Hepatitis: Echevarría JM

León P, Echevarría JM. · No affiliation provided · Sangre (Barc). · Pubmed #10618905 No free full text.

This publication has no abstract.

Echevarría JM, Avellón A. · Unidad de Hepatitis Víricas, Servicio de Microbiología Diagnóstica, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, España. · Enferm Infecc Microbiol Clin. · Pubmed #19195449 links to  free full text

Abstract: Viral hepatitides are satisfactorily diagnosed in the laboratory by immunoassays for either antigen or antibody detection in serum samples. However, the early detection of acute infections during the window period, investigation of occult infections, and issues related to the establishment and follow-up of antiviral therapy in chronic infections pose new challenges that only molecular methods can meet. In addition, full characterization of epidemic outbreaks and surveillance of the emergence of viral variants able to escape from vaccine protection are major public health objectives that can only be achieved through the use of these techniques. As a further attempt to improve the viral safety of blood transfusions, the incorporation of molecular biology techniques into the routine work of transfusion centers has generated new technical and scientific demands on microbiology laboratories, which must in turn incorporate these methods to respond to the challenge. After more than a decade, automatic methods for the detection, quantification, characterization and sequencing of the genomes of these viruses have become a reality for the clinical laboratory, reaffirming the essential role of the microbiologist in the hospital setting.

Echevarría JM, León P. · Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, 28220, España. · Cad Saude Publica. · Pubmed #14999325 links to  free full text

Abstract: On the last twenty years, viral hepatitis has emerged as a serious problem in almost all the Amerindian communities studied in the Amazon Basin and in other Amazon-related ecological systems from the North and Center of South America. Studies performed on communities from Bolivia, Brazil, Colombia, Peru and Venezuela have shown a high endemicity of the hepatitis B virus (HBV) infection all over the region, which is frequently associated to a high prevalence of infection by hepatitis D virus among the chronic HBV carriers. Circulation of both agents responds mainly to horizontal virus transmission during childhood through mechanisms that are not fully understood. By contrast, infection by hepatitis C virus (HCV), which is present in all the urban areas of South America, is still very uncommon among them. At the moment, there is not data enough to evaluate properly the true incidence that such endemicity may have on the health of the populations affected. Since viral transmission might be operated by mechanisms that could not be acting in other areas of the World, it seems essential to investigate such mechanisms and to prevent the introduction of HCV into these populations, which consequences for health could be very serious.

León P, Venegas E, Bengoechea L, Rojas E, López JA, Elola C, Echevarría JM. · Instituto de Salud Carlos III, Centro Nacional de Microbiología, Madrid, España. · Rev Panam Salud Publica. · Pubmed #10355311 No free full text.

Abstract: In Bolivia, no studies have been carried out specifically on hepatitis viruses. Thus, their prevalence and circulation patterns are virtually unknown. A seroepidemiologic study was performed from 1992 to 1996 to generate a preliminary idea of the overall prevalence of infection from hepatitis B, C, D, and E viruses (HBV, HCV, HDV, and HEV, respectively) in different Bolivian population groups. Prompted by the data obtained in other areas of Latin America, the study focused on indigenous communities in the Amazon region. In rural areas of the high Andean plateau, HBV infection showed an overall prevalence compatible with medium to low endemicity (11.2%), and no carriers of HCV or HDV antibodies were found. In two high-risk groups in the city of Cochabamba (homeless children and sexual workers), the prevalence of HBV infection was similar (11.6%) and could be considered low by comparison to that of similar population groups in Latin American urban centers. The prevalence of HCV (one positive case, or 0.5%) was similar to that found in similar population groups, although the small number of samples precludes drawing more definite conclusions. As has been noted previously with similar communities in tropical areas of South America, HBV infection is highly endemic in indigenous populations of the Bolivian Amazon (with an overall prevalence of 74.0%), but circulation of HCV has not been detected. It is a well-known fact that HBV is horizontally transmitted and that transmission can take place very early in life, but the mechanisms involved are unknown. By 10 years of age, more than half the population has already had the natural infection that, in approximately 10 more years will have affected virtually the entire population. The very low rate of positivity to HBsAg (1.6%), the absence of viral DNA in samples showing isolated positivity to anti-HBc, and the high prevalence of anti-HBs among individuals who show markers for natural infection (92.4%) suggest vertical transmission plays no role in persistent endemicity. So far, no outbreak of HDV infection has been documented in these communities, but the high endemicity shown by HBV points to the possibility of future outbreaks. Results obtained with tests for the detection of antibodies against HEV suggest that this virus is circulating widely in Bolivia and that it could have caused recent outbreaks in Cochabamba state. Vaccination against HBV in endemic populations is recommended as a short-term measure. Also recommended are actively searching for outbreaks and sporadic cases of hepatitis E in the entire country and performing additional research that will help in assessing the public health consequences of the situation described in this article.

