Pertussis seroprevalence among adults of reproductive age (20-39 years) in fourteen European countries.

The reported incidence of pertussis in European countries varies considerably. We aimed to study specific Bordetella pertussis seroprevalence in Europe by measuring serum IgG antibody levels to pertussis toxin (anti-PT IgG). Fourteen national laboratories participated in this study including Belgium, Denmark, Finland, Greece, Hungary, Italy, Lithuania, Malta, Norway, Poland, Portugal, Romania, Spain, and Sweden. Each country collected approximately 250 samples (N = 7903) from the age groups 20-29 years (N = 3976) and 30-39 years (N = 3927) during 2010-2013. Samples were anonymous residual sera from diagnostic laboratories and were analyzed at the national laboratories by a Swedish reference method, a commercial ELISA kit, or were sent to Sweden for analysis. The median anti-PT IgG concentrations ranged from 4 to 13.6 IU/mL. The proportion of samples with anti-PT IgG ≥100 IU/mL, indicating a recent infection ranged from 0.2% (Hungary) to 5.7% (Portugal). The highest proportion of sera with anti-PT IgG levels between 50 and <100 IU/mL, indicating an infection within the last few years, was found in Portugal (12.3%) and Italy (13.9%). This study shows that the circulation of B. pertussis is quite extensive in adults, aged 20-39 years, despite well-established vaccination programs in Europe.

New circulation of genotype V of Crimean-Congo haemorrhagic fever virus in humans from Spain.

BACKGROUND: Crimean-Congo haemorrhagic fever (CCHF) is a widespread tick-borne viral disease caused by the Crimean-Congo haemorrhagic fever virus (CCHFV). CCHFV has been implicated in severe viral haemorrhagic fever outbreaks. During the summer of 2016, the first two cases with genotype III (Africa 3) were reported in Spain. The first objective of our study was to determine the presence of CCHFV among patients with febrile illness during the spring and summer periods in 2017 and 2018. Finally, we perform a phylogenetic analysis to determine the genotype of the virus. METHODOLOGY: We prospectively evaluated patients aged 18 years and older who came to the emergency department at the Salamanca's University Hospital (HUS) with fever. Specific IgM and IgG antibodies against CCHFV by ELISA and one immunofluorescence assay against two different proteins (nucleoprotein and glycoprotein C) was done. Moreover, molecular detection by Real Time PCR was performed in all collected samples. A phylogenetic analysis was carried out to genetically characterize CCHFV detected in this study. PRINCIPAL FINDINGS: A total of 133 patients were selected. The mean age was 67.63 years and 60.9% were male. One-third of the patients presented an acute undifferentiated febrile illness. Three patients had anti-CCHFV IgG antibodies, suggesting a previous infection. One patient had anti-CCHFV IgM antibodies and a confirmatory RT-PCR. Phylogenetic analysis indicated that the virus corresponds to the European genotype V. This patient came to the emergency department at HUS in August 2018 presenting an acute febrile syndrome with thrombopenia and liver impairment. CONCLUSIONS: We describe a new circulation of European genotype V CCHFV in Spain. Moreover, this study suggests that CCHFV is an identifiable cause of febrile illness of unknown origin in Spain. Thus, CCHF could be suspected in patients with fever, liver damage, and/or haemorrhagic disorders, particularly in people with risk activities who present in the spring or summer.

Crimean-Congo haemorrhagic fever (CCHF) virus-specific antibody detection in blood donors, Castile-León, Spain, 2017 and 2018.

BackgroundCrimean-Congo haemorrhagic fever virus (CCHFV) is considered an emerging or even a probable re-emerging pathogen in southern Europe. Presence of this virus had been reported previously in Spain in 2010.AimWe aimed to evaluate the potential circulation of CCHFV in western Spain with a serosurvey in asymptomatic adults (blood donors).MethodsDuring 2017 and 2018, we conducted a CCHFV serosurvey in randomly selected asymptomatic blood donors from western Spain. Three assays using specific IgG antibodies against CCHFV were performed: the VectoCrimea ELISA test, an in-house ELISA and indirect immunofluorescence (EuroImmun) test with glycoprotein and nucleoprotein.ResultsA total of 516 blood donors participated in this cross-sectional study. The majority of the study participants were male (68.4%), and the mean age was 46.3 years. Most of the participants came from rural areas (86.8%) and 68.6% had contact with animals and 20.9% had animal husbandry practices. One in five participants (109/516, 21.1%) were engaged in at-risk professional activities such as agriculture and shepherding, slaughtering, hunting, veterinary and healthcare work (mainly nursing staff and laboratory technicians). A total of 15.3% of the participants were bitten by ticks in the days or months before the date of sampling. We detected anti-CCHFV IgG antibodies with two diagnostic assays in three of the 516 individuals and with one diagnostic assay in six of the 516 individuals.ConclusionSeroprevalence of CCHFV was between 0.58% and 1.16% in Castile-León, Spain. This is the first study in western Spain that showed circulation of CCHFV in healthy people.

[Methodology of the 2nd seroprevalence study in Spain]. / Metodología del 2º estudio de seroprevalencia en España.

Seroprevalence studies are designed in population samples to assess the level and distribution of immunity induced by natural infection of certain infectious agents or by immunization against them. The purpose of the 2nd Seroprevalence Study in Spain is to assess the prevalence and distribution of immune status against vaccine-preventable diseases and generated by natural infection by other microorganisms. Pathologies specifically included in the study are: poliomyelitis, diphtheria, tetanus, pertussis, measles, rubella, mumps, varicella, invasive meningococcal disease by serogroup C, hepatitis A, hepatitis B, hepatitis E, hepatitis C and HIV. The study has a similar design of that conducted in 1996, as it is a descriptive cross-sectional study in resident population of 2 to 80 years of age in Spain. Two-stage conglomerate sampling was carried out on the population aged 2 to 80 years living in Spain, with an initial sample size of 10,000 people. The methodology of the study is described in this article.

Los estudios de seroprevalencia se elaboran en muestras poblacionales con el fin de investigar el nivel y distribución de la inmunidad inducida por infección natural de determinados agentes infecciosos o por vacunación frente a los mismos. El 2º Estudio de Seroprevalencia en España tiene el objetivo de estimar la prevalencia y distribución del estado inmune frente a las enfermedades inmunoprevenibles y de la generada por infección natural por otros microrganismos. En concreto, las patologías incluidas en el estudio son: poliomielitis, difteria, tétanos, tosferina, sarampión, rubéola, parotiditis, varicela, enfermedad meningocócica invasora por serogrupo C, hepatitis A, hepatitis B, hepatitis C, hepatitis E e infección por virus de la inmunodeficiencia humana (VIH). Para ello, se ha diseñado un estudio similar al realizado en 1996, observacional de tipo transversal en la población residente en España de 2 a 80 años de edad. Se ha realizado un muestreo por conglomerados bietápico de la población de 2 a 80 años residente en España, con un tamaño muestral inicial de 10.000 personas. En este artículo se describe la metodología utilizada en la realización del estudio.

[Serological diagnosis of congenital infections and algorithms to improve diagnostic efficacy]. / Diagnóstico serológico de las infecciones congénitas y algoritmos para mejorar la eficacia diagnóstica.

Congenital infection is those transmitted by the mother to the fetus before delivery. It can occur transplacentally or by direct contact with the pathogen during birth or in the immediate postnatal period. Congenital infection can be due to viruses (rubella, cytomegalovirus, herpes simplex, varicella-zoster, hepatitis B and C virus, human inunodeficiencia, erythrovirus B19) as bacteria (Treponema pallidum) and parasites (Toxoplasma gondii and Trypanosoma cruzi). Serological diagnosis of congenital infection is based on both the knowledge of infectious serology in the mother, including the systematic serological screening and diagnostic aspects of the determination of IgM and confirmatory methods, IgG avidity tests, establishment of antibody profiles, and in the diagnosis the neonate. Serological diagnosis of congenital infection in the newborn is mainly based on the detection of specific IgM usually by immunoenzymatic assays or immunochemiluminescence techniques. In some instances it is important to perform the serological follow up of the newborn to confirm the congenital infection.

Diagnóstico serológico de las infecciones congénitas y algoritmos para mejorar la eficacia diagnóstica / Serological diagnosis of congenital infections and algorithms to improve diagnostic efficacy

Puede ocurrir por vía transplacentaria o por contacto directo con el patógeno durante el parto o en el período posnatal. Se puede producir infección congénita tanto por virus (rubéola, citomegalovirus, herpes simple, varicela-zóster, hepatitis B y C, virus de la inmunodeficiencia humana, erythrovirus B19) como por bacterias (Treponema pallidum) y parásitos (Toxoplasma gondii y Trypanosoma cruzi). El diagnóstico serológico de la infección congénita se basa tanto en el conocimiento de la serología infecciosa en la madre, incluyendo el control serológico sistemático y aspectos del diagnóstico por determinación de IgM y métodos confirmatorios, como los ensayos de avidez de IgG o el establecimiento de perfiles de anticuerpos, como en el diagnóstico en el neonato. El diagnóstico serológico de la infección congénita en el recién nacido se basa fundamentalmente en la detección de IgM específica, generalmente mediante técnicas inmunoenzimáticas o de inmunoquimioluminiscencia; en ocasiones es de importancia realizar el seguimiento serológico del recién nacido para confirmar la infección congénita

