Características de recién nacidos hijos de madre con IgM positiva para el Virus Herpes Simplex

Introducción: El herpes connatal es una entidad infrecuente asociada a elevada morbimortalidad. La probabilidad de transmisión al recién nacido va de 5% al 85%. El diagnóstico se dificulta por falta de clínica, serología no confiable y por la no disponibilidad de PCR en los servicios públicos de países en vías de desarrollo. La IgM en gestantes podría ser utilizada como un marcador de sospecha para evaluar al neonato. Objetivo: Caracterizar a los recién nacidos, hijos de gestantes con IgM positiva para HVS 1-2 y la frecuencia de encefalitis en los infantes. Materiales y métodos : Estudio observacional, descriptivo, prospectivo, realizado de mayo de 2020 a octubre de 2021. Se incluyeron recién nacidos (RN) de madres con IgM positiva para Herpes Virus Simplex (HVS) a partir de la segunda mitad del embarazo. En el RN se realizó serología IgG e IgM, y además, PCR- RT para HVS 1-2 en sangre y/o LCR, excluyéndose los nacidos en otras maternidades y/o sin datos de serología materna. Resultados: 36 pacientes. Edad materna 28 años (DS + 4), 5% con antecedentes de HVS, 61% cesárea. 36% prematuros, 13% RCIU. Síntomas agudos en el RN 22%. De ellos, 19% plaquetopenia, 44% alteración de GOT. 63% PCR HVS en sangre y 44% en LCR. Se encontró hemorragia, hidrocefalia, leucomalacia en 27%. No se encontró diferencias en la expresión clínica por tipo de parto. Conclusiones: Los RN hijos de gestantes con IgM positiva para VHS desde la segunda mitad del embarazo o periparto, presentaron infección por VHS determinada por PCR en sangre o LCR, independiente de la vía del parto. El diagnóstico serológico en embarazadas permite la pesquisa, diagnóstico y tratamiento temprano del RN.

Introduction: neonatal herpes is a rare entity associated with high morbidity and mortality. The probability of transmission to the newborn ranges from 5% to 85%. The diagnosis is difficult due to the lack of clinical signs, unreliable serology and the non-availability of PCR in public services in developing countries. IgM in pregnant women could be used as a suspected marker to evaluate the neonate. Objective: To characterize newborn children of pregnant women with positive IgM for HSV 1-2 and the prevalence of encephalitis in infants. Materials and methods: Observational, descriptive, prospective study, carried out from May 2020 to October 2021. Newborns (NB) of mothers with positive IgM for Herpes Virus Simplex (HSV) from the second half of pregnancy were included. In newborns, IgG and IgM were performed, and in addition, PCR-RT for HSV 1-2 in blood and/or CSF, excluding those born in other hospitales and/or without maternal serology data. Results: We included 36 patients. Maternal age was 28 years (DS + 4), 5% with a history of HSV. 61% were delivered via cesarean section, 36% were premature, 13% had IUGR. 22% of the newborns had acute symptoms. 19% had thrombocytopenia, 44% had GOT alteration. 63% were PCR positive for HSV in serum and 44% were CSF-positive. Hemorrhage, hydrocephalus and leukomalacia were found in 27%. No differences were found in clinical expression by type of delivery. Conclusions: Newborns born to pregnant women with positive IgM for HSV from the second half of pregnancy or peripartum, presented HSV infection as determined by PCR in blood or CSF, regardless of the route of delivery. Serological diagnosis in pregnant women allows early screening, diagnosis and treatment of the NB.

Performance of Chimeric Trypanosoma cruzi Antigens in Serological Screening for Chagas Disease in Blood Banks.

Chagas disease (CD) is among the top 10 causes of inability to blood donation. Blood donation centers screen for anti-Trypanosoma cruzi antibodies using highly sensitive immunoenzymatic (ELISA) or chemiluminescent methods, which can lead to false positive results. Since positive samples cannot be used, to avoid the loss of valuable blood donations, it is necessary to improve specificity without reducing the sensitivity of the tests used for blood screening. For this purpose, our group has developed four chimeric proteins (IBMP-8.1, IBMP-8.2, IBMP-8.3, and IBMP-8.4) that have been evaluated in phase I and II studies with high performance and low cross-reactivity rates. The study included a panel of 5,014 serum samples collected from volunteer blood donors at the Hematology and Hemotherapy Foundation of the State of Bahia (Brazil). They were subjected to the detection of anti-T. cruzi antibodies, using all four IBMP antigens individually and latent class analysis (LCA) as a reference test, since there is no gold standard test for this purpose. Considering the sample size analyzed, LCA classified 4,993 (99.6%) samples as T. cruzi-negative and 21 (0.42%) as T. cruzi-positive. Sensitivity values ranged from 85.71% for IBMP-8.1 and 90.48% for IBMP-8.2-95.24% for IBMP-8.3 and 100% for IBMP-8.4, while specificity ranged from 99.98% for IBMP-8.3 and IBMP-8.4-100% for IBMP-8.1 and IBMP-8.2. Accuracy values ranged from 99.4 to 99.98%. The pretest probability for the molecules was 0.42, whereas the positive posttest probability ranged from 95.24 to 99.95% and the negative posttest probability ranged from 0.00001 to 0.0006% for all antigens. The higher odds ratio diagnosis was found for IBMP-8.4, which has been shown to be a safe single antigen for serological screening of CD in blood samples. The use of chimeric IBMP antigens is an alternative to reduce the number of bags discarded due to false-positive results. These molecules have high diagnostic performance and were shown to be suitable for use in screening CD in blood banks, isolated (IBMP-8.4) or in combination; and their use in blood banks could significantly reduce unnecessary disposal of blood bags or the risk of T. cruzi transmission.

