnostic test in clinical laboratories.

Detection of varicella-zoster virus-specific DNA sequences in cerebrospinal fluid from patients with acute aseptic meningitis and no cutaneous lesions

Acute aseptic meningitis (AAM) is considered as an uncommon manifestation of varicella-zoster virus (VZV) recrudescence and is usually regarded as a complication of the cutaneous infection in patients with impaired cellular immunity. Indirect evidence suggests, however, that VZV-associated AAM may also respond to direct spread of the virus to the leptomeninges from the cells supporting the latency. The polymerase chain reaction (PCR) was used to amplify VZV-specific DNA sequences in serial cerebrospinal fluid (CSF) samples from 21 patients with AAM, who presented laboratory evidence of intrathecal production of VZV-specific antibody on follow-up. Eleven of these patients never showed cutaneous zosteriform lesions. VZV-DNA sequences were detected in the CSF from all patients with cutaneous zoster, as well as from six patients (55%) lacking skin lesions. Viral DNA sequences were present in six cases before the rise in specific antibody was seen in CSF, disappearing during follow-up in the seven positive cases. These results support the proposed involvement of VZV in the etiology of AAM seen among normal young adults and strongly suggest that the virus can reach directly and infect the CNS from the latently infected spinal ganglia.

Application of low-avidity immunoglobulin G studies to diagnosis of Epstein-Barr virus infectious mononucleosis

Single serum samples from 121 patients suffering from clinical infectious mononucleosis were tested by an indirect immunofluorescence assay for avidity of Epstein-Barr virus (EBV) capsid antigen immunoglobulin G (IgG), involving a wash step with phosphate-buffered saline-8 M urea. Ninety-four samples showed serological markers of recent EBV infection (presence of viral-capsid antigen-specific IgM [87 cases] and/or presence of IgG in the absence of EBV nuclear antigen antibodies [85 cases]). The remaining 27 cases had serological evidence of prior infection (presence of viral-capsid IgG and EBV nuclear antibodies and absence of IgM). In the avidity assay, 89 samples from patients with recent infection showed low-avidity IgG and 25 samples from patients with prior infection had high-avidity IgG. The avidity assay showed a sensitivity that was at least equal to those of classical serological procedures for diagnosing EBV infectious mononucleosis. Further studies are necessary, however, to establish the specificity of the assay and the duration of low-avidity antibodies.

[Evaluation of serological criteria for the diagnosis of infectious mononucleosis]

We have evaluated the application for the diagnosis of infectious mononucleosis of several serologic criteria, including measurement of concentrations of IgM against viral capsid antigen (VCA) of Epstein-Bar virus (EBV) by ELISA, detection of heterophil antibodies and the presence of anti-VCA IgG in absence of IgG against nuclear antigen of EBV (EBNA). Such criteria were evaluated by using a board of sera obtained from cases who had clinically been diagnosed of infectious mononucleosis and identified in the laboratory as produced by EBV (84 sera) or cytomegalovirus (CMV) (9 sera). The measurement of anti-VCA IgM by any of the two tested methods is the best criteria for the serologic diagnosis of infectious mononucleosis. Positive anti-VCA IgM reactions were detected by IIF and ELISA in sera of patients with infectious mononucleosis-like syndrome due to cytomegalovirus, so an alternative method to the measurement of anti-VCA IgM is needed, the most adequate is the measurement of anti-VCA IgG in the absence of anti-EBNA IgG.

Definition of high-proficiency serological markers for diagnosis of varicella-zoster virus infections by enzyme immunoassay

The levels of Varicella-zoster virus (VZV)-specific IgG, IgM, and IgA antibodies produced in 22 cases of varicella, 22 cases of cutaneous zoster, and 12 cases of acute aseptic meningitis due to VZV in the absence of cutaneous lesions, were measured by indirect enzyme immunoassay (EIA) and compared with those observed in a group of 34 age-matched controls. The definition of cutoff titres for each serological marker and combinations of them allowed early diagnosis of infection in 82% of varicella patients and 91% of patients with acute aseptic meningitis lacking cutaneous lesions on a single serum sample, the specificity being over 90%. The system was as sensitive as the demonstration of intrathecally produced IgG antibodies for the early diagnosis of the infection in 22 cases of neurological disease due to VZV. A working protocol for the serological diagnosis of VZV infections, using currently available EIA reagents, is described.

[Lymphocytic meningitis. Virologic study. Analysis of the study carried out from 1984 to 1986 (632 cases)]

The experience with the virological diagnosis of lymphocytic meningitis in the Centro Nacional de Microbiología during 3 years (1984-1986) included 632 cases. The most common causative organism was the parotiditis virus (46.9%), particularly in children (64.6%), followed by the non-polio enteroviruses (25.3%). The varicella-zoster virus was the most common organism found in adults (33.3%). We describe some clinical and epidemiological aspects, emphasizing the absence of clinical features suggesting herpesvirus infection in about 50% of cases. Finally, we indicate the study techniques or methods more adequate in each instance (specific IgM detection, isolation techniques or detection of intrathecal antibody production), and we define a study protocol for cases of acute lymphocytic meningitis which permits a high diagnostic yield (44.1-54.9%).