RESUMO

Toxoplasma gondii is described as a potential cause of abortion in goats and as a threat to public health. To estimate the prevalence of goats infected by T. gondii, in different cities in the Espírito Santo State, and to identify possible risk factors for infection a serological study was conducted. A total of 146 goat serum samples from the cities of Cariacica, Serra and Vila Velha were analyzed. The presence of IgG Class Immunoglobulins was serologically evaluated by Immunofluorescence antibody test (IFAT) and by Enzyme-linked Immunosorbent Assay (ELISA). The seroprevalence of anti-T. gondii was 46.6% (68/146) in both techniques and the same samples got the same results in both techniques. Among the analyzed sera, 70.6% (48/68) exhibited high-avidity IgG antibodies, and 29.4% (20/68) exhibited low-avidity IgG antibodies, suggesting that the infection was chronic in the infected animals. Female sex, age group over two years old, water from the public supply system, storage of food and supplies in an open and unprotected place, and the presence of a domestic cat on the property were identified as risk factors for T. gondii infection in goats. The state of Espirito Santo has a high frequency of infected goats, and this is the first research on caprine toxoplasmosis seroepidemiology in that region.

Assuntos

Anticorpos Antiprotozoários , Doenças das Cabras , Cabras , Imunoglobulina G , Toxoplasma , Toxoplasmose Animal , Animais , Cabras/parasitologia , Estudos Soroepidemiológicos , Brasil/epidemiologia , Toxoplasmose Animal/epidemiologia , Toxoplasmose Animal/parasitologia , Doenças das Cabras/epidemiologia , Doenças das Cabras/parasitologia , Fatores de Risco , Toxoplasma/imunologia , Feminino , Masculino , Anticorpos Antiprotozoários/sangue , Imunoglobulina G/sangue , Ensaio de Imunoadsorção Enzimática/veterinária , Prevalência

RESUMO

The study evoluated an in-house Spike Receptor Binding Domain Enzyme-Linked Immunosorbent Assay (RBD-IgG-ELISA) for detecting SARS-CoV-2 IgG antibodies in infected and vaccinated individuals. The assay demonstrated a sensitivity of 91%, specificity of 99.25%, and accuracy of 95.13%. Precision and reproducibility were highly consistent. The RBD-IgG-ELISA was able to detect 96.25% of Polymerase chain reaction (PCR) confirmed cases for SARS-CoV-2 infection, demonstrating positive and negative predictive values of 99,18% and 91,69%, respectively. In an epidemiological survey, ELISA, lateral flow immunochromatographic assay (LFIA), and electrochemiluminescence immunoassay (ECLIA) exhibited diagnostic sensitivities of 68.29%, 63.41%, and 70.73%, respectively, along with specificities of 82.93%, 80.49%, and 80.49%, respectively. Agreement between RBD-IgG-ELISA/PCR was moderate (k index 0.512). However, good agreement between different assays (RBD-IgG-ELISA/LFIA k index 0.875, RBD-IgG-ELISA/ECLIA k index 0.901). Test performance on individuals' samples were inferior due to seroconversion time and chronicity. The IgG-RBD-ELISA assay demonstrated its effectiveness in monitoring antibody levels among healthcare professionals, revealing significant differences both before and after the administration of the third vaccine dose, with heightened protection levels observed following the third dose in five Coronavirus disease (COVID-19) vaccine regimens. In conclusion, the RBD-IgG-ELISA exhibits high reproducibility, specificity, and sensitivity, making it a suitable assay validated for serosurveillance and for obtaining information about COVID-19 infections or vaccinations.

Assuntos

Anticorpos Antivirais , Vacinas contra COVID-19 , COVID-19 , Ensaio de Imunoadsorção Enzimática , Imunoglobulina G , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Humanos , Ensaio de Imunoadsorção Enzimática/métodos , COVID-19/diagnóstico , COVID-19/imunologia , COVID-19/prevenção & controle , SARS-CoV-2/imunologia , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Vacinas contra COVID-19/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Reprodutibilidade dos Testes , Pessoa de Meia-Idade , Masculino , Feminino , Adulto , Teste Sorológico para COVID-19/métodos , Sensibilidade e Especificidade , Idoso , Vacinação , Adulto Jovem

RESUMO

Background/Objective: Myasthenia Gravis (MG) is an autoimmune disorder characterized by pathogenic autoantibodies (AAbs) targeting nicotinic acetylcholine receptors (AChR), disrupting neuromuscular communication. RadioImmunoPrecipitation Assay (RIPA) is recommended to detect AChR AAbs, but its complexity and radioactive requirements limit widespread use. We compare non-RIPA anti-AChR immunoassays, including Cell-Based Assay (CBA) and two ELISA kits, against the gold standard RIPA. Methods/Results: 145 samples were included with medical indication for anti-AChR testing. By the RIPA method, 63 were negative (RIPA-Neg < 0.02 nmol/L), 18 were classified as Borderline (≥0.02 -1 nmol/L), and 64 were positive (RIPA-Pos > 1 nmol/L). The competitive ELISA showed poor agreement with RIPA (Kappa = 0.216). The indirect ELISA demonstrated substantial agreement with RIPA (Kappa = 0.652), with ∼76% sensitivity and ∼94% specificity for MG diagnostic. The CBA, where fixed cells expressing clustered AChR were used as substrate, exhibited almost perfect agreement with RIPA (Kappa = 0.984), yielding ∼98% sensitivity and 96% specificity for MG. In addition, a semiquantitative analysis showed a strong correlation between CBA titration, indirect ELISA, and RIPA levels (r = 0.793 and r = 0.789, respectively). Conclusions: The CBA displayed excellent analytical performance for MG diagnostic when compared to RIPA, making it a potential replacement for RIPA in clinical laboratories. Some solid-phase assays (such as the indirect ELISA applied here), as well as CBA titration, offer reliable options to estimate anti-AChR AAb levels after confirming positivity by the CBA.∥.

Assuntos

Autoanticorpos , Ensaio de Imunoadsorção Enzimática , Miastenia Gravis , Ensaio de Radioimunoprecipitação , Humanos , Ensaio de Imunoadsorção Enzimática/métodos , Miastenia Gravis/imunologia , Miastenia Gravis/diagnóstico , Sensibilidade e Especificidade , Receptores Colinérgicos/imunologia , Feminino , Masculino , Pessoa de Meia-Idade , Adulto , Idoso , Adulto Jovem

RESUMO

INTRODUCTION: The prime responsibility of blood transfusion services in India is to provide safe blood. The donated blood is tested for human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), malaria and syphilis. In India, the screening of donated blood for syphilis is performed by rapid plasma reagin (RPR) or venereal disease research laboratory (VDRL), whereas the World Health Organization (WHO) recommends screening of syphilis in blood donors by enzyme-linked immunosorbent assay (ELISA). Therefore, the aim of this study was to evaluate the performance of RPR and ELISA with the Treponema pallidum hemagglutination assay (TPHA - the gold standard) for the detection of syphilis in blood donors. METHODS: In this cross-sectional study, 1524 consecutive whole blood donors were screened from April to October 2022. All blood samples collected during the study period were tested by RPR, ELISA and the TPHA and the results obtained were compared. RESULTS: The seroprevalence of syphilis in blood donors in this study was 0.06% by RPR and 0.72% by ELISA and TPHA. On considering ELISA and the TPHA as the gold standard, ELISA had comparable sensitivity (100%), a higher specificity (100% vs. 99.34%), a higher positive predictive value (PPV - 100% vs. 9.1%) and no biological false positive/false negative results (0 vs. 10 false negatives) when compared to RPR. CONCLUSION: ELISA performed better as a screening assay than RPR in the detection of syphilis in blood donors, which is in agreement with the WHO recommendations for syphilis testing in blood donors with low prevalence.

RESUMO

OBJECTIVES: This study aimed to investigate changes in salivary flow rates, buffering capacity, and salivary chromogranin A (CHGA) levels in adults undergoing bariatric surgery (BS) compared with a non-obese control group. MATERIALS AND METHODS: Salivary analyses were performed on 62 participants aged over 50 years, stratified into two groups matched for age and gender-individuals who had undergone bariatric surgery (BS) (n = 31) and a corresponding healthy control group (n = 31). Before saliva collection, participants completed a comprehensive 11-point visual numerical rating scale (NRS 0-10) xerostomia questionnaire, assessing subjective perceptions of two key aspects: dryness of the oral mucosa and resultant impact on oral functional ability. Three distinct saliva measurements were obtained: unstimulated whole saliva (UWS), stimulated whole saliva (SWS), and unstimulated upper labial saliva (ULS). The buffering capacity of unstimulated saliva was assessed using pH indicator strips, and concentrations of salivary Chromogranin A (CHGA) were quantified in stimulated saliva via enzyme-linked immunosorbent assay (ELISA). RESULTS: After BS, more than 40% of BS group patients reported xerostomia, with 16.1% experiencing only mild symptoms without significant functional impact (p = 0.009). The prevalence of xerostomia and tongue dryness was higher in the BS group compared to the control group (p = 0.028 and p = 0.025, respectively). The comparative analysis unveiled no statistically significant differences in flow rates of unstimulated upper labial saliva (ULS), unstimulated whole saliva (UWS), and stimulated whole saliva (SWS) between the control group and patients who underwent bariatric surgery. However, in patients undergone BS with xerostomia, both ULS and UWS flow rates were significantly lower than in controls with xerostomia (p = 0.014 and p = 0.007, respectively). The buffering capacity was significantly lower in patients undergone BS than in controls (p = 0.009). No differences were found between groups regarding CHGA concentration and output values, nevertheless, higher values of CHGA concentrations were significantly correlated to lower flow rates. CONCLUSION: According to the results, this study suggests that individuals undergoing BS may exhibit altered salivary buffering capacity and reduced unstimulated salivary flows in the presence of xerostomia. Additionally, the findings suggest that elevated concentration of salivary CHGA might be associated, in part, with salivary gland hypofunction. CLINICAL RELEVANCE: The clinical significance of this study lies in highlighting the changes in salivary functions after BS. The identified salivary alterations might be attributed to adverse effects of BS such as vomiting, gastroesophageal reflux, and dehydration. Understanding these changes is crucial for healthcare professionals involved in the care of post-BS patients, as it sheds light on potential oral health challenges that may arise as a consequence of the surgical intervention. Monitoring and managing these salivary alterations can contribute to comprehensive patient care and enhance the overall postoperative experience for individuals undergoing BS.

Assuntos

Cirurgia Bariátrica , Xerostomia , Humanos , Pessoa de Meia-Idade , Cromogranina A , Saliva , Glândulas Salivares , Xerostomia/complicações

RESUMO

The protozoan parasite Leishmania (Viannia) braziliensis is among Latin America's most widespread Leishmania species and is responsible for tegumentary leishmaniasis (TL). This disease has multiple clinical presentations, with cutaneous leishmaniasis (CL) being the most frequent. It manifests as one or a few localized skin ulcers, which can spread to other body areas. Hence, early diagnosis and treatment, typically with pentavalent antimonials, is critical. Traditional diagnostic methods, like parasite culture, microscopy, or the polymerase chain reaction (PCR) for detection of the parasite DNA, have limitations due to the uneven distribution of parasites in biopsy samples. Nonetheless, studies have revealed high levels of parasite-specific anti-α-Gal antibodies in L. (V.) braziliensis-infected patients. Previously, we demonstrated that the neoglycoprotein NGP28b, consisting of the L. (Leishmania) major type-2 glycoinositolphospholipid (GIPL)-3-derived trisaccharide Galpα1,6Galpα1,3Galfß conjugated to bovine serum albumin (BSA) via a linker, acts as a reliable serological biomarker (BMK) for L. (V.) braziliensis infection in Brazil. This indicates the presence of GIPL-3 or a similar structure in this parasite, and its terminal trisaccharide either functions as or is part of an immunodominant glycotope. Here, we explored whether extending the trisaccharide with a mannose unit would enhance its efficacy as a biomarker for the serological detection of L. (V.) braziliensis. We synthesized the tetrasaccharide Galpα1,6Galpα1,3Galfß1,3Manpα(CH2)3SH (G31SH) and conjugated it to maleimide-functionalized BSA to afford NGP31b. When we assessed the efficacy of NGP28b and NGP31b by chemiluminescent enzyme-linked immunosorbent assay on a cohort of CL patients with L. (V.) braziliensis infection from Bolivia and Argentina against a healthy control group, both NGPs exhibited similar or identical sensitivity, specificity, and accuracy. This finding implies that the mannose moiety at the reducing end is not part of the glycotope recognized by the parasite-specific anti-α-Gal antibodies in patients' sera, nor does it exert a relevant influence on the terminal trisaccharide's conformation. Moreover, the mannose does not seem to inhibit glycan-antibody interactions. Therefore, NGP31b is a viable and dependable BMK for the serodiagnosis of CL caused by L. (V.) braziliensis.

Assuntos

Leishmania braziliensis , Leishmaniose Cutânea , Humanos , Leishmania braziliensis/genética , Manose , Leishmaniose Cutânea/diagnóstico , Leishmaniose Cutânea/tratamento farmacológico , Glicoproteínas , Trissacarídeos

RESUMO

INTRODUCTION: Laboratory diagnosis of measles can be challenging, and the reintroduction of the measles virus in Brazil has brought about new issues. The aim of this study was to analyze the qPCR results of swab and urine samples and compare them with those of immunological methods for the diagnosis of measles. METHODS: This was a cross-sectional study based on a retrospective analysis of 3,451 suspected cases using laboratory test surveillance databases for qPCR (respiratory swabs and urine) and serologic tests for IgM and paired IgG. Sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and agreement through kappa and adjusted kappa coefficients (PABAK) were calculated using different diagnostic strategies. RESULTS: The swab and urine samples obtained using real-time qPCR were equivalent. Samples collected simultaneously and the combined samples showed moderate agreement between IgM ELISA and real-time qPCR; however, 48.9 % of the IgM ELISA analyses did not demonstrate detectable qPCR concentrations during simultaneous collections and 43.9 % of combined collections. The paired analysis of IgG showed an accuracy of 67.5 % for IgM and 90.7 % for real-time qPCR. CONCLUSIONS: Diagnosis based on IgM presents detection delimitation in samples collected early (1-5 days), suggesting that these individuals satisfy at least two criteria. In addition to qPCR, paired analysis of IgG using ELISA can be used to increase the sensitivity and specificity of laboratory diagnoses.

Assuntos

Anticorpos Antivirais , Sarampo , Humanos , Brasil/epidemiologia , Estudos Retrospectivos , Estudos Transversais , Sarampo/diagnóstico , Sarampo/epidemiologia , Técnicas de Laboratório Clínico , Ensaio de Imunoadsorção Enzimática/métodos , Sensibilidade e Especificidade , Surtos de Doenças , Imunoglobulina M , Imunoglobulina G

RESUMO

Resumen Objetivo: Establecer un inmunoensayo semicuantitativo para la detección de anticuerpos contra el dominio de unión al receptor de la proteína de espícula del coronavirus del síndrome respiratorio agudo grave tipo 2 y la evaluación de su desempeño como herramienta de apoyo diagnóstico. Métodos: Se generó una proteína recombinante del dominio de unión a receptor de la proteína de espícula del coronavirus del síndrome respiratorio agudo grave tipo 2. Dicha proteína se empleó como sustrato antigénico en la estandarización de dos ensayos semicuantitativos por inmunoadsorción ligados a enzima para la detección de inmunoglobulinas M e inmunoglobulinas G humanas. Se utilizó un conjunto de muestras de suero positivas (n=129), provenientes de donantes voluntarios con infección previa por el virus SARS-CoV-2, confirmada mediante reacción en cadena de la polimerasa con transcriptasa reversa, y tomadas entre agosto de 2020 y noviembre de 2021. Además, se empleó un panel de muestras prepandémicas negativas (n=196) obtenidas antes de diciembre de 2019 para la evaluación del desempeño de los ensayos; se recibieron muestras múltiples seriadas de 99 donantes voluntarios para examinar la respuesta de la prueba ante la seroconversión y se estudió la posible asociación entre las seropositividades por coronavirus del síndrome respiratorio agudo grave tipo 2 y por el virus del dengue para la evaluación de reacciones cruzadas inespecíficas. Resultados: El ensayo de detección de inmunoglobulina G mostró 81.4 % de sensibilidad, 86.2 % de especificidad y valores predictivos positivos y negativos de 79.5 % y 87.6 % respectivamente. Por su parte, el ensayo de detección de inmunoglobulina M mostró solamente 72.1 % de sensibilidad, 54.1 % de especificidad y valores predictivos positivos y negativos de 25.6 % y 89.8 % respectivamente. No se encontraron diferencias significativas entre las mediciones semicuantitativas según sexo ni correlación lineal entre esta variable y la edad. Los valores obtenidos para el inmunoensayo presentaron diferencias significativas según el autorreporte de presencia o ausencia de síntomas compatibles con COVID-19. No se encontró correlación entre las seropositividades contra el coronavirus del síndrome respiratorio agudo grave tipo 2 y el virus del dengue. El ensayo de detección de inmunoglobulina G generó valores inferiores pero constantes en muestras de donantes voluntarios que autorreportaron no haber tenido contacto con el virus SARS-CoV-2. En contraste, las muestras de donantes expuestos al virus SARS-CoV-2 mostraron valores elevados pero variables en magnitud. Además, se observaron valores elevados y variables en muestras de voluntarios vacunados o con infección previa. Conclusiones: Nuestro ensayo de detección de inmunoglobulina M presenta escaso valor diagnóstico. Por el contrario, el ensayo de detección de inmunoglobulina G muestra un rendimiento satisfactorio y se apega al comportamiento reportado para este tipo de prueba según las características demográficas y clínicas de los usuarios; por lo tanto, este ensayo podría ser empleado como herramienta fiable y práctica en aplicaciones clínicas y como apoyo al diagnóstico. Es necesario desarrollar más estudios sobre reacciones cruzadas entre los anticuerpos contra el coronavirus del síndrome respiratorio agudo grave tipo 2 con aquellos de otras entidades de interés clínico, sobre todo las presentes en países tropicales como el nuestro.

---

Abstract Aim: To establish a semiquantitative immunoassay for antibody detection against the RBD of the severe acute respiratory syndrome coronavirus 2 spike protein and to evaluate its performance to be used as a diagnostic supporting tool. Methods: A recombinant severe acute respiratory syndrome coronavirus 2 spike protein was produced. This protein was used as antigenic substrate in two semiquantitative enzyme-linked immunoassays for the detection of human immunoglobulins M and immunoglobulins G. A set of serum samples (N=129) from patients with prior viral infection confirmed by reverse transcription polymerase chain reaction, processed between August 2020 and November 2021, were used as positive samples. A panel of pre-pandemic samples (N=196), obtained prior to December 2019, were used as negative samples to evaluate the assay performance. Multiple samples from 99 volunteers were used to examine test response to seroconversion. The interference between seropositivity against severe acute respiratory syndrome coronavirus 2 and dengue virus was also evaluated. Results: The immunoglobulin G detection assay showed 81.4% sensitivity, 86.2% specificity, and positive and negative predictive values of 79.5% and 87.6% respectively. The immunoglobulin M detection assay yielded 72.1% sensitivity, 54.1% specificity, and positive and negative predictive values of 25.6% and 89.8% respectively. No significant differences were found between the measurements according to sex or linear correlation between this variable and age. The values presented significant differences according to the condition of self-reported presence or absence of COVID-19 like symptoms. No correlation was found between seropositivity for severe acute respiratory syndrome coronavirus 2 and dengue virus. The immunoglobulin G detection assay generated lower but constant values on samples from voluntary donors who reported not having any contact with the virus compared to samples from donors exposed to it, and high but variable values in magnitude on samples from vaccinated volunteers or those with previous severe acute respiratory syndrome coronavirus 2 infection compared to samples from donors without exposure to the viral antigen. Conclusions: Our established immunoglobulin M detection assay presents poor diagnostic value. On the other hand, the immunoglobulin G detection assay shows satisfactory performance, and coheres to the behavior reported for this type of test according to the demographic and clinic characteristics of the volunteer, so it could be used as a reliable and practical tool in clinical applications and as diagnostic complement. It is necessary to develop more studies on cross-reactions of antibodies against severe acute respiratory syndrome coronavirus 2 with other entities of clinical interest and present in our tropical area.

Assuntos

Humanos , Masculino , Feminino , Pré-Escolar , Criança , Adolescente , Adulto , Pessoa de Meia-Idade , Idoso , Imunoensaio , SARS-CoV-2/imunologia , Imunoglobulina G/análise , Imunoglobulina M/análise , Ensaio de Imunoadsorção Enzimática/tendências , Costa Rica , COVID-19

RESUMO

Bovine leukemia virus (BLV) causes enzootic bovine leukosis, a persistent infection and the most important neoplastic disease in cattle. It is spread primarily by transferring infected lymphocytes through blood from carriers to healthy animals. The present study is aimed at determining the seropositivity of BLV in breeding bulls from Costa Rica and at detecting for the first time in the country BLV DNA in bull semen. Between May 2011 and August 2018, 379 blood and 133 semen samples were collected from bulls distributed in 118 farms. The serum was analyzed by an enzymatic immunoassay and the semen by polymerase chain reaction and sequencing. BLV seropositivity was 43.5% (165/379), while 64.4% (76/118) of the farms had positive reactors. Holstein (75.7%) and Jersey (73.0%) breeds showed the highest seropositivity. In addition, Bos taurus bulls (68.1%), older than seven years (50.0%), and those belonging to dairy farms (75.5%) had higher seropositivity compared to Bos indicus (17.7%), younger than seven years (42.2%), and those from beef farms (15.5%), respectively. Moreover, Bos taurus bulls had a higher risk of being seropositive than Bos indicus (OR = 3.4; 95% CI: 1.7-6.8). BLV DNA was found in one semen sample (2.5%; 1/40) from a seropositive bull. The importance of serum and molecular BLV screening in semen samples and the potential role of some risk factors associated with the disease, such as the bull's age, genotype, and type of livestock productive system, is argued in the present report.

Assuntos

Doenças dos Bovinos , Leucose Enzoótica Bovina , Vírus da Leucemia Bovina , Bovinos , Animais , Masculino , Sêmen , Leucose Enzoótica Bovina/epidemiologia , Costa Rica/epidemiologia , Estudos Soroepidemiológicos

RESUMO

Chikungunya (CHIK) is a debilitating mosquito-borne disease with an epidemiology and early clinical symptoms similar to those of other arboviruses-triggered diseases such as dengue or Zika. Accurate and rapid diagnosis of CHIK virus (CHIKV) infection is therefore challenging. This international study evaluated the performance of the automated VIDAS® anti-CHIKV IgM and IgG assays compared to that of manual competitor IgM and IgG ELISA for the detection of anti-CHIKV IgM and IgG antibodies in 660 patients with suspected CHIKV infection. Positive and negative agreements of the VIDAS® CHIKV assays with ELISA ranged from 97.5% to 100.0%. The sensitivity of the VIDAS® CHIKV assays evaluated in patients with a proven CHIKV infection confirmed reported kinetics of anti-CHIKV IgM and IgG response, with a positive detection of 88.2-100.0% for IgM ≥ 5 days post symptom onset and of 100.0% for IgG ≥ 11 days post symptom onset. Our study also demonstrated the superiority of ELISA and VIDAS® assays over rapid diagnostic IgM/IgG tests. The analytical performance of VIDAS® anti-CHIKV IgM and IgG assays was excellent, with a high precision (coefficients of variation ≤ 7.4%) and high specificity (cross-reactivity rate ≤ 2.9%). This study demonstrates the suitability of the automated VIDAS® anti-CHIKV IgM and IgG assays to diagnose CHIKV infections and supports its applicability for epidemiological surveillance and differential diagnosis in regions endemic for CHIKV.