HCV, HIV AND HBV rapid test diagnosis in non-clinical outreach settings can be as accurate as conventional laboratory tests

Point of care rapid diagnostic tests (POC-RDT) for Hepatitis C virus (HCV), Human Immunodeficiency virus (HIV) and Hepatitis B virus (HBV), are ideal for screening in non-clinical outreach settings as they can provide immediate results and facilitate diagnosis, allowing high risk population screening. The aim of this study was to compare POC-RDT with laboratory conventional tests. A total of 301 vulnerable evaluable subjects (drug users, migrants and homeless population) were recruited at a mobile screening unit in outreach settings in Madrid. Fingerprick whole blood capillary samples were tested using the SD BIOLINE HCV POC-RDT, Determine HIV Early Detect and Determine HBsAg 2, and the results were assessed against the LIAISON XL HCV, HIV and Murex-HBsAg-Quant, reference assays, respectively. The feasibility and user satisfaction of the POC-RDT were evaluated through a questionnaire. The resolved sensitivity and resolved specificity and their 95% confidence intervals (95% CI) were as follows, respectively: SD-BIOLINE-HCV: 98.8% (95% CI 93.4, 100.0) and 100.0% (95% CI 98.3, 100.0); Determine HIV Early Detect: 100% (95% CI 85.2, 100.0) and 100% (95% CI 98.7, 100); and Determine HBsAg 2: 66.7% (95% CI 9.4, 99.2) and 100.0% (95% CI 98.7, 100.0). As expected, the number of subjects with a confirmed positive result for HBsAg was very low (n = 4). Therefore, the analytical sensitivity has been evaluated in addition: The Determine HBsAg 2 test demonstrated 100% sensitivity for standard concentrations ≥ 0.125 IU/mL. The subject questionnaire yielded positive feedback for most subjects. The POC-RDT fingerprick blood collection method was well received, and the tests demonstrated a comparable clinical performance with conventional tests in outreach settings and vulnerable high-risk populations.

Epidemiological Characteristics and Spatio-Temporal Distribution of Hepatitis A in Spain in the Context of the 2016/2017 European Outbreak

The aim of our study was to describe the results of the epidemiological surveillance of hepatitis A infections in Spain in the context of the 2016/2017 European outbreak, particularly of hepatitis A outbreaks reported in the MSM population, incorporating the results of a spatio-temporal analysis of cases. Hepatitis A cases and outbreaks reported in 2016-2017 to the National Epidemiological Surveillance Network were reviewed: outbreaks in which some of the cases belonged to the MSM group were described, and clusters of hepatitis A cases in men and women were analysed using a space-time scan statistic. Twenty-six outbreaks were identified, with a median size of two cases per outbreak, with most of the outbreak-related cases belonging to the 15-44 years-old group. Nearly 85% occurred in a household setting, and in all outbreaks, the mode of transmission was direct person-to-person contact. Regarding space-time analysis, twenty statistically significant clusters were identified in the male population and eight in the female population; clusters in men presented a higher number of observed cases and affected municipalities, as well as a higher percentage of municipalities classified as large urban areas. The elevated number of cases detected in clusters of men indicates that the number of MSM-related outbreaks may be higher than reported, showing that spatio-temporal analysis is a complementary, useful tool which may improve the detection of outbreaks in settings where epidemiological investigation may be more challenging.

Hepatitis of unknown aetiology in children - epidemiological overview of cases reported in Europe, 1 January to 16 June 2022

Following the report of an excess in paediatric cases of severe acute hepatitis of unknown aetiology by the United Kingdom (UK) on 5 April 2022, 427 cases were reported from 20 countries in the World Health Organization European Region to the European Surveillance System TESSy from 1 January 2022 to 16 June 2022. Here, we analysed demographic, epidemiological, clinical and microbiological data available in TESSy. Of the reported cases, 77.3% were 5 years or younger and 53.5% had a positive test for adenovirus, 10.4% had a positive RT-PCR for SARS-CoV-2 and 10.3% were coinfected with both pathogens. Cases with adenovirus infections were significantly more likely to be admitted to intensive care or high-dependency units (OR = 2.11; 95% CI: 1.18–3.74) and transplanted (OR = 3.36; 95% CI: 1.19–9.55) than cases with a negative test result for adenovirus, but this was no longer observed when looking at this association separately between the UK and other countries. Aetiological studies are needed to ascertain if adenovirus plays a role in this possible emergence of hepatitis cases in children and, if confirmed, the mechanisms that could be involved.

Hepatitis E virus genotype 3 microbiological surveillance by the Spanish Reference Laboratory: geographic distribution and phylogenetic analysis of subtypes from 2009 to 2019

Background

Hepatitis E virus genotype 3 (HEV-3) is widely distributed throughout Europe, with incidence of infections increasing in many countries. Belgium, Bulgaria, France, Germany, Italy, the Netherlands and the United Kingdom have reported the distribution of HEV-3 subtypes in cohorts of patients with hepatic disease.

Aim

To describe the distribution of the HEV-3 subtypes in Spain at national and autonomous community (AC) levels between 2009 and 2019. The study was also extended to Andorra.

Methods

Of 5,197 samples received by the National Reference Laboratory during the study, 409 were HEV-RNA-positive. Among these, 294 (71.9%) were further typed based on an ORF2 sequence fragment, or, for a subset of 74, based on the full-coding genome sequence.