Fogeda M, de Ory F, Avellón A, Echevarría JM. · Service of Diagnostic Microbiology, National Centre of Microbiology, Instituto de Salud Carlos III, Madrid, Spain. · J Clin Virol. · Pubmed #19505848 No free full text.

Abstract: 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.

Monsalve-Castillo F, Echevarría JM, Atencio R, Suárez A, Estévez J, Costa-León L, Montiel P, Molero T, Zambrano M. · Facultad de Medicina, Universidad del Zulia, Calle 14 no. 15a-198, Lago Marbeach, Maracaibo, Venezuela. · Cad Saude Publica. · Pubmed #18461250 links to  free full text

Abstract: The aim of this study was to determine the prevalence of hepatitis B virus (HBV) infection in the Japreira indigenous community, Venezuela, and its relationship to age and gender. An intentional, non-probabilistic sample of 149 individuals was selected from a total of 300. All samples were studied for the presence of total HBV antibodies (total anti-HBc), and the positive samples were tested for HBV surface and "e" antigens (HBsAg, HBeAg). Overall prevalence rates of total anti-HBc were 72.9% in females and 81.1% in males. The highest prevalence of HBsAg was observed in males 26-35 years of age. Only four of the 44 HBsAg carriers were positive for HBeAg. The results showed a high endemic HBV infection rate and indicated that its spread begins at early ages. Sexual transmission may be the main route for spread of the virus. Crowding, close contact with bodily fluids, specific social practices, and features of the circulating viral strain among members of this community could be involved in the high chronicity observed in the Japreira indigenous community.

Echevarría JM, Avellón A. · Service of Diagnostic Microbiology, National Centre for Microbiology, Instituto de Salud Carlos III. Majadahonda, Madrid, Spain. · J Med Virol. · Pubmed #18297712 No free full text.

Abstract: 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.

Monsalve-Castillo F, Chacín-Bonilla L, Atencio RJ, Espinoza LP, Costa-León L, Echevarría JM. · Escuela de BioanálisisEstado Zulia, Venezuela. · Mem Inst Oswaldo Cruz. · Pubmed #17294009 links to  free full text

Abstract: Previous studies have not found hepatitis C virus (HCV) infection in Amerindians from Western Venezuela. A survey of 254 Bari and Yukpa natives aged 10-60 years (mean +/- SD age = 35 +/- 5.4 years) from four communities, two Bari and two Yukpa, in this area were studied to assess the prevalence of antibodies to HCV (anti-HCV) and HCV RNA among these indigenous populations. Serum samples were examined initially for anti-HCV by a four generation enzyme-linked immunosorbent assay (ELISA). Reactive samples were then tested using a third generation recombinant immunoblot assay (RIBA-3). Viral RNA was investigated in all immunoblot-reactive samples by a nested polymerase chain reaction (PCR) method. Six (2.3%) of 254 natives were positive by ELISA, one (2.2%) of these reactive samples were positive by RIBA, and four (1.5%) were indeterminate. Only two (0.8%) were positive by PCR, corresponding to 1 (2.1%) of 47 inhabitants of a Yukpa community and to 1 (2.2%) of 45 subjects of a Bari community. Iatrogenic is thought to play a role in acquisition of the infection. The findings indicate a HCV focus of low endemicity and are compatible with a low degree of exposures of the natives to the virus. Studies are necessary to assess the risk factors for infection in these Amerindians.