Assessment of Liaison XL Murex Chagas diagnostic performance in blood screening for Chagas disease using a reference array of chimeric antigens.

BACKGROUND: Chagas disease (CD) serological screening at blood banks is usually performed by a single highly sensitive serological assay, with chemiluminescent immunoassays (CLIAs) being the method of choice. CLIAs employ recombinant, fusion peptides and/or chimeric antigens that selectively capture anti-Trypanosoma cruzi antibodies. However, despite high sensitivity, the ability of these tests to identify CD-positive cases should be evaluated against T. cruzi strains circulating in specific locales. Herein, we used a latent class analysis (LCA) approach employing an array of four chimeric antigens to assess the diagnostic performance of the Liaison XL Murex Chagas CLIA for the detection of anti-T. cruzi IgG in serum samples. STUDY DESIGN AND METHODS: The study included a panel of 5014 serum samples collected from volunteer blood donors at the Hematology and Hemotherapy Foundation of the State of Bahia, submitted to anti-T. cruzi antibody detection using Liaison Chagas CLIA and LCA as a reference test in the absence of a gold standard. RESULTS: LCA classified 4993 samples as negative, while positivity for T. cruzi antibodies was predicted in 21 samples. Compared with LCA, CLIA demonstrated sensitivity and specificity of 76.2% and 99.5%, respectively, providing an overall accuracy of 99.4%. DISCUSSION: In blood banks lacking a de facto highly sensitive screening immunoassay, the low sensitivity offered by Liaison Chagas CLIA renders it unsuitable for standalone use in serological screening procedures for CD. Moreover, blood banks are encouraged to carefully assess the ability of diagnostic methods to identify local T. cruzi strains in circulation.

Serological response to Neospora caninum infection in goats and agreement between three diagnostic techniques to detect caprine neosporosis / Resposta sorológica à infecção por Neospora caninum em cabras e concordância entre três técnicas diagnósticas para detecção de neosporose caprina

The present study aimed to measure the serological response of goats infected with Neospora caninum by assessing the diagnostic performance and agreement between three techniques (indirect immunofluorescent antibody test, IFAT; Neospora agglutitation test, NAT; enzyme-linked immunosorbent assay, ELISA). The panel of sera were comprised of 500 samples of goats, and 60 reference serum samples. These reference and field serum samples were tested by ELISA, NAT, and IFAT. In the field serum samples tested, the seroprevalences of anti-N. caninum antibodies were 3.2%, 4.6%, and 6.4% in the NAT, IFAT and ELISA, respectively. Using the IFAT as the gold standard, the NAT and the ELISA agreement was considered weak (k=0.28) and strong (k=0.75), respectively. When the IFAT performance was used for comparison purposes, the ELISA showed 91.3% sensitivity and 97.7%, specificity with a PPV of 65.2% and a NPV of 99.6%; The NAT presented sensitivity of 26.1% and specificity of 97.9% with a PPV of 37.5% and a NPV of 96.5%. Accordingly, the IFAT should remain the assay of choice for studies about N. caninum infection in goats in individual serum samples. A combination of serological assays with high sensitivity and specificity is recommended in serosurveys of caprine neosporosis.(AU)

Objetivou-se avaliar a resposta sorológica de caprinos infectados com Neospora caninum mediante o estudo da performance e concordância de três técnicas sorológicas (RIFI, NAT e ELISA). O painel de soros testes foi composto por 500 amostras de caprinos e ainda 60 soros classificados como de referência. Todos os soros de referência e de campo foram testados por ELISA, NAT e RIFI. Nos soros de campo, as soroprevalências de anticorpos anti-N. caninum foram de 3,2% no NAT, 4,6% na RIFI e 6,4% no ELISA. Utilizando a RIFI como técnica de referência, a concordância de NAT e ELISA foi considerada fraca (k=0,28) e substancial (k=0,75), respectivamente. Ainda utilizando a RIFI como comparação, foram obtidos valores de sensibilidade de 91,3% e 97,7% de especificidade no ELISA, e valores preditivos positivo de 65,2% e negativo de 99,6%; NAT apresentou resultados de sensibilidade de 26,1% e de especificidade de 97,9% com valores preditivos positivo de 37,5% e negativo de 96,5%. Com base nos resultados deste trabalho, sugerimos que a RIFI permaneça como técnica de escolha no estudo da neosporose caprina em amostras individuais, resguardando as recomendações e pontos de corte adotados neste estudo. Indicamos a associação de técnicas sorológicas de alta sensibilidade e especificidade.(AU)

Serological response to Neospora caninum infection in goats and agreement between three diagnostic techniques to detect caprine neosporosis / Resposta sorológica à infecção por Neospora caninum em cabras e concordância entre três técnicas diagnósticas para detecção de neosporose caprina

The present study aimed to measure the serological response of goats infected with Neospora caninum by assessing the diagnostic performance and agreement between three techniques (indirect immunofluorescent antibody test, IFAT; Neospora agglutitation test, NAT; enzyme-linked immunosorbent assay, ELISA). The panel of sera were comprised of 500 samples of goats, and 60 reference serum samples. These reference and field serum samples were tested by ELISA, NAT, and IFAT. In the field serum samples tested, the seroprevalences of anti-N. caninum antibodies were 3.2%, 4.6%, and 6.4% in the NAT, IFAT and ELISA, respectively. Using the IFAT as the gold standard, the NAT and the ELISA agreement was considered weak (k=0.28) and strong (k=0.75), respectively. When the IFAT performance was used for comparison purposes, the ELISA showed 91.3% sensitivity and 97.7%, specificity with a PPV of 65.2% and a NPV of 99.6%; The NAT presented sensitivity of 26.1% and specificity of 97.9% with a PPV of 37.5% and a NPV of 96.5%. Accordingly, the IFAT should remain the assay of choice for studies about N. caninum infection in goats in individual serum samples. A combination of serological assays with high sensitivity and specificity is recommended in serosurveys of caprine neosporosis.(AU)

Objetivou-se avaliar a resposta sorológica de caprinos infectados com Neospora caninum mediante o estudo da performance e concordância de três técnicas sorológicas (RIFI, NAT e ELISA). O painel de soros testes foi composto por 500 amostras de caprinos e ainda 60 soros classificados como de referência. Todos os soros de referência e de campo foram testados por ELISA, NAT e RIFI. Nos soros de campo, as soroprevalências de anticorpos anti-N. caninum foram de 3,2% no NAT, 4,6% na RIFI e 6,4% no ELISA. Utilizando a RIFI como técnica de referência, a concordância de NAT e ELISA foi considerada fraca (k=0,28) e substancial (k=0,75), respectivamente. Ainda utilizando a RIFI como comparação, foram obtidos valores de sensibilidade de 91,3% e 97,7% de especificidade no ELISA, e valores preditivos positivo de 65,2% e negativo de 99,6%; NAT apresentou resultados de sensibilidade de 26,1% e de especificidade de 97,9% com valores preditivos positivo de 37,5% e negativo de 96,5%. Com base nos resultados deste trabalho, sugerimos que a RIFI permaneça como técnica de escolha no estudo da neosporose caprina em amostras individuais, resguardando as recomendações e pontos de corte adotados neste estudo. Indicamos a associação de técnicas sorológicas de alta sensibilidade e especificidade.(AU)

Problemas de salud en individuos que acuden a donar sangre en Cienfuegos / Health problems in individuals attending in Cienfuegos to donate blood

Introducción: a través de la selección médica predonación y la pesquisa de infecciones postdonación se reconocen enfermedades ocultas o en sus estadios asintomáticos iniciales, sus factores de riesgos o ambos.Objetivos: determinarlos principales problemas de salud en donantes de sangre de Cienfuegos.Métodos: estudio observacional descriptivo de corte transversal retrospectivocon los individuos que acudieron a donar sangre total en la provincia de Cienfuegos desde 2010 hasta 2014.Las unidades de análisis fueron los donantes identificados como no aptos para donar sangre y aquellos con resultados positivos en las pruebas de tamizaje postdonación.Resultados: la décima parte de los individuos presentaronalgún problema o desviación de la salud presente o potencial. Las principales causas vinculadas al rechazo del donante fueron: el aspecto turbio del plasma, alteraciones en las cifras de tensión arterial, concentración de hemoglobinafuera de los valores aceptados, enfermedades infecciosas o sus factores de riesgos, el uso de medicamentos y otras condiciones médicas. Además, entre los individuos que donaron hubo una proporción pequeña que presentaron resultados positivos / reactivos a las pruebas infecciosas, en lo fundamental para anticuerpos contra la hepatitis C.Conclusiones: aunque los hallazgos de este estudio son consistentes con la mayoría de otros autores, la presencia de desviaciones de la salud en una población supuestamente sana resulta significativa. Futuras investigaciones deberían centrarse en esta temática, puntualizando en elcomponente educativo, las políticas y los procedimientos de selección, consejería y seguimiento clínico-epidemiológico de donantes de sangre, entre otras(AU)

Introduction: Through medical selection and pre-donation screening for hidden infections post-donation illness or asymptomatic in its early stages, its risk factors or both are recognized.Aims: Identify the main health problems in Cienfuegos blood donors.Methods: A descriptive cross section study with all individuals who came to donate whole blood in the province of Cienfuegos from 2010 to 2014 was performed. The analysis units were the donors identified as ineligible to donate blood and those with positive results in screening tests post-donation.Results: Tenth of the individuals had a problem or deviation from present or potential health. The main causes linked to rejection of the donor were: the cloudy appearance of plasma, alterations in blood pressure levels, hemoglobin concentration outside the accepted values, infectious diseases or risk factors, use of medicines and other medical conditions . Also among individuals who donated there was a small proportion had positive / reactive to infectious test results, fundamentally for antibodies to hepatitis C. Conclusions. Although the findings of this study are consistent with most other authors, the presence of deviations from health in a supposedly healthy population is significant. Future research should focus on this subject, pointing in the educational component, policies and selection procedures, counseling and clinical and epidemiological monitoring of blood donors, among others(AU)

Problemas de salud en individuos que acuden a donar sangre en Cienfuegos / Health problems in individuals attending in Cienfuegos to donate blood

Introducción: a través de la selección médica predonación y la pesquisa de infecciones postdonación se reconocen enfermedades ocultas o en sus estadios asintomáticos iniciales, sus factores de riesgos o ambos. Objetivos: determinarlos principales problemas de salud en donantes de sangre de Cienfuegos. Métodos: estudio observacional descriptivo de corte transversal retrospectivocon los individuos que acudieron a donar sangre total en la provincia de Cienfuegos desde 2010 hasta 2014.Las unidades de análisis fueron los donantes identificados como no aptos para donar sangre y aquellos con resultados positivos en las pruebas de tamizaje postdonación. Resultados: la décima parte de los individuos presentaron algún problema o desviación de la salud presente o potencial. Las principales causas vinculadas al rechazo del donante fueron: el aspecto turbio del plasma, alteraciones en las cifras de tensión arterial, concentración de hemoglobina fuera de los valores aceptados, enfermedades infecciosas o sus factores de riesgos, el uso de medicamentos y otras condiciones médicas. Además, entre los individuos que donaron hubo una proporción pequeña que presentaron resultados positivos / reactivos a las pruebas infecciosas, en lo fundamental para anticuerpos contra la hepatitis C. Conclusiones: aunque los hallazgos de este estudio son consistentes con la mayoría de otros autores, la presencia de desviaciones de la salud en una población supuestamente sana resulta significativa. Futuras investigaciones deberían centrarse en esta temática, puntualizando en el componente educativo, las políticas y los procedimientos de selección, consejería y seguimiento clínico-epidemiológico de donantes de sangre, entre otras(AU)

Introduction: Through medical selection and pre-donation screening for hidden infections post-donation illness or asymptomatic in its early stages, its risk factors or both are recognized. Aims: Identify the main health problems in Cienfuegos blood donors. Methods: A descriptive cross section study with all individuals who came to donate whole blood in the province of Cienfuegos from 2010 to 2014 was performed. The analysis units were the donors identified as ineligible to donate blood and those with positive results in screening tests post-donation. Results: Tenth of the individuals had a problem or deviation from present or potential health. The main causes linked to rejection of the donor were: the cloudy appearance of plasma, alterations in blood pressure levels, hemoglobin concentration outside the accepted values, infectious diseases or risk factors, use of medicines and other medical conditions . Also among individuals who donated there was a small proportion had positive / reactive to infectious test results, fundamentally for antibodies to hepatitis C. Conclusions. Although the findings of this study are consistent with most other authors, the presence of deviations from health in a supposedly healthy population is significant. Future research should focus on this subject, pointing in the educational component, policies and selection procedures, counseling and clinical and epidemiological monitoring of blood donors, among others(AU)

Perfil de inaptidão na triagem clínica e sorológica de candidatos à doação de sangue / Profile of inability in the clinic and serological screening of candidates for blood donation

Objetivo: Caracterizar os candidatos quanto ao gênero e analisar a prevalência dos critérios de inaptidão adotados às doações de sangue, realizadas no Banco de Sangue Santa Maria, em Santa Maria, RS. Métodos: Dados retrospectivos arquivados foram avaliados, analisando-se os critérios de exclusão na triagem clínica e sorológica, no período de janeiro de 2005 até dezembro de 2010. Foram analisados 20.264 doadores. O estudo foi aprovado pelo Comitê de Ética e Pesquisa da Universidade Federal do Rio Grande do Sul-UFRGS, sob número de protocolo 18147. Resultados: Novecentos e setenta e seis (5%) candidatos foram considerados inaptos pela triagem clínica e 19.288 (95%) foram considerados aptos para prosseguirem com os testes laboratoriais. Dos doadores aptos, 941 (5%) foram excluídos na triagem sorológica, totalizando 18.347 bolsas de sangue disponíveis para uso. Predominaram os doadores do sexo masculino (62%) e a principal causa de exclusão, na triagem clínica, foi hipertensão (0,7%). Para a triagem sorológica, a principal causa de exclusão foi a Doença de Chagas (1,5%). Conclusão: Ressaltou-se a importância da triagem clínica, tendo em vista que ela excluiu 5% dos candidatos à doação e a relevância da triagem sorológica ser feita corretamente, evitando que resultados falso-negativos sejam liberados.

Objective: Characterize donors by gender and analyze theprevalence of the inability criteria of donations made at the SantaMaria Blood Bank, located at Santa Maria, Brazil. Methods: First,we searched historical data for exclusion criteria used in clinicaland serological screenings during the period from January, 2005 toJuly, 2010. We evaluated 20,264 blood donors' data for this study.The Ethical Committee of Rio Grande do Sul Federal UniversityUFRGSapproved this study under the protocol number 18147.Results: Nine hundred and seventy-six (5%) candidates wereconsidered unfit by the clinical screening and 19,288 (95%) wereconsidered fit. From the resulting fit population of the clinicalscreening, 941 (5%) were excluded from donating by the serologicalscreening, totaling 18.347 blood donations fit for use. The resultsshows that majority of the donors were male (62%) and the leadingcause of exclusion from donating in the clinical screening washypertension (0.7%). As for the serological screening, the leadingcause for exclusion was Chagas disease (1.5%). Conclusion: Thestudy stress the importance of the clinical screening process, giventhat it excluded 5% of blood donations, which were unfit for use. Wealso notice the relevance of a correctly done serological screening,thus avoiding that false-negative results are released.

Prevalência de infecção chagásica em doadores de sangue no estado de Pernambuco, Brasil / The prevalence of chagasic infection among blood donors in the State of Pernambuco, Brazil

A doença de Chagas é uma infecção sistêmica de evolução crônica cujo agente etiológico é o parasita Trypanosoma cruzi. O último relato encontrado sobre a soroprevalência da doença em doadores de sangue realizado na capital pernambucana, Recife, data de 1970, onde foi encontrada uma prevalência de 4,4 por cento em doadores de um hospital local. Devido à falta de informações divulgadas sobre a infecção por T. cruzi e sendo Pernambuco uma região endêmica para esta enfermidade, o presente estudo se propôs a analisar o perfil dos doadores de sangue do Hemocentro de Pernambuco (Hemope), que apresentaram reatividade para doença de Chagas, no período de 2002 a 2007. O perfil dos doadores inaptos foi avaliado de acordo com gênero, idade e procedência segundo as mesorregiões de Pernambuco. Foi encontrada uma prevalência de 0,17 por cento para doença de Chagas e 6,89 por cento das bolsas descartadas deveram-se a essa reatividade. Em relação ao gênero dos doadores, foi significativamente maior a contribuição dos homens (p<0,0001). A faixa etária de 18-30 anos apresentou menor quantidade de sorologias reativas (20,21 por cento). Foi verificado também que, na Região Metropolitana do Recife, a quantidade de reações inconclusivas foi estatisticamente maior que a quantidade de sorologias reagentes (p=0,0440). Desta forma, estudos epidemiológicos fornecem dados importantes no sentido de se avaliar diretamente o risco de transmissão de uma doença por transfusão sanguínea e permitem que também em regiões endêmicas se avalie a eficácia das medidas para o controle vetorial.

Chagas disease is a systemic infection with a chronic onset transmitted by Trypanosoma cruzi. The last study conducted in Recife, capital of Pernambuco state, was carried out during 1970. At that time a prevalence of 4.4 percent was found among blood donors of a local hospital. Due to the lack of epidemiology data on T. cruzi infection and as Pernambuco is an endemic region, the present study describes the profile of blood donors who presented reactivity for Chagas disease during the period of 2002 to 2007 in the state's blood bank (Hemope). The profile of unsuitable donors was evaluated according to gender, age and according to the meso-regions of Pernambuco. A prevalence of 0.17 percent was found for Chagas disease, whereas 6.89 percent of the rejected blood bags were due to this reactivity. As far as gender is concerned, the reactivity of men was higher than that of women (p<0.0001). Additionally, the age group between 18-30 years was less infected (20.21 percent). On analyzing the reactivity in each one of the meso-regions of the state, it was found that, in the Metropolitan Region of Recife, the number of inconclusive reaction cases was statistically higher than the number of reactive serology cases (p=0.0440). Thus, epidemiological studies provide important data to indirectly evaluate the risk of blood-borne diseases and allow indirect evaluation of the effectiveness of vectorial control measures in endemic regions.

Epidemiological profile of hepatitis C in blood donors at the Uberaba Regional Blood Center / Perfil epidemiológico para hepatite C em doadores de sangue do Hemocentro Regional de Uberaba

The aim of the present study was to outline the serological profile of hepatitis C among blood donors seen at the Uberaba Regional Blood Center, Hemominas Foundation, over the last 14 years. The frequency of hepatitis C was compared between first-time and repeat donors and the epidemiological characteristics of those with positive and indeterminate ELISA anti-HCV (third and fourth generation) were analyzed based on the donor histories kept in the archives of the Uberaba Regional Blood Center. The serological ineligibility rate was 0.3 percent, with higher prevalence in the group of first-time donors. We did not find any significant differences regarding age, skin color, marital status or place of residence between eligible and ineligible donors; however, the frequency of positive serology was higher among men. The lower (0.3 percent) rate of ineligibility due to hepatitis C that was observed at the Uberaba Regional Blood Center, in relation to most Brazilian blood centers, is probably due to the large number of repeat donors (83.3 percent). This reinforces the importance of achieving donor commitment for increasing transfusion safety.

O objetivo deste estudo foi traçar o perfil sorológico para a hepatite C nos doadores de sangue do Hemocentro Regional de Uberaba/Fundação Hemominas nos últimos 14 anos, comparando a sua ocorrência em doadores iniciais e de retorno e analisando as características epidemiológicas daqueles com ELISA anti-HCV (terceira e quarta geração) positivo e indeterminado, a partir dos históricos dos doadores nos arquivos do Hemocentro Regional de Uberaba. A inaptidão sorológica encontrada foi de 0,3 por cento, com maior ocorrência no grupo de doadores iniciais. Não encontramos diferenças significativas quanto à idade, cor da pele, estado civil e local de residência entre os aptos e os inaptos, porém a ocorrência de sorologia positiva foi maior nos homens. A menor prevalência de inaptidão para hepatite C (0,3 por cento) no Hemocentro Regional de Uberaba, em relação à maioria dos hemocentros do país, é provavelmente devido ao grande (83,3 por cento) número de doadores de repetição, reforçando assim a importância da fidelização do doador para o aumento da segurança transfusional.

Anti-Trypanosoma cruzi antibody detection in blood donors in the Southern Brazil

Trypanosoma cruzi, the causal agent of Chagas' Disease, is a widely spread protozoa in America. Blood transfusion is the secondly most important way of acquiring the infection. In blood banks, tests are performed to eliminate potentially infected blood. This study aimed to evaluate the positivity for T. cruzi in blood samples of donor's candidates in Southern Brazil. The study was based on a sampling containing all blood donors of Hemopel - a Pelotas City Blood Center, Rio Grande do Sul State, Brazil, from 2004 to 2005. Serological study was performed using ELISA Chagatest. Sampling containing values ± 20 percent cut off were evaluated using ELISA Chagatek, ELISA Alka/Adaltis, IHA Chagatest and IIF Imunocruzi. TESA-Blot was used as a confirmatory procedure in situations where blood samples showed conflicting results. From 4,482 samples collected in 2004 and 2005, the reactivity for anti-T. cruzi was 0.96 percent (43). Among those, 21 cases (0.47 percent) were confirmed as positive - most of them were female, with low school level and averaging 47.2 percent years old. Interestingly, the blood donors are not aware of being contaminated and this fact makes it difficult for controlling the disease. Chagas' Disease was one of the main reasons for discarding blood bags through serological control in Southern Brazil. Sampling reactivity showed variation among the different techniques used for anti-T. cruzi research. In order to obtaining more secure and conclusive results, more than one diagnostic technique must be used.

Importância dos testes sorológicos de triagem e confirmatórios na detecção de doadores de sangue infectados pelo vírus da hepatite C / Importance of screening and confirmatory tests to detect blood donors infected by the hepatitis C virus

A triagem sorológica de doadores de sangue com baixos índices de prevalência de infecção, como no caso da hepatite C (HCV), gera um percentual considerável de resultados falso-positivos e descarte de bolsas de hemocomponentes freqüentemente não infectados. O objetivo deste estudo foi pesquisar o perfil sorológico e, com base no teste confirmatório, a ocorrência de hepatite C nos doadores com sorologia positiva ou indeterminada do Hemocentro Regional de Uberaba (HRU). Os testes confirmatórios foram realizados por meio da detecção do RNA do HCV no plasma, utilizando-se o método RT-PCR qualitativa. Foram realizadas, no período de 1992 a 2005, 171.027 doações de sangue no HRU, sendo 24,3 por cento de doadores iniciais e 75,7 por cento de retorno. O índice de inaptidão para HCV foi de 0,3 por cento (561 doações), sendo que 53,0 por cento destas eram de doadores iniciais e 47,0 por cento de retorno, com prevalências de 0,5 por cento e 0,2 por cento, respectivamente (p<0,0001). O índice de reações inconclusivas foi significativamente maior nos doadores de retorno (p=0,0214). Noventa e oito candidatos foram submetidos à PCR qualitativa e apenas 34 (34,7 por cento) apresentaram resultados positivos, com índice de positividade significativamente menor nos doadores de retorno (p=0,0184) e quase três vezes menor nos inconclusivos. Assim, verificamos que grande número de doadores, tanto anti-HCV positivos quanto indeterminados, não tiveram confirmada a presença da infecção pelo HCV, levando-nos a concluir que a inaptidão sorológica para hepatite C no HRU, na maioria das vezes, não correspondeu à presença de infecção viral no doador.

Serological screening of blood donors with low indexes of infection, including hepatitis C virus (HCV), accounts for a substantial percentage of false-positive results with consequent loss of non-infected blood components. The aim of this study was to evaluate the occurrence of hepatitis C using confirmatory tests for blood donors with positive or inconclusive results at Hemocentro Regional de Uberaba (HRU). Confirmatory tests were performed by the detection of HCV RNA in plasma using qualitative RT-PCR. The study was carried out from 1992 to 2005 for 171,027 blood donors, 24.3 percent first-time and 75.7 percent repeat donors. The ineligibility rate to HCV was 0.3 percent (561 donors) with 52.9 percent of them being first-time donors and 47.0 percent repeat donors with prevalences of 0.5 percent and 0.2 percent respectively (p<0.0001). The rate of inconclusive results was significantly higher among repeat donors (p=0.0214). Ninety-eight samples were subjected to qualitative PCR and only 34.7 percent (34) had positive results, with a significantly lower rate of positiveness for repeat donors (p = 0.0184) and almost a threefold lower rate of inconclusive results for the same donors. These results showed that, for a large number of donors with positive and inconclusive tests for anti-HCV, the infection was not confirmed. We concluded that serological ineligibility for hepatitis C of donors at HRU was not always associated with the presence of viral infection.

Serological screening for infectious cattle diseases: i. influence of reproductive status

A cohort of 125 cows (Zebu-Holstein crosses) were screened every two months during a period of two years for IgG antibodies to 20 viral, bacterial, rickettsial and parasitic agents. The screening was performed on sera using the ELISA procedure. The IgG levels fluctuated during pregnancy in a regular and similar way for all the antigens tested. IgG reached its lowest levels in the fourth and seventh month of pregnancy, a significant increase ocurred during the last month of pregnancy and this was followed by a precipitous decline during the first month post partum. The IgG fluctuations associated with the different phases of reproductive status may interact with seasonal changes in IgG levels. The changes in IgG levels during pregnancy may have the result that an individual animal oscillates between being seropositive and seronegative. This can have an important impact on serological studies of abortion epidemiology.

Um estudo de coortes de 125 vacas cruza Zebu-Holandês foram monitoradas durante um período de dois anos para anticorpos do tipo IgG contra 21 agentes: vírus, bactérias, rickétsias e parasitas. A triagem sorológica foi realizada utilizando-se uma prova imuno-enzimática (ELISA). Os níveis de IgG flutuaram de forma regular e similar durante a gestação para todos os antígenos testados. Os níveis mais baixos de IgG foram encontrados no 4° e 7° mês de gestação. Houve um aumento significativo dos títulos no último mês de gestação sendo seguido por um declínio acentuado durante o primeiro mês pós-parto. A flutuação dos níveis de IgG pode estar associada com as diferentes fases reprodutivas podendo interagir com as variações estacionais dos níveis de IgG. As alterações de níveis de IgG durante a gestação pode levar a resultados onde o animal oscila entre positivo e negativo. Isso pode ter um importante impacto em estudos sorológicos na epidemiologia de abortos.

Serological screening for infectious cattle diseases: ii. association between prevalence and level of elisa response

A herd of cattle (Holstein-Zebu crosses) was screened every two months by ELISA during a period of two years for IgG antibodies against 19 infectious disease agents. Two hundred and ninety five sera were collected from 157 young animals (0-4 months of age), 1037 sera from 292 developing animals (4-36 months of age) and 1468 sera from 259 producing animals (> 36 months of age). The results indicate that the difference in ELISA between positive and negative tests is associated with the overall prevalence of positive tests. When the prevalence of positive tests is low the difference between positive and negative tests is greater than when the prevalence is intermediate or high. This means that ELISA, presumably other serological tests for IgG antibodies, is more reliable at low disease (antibody) prevalence. This will tend to offset the declining predictive value of positive tests at low prevalence and may contribute to the successful use of serological tests in disease eradication.