Results

HEV-3 was detected in 291 samples. The dominant subtype in Spain was HEV-3f (88.3%; 257/291), which occurred in all ACs, with no change in detection level over time. Within this subtype, three subclusters were characterised: HEV-3f-B, HEV-3f-A1 and HEV-3f-A2. The second most common HEV subtype was the recently described HEV-3m (7%; 21/291), with two subclusters identified: HEV-3m-A, which has been known since 2010, and HEV-3m-B, since 2014. The third most encountered subtype was HEV-3c (4.1%; 12/291), with a frequency not increasing over time, unlike observations in some European countries.

Conclusion

The importance of the surveillance of HEV-3 subtype and subcluster circulation is yet to be assessed. This surveillance together with the comprehensive epidemiological characterisation of clinical cases, could support the identification of sources of transmission and the establishment of control measures nationally and internationally.

Prevalence and undiagnosed fraction of hepatitis C infection in 2018 in Spain: results from a national population-based survey

BACKGROUND

A national strategy against hepatitis C virus (HCV) was implemented in Spain in 2015 with the aim of reducing associated morbidity and mortality. In order to improve our understanding of the epidemiology of HCV, we analysed the prevalence of HCV antibodies and active infection overall and by age and sex in the general population aged 20-80 years. We also aimed to report the undiagnosed fraction.

METHODS

A national population-based seroprevalence survey was conducted in 2017-2018. A representative sample from the general population was selected using two-stage sampling. The prevalence of total HCV antibodies and of HCV RNA was calculated using inverse probability weighting based on bootstrapping.

RESULTS

Overall, we approached 17 496 persons; 9103 agreed to participate and met the eligibility criteria and 7675 were aged 20-80. We obtained a prevalence of HCV antibodies of 0.85% [95% confidence interval (CI): 0.64-1.08%] and of active infection of 0.22% (95% CI: 0.12-0.32%). The prevalence of active HCV infection was highest in men aged 50-59 (0.86%; 95% CI: 0.28-1.57%) and in men aged 60-69 years (0.72%; 95% CI: 0.27-1.28%). Prevalence was below 0.20% in the remaining age groups. The undiagnosed fraction for active HCV infection was 29.4%.

CONCLUSION

This study shows that prevalence of HCV in the general population in Spain is low and reflects the impact of scaling up treatment with direct acting antivirals, together with other prevention strategies, from 2015 onwards. The data reported can guide subsequent public health actions.

Improving preparedness to respond to cross-border hepatitis A outbreaks in the European Union/European Economic Area: towards comparable sequencing of hepatitis A virus

Introduction

Sequence-based typing of hepatitis A virus (HAV) is important for outbreak detection, investigation and surveillance. In 2013, sequencing was central to resolving a large European Union (EU)-wide outbreak related to frozen berries. However, as the sequenced HAV genome regions were only partly comparable between countries, results were not always conclusive.

Aim

The objective was to gather information on HAV surveillance and sequencing in EU/European Economic Area (EEA) countries to find ways to harmonise their procedures, for improvement of cross-border outbreak responses.

Methods

In 2014, the European Centre for Disease Prevention and Control (ECDC) conducted a survey on HAV surveillance practices in EU/EEA countries. The survey enquired whether a referral system for confirming primary diagnostics of hepatitis A existed as well as a central collection/storage of hepatitis A cases’ samples for typing. Questions on HAV sequencing procedures were also asked. Based on the results, an expert consultation proposed harmonised procedures for cross-border outbreak response, in particular regarding sequencing. In 2016, a follow-up survey assessed uptake of suggested methods.

Results

Of 31 EU/EEA countries, 23 (2014) and 27 (2016) participated. Numbers of countries with central collection and storage of HAV positive samples and of those performing sequencing increased from 12 to 15 and 12 to 14 respectively in 2016, with all countries typing an overlapping fragment of 218 nt. However, variation existed in the sequenced genomic regions and their lengths.

Conclusions

While HAV sequences in EU/EEA countries are comparable for surveillance, collaboration in sharing and comparing these can be further strengthened.

Occurrence of Hepatitis E Virus in Pigs and Pork Cuts and Organs at the Time of Slaughter, Spain, 2017

Zoonotic hepatitis E, mainly caused by hepatitis E virus (HEV) genotype (gt) 3, is a foodborne disease that has emerged in Europe in recent decades. The main animal reservoir for genotype 3 is domestic pigs. Pig liver and liver derivates are considered the major risk products, and studies focused on the presence of HEV in pig muscles are scarce. The objective of the present study was to evaluate the presence of HEV in different organs and tissues of 45 apparently healthy pigs from nine Spanish slaughterhouses (50% national production) that could enter into the food supply chain. Anti-HEV antibodies were evaluated in serum by an ELISA test. Ten samples from each animal were analyzed for the presence of HEV RNA by reverse transcription real-time PCR (RT-qPCR). The overall seroprevalence obtained was 73.3% (33/45). From the 450 samples analyzed, a total of 26 RT-qPCR positive samples were identified in the liver (7/45), feces (6/45), kidney (5/45), heart (4/45), serum (3/45), and diaphragm (1/45). This is the first report on detection of HEV RNA in kidney and heart samples of naturally infected pigs. HEV RNA detection was negative for rib, bacon, lean ham, and loin samples. These findings indicate that pig meat could be considered as a low risk material for foodborne HEV infection.

Standardising surveillance of hepatitis E virus infection in the EU/EEA: A review of national practices and suggestions for the way forward

BACKGROUND

Hepatitis E virus (HEV) infection is not notifiable at EU/EEA level, therefore surveillance relies on national policies only. Between 2005 and 2015, more than 20,000 cases were reported in EU/EEA countries. HEV testing is established in 26 countries and 19 countries sequence HEV viruses.

OBJECTIVE AND STUDY DESIGN

WHO's European Action plan for viral hepatitis recommends harmonised surveillance objectives and case definitions. ECDC's HEV expert group developed minimal and optimal criteria for national hepatitis E surveillance to support EU/EEA countries in enhancing their capacity and to harmonise methods.

RESULTS

The experts agreed that the primary objectives of national surveillance for HEV infections should focus on the basic epidemiology of the disease: to monitor the incidence of acute cases and chronic infections. The secondary objectives should be to describe viral phylotypes or subtypes and to identify potential clusters/outbreaks and possible routes of transmission. Seventeen of 20 countries with existing surveillance systems collect the minimal data set required to describe the epidemiology of acute cases. Eleven countries test for chronic infections. Twelve countries collect data to identify potential clusters/outbreaks and information on possible routes of transmission.

DISCUSSION

Overall, the majority of EU/EEA countries collect the suggested data and meet the outlined requirements to confirm an acute case.

Prevalence of hepatitis E infection in HIV/HCV-coinfected patients in Spain (2012-2014)

Hepatitis E virus (HEV) has emerged as a relevant pathogen for HIV-infected patients. However, there is scarce data on HEV infection in HIV/HCV-coinfected individuals with advanced fibrosis, which seems to increase the risk of HEV infection and worsen the prognosis of liver disease. We aimed to determine the prevalence of anti-HEV antibodies, acute hepatitis E, resolved hepatitis E, and exposure to HEV in HIV/HCV-coinfected patients and to evaluate associations with clinical and epidemiological characteristics. We performed a cross-sectional study on 198 HIV/HCV-coinfected patients, 30 healthy controls and 36 HIV-monoinfected patients. We found a low concordance between techniques used for detection of anti-HEV antibodies (ELISA versus Immunoblot), particularly in HIV/HCV-coinfected patients. HIV/HCV-coinfected patients showed the highest prevalence of IgG against HEV, resolved hepatitis E, and exposure to HEV (19.2%, 17.2%, and 22.2% respectively). However, we did not find any samples positive for HEV-RNA nor significant differences between groups. Moreover, HIV/HCV-coinfected patients with CD4 T-cells <350 cells/mm³ had higher prevalence for anti-HEV IgG antibodies, resolved hepatitis E, and exposure to HEV than healthy controls or those with CD4 T-cells ≥ 350 cells/mm³ (p = 0.034, p = 0.035, and p = 0.053; respectively). In conclusion, HIV/HCV-coinfected patients in Spain have a high prevalence for IgG anti-HEV antibodies, resolved hepatitis E, and exposure to HEV; particularly patients with CD4+T-cells <350 cells/mm³.

Hepatitis A outbreak disproportionately affecting men who have sex with men (MSM) in the European Union and European Economic Area, June 2016 to May 2017

Between 1 June 2016 and 31 May 2017, 17 European Union (EU) and European Economic Area countries reported 4,096 cases associated with a multi-country hepatitis A (HA) outbreak. Molecular analysis identified three co-circulating hepatitis A virus (HAV) strains of genotype IA: VRD_521_2016, V16-25801 and RIVM-HAV16-090. We categorised cases as confirmed, probable or possible, according to the EU outbreak case definitions. Confirmed cases were infected with one of the three outbreak strains. We investigated case characteristics and strain-specific risk factors for transmission. A total of 1,400 (34%) cases were confirmed; VRD_521_2016 and RIVM-HAV16-090 accounted for 92% of these. Among confirmed cases with available epidemiological data, 92% (361/393) were unvaccinated, 43% (83/195) travelled to Spain during the incubation period and 84% (565/676) identified as men who have sex with men (MSM). Results depict an HA outbreak of multiple HAV strains, within a cross-European population, that was particularly driven by transmission between non-immune MSM engaging in high-risk sexual behaviour. The most effective preventive measure to curb this outbreak is HAV vaccination of MSM, supplemented by primary prevention campaigns that target the MSM population and promote protective sexual behaviour.

Evaluation of dried blood spot samples for screening of hepatitis C and human immunodeficiency virus in a real-world setting

Both hepatitis C virus (HCV) infection and human immunodeficiency virus (HIV) infection are underdiagnosed, particularly in low-income countries and in difficult-to-access populations. Our aim was to develop and evaluate a methodology for the detection of HCV and HIV infection based on capillary dry blood spot (DBS) samples taken under real-world conditions. We carried out a cross-sectional study of 139 individuals (31 healthy controls, 68 HCV-monoinfected patients, and 40 HCV/HIV-coinfected patients). ELISA was used for anti-HCV and anti-HIV antibody detection; and SYBR Green RT-PCR was used for HCV-RNA detection. The HIV serological analysis revealed 100% sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). The HCV serological analysis revealed a sensitivity of 92.6%, specificity of 100%, PPV of 100%, and NPV of 79.5%. Finally, the HCV-RNA detection test revealed a detection limit of 5 copies/µl with an efficiency of 100% and sensitivity of 99.1%, specificity of 100%, PPV of 100%, and NPV of 96.9%. In conclusion, our methodology was able to detect both HCV infection and HIV infection from the same DBS sample with good diagnostic performance. Screening for HCV and HIV using DBS might be a key strategy in the implementation of national programs for the control of both infections.

[Severe acute hepatitis by delta virus superinfection: diagnostic significance of molecular biology.]

HDV infection may occur within a primary HBV infection (co-infection) or by sub sequent acquisition ofthe virus in patients with chronic hepatitis B (superinfection). Acute HDV infection is rarely diagnosed. Since cero conversion usually takes place about six weeks after viral infection, early diagnosis requires the use of direct diagnostic techniques, such as antigen HD V (HDAg) detection, or genomic amplification by means of molecular biology methods (RT-PCR). Here were port the case of a patient with chronic HBV infection that develops a severe acute hepatitis due to VHD superinfec- tion only detected by molecular biology.