Echevarría JM, Avellón A. · Service of Diagnostic Microbiology, National Centre of Microbiology, Instituto de Salud Carlos III, Madrid, Spain. · J Med Virol. · Pubmed #16622876 No free full text.

Abstract: 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.

Echevarría JM, León P, Pozo F, Avellón A. · Servicio de Microbiología Diagnóstica, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain. · Enferm Infecc Microbiol Clin. · Pubmed #16537058 links to  free full text

Abstract: 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.

Echevarría JM, Avellón A, Jonas G, Hausmann M, Vockel A, Kapprell HP. · Service of Diagnostic Microbiology, National Centre of Microbiology, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid, Spain. · J Clin Virol. · Pubmed #16406797 No free full text.

Abstract: 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.

Echevarría JM, Avellón A, Magnius LO. · Service of Diagnostic Microbiology, National Centre of Microbiology, Instituto de Salud Carlos III, Madrid, Spain. · J Med Virol. · Pubmed #15834869 No free full text.

Abstract: 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.

Echevarría JM, León P. · Servicio de Microbiología Diagnóstica, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain. · Enferm Infecc Microbiol Clin. · Pubmed #15482686 links to  free full text

Abstract: Genotypes A and D of the hepatitis B virus were found to be prevalent among 278 chronic carriers residing in Spain, and genotypes B, C, E and F were detected with significant frequency (9%). Two genotype E infections corresponded to carriers born in Spain who had never traveled to Africa. These results indicate that genotype E is beginning to circulate in the Spanish population in the same way that genotype F did in the past.

Echevarría JM. · No affiliation provided · Enferm Infecc Microbiol Clin. · Pubmed #15207125 links to  free full text

This publication has no abstract.

León P, Pozo F, Echevarría JM. · Diagnostic Microbiology Department, National Center for Microbiology. Instituto de Salud Carlos III, Majadahonda, Madrid, Spain. · Enferm Infecc Microbiol Clin. · Pubmed #14987532 links to  free full text

Abstract: BACKGROUND: Treatment for chronic hepatitis B with lamivudine is often hampered by the emergence of point mutations in the YMDD motif of the HBV DNA polymerase gene that confer drug resistance. This usually occurs after several months of therapy, but early detection of lamivudine-resistant mutants has been reported among patients in South Korea. Data from Japan and France suggest that naturally occurring, lamivudine-resistant hepatitis B virus (HBV) variants can be found among chronic carriers who have never received lamivudine treatment. Famciclovir can be used as an alternative when lamivudine-resistant variants emerge, though the substitute treatment may also give rise to the emergence and selection of drug-resistant variants. METHODS: The presence of mutations related with lamivudine and famciclovir resistance was studied in serum samples from 79 randomly selected Spanish HBV carriers, using a line probe assay (LiPA) on HBV genome fragments amplified by polymerase chain reaction. Data concerning antiviral therapy prior to sampling were available for these patients. RESULTS: Mutations related with resistance to either drug were detected in ten patients. Three of them (3.8% of the 79 carriers studied) had no record of prior lamivudine or famciclovir treatment at the time of sampling. Wild-type strains together with either the rtM204I (M552I) or rtV207I (V555I) point mutation were found in two of these cases, and the rtV207I mutation alone was detected in the third. CONCLUSIONS: These findings seem to indicate that lamivudine and famciclovir-resistant variants circulate among Spanish HBV carriers. Since it is expected that antiviral therapy will be ineffective when drug-resistant variants are present before the beginning of treatment, it could be beneficial to test for these variants as an additional routine procedure when designing antiviral therapy on an individual basis.

Echevarría JM, León P, Pozo F. · Servicio de Microbiología Diagnóstica. Centro Nacional de Microbiología. Instituto de Salud Carlos III. Majadahonda. Madrid. España. · Enferm Infecc Microbiol Clin. · Pubmed #14757001 links to  free full text

Abstract: BACKGROUND: Reactivity for hepatitis B virus (HBV) surface antigen (HBsAg) in samples lacking antibody to the HBV core antigen (anti-HBc) may be due to either non-specific reactions or sample contamination, but it can also reflect other situations that may present clinical relevance. In Spain, the frequency described for this atypical pattern of HBV markers ranged from 0.05 to 1.3% in different series, so that it can be considered as moderately frequent. METHODS: Confirmatory assays for HBsAg and tests for detecting total and IgM anti-HBc, HBV "e" antigen and viral DNA were performed on serum samples taken from 96 patients who showed reactivity for HBsAg in absence of total anti-HBc on routine studies. These samples were collected between January, 2001 and May, 2002 and were sent for study from different Spanish laboratories. Follow-up samples were also studied from selected cases. RESULTS: Presence of HBsAg was excluded in 70 cases (72.9%) and total anti-HBc was detected in two additional patients, so that the original results were confirmed in 24 patients (25.0%). After further investigations, two early phases of the window period of the acute HBV infection were identified, as well as a further case of chronic HBV carriage in absence of antibody response. A single case could be confirmed as due to a contamination of the aliquot of sample studied. The pattern of HBV markers and its evolution on the follow-up were the characteristic of the phenomenon known as "hepatitis B virus type 2 infection" in eight patients. No conclusions could be drawn from the remainder 12 cases, since no follow-up samples were available for study. CONCLUSIONS: Besides most cases respond to non-specific reactions or reflect situations of low clinical relevance, the reactivity for HBsAg in samples lacking anti-HBc should be taken into consideration and routinely investigated, since this atypical pattern can also reflect unusual, but clinically relevant facts of the HBV infection that must be noticed.

Echevarría JM. · Servicio de Microbiología Diagnóstica, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid. · Enferm Infecc Microbiol Clin. · Pubmed #11149171 links to  free full text

This publication has no abstract.

León P, López JA, Amela C, Elola C, Echevarría JM. · Servicio de Microbiología Diagnóstica, Centro Nacional de Epidemiología, Madrid. · Enferm Infecc Microbiol Clin. · Pubmed #10614078 No free full text.

Abstract: BACKGROUND: The prevalences established up to the present in Spain for the different types of hepatitis C virus are based on data obtained in populations in which the nature of the population itself may have based the data in favor of certain types of the virus. The study of seropositive blood donors identified through screening of blood donations may provide prevalences closer to the truth among the general population. MATERIALS AND METHODS: Typing of genomes in samples from 441 donors was performed using the blood bank generated during the multicenter study performed by the Spanish Study Group of Blood Donors with Risk of Transmission of the Hepatitis C Virus. The antibodies present were typed in the seropositive samples in the above donors and in 337 more in whom a viral genoma was not detected. RESULTS: In total, the infection was typed in 685 donors. On analysis of the results corresponding to 386 donors, whose number and distribution by autonomous communities were previously fixed to represent all of Spain, type 1 was largely the more prevalent (85.5%) followed by types 3 (4.4%), 2 (4.1%), 4 (3.4%) and 5 (0.5%) and by a group of apparent mixed infections which altogether represented 2.1% of the total. Among the donors in whom the genomes were typed, infectious due to the 1b subtype (78% of the 441 samples genotypes) clearly predominated. The participation of the different types of type 1 was significantly greater in those lacking antibodies detectable versus epitopes codified in the NS4 region of the viral genome. CONCLUSIONS: This study avoids some bias in sampling which may have affected previous studies and provides data which should more closely approach the real prevalence in the general Spanish population. Thus, it should provide a better base of comparison for any study on the distribution of the types of the hepatitis C virus in selected populations or others performed during tha investigation of outbreaks of hepatitis C virus infection.