RONALDO CESAR BORGES GRYSCHEK
Projetos de Pesquisa
Unidades Organizacionais
Departamento de Moléstias Infecciosas e Parasitárias, Faculdade de Medicina - Docente
LIM/06 - Laboratório de Imunopatologia da Esquistossomose e outras Parasitoses, Hospital das Clínicas, Faculdade de Medicina
LIM/06 - Laboratório de Imunopatologia da Esquistossomose e outras Parasitoses, Hospital das Clínicas, Faculdade de Medicina
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- Seroprevalence and associated risk factors of strongyloidiasis in indigenous communities and healthcare professionals from Brazil(2023) SANTAREM, Vamilton Alvares; DOLINE, Fernando Rodrigo; SANTOS, Joao Henrique Farinhas dos; FERREIRA, Isabella Braghin; GOMES, Bruna Barroso; MEISEL, Dirce Mary Correa; BIONDO, Leandro Meneguelli; LESCANO, Susana Angelica Zevallos; GRYSCHEK, Ronaldo Cesar Borges; GIUFFRIDA, Rogerio; SANTOS, Andrea Pires dos; KMETIUK, Louise Bach; PAULA, Fabiana Martins de; BIONDO, Alexander WelkerAuthor summaryHuman strongyloidiasis, caused mainly by nematoda Strongyloides stercoralis, with estimate of infecting around 613.9 million people worldwide, and may play a pivotal role in causing morbidity in aboriginals and indigenous populations worldwide. Nevertheless, prevalence and risk factors for Strongyloides stercoralis in Brazilian indigenous populations remains to be fully established. The present study was the first comparative report of S. stercoralis seroprevalence in indigenous population and healthcare professionals. A high seroprevalence to Strongyloides stercoralis in indigenous communities of Brazil along with even higher exposure of healthcare professionals was reported and should be considered as vulnerability and health worker exposure. Male and adult indigenous persons were more likely seropositive as associated risk factors, while having septic tank as a sanitary facility represented a protective factor for S. stercoralis exposure. Thus, the present study has alerted for the public health concerns of strongyloidiasis in such vulnerable populations, particularly when lacking sanitation conditions. Finally, a further One Health approach may contribute for better understanding the strongyloidiasis exposure including the environmental, animal, and human components to battle this important parasitic neglected disease in indigenous communities. Strongyloides stercoralis, a pathogenic roundworm, is considered endemic in several tropical and subtropical areas worldwide. Indigenous populations have the highest soil-transmitted helminthiases-related mortality rates, but the prevalence and risk factors associated with S. stercoralis in Brazilian indigenous populations have not been established. Thus, the present study aimed to assess the seroprevalence and associated risk factors for S. stercoralis in indigenous communities and the healthcare professionals serving them in Brazil. Indigenous populations living in nine communities and healthcare professionals were tested for anti- S. stercoralis antibodies by ELISA. A questionnaire was used to assess socio-epidemiological information. Associated risk factors for seropositivity were tested by chi-square or Fisher's exact tests, using bivariate analyses and multivariate logistic regression. Overall, 174/463 (37.6%; CI 95%: 33.3-42.1) indigenous persons and 77/147 (52.4%; 95% CI: 44.3-60.3) healthcare professionals were seropositive for anti- S. stercoralis antibodies. Seropositivity among the two groups was statistically significant (p = 0.0016; OR = 0.547; 95% CI: 0.376-0.796) and revealed that healthcare professionals were 1.83 times more likely to be seropositive. The multivariate analysis showed that being male or being adult were also risk factors, while having a septic tank as a sanitary facility represented a protective factor for S. stercoralis exposure in indigenous persons. None of the variables evaluated were associated with S. stercoralis exposure in the professional group. The study herein has reported a high seroprevalence to Strongyloides stercoralis in indigenous communities of Brazil and healthcare professionals, warning for potential public health concerns of strongyloidiasis in such populations.