[Role of the National Poliovirus Laboratory for the Program of eradication and poliomyelitis surveillance]

The Spanish acute flaccid paralysis surveillance network is coordinated by the National Poliovirus Laboratory (NPL), which, since 1998, carries out polioviruses (PV) and other enteroviruses detected characterization by cell culture and molecular techniques. A total of 110,725 (70046+40679) samples were studied between 1998-2012 and enteroviruses were detected in 8% of these. Among these enteroviruses 241 PV were characterized as PV Sabin-like, except samples belong to an imported poliomyelitis case, all of which were characterised as vaccine derived PV type 2. The NPL has carried out the serotyping and the intratypic differentiation of all the isolated PV in Spain of any syndrome. It is shown that wild PV has not circulated in our country during the 15 years studied and that has led to the signing of the Act of the "eradication of poliomyelitis in Spain" by WHO in 2001, and the /"certification of the eradication of wild PV free for European countries" on 21 June 2002. Currently only 3 countries have endemic transmission of wild PV (Pakistan, Afghanistan and Nigeria). Until a complete worldwide eradication, was achieved, Spain will actively continue to participate in the maintenance of the poliomyelitis eradication infrastructure by monitoring and vaccination as well as the wild PV containment plan to avoid the spread of wild PV.

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.

Chronic hepatitis E in HIV patients: rapid progression to cirrhosis and response to oral ribavirin

Chronic hepatitis E virus infection with rapid progression to cirrhosis is reported in 2 human immunodeficiency virus (HIV)-infected patients with severe immunosuppression. Monotherapy with ribavirin led to temporary viral response and marked improvement of liver damage. Chronic hepatitis E should be regarded as another opportunistic event within HIV infection.

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.

Diagnosis of acute hepatitis E by antibody and molecular testing: a study on 277 suspected cases

BACKGROUND

Acute hepatitis due to hepatitis E virus (HEV) infection is both indigenous and imported to Europe. Few studies provide information about the role of HEV as an agent for acute hepatitis in Spain.

OBJECTIVES

To investigate the frequency of the HEV infection among patients displaying acute hepatitis of unexplained origin in Spain, comparing the performance of two different diagnostic approaches.

STUDY DESIGN

Specific IgM antibody and HEV RNA tests were used to study samples from 277 patients with acute hepatitis of unknown aetiology received during a six-year period. Samples were sent by 52 hospitals from almost all regions of Spain.

RESULTS

Evidence of acute infection by HEV was obtained for 30 patients in total (10.8%), and 16 cases were unrelated to recent international travel. On samples from 158 patients tested for both anti-HEV IgM and HEV RNA at admission, the yield of IgM antibody testing (11.4%) was higher than the yield of HEV RNA testing (9.5%).

CONCLUSIONS

HEV could be responsible in Spain of about 11% of cases of acute hepatitis of unknown origin overall, and of about 8% of cases unrelated to international travel or immigration. India and neighbour countries represent the highest risk for import of epidemic HEV strains into Spain. Both antibody assays and molecular tests are required to optimise the final yield of laboratory diagnosis.

Imported and autochthonous hepatitis E virus strains in Spain

Hepatitis E virus (HEV) causes hepatitis E, an acute liver disease displaying diverse epidemiological patterns that correlate with the genetic diversity of the virus. Only a few strains have been characterized to date from cases of hepatitis E in Spain. Using three sets of new, HEV-specific primers, viral genome fragments were amplified from serum samples from 13 patients with acute hepatitis in different regions of Spain. Direct sequencing of these fragments and analysis of sequences lead to identify six genotype 1, six genotype 3, and one genotype 4 viral strains. Genotype 1 sequences were found in the clade with subtype 1a strains, and were amplified from travelers from India and Bangladesh, and from an African immigrant. Genotype 3 sequences were found in the clade with subtype 3f strains, were always amplified from patients who did not travel abroad recently, and were closely related to sequences from swine strains isolated in Spain. Patients infected by these strains lived in different regions and were mainly men aged above 50 years. The single genotype 4 sequence detected was amplified from a traveler returning from Vietnam. Hepatitis E is both an imported and an autochthonous disease in Spain, and closely related HEV genotype 3f strains are responsible for infections acquired locally in different regions of the country within a given time. Studies involving a significant number of human, swine, and environmental viral strains collected prospectively are, however, required in order to confirm a swine origin for autochthonous HEV genotype 3 human infections.

Occurrence and distribution of culturable enteroviruses in wastewater and surface waters of north-eastern Spain

AIMS

Update information regarding occurrence and levels of culturable enteroviruses in several types of surface polluted waters in north-eastern Spain and determine the proportion of the different species and serotypes.

METHODS AND RESULTS

The best procedures on hand in our laboratory for concentrating and quantifying culturable enteroviruses from different water sample types were used. Sequencing was used for typing the virus isolates. Geometric means of enteroviruses densities expressed in plaque forming units per litre were 968 in raw sewage, 12.51 in secondary effluents, 0.017 in tertiary effluents, 0.4 in river water and 0.36 in seawater. Enterovirus densities in wastewater revealed certain seasonality with a maximum at the end of spring - beginning of the summer. Coxsackievirus B, and amid them serotype CB4, were the most abundant species and serotypes detected.

CONCLUSIONS

Densities of enteroviruses in different north-eastern Spain surface waters are similar to those present in industrialized countries with temperate climate. No wild polioviruses were detected. Distribution of species showed a clear prevalence of coxsackieviruses.

SIGNIFICANCE AND IMPACT OF THE STUDY

Information regarding enteroviruses in this geographical area provides valuable information to estimate the risk of enteroviruses transmission through water and for complementing clinical epidemiological data.

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.

Endemic circulation of European bat lyssavirus type 1 in serotine bats, Spain

To determine the presence of European bat lyssavirus type 1 in southern Spain, we studied 19 colonies of serotine bats (Eptesicus isabellinus), its main reservoir, during 1998–2003. Viral genome and antibodies were detected in healthy bats, which suggests subclinical infection. The different temporal patterns of circulation found in each colony indicate independent endemic circulation.

Endemic circulation of European bat lyssavirus type 1 in serotine bats, Spain

To determine the presence of European bat lyssavirus type 1 in southern Spain, we studied 19 colonies of serotine bats (Eptesicus isabellinus), its main reservoir, during 1998-2003. Viral genome and antibodies were detected in healthy bats, which suggests subclinical infection. The different temporal patterns of circulation found in each colony indicate independent endemic circulation.

Improved detection of natural hepatitis B virus surface antigen (HBsAg) mutants by a new version of the VITROS HBsAg assay

The sensitivity of immunoassays for hepatitis B virus (HBV) surface antigen (HBsAg) detection may be hampered by the presence of mutants involving the major antigenic determinant of the protein. The performance of the VITROS HBsAg Assay has been shown to be affected by mutations comprising amino acid changes at residues 143, 144, and 145 of the HBsAg molecule. Sixty-seven serum samples from HBV carriers containing major populations of natural HBsAg mutants assayed previously by that assay were tested by the new VITROS HBsAg ES Assay. Samples displayed either single or multiple amino acid substitutions between positions 112 and 145 of the HBsAg, including changes in relevant residues such as 118-120, 125-127, and 143-145. Testing of undiluted samples by the current assay gave rise to false negative results in two samples displaying the single substitutions 145A and 145R, and in one additional sample displaying a dual mutation 118A + 145A. Unusually weak reactivity (<25 S/CO units) was, in addition, recorded in samples containing mutants 143L (2 samples) and 115N + 120Q + 131K + 144A (1 sample). Testing samples at the 1/40 dilution by the modified assay did not produce, in contrast, false negative results, and reactivity below 25 S/CO units was recorded only in three cases. These results confirm that the capability of immunoassays to detect the presence of natural HBsAg mutants in clinical samples may be improved significantly by introducing changes in their design, and show that such improvement has been achieved successfully with the new VITROS HBsAg ES Assay.

Dependence of correlations between antibody titres and opsonophagocytosis on pneumococcal serotype and patient morbidity in pre- and post-pneumococcal vaccination states

Pre- vs. post-vaccination changes in correlations between IgG concentrations (ELISA titres) and opsonophagocytic activity (OPA) against Streptococcus pneumoniae serotypes 6B, 14 and 23F induced by the 23-valent polysaccharide vaccine were studied in paired serum samples received from elderly individuals, haemodialysed patients and kidney transplant recipients by the Spanish Pneumococcal Reference Laboratory. The pre- and post-vaccination parameters considered were: ELISA and OPA titres and the percentage of subjects with post-vaccination OPA values above the cut-off levels; the correlations between OPA and ELISA (Spearman correlation coefficient, r); and the amount of IgG needed to obtain OPA (beta coefficient). Non-significant pre-vaccination correlations between OPA and ELISA were found. Vaccination increased the correlation coefficient between OPA and ELISA to a statistically significant level for serotypes 6B, 14 and 23F in samples from haemodialysed patients, for serotypes 14 and 23F in samples from elderly individuals, and for none of the serotypes in samples from transplant recipients. In all cases, except for serotype 23 in transplant recipients, vaccination increased the beta coefficient, indicating that lower amounts of IgG were needed to obtain high OPA titres. A globally lower response was obtained for serotype 23 and/or transplant recipients.

Acute hepatitis B virus window-period blood donations detected by individual-donation nucleic acid testing: a report on the first two cases found and interdicted in Spain

BACKGROUND

Mathematical models predict that, in Spain, a significant number of blood units will be obtained during the window period of the hepatitis B virus (HBV) infection. Routine nucleic acid testing (NAT) on individual blood units may provide experimental data to evaluate such a theoretical risk.

STUDY DESIGN AND METHODS

Between February and July 2005, a total of 34,631 individual units were screened for HBV DNA by a multiplex transcription-mediated amplification (TMA) test. Units that repeatedly reacted in the test, but did not react for HBV surface antigen (HBsAg), were submitted to additional testing by both molecular and conventional assays, and the donors were recalled for follow-up studies and the collection of clinical and epidemiologic data.

RESULTS

Confirmatory testing and follow-up studies identified 2 blood units donated during the HBV infection window period (1/17,316 units studied). Sequencing of amplification products obtained by nested polymerase chain reaction (n-PCR) revealed two HBV strains from genotypes D/ayw3 and F/adw4q-, but did not identify HBsAg mutants. The HBV DNA concentration in the index donations was estimated to be below the n-PCR detection level (180 IU/mL), in both cases. One donor developed acute hepatitis 2 months after donating blood, but the other remained asymptomatic and displayed normal alanine aminotransferase levels at follow-up.

CONCLUSIONS

The HBV infection window period is a real issue in the setting of Spanish blood transfusions. NAT of individual units by TMA would make a significant contribution to improving the safety of the blood supply in Spain. Additional studies involving a larger number of units and longer periods of time are required, however, to ascertain the true incidence of the problem in this country.

[Microbiological diagnosis of viral hepatitis]

Hepatitis of viral aetiology caused by hepatotropic virus (A, E, B, D and C) represents an important work load for the clinical virology laboratory. Most of the diagnostic is based upon detection in serum and plasma samples of different serological and virological markers, which correlates with different infection stages. In chronic infection by HBV and HCV is necessary to perform diagnostic by molecular methods as well as antigen detection in sequential samples along the course of the disease taking into account that a reliable storage must be provided for stability of structural components of the virus. Recent knowledge about mutations variants in some of the virus may alter the validity of particular markers.

RT-PCR for detection of all seven genotypes of Lyssavirus genus

The Lyssavirus genus includes seven species or genotypes named 1-7. Rabies genotypes correlate with geographical distribution and specific hosts. Co-circulation of different lyssaviruses, imported cases, and the presence of unknown viruses, such as Aravan, Khujand, Irkut and West Caucasian Bat Virus, make it necessary to use generic methods able to detect all lyssaviruses. Primer sequences were chosen from conserved regions in all genotypes in order to optimise a generic RT-PCR. Serial dilutions of 12 RNA extracts from all seven Lyssavirus genotypes were examined to compare the sensitivity of the RT-PCR standardised in this study with a published RT-PCR optimised for EBLV1 detection and capable of amplifying RNA from all seven lyssaviruses. All seven genotypes were detected by both RT-PCRs, however, the sensitivity was higher with the new version of the test. Twenty samples submitted for rabies diagnosis were tested by the new RT-PCR. Eight out of 20 samples from six dogs, one horse and one bat were found positive, in agreement with immunofluorescence results. Seven samples from terrestrial mammals were genotype 1 and one from a bat was genotype 5. In conclusion, this method can be used to complement immunofluorescence for the diagnosis of rabies, enabling the detection of unexpected lyssaviruses during rabies surveillance.

Frequency of hepatitis B virus 'a' determinant variants in unselected Spanish chronic carriers

The prevalence in the population of hepatitis B virus (HBV) surface antigen (HBsAg) variants that may impair diagnosis, or allow the virus to escape vaccine-induced immunity or passive immunoglobulin therapy is unknown. A genome fragment encoding HBsAg amino acids 112-212 was amplified and sequenced from the sera of 272 unselected DNA-positive, HBV-chronic carriers from Spain. The genotype and the HBsAg subtype were predicted from the sequences. Analysis of amino-acid positions 112-157 revealed single or multiple substitutions in 39% of the carriers studied. Mutations were not detected for residues 121, 135, 137, 139, 140, 141, 142, 146, 147, 148, 149, 151, 152, 153, 155, 156, and 157. Substitutions reported previously to be in association with failures of diagnostic tests or with vaccine or immunoglobulin therapy escape were found in 12.5%, 6.6%, and 9.2% of carriers, respectively. Met133Thr (2.2%); Gln129His, Met133Ile, Phe/Tyr134Asn (1.8%); Phe/Tyr134Leu, Gly145Ala (1.5%), and Pro120Thr (1.1%) were the most frequent. Other substitutions, including Gly145Arg (0.4%), were found at a frequency of less than 1%. Samples containing HBV mutants were tested with three commercial assays for HBsAg screening. Almost all the mutants reacted to the upper cut-off values of the assays, but six samples with weak reactivity with one or more of the methods were also found. Thus, HBV mutants with a potential impact on clinical and public health issues are moderately frequent among chronic carriers from Spain, although their influence on the performance of diagnostic tests seems to be slight.

Red de Laboratorios del Plan de Erradicación de la Poliomielitis (1998-2003): 6 años de vigilancia de parálisis flácida aguda en España

INTRODUCTION

Worldwide poliomyelitis eradication was proposed in 1988 by the World Health Organization (WHO), based on reaching and maintaining high vaccination coverage and on implementing effective poliovirus infection surveillance systems.

METHODS

In Spain the surveillance system focuses on active searching for acute flaccid paralysis cases through a nine-laboratory network, coordinated by the National Poliovirus Laboratory (NPL) in the National Center of Microbiology, and supported by Autonomous Community epidemiologists. Additionally, the Network sends enterovirus isolation data from other syndromes. The Laboratory Network is responsible for the primary virological study, while the NPL characterizes all polioviruses and the most epidemiologically relevant non-polio enteroviruses.

RESULTS

A total of 54,533 samples were studied during the six-year period, and enteroviruses were detected in 9%. All the polioviruses isolated (n = 196), were characterized as Sabin-like (poliovirus vaccine), and among the non-polio enteroviruses, the most frequent was Echovirus 30. A total of 3% of the samples studied corresponded to the 268 acute flaccid paralysis cases or their contacts.

DISCUSSION

According to the results and the WHO virological classification, Spain can be considered polio-free. However, the geographic situation of our country may facilitate the introduction of wild polioviruses that can give rise to imported poliomyelitis. Hence, the laboratory network should actively continue to participate in all the proposed WHO strategies, particularly maintenance of the poliomyelitis eradication infrastructures, and continuing monitoring and vaccination.

Sensitivity of a modified version of the ARCHITECT Anti-HCV test in detecting samples with immunoblot-confirmed, low-level antibody to hepatitis C virus

BACKGROUND AND OBJECTIVES

Compliance with current regulations regarding the prevention of hepatitis C virus (HCV) transmission in the blood transfusion setting requires the use of sensitive assays for HCV antibody (anti-HCV) detection, which should, ideally, identify any donor having had prior contact with the virus. Therefore, low-level anti-HCV positive blood units should be detected by the screening assays, even those reflecting a past and resolved infection. To assess the sensitivity of two versions of an automated chemiluminescent microparticle immunoassay (CMIA) for anti-HCV screening (ARCHITECT Anti-HCV), 113 single serum samples containing low levels of anti-HCV, assessed by two immunoblot tests, were selected from 3686 samples received for confirmation of HCV infection by a reference laboratory over a 2-year period.

MATERIALS AND METHODS

The panel included 17 samples with HCV RNA detected by the polymerase chain reaction (PCR) and 96 PCR negative samples with either positive or indeterminate (anti-Core and anti-NS3 alone) results by immunoblot.

RESULTS

All but 13 specimens (100/113, 88.5%) were detected by the current version of the ARCHITECT Anti-HCV assay and 10 additional samples (110/113, 97.3%) tested positive in a modified version of the test.

CONCLUSION

The results showed that the modification introduced in the ARCHITECT Anti-HCV assay achieves a significant sensitivity improvement including samples with low-level anti-HCV which are either PCR positive or negative.

Hepatitis B virus genetic diversity

Hepatitis B virus (HBV) is a human DNA virus, which replicates through an RNA intermediate because of the reverse-transcriptase (RT) activity of its DNA polymerase. As a result, the mutation rate for HBV is higher than the rate observed for most DNA viruses. HBVs are classified into genotypes based on genomic sequencing, and antigenic subtypes based on the antigenic properties of its major surface glycoprotein, the HBV surface antigen (HBsAg). Subgenotypes have been identified within most of the HBV genotypes. The HBV groups defined by the different genotype-HBsAg subtype associations found over the world display characteristic geographical distributions, reflecting the movements of human populations and other epidemiologically significant events. Such HBV groups constitute genetically stable viral populations sharing a common evolutionary history, but additional stable changes, originating from mutation and mutant selection, are observed within all of them. These viral sub-populations are known as the HBV variants, and some of which have medical and public health relevance. Pre-core (pre-C) defective variants have been shown to make HBV infection much less susceptible to interferon treatment, and treatment failures with other antiviral drugs have been associated with selection of resistant variants that display specific mutations in the genome region encoding the viral RT activity. Since the RT region of the genome overlaps the sequence encoding the HBsAg molecule, selection of drug resistant variants involves, in some cases, the indirect selection of HBsAg variants. Viral variants displaying changes in HBsAg seem to be very common among chronic HBV carriers; and some of these variants may emerge under the pressure of the neutralizing antibody response, leading to vaccine resistance and resistance to immunotherapy. Mutations conferring resistance to immunotherapy are noted often among liver transplant recipients and among babies born to HBV-carrier mothers. In addition, some of these HBsAg variants have been associated with lack of detection by HBsAg tests used for the diagnosis of HBV infection, for the identification of chronic carriers, for screening of blood donations for transfusion, and in the manufacture of therapeutic blood products.

Follow-up of the prevalence of hepatitis C virus genotypes in Spain during a nine-year period (1996-2004)

BACKGROUND

Recent data suggest that the prevalence of genotype 4 HCV strains among Spanish carriers is increasing.

OBJECTIVE

To assess changes in the prevalence of HCV genotypes in Spain during the last nine years.

METHODS

HCV RNA was amplified by the polymerase chain reaction from 3161 serum samples from unselected, anti-HCV-positive individuals, and the HCV genotype was identified by a reverse hybridisation assay (line probe assay, LiPA). Samples came from 17 different regions of Spain and were obtained between January, 1996 and December, 2004.

RESULTS

The overall prevalence of HCV genotypes was: 1b, 41.3%; 1a, 24.1%; 3, 19.6%; 4, 11.6%; 2, 3.1%; and 5, 0.3%. The prevalence of genotypes 1a, 3 and 4 increased significantly among patients born after 1950, and that of genotype 1b decreased among them. These significant differences in regard to age were also observed among patients lacking notified high-risk factors. A main switch-up in prevalence of genotypes 1a and 3 was found when patients born in 1941-1950 were compared with those born in 1951-1960, but the same finding in genotype 4 was delayed to patients born in 1961-1970.

CONCLUSIONS

Two separate epidemics of HCV seem to have occurred in Spain during the last 30 years. The former one involved the spread of HCV genotypes 1a and 3. The second was more recent, and involved the spread of genotype 4.

Molecular epidemiology of hepatitis B virus in Spain: identification of viral genotypes and prediction of antigenic subtypes by limited sequencing

The hepatitis B virus (HBV) genotypes were studied by a line probe assay (LiPA) and by direct sequencing of a 339 nucleotide fragment from the S region of the viral genome in samples from 269 carriers living in Spain, either native to Spain (231) or immigrants from Africa, Asia, and Eastern Europe (38). The sequences were also used to predict the HBV surface antigen (HBsAg) subtype on the basis of the amino acids specified at selected positions of the HBsAg molecule. Agreement between the two genotyping methods was found in most cases (98.1%) and a HBV genotype could be assigned to all samples. The viral groups D/ayw2 (30.1%), D/ayw3 (28.6%), and A/adw2 (21.2%) were prevalent, with an additional participation of the groups D/ayw4 (4.8%), F/adw4q- (1.9%), A/ayw1 (1.9%), and D/adw3 (0.7%), all of them present among the autochthonous carriers. Strains from genotypes B and C were found exclusively among Chinese immigrants. Genotype E strains were found in immigrants from Central Africa and in one patient native of Spain. Point mutations leading to amino acid changes of residues involved in the expression of the HBsAg subtype determinants were found in 12 samples (4.5%). Some mutations would predict the putative novel genotype-subtype associations A/adw4q+, A/ayr, D/ayr, and E/ayw1, while others would suggest the loss of subtype-specific determinants. The finding of HBV strains characteristic for Africa among the autochthonous carriers confirms the emergence of African HBV strains in Spain.

Quantitation of cytomegalovirus DNA in cerebrospinal fluid and serum specimens from AIDS patients using a novel highly sensitive nested competitive PCR and the cobas amplicor CMV monitor

A novel nested quantitative-competitive polymerase chain reaction (nQC-PCR) assay was developed to quantify as few as ten copies per tube of human cytomegalovirus DNA with an overall dynamic range of 10-10(5) copies per tube. This nQC-PCR assay is based on co-amplification of a mimic DNA and it was evaluated with 26 cerebrospinal fluid (CSF) specimens and 44 serum specimens from 70 CMV-infected AIDS patients, 35 of them were diagnosed of CMV retinitis. An excellent correlation was found between nQC-PCR assay and the commercially available Cobas Amplicor CMV Monitor trade mark (CACM) assay (R = 0.9999; P < 0.001; n = 42). Moreover, 13 serum samples with CMV viral loads undetectable with the CACM were successfully quantified by nQC-PCR. CMV viral load was significantly higher in patients with CMV retinitis (P = 0.003). The nQC-PCR assay described below is a very sensitive test for accurate quantitative detection of CMV DNA in different clinical specimens that avoids the need for high-cost instrumentation.

Erradicación de la poliomielitis. Búsqueda y control de poliovirus salvajes almacenados en los laboratorios españoles

INTRODUCTION

An initiative to achieve global eradication of poliomyelitis was proposed in 1988. Since then, World Health Organization (WHO) efforts have been focused on reaching and maintaining high vaccination coverage and on implementing effective surveillance systems. Additionally, since 1998 the WHO has urged health authorities from countries over the world to locate and control the wild polioviruses stored in laboratories as well as potentially infectious materials that could contain these viruses or originate them under particular circumstances.

METHODS

In Spain the Wild Poliovirus Containment Plan was initiated in 1999. All Spanish laboratories were inventoried and a specially designed questionnaire was distributed to them. The responses were analyzed.

RESULTS

A total of 3209 laboratories were surveyed and 10 of them were found to contain infectious or potentially infectious material with wild poliovirus. The heads of these laboratories were informed about the Containment Plan and were requested to destroy this material under proper conditions. The laboratories that did not destroy the viruses adopted the BSL2/polio bio-safety measures.

CONCLUSION

Despite its complexity, the search process was completed within the schedule established by the WHO, thanks to the efforts of health authorities from the Autonomous Communities. Spain reported its results to the WHO Regional Commission for the Certification of Poliomyelitis Eradication in May 2002.

Molecular analysis of echovirus 13 isolates and aseptic meningitis, Spain

Echovirus 13 (EV13), considered rare, was reported worldwide in 2000, mostly related to aseptic meningitis outbreaks. In Spain, 135 EV13 isolates were identified. The genetic relationships between 64 representative strains from Spain and other reported isolates from the United States, Germany, Italy, Japan, and Sweden were described by analyzing the partial sequence of the major capsid protein (VP1) gene. The strains from Spain were clearly identified as EV13 (79.5% similarity with the EV13 reference strain) and were grouped phylogenetically into two different clusters (by origination on either the Iberian Peninsula or Canary Islands). Isolates from Germany from 2000 clustered with the Canary Islands group. The isolates from other countries obtained before 2000 were genetically distant. Changes in EV13 coding sequence involved several differences in the C-terminal extreme of the VP1 protein. Part of the neutralizing antigenic site III has been described in this genome region in poliovirus and swine vesicular disease virus.

First epidemic of aseptic meningitis due to echovirus type 13 among Spanish children

Echoviruses are the commonest cause of aseptic meningitis (AM). Echovirus type 13 (EV-13) was the second enterovirus serotype associated with different local outbreaks of AM in Spain between February and October 2000. It was the first time that an epidemic AM caused by this virus was recognized in Spain. The index case appeared in the Canary Islands (Canarias). The EV-13 virus was isolated from 135 patients, predominantly from cerebrospinal fluid (CSF). All isolates were from children under 13 years. The age specific peak incidence was in infants under 1 year. Most patients had fever, headache and other meningeal signs. This enterovirus serotype, not previously detected in Spain, caused severe illness with a high attack rate.

Screening of active lyssavirus infection in wild bat populations by viral RNA detection on oropharyngeal swabs

Brain analysis cannot be used for the investigation of active lyssavirus infection in healthy bats because most bat species are protected by conservation directives. Consequently, serology remains the only tool for performing virological studies on natural bat populations; however, the presence of antibodies merely reflects past exposure to the virus and is not a valid marker of active infection. This work describes a new nested reverse transcription (RT)-PCR technique specifically designed for the detection of the European bat virus 1 on oropharyngeal swabs obtained from bats but also able to amplify RNA from the remaining rabies-related lyssaviruses in brain samples. The technique was successfully used for surveillance of a serotine bat (Eptesicus serotinus) colony involved in a case of human exposure, in which 15 out of 71 oropharyngeal swabs were positive. Lyssavirus infection was detected on 13 oropharyngeal swabs but in only 5 brains out of the 34 animals from which simultaneous brain and oropharyngeal samples had been taken. The lyssavirus involved could be rapidly identified by automatic sequencing of the RT-PCR products obtained from 14 brains and three bat oropharyngeal swabs. In conclusion, RT-PCR using oropharyngeal swabs will permit screening of wild bat populations for active lyssavirus infection, for research or epidemiological purposes, in line not only with conservation policies but also in a more efficient manner than classical detection techniques used on the brain.