Congenital infection is those transmitted by the mother to the fetus before delivery. It can occur transplacentally or by direct contact with the pathogen during birth or in the immediate postnatal period. Congenital infection can be due to viruses (rubella, cytomegalovirus, herpes simplex, varicella-zoster, hepatitis B and C virus, human inunodeficiencia, erythrovirus B19) as bacteria (Treponema pallidum) and parasites (Toxoplasma gondii and Trypanosoma cruzi). Serological diagnosis of congenital infection is based on both the knowledge of infectious serology in the mother, including the systematic serological screening and diagnostic aspects of the determination of IgM and confirmatory methods, IgG avidity tests, establishment of antibody profiles, and in the diagnosis the neonate. Serological diagnosis of congenital infection in the newborn is mainly based on the detection of specific IgM usually by immunoenzymatic assays or immunochemiluminescence techniques. In some instances it is important to perform the serological follow up of the newborn to confirm the congenital infection

[Microbiological diagnosis of emerging arboviral and rodent borne diseases]. / Diagnóstico microbiológico de arbovirosis y robovirosis emergentes.

Vector borne viruses (VBV) include viruses transmitted by arthropods, rodents and other animals. In Spain the three main autochthonous VBVs causing human diseases are: Toscana, West Nile and Lymphocytic Choriomeningitis viruses. There are also other imported viruses that are potential threats to our public health, due to the presence of competent transmission vectors (dengue and chikungunya viruses in areas infested with Aedes albopictus), or due to the potential person-to-person transmission (Lassa and other viruses causing haemorrhagic fever). The Spanish Society for Infectious Diseases and Clinical Microbiology has responded to the emergence of VBVs by publishing a special issue of Microbiological Proceedings focused on the diagnosis of those emerging vector borne viruses of major concern in our country.

Lymphocytic choriomeningitis virus-associated meningitis, southern Spain.

Lymphocytic choriomeningitis virus (LCMV) was detected in 2 patients with acute meningitis in southern Spain within a 3-year period. Although the prevalence of LCMV infection was low (2 [1.3%] of 159 meningitis patients), it represents 2.9% of all pathogens detected. LCMV is a noteworthy agent of neurologic illness in immunocompetent persons.

Comparison of IgG avidity assays in the confirmation of the diagnosis of cytomegalovirus primary infection.

We have compared three ELISA techniques and one chemiluminescence immunoassay technique for determining cytomegalovirus (CMV) immunoglobulin G (IgG) avidity in serum samples from patients with recent and past CMV infections. Sensitivity varied from 84.6% to 100%; and specificity from 78.6% to 100%. IgG avidity assays appear to be adequate additional tools for characterizing CMV infections.

[Seroepidemiological surveys of non vaccine-preventable diseases and their interest in public health]. / Encuestas seroepidemiológicas en enfermedades no inmunoprevenibles y su interés en salud pública.

Seroepidemiological surveys are epidemiological studies carried out by the use of serum tests to detect infection; they can be applied to infections in general and to vaccine-preventable diseases in particular. Among other applications, seroepidemiological studies are useful for determining groups at risk for a specific disease; evaluating transmission mechanisms; and determining population groups who are critical in maintaining the transmission of infectious agents. We analysed the results of seroprevalence studies in Spain on vertically-transmitted non vaccine-preventable diseases (Toxoplasma gondii, Treponema pallidum, cytomegalovirus, herpes simplex virus type 2, and parvovirus human B19), blood-borne diseases (hepatitis C virus, human immunodeficiency virus and Trypanosoma cruzi) and emerging diseases (West Nile virus, Toscana virus, and lymphocytic choriomeningitis virus). We found a reduced seroprevalence against Toxoplasma gondii, Treponema pallidum, cytomegalovirus and human immunodeficiency virus in the Spanish indigenous population. The results found in immigrants reflect the situation of these diseases in their countries of origin and suggest they could have a substantial public health impact in Spain (Trypanosoma cruzi, in association with blood donation). We highlight the circulation in Spain of the West Nile virus and the importance of Toscana virus infection.

Synthesis of recombinant human parainfluenza virus 1 and 3 nucleocapsid proteins in yeast Saccharomyces cerevisiae.

Human parainfluenza virus types 1 and 3 (HPIV1 and HPIV3, respectively), members of the virus family Paramyxoviridae, are common causes of lower respiratory tract infections in infants, young children, the immunocompromised, the chronically ill, and the elderly. In order to synthesize recombinant HPIV1 and HPIV3 nucleocapsid proteins, the coding sequences were cloned into the yeast Saccharomyces cerevisiae expression vector pFGG3 under control of GAL7 promoter. A high level of recombinant virus nucleocapsid proteins expression (20-24 mg l(-1) of yeast culture) was obtained. Electron microscopy demonstrated the assembly of typical herring-bone structures of purified recombinant nucleocapsid proteins, characteristic for other paramyxoviruses. These structures contained host RNA, which was resistant to RNase treatment. The nucleocapsid proteins were stable in yeast and were easily purified by caesium chloride gradient ultracentrifugation. Therefore, this system proved to be simple, efficient and cost-effective, suitable for high-level production of parainfluenza virus nucleocapsids as nucleocapsid-like particles. When used as coating antigens in an indirect ELISA, the recombinant N proteins reacted with sera of patients infected with HPIV1 or 3. Serological assays to detect HPIV-specific antibodies could be designed on this basis.

[Age-dependent seroprevalence of Toscana virus in the Community of Madrid: 1993-1994 and 1999-2000]. / Seroprevalencia edad dependiente frente al virus Toscana en la Comunidad de Madrid: años 1993-1994 y 1999-2000.

OBJECTIVE: The aim of this study was to assess the seroprevalence of Toscana virus (TOSV) in the Community of Madrid. METHODS: Samples from two serosurveys obtained during 1993-1994 (2262 individuals) and 1999-2000 (1945 individuals) were studied. Samples were tested by ELISA for TOSV IgG detection. RESULTS: The seroprevalence of TOSV IgG was significantly higher in 1993-1994 (7.2%; 95% CI 6.2-8.4) than in 1999-2000 (5.7%; 95% CI 4.7-6.9) (chi-square, p < 0.05). In both periods, the prevalence increased significantly with age. CONCLUSION: These results confirm that TOSV has been circulating in the Community of Madrid over the last years.

Detection of secondary mumps vaccine failure by means of avidity testing for specific immunoglobulin G.

The aim of this study was to discriminate between primary and secondary vaccine failure in children with mumps using IgG avidity testing. Thirty-nine serum samples from children with mumps, confirmed by specific IgM, were studied. The patients were grouped according to their immunization status. The secondary immune response was defined by IgG with an avidity index >32%. A secondary response in infected children previously immunized was considered as a secondary vaccine failure. Vaccinated children presented higher IgG titers and IgG avidity than unvaccinated children. The proportion of secondary immune responses in unvaccinated patients was lower than that obtained in previously vaccinated infected patients. Avidity testing can be a useful tool to detect secondary vaccine failure in mumps.

[Pertussis outbreak in a poorly immunized community]. / Brote de tos ferina en una comunidad insuficientemente vacunada.

BACKGROUND: The aim of this study was to describe the clinical, serological and epidemiological findings of a pertussis outbreak in an insufficiently vaccinated gipsy community. PATIENTS AND METHOD: Ten cases (catarrhal illness with cough of 2 weeks duration) were identified through an active search. In four of them, two paired serum samples were obtained and total IgG against Bordetella pertussis and IgG and IgA against pertussis toxin (PT) and filamentous hemagglutinin (FHA) were determined. The diagnostic criteria was seroconversion. A comparative analysis between cases and healthy children younger than 15 years (gipsy community) was carried out and we estimated, by means of a logistical regression analysis, the odds ratio (OR) of several factors. RESULTS: The highest attack rate (50%) was found in the 5 to 9 year-old group; 30% cases had not been vaccinated while 50% had been incorrectly vaccinated. No significant differences for age, gender or the vaccine status were detected. Three cases showed seroconversion for total IgG and two for IgG-PT and IgA-PT. Other possible pathogens were ruled out by serology. CONCLUSIONS: Despite the high vaccine coverage against pertussis in paediatric age in Spain, some susceptible population groups remain, mainly due to an incorrect vaccination. Our serological results firmly support the suspicion of B. pertussis as the etiologic agent of the outbreak.

[Laboratory diagnosis of pertussis. Role of serology]. / Diagnóstico de laboratorio de tos ferina. Papel de la serología.

Culture is the reference method for the diagnosis of infection by Bordetella pertussis. Nevertheless, delayed sample collection and previous antibiotic treatment can limit culture sensitivity. In principle, direct immunofluorescence provides immediate diagnosis. It is, however, a subjective procedure that shows low sensitivity and specificity. PCR techniques increase culture sensitivity while maintaining high specificity, but their performance decreases along the evolution of the disease. Serologic methods are the main alternative for cases in which diagnosis is delayed. Current recommendations center on ELISA techniques that include purified antigens, such as filamentous hemaglutinin, and particularly, pertussis toxin. Traditionally, serological diagnosis requires confirmation by demonstrated seroconversion, but now the possibility of diagnosis based on titration of a single serum sample is being evaluated.