Um rebanho bovino (cruza Holandês-Zebu) foi monitorado durante um período de dois anos pelo teste imuno-enzimático (ELISA) para detectar anticorpos contra 19 agentes infecciosos. Duzentos e noventa e cinco soros foram coletados de 157 animais jovens (0-4 meses de idade), 1037 soros de 292 animais em crescimento (4-36 meses de idade) e 1468 soros de 259 animais em produção (>36 meses de idade). Os resultados indicam que a diferença entre resultados positivos e negativos ao ELISA está associada com a prevalência geral de testes positivos. Quando esta prevalência for baixa a diferença entre resultados positivos e negativos é maior do que quando esta for intermediária ou alta. Isto significa que o ELISA é mais confiável quando em prevalências baixas. Isto tenderá a compensar diminuindo a probabilidade de valores positivos em prevalências baixas podendo contribuir no uso da sorologia em programas de erradicação.

SEROLOGICAL SCREENING FOR INFECTIOUS CATTLE DISEASES: II. ASSOCIATION BETWEEN PREVALENCE AND LEVEL OF ELISA RESPONSE

A herd of cattle (Holstein-Zebu crosses) was screened every two months by ELISA during a period of two years for IgG antibodies against 19 infectious disease agents. Two hundred and ninety five sera were collected from 157 young animals (0-4 months of age), 1037 sera from 292 developing animals (4-36 months of age) and 1468 sera from 259 producing animals (> 36 months of age). The results indicate that the difference in ELISA between positive and negative tests is associated with the overall prevalence of positive tests. When the prevalence of positive tests is low the difference between positive and negative tests is greater than when the prevalence is intermediate or high. This means that ELISA, presumably other serological tests for IgG antibodies, is more reliable at low disease (antibody) prevalence. This will tend to offset the declining predictive value of positive tests at low prevalence and may contribute to the successful use of serological tests in disease eradication.

Um rebanho bovino (cruza Holandês-Zebu) foi monitorado durante um período de dois anos pelo teste imuno-enzimático (ELISA) para detectar anticorpos contra 19 agentes infecciosos. Duzentos e noventa e cinco soros foram coletados de 157 animais jovens (0-4 meses de idade), 1037 soros de 292 animais em crescimento (4-36 meses de idade) e 1468 soros de 259 animais em produção (>36 meses de idade). Os resultados indicam que a diferença entre resultados positivos e negativos ao ELISA está associada com a prevalência geral de testes positivos. Quando esta prevalência for baixa a diferença entre resultados positivos e negativos é maior do que quando esta for intermediária ou alta. Isto significa que o ELISA é mais confiável quando em prevalências baixas. Isto tenderá a compensar diminuindo a probabilidade de valores positivos em prevalências baixas podendo contribuir no uso da sorologia em programas de erradicação.

SEROLOGICAL SCREENING FOR INFECTIOUS CATTLE DISEASES: I. INFLUENCE OF REPRODUCTIVE STATUS

A cohort of 125 cows (Zebu-Holstein crosses) were screened every two months during a period of two years for IgG antibodies to 20 viral, bacterial, rickettsial and parasitic agents. The screening was performed on sera using the ELISA procedure. The IgG levels fluctuated during pregnancy in a regular and similar way for all the antigens tested. IgG reached its lowest levels in the fourth and seventh month of pregnancy, a significant increase ocurred during the last month of pregnancy and this was followed by a precipitous decline during the first month post partum. The IgG fluctuations associated with the different phases of reproductive status may interact with seasonal changes in IgG levels. The changes in IgG levels during pregnancy may have the result that an individual animal oscillates between being seropositive and seronegative. This can have an important impact on serological studies of abortion epidemiology.

Um estudo de coortes de 125 vacas cruza Zebu-Holandês foram monitoradas durante um período de dois anos para anticorpos do tipo IgG contra 21 agentes: vírus, bactérias, rickétsias e parasitas. A triagem sorológica foi realizada utilizando-se uma prova imuno-enzimática (ELISA). Os níveis de IgG flutuaram de forma regular e similar durante a gestação para todos os antígenos testados. Os níveis mais baixos de IgG foram encontrados no 4° e 7° mês de gestação. Houve um aumento significativo dos títulos no último mês de gestação sendo seguido por um declínio acentuado durante o primeiro mês pós-parto. A flutuação dos níveis de IgG pode estar associada com as diferentes fases reprodutivas podendo interagir com as variações estacionais dos níveis de IgG. As alterações de níveis de IgG durante a gestação pode levar a resultados onde o animal oscila entre positivo e negativo. Isso pode ter um importante impacto em estudos sorológicos na epidemiologia de abortos.