- Strongyloides infection screening in transplant candidates: What is the best strategy?(2023) GRYSCHEK, Ronaldo Cesar Borges; CORRAL, Marcelo Andreetta; SITTA, Renata Barnabe; GOTTARDI, Maiara; PIERROTTI, Ligia Camera; COSTA, Silvia Figueiredo; ABDALA, Edson; CHIEFFI, Pedro Paulo; PAULA, Fabiana Martins deBackground: The potential that Strongyloides stercoralis infection has to cause major morbidity and high mortality when the disseminated form occurs in transplant patients is of particular concern.Methods: In this study, the objective was to observe S. stercoralis infection in patients who are candidates for transplantation by using parasitological, serological, and molecular techniques and to propose an algorithm for the detection of that infection in transplant candidates.Results: By parasitological techniques, 10% of fecal samples were positive. Anti-Strongyloides antibodies immunoglobulin G were detected in 19.3% and 20.7% of patients by immunofluorescence assay and enzyme-linked immunosorbent assay, respectively. S. stercoralis DNA was observed in 17.3% of samples by conventional polymerase chain reaction and 32.7% of samples by quantitative polymerase chain reaction (qPCR).Conclusion: The set of results allows us to reinforce that a positive result by parasitological techniques and/or qPCR indicates that the specific treatment should be applied. However, the improvement of diagnostic techniques may suggest changes in the screening for strongyloidiasis in these patients. image
- Evaluation of larval surface antigens from infective larvae of Strongyloides venezuelensis for the serodiagnosis of human strongyloidiasis(2023) GOMES, Bruna Barroso; GONZALES, William Henry Roldan; MEISEL, Dirce Mary Correa; GRYSCHEK, Ronaldo Cesar Borges; PAULA, Fabiana Martins deSerodiagnosis of strongyloidiasis is usually performed by ELISA for the detection of IgG antibodies due to its high sensitivity and practicality, but its main limitation is a constant source of S. stercoralis antigens. The use of S. venezuelensis as a heterologous source of antigens has facilitated several published studies on the serodiagnosis and epidemiology of human strongyloidiasis. The main objective of this study was to evaluate the diagnostic accuracy of surface cuticle antigens of infective larvae of S. venezuelensis extracted with CTAB detergent (L3-CTAB) in comparison with soluble somatic extracts (L3-SSE) using a panel of sera from immunocompetent and immunocompromised individuals, at three different cut-offs. ROC curve analysis showed that L3-CTAB had an AUC of 0.9926. At the first cut-off value (OD 450 nm = 0.214), sensitivity and specificity were 100% and 90.11%, respectively, with a diagnostic accuracy of 0.93. At a second cut-off value (OD 450 nm = 0.286), sensitivity and specificity were 70% and 100%, respectively, with a diagnostic accuracy of 0.91. However, at an alternative third cut-off value (OD 450 nm = 0.589), sensitivity and specificity were 95% and 97.8%, respectively, with a diagnostic accuracy of 0.97. Using L3-CTAB as an antigenic source, the seropositivity rate in immunocompromised patients was 28.13% (9/32) whereas a seropositivity rate of 34.38% (11/32) was found when L3-SSE was used in ELISA. Therefore, the L3-CTAB is simple and practical to obtain and was found to be highly sensitive and specific.
- Immunofluorescence assay for diagnosis of strongyloidiasis in immunocompromised patients(2015) GOTTARDI, Maiara; PAULA, Fabiana M.; CORRAL, Marcelo A.; MEISEL, Dirce Mary C.; COSTA, Silvia F.; ABDALA, Edson; PIERROTTI, Ligia C.; YAMASHIRO, Juliana; CHIEFFI, Pedro Paulo; GRYSCHEK, Ronaldo Cesar B.Background: Strongyloides stercoralis is a parasite that causes human strongyloidiasis. The disease ranges from asymptomatic to severe forms, which are often fatal in immunocompromised individuals. Laboratory diagnosis is challenging owing to limitations in the use of conventional parasitological techniques. The present study aimed to evaluate the indirect immunofluorescence assay (IFA) using infective larvae of S. venezuelensis as an antigen for the immunodiagnosis of human strongyloidiasis in immunocompromised patients. Methods: Serum and stool samples from 200 immunocompromised patients (HIV-positive, HTLV-1-positive, and renal, liver, and/or bone marrow transplantation candidates) were used. Stool samples were examined using three parasitological methods: Lutz, Rugai, and culture agar plate. IFA was performed using sections of infective larvae of S. venezuelensis as antigens, and showed 95.4% sensitivity and 95.8% and specificity. Results: Among the 200 patients, 17 (8.5%) were positive for S. stercoralis by at least one parasitological method, and 43 (21.5%) were positive by IFA. Conclusions: IFA can be used as a screening method for the detection of S. stercoralis in immunocompromised patients.
- Prevalence and Associated Factors of Cryptococcal Antigenemia in HIV-Infected Patients with CD4 < 200 Cells/mu L in Sao Paulo, Brazil: A Bayesian Analysis(2022) MIMICOS, Evanthia Vetos; FOSSALUZA, Victor; PICONE, Camila de Melo; SENA, Camila Caroline de; GOMES, Helio Rodrigues; LