Pilar León

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 (κ index ≤ 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.

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.

Epidemiology of viruses causing chronic hepatitis among populations from the Amazon Basin and related ecosystems

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.

Diagnosis ofMycoplasma pneumoniae infection by microparticle aggluination and antibody-capture enzyme-immunoassay

The performance of two new commercial assays for the serological diagnosis ofMycoplasma pneumoniae infection (microparticle agglutination and antibody-capture enzyme-immunoassay) was studied using a panel of 169 serum samples from patients withMycoplasma pneumoniae pneumonia and a control group. Both assays were shown to be sensitive and specific for diagnosis. The performance of the capture immunoassay, however, decreased in older patients, probably due to its inability to detect cases of reinfection without IgM antibody response.

Prevalencia de las infecciones por virus de las hepatitis B, C, D y E en Bolivia

En Bolivia no se han realizado estudios especificos sobre los virus de la hepatitis, por lo que su prevalencia y patrones de circulacion son practicamente desconocidos. De 1992 a 1996 se realizo un estudio seroepidemiologico con el fin de adquirir una primera vision de conjunto sobre las prevalencias de las infecciones por virus de la hepatitis B (VHB), C (VHC), D (VHD) y E (VHE) en distintas poblaciones de Bolivia. Sobre la base de los datos obtenidos en otros lugares de America Latina, se presto atencion especial al estudio de las comunidades autoctonas de la region amazonica. En las zonas rurales del altiplano andino, la infeccion por VHB presento una prevalencia general que corresponderia a una situacion de endemia media o baja (11,2%) y no se encontro ningun portador de anticuerpos contra VHC o VHD. En dos poblaciones de alto riesgo de la ciudad de Cochabamba (ninos sin hogar y trabajadoras del sexo), la prevalencia de infeccion por VHB fue similar (11,6%) y podria considerarse baja en comparacion con la de otras poblaciones analogas de nucleos urbanos en America Latina. La correspondiente al VHC (un caso positivo, 0,5%) seria parecida a la descrita en esas mismas poblaciones, si bien el escaso numero de muestras estudiadas no permite extraer conclusiones mas firmes. En concordancia con observaciones anteriores de comunidades similares de zonas tropicales de Suramerica, en las poblaciones autoctonas de la Amazonia boliviana la infeccion por VHB es sumamente endemica (prevalencia general de 74,0%), pero no se ha detectado la circulacion de VHC. Se sabe que la transmision de VHB es horizontal y tiene lugar desde edades muy tempranas, pero se desconocen los mecanismos de esa actividad. A los 10 anos de edad, mas de la mitad de la poblacion ya ha experimentado la infeccion natural que, 10 anos mas tarde, se habra difundido a practicamente toda la poblacion. La tasa muy baja de individuos positivos al HbsAg (1,6%), la ausencia de ADN virico en las muestras con reactividad aislada a anti-HBc y la alta prevalencia de anti-HBs entre los individuos que presentan marcadores de infeccion natural (92,4%) excluyen la participacion de la transmision vertical en el mantenimiento de la endemia. Hasta el momento, no se ha documentado ningun brote de infeccion por VHD en estas comunidades, pero la alta endemia de infeccion por VHB alerta sobre el riesgo de posibles brotes en el futuro. Los resultados obtenidos con las pruebas de anticuerpos contra VHE sugieren que este virus circula ampliamente en Bolivia y que podria haber producido brotes recientes en el departamento de Cochabamba. Se recomienda vacunar contra VHB en las poblaciones endemicas como medida de corto plazo; buscar activamente en todo el pais brotes y casos esporadicos de hepatitis E y continuar realizando estudios que permitan evaluar las repercusiones sanitarias de la situacion documentada en este estudio.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.

Detection of hepatitis B virus variants resistant to lamivudine and famciclovir among randomly selected chronic carriers from Spain

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.

Hepatitis B virus genotypes identified by a Line Probe Assay (LiPA) among chronic carriers from Spain

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.

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.

Use of Overlapping Synthetic Peptides to Characterize Samples from Blood Donors with Indeterminate Results to Hepatitis C Virus Core Antigen

Background and Objectives: Despite recent improvements in supplemental assays, isolated reactivity to the hepatitis C virus (HCV) core antigen continues as one of the main problems in the confirmation of anti-HCV in blood donors. Reactivity against individual peptides from the c22-3 HCV recombinant antigen has been described as a useful tool for anti-HCV confirmation and donor counseling in such cases. Materials and Methods: We used a previously described set of overlapping peptides spanning the entire sequence of the c22-3 antigen to study 87 single serum samples from blood donors with reactivity for c22-3 antigen alone in second generation recombinant immunoblot assay (RIBA-2). All of them had been previously studied by RIBA-3, anti-HCV E2 EIA and HCV PCR. Results: 66 of the 87 samples studied could be classified as positive or negative for anti-HCV core using the multipeptide assay and such classification correlated well with the results obtained with RIBA-3 and the anti-E2 EIA. However, some discrepancies were found. The epitopes located along the N-terminal half of the molecule were mainly responsible for the specific antibody recognition but those enclosed within amino acids 1–15 were frequently involved in nonspecific reactivity. Some 38% of samples were considered to have specific antibody to the c22-3 antigen and a further 9% reacted for both anti-E2 and single core peptides that were often involved in specific antibody recognision. Conclusion: Testing of blood donor samples indeterminate to the HCV c22-3 antigen for reactivity against individual core peptides can confirm the presence of specific antibody and recognize nonspecific reactivity with certain cross-reacting epitopes. Third generation supplemental tests have reduced such false reactivity, but confirmation of samples with anticore alone is still necessary. Single reactivity to the HCV core antigen is likely to reflect prior exposure to the virus, but rarely active infection, either acute or chronic.

Typing of hepatitis C virus antibody with specific peptides in seropositive blood donors and comparison with genotyping of viral RNA

Background and objectives: Serotyping of antibody to hepatitis C virus (anti‐HCV) with specific peptides has been developed as an alternate method for typing HCV infections. The method does not require a prior amplification of viral RNA sequences from the sample. Identification of the viral genotype may be relevant for prognosis and clinical management. Materials and methods: We used a previously described HCV serotyping assay (RIBA™ HCV Serotype SIA kit, Chiron Corp.) to investigate the serotype in 191 samples from blood donors selected for anti‐HCV patterns (positive and indeterminate), ALT levels, and the presence or absence of viral RNA. The serotypes were compared with the genotypes obtained from typing the 5′‐noncoding region of the viral RNA in 82 viremic samples. Results: We were able to obtain the viral serotype in 85% (114/134) of samples positive for anti‐HCV but in only 3.5% (2/57) of the indeterminates. Lack of anti‐NS4 in the sample was significantly associated with both untypable results and the presence of HCV serotypes other than serotype 1. The overall correlation with genotyping was 78% (64/82), rising to 95.5% (64/67) if only samples that could be both genotyped and serotyped were considered. The assay was easy to perform, gave reactivity patterns easy to interpret, and performed with high proficiency on anti‐HCV‐positive samples lacking detectable levels of viral RNA. Conclusions: This is a practical and useful method for typing HCV infections in the clinical setting. The poor ability of the Core peptides to give the serotype in samples lacking anti‐NS4 and the lack of specific peptides to recognize HCV types other than 1, 2, and 3 are, however, some aspects of the method that need improvement in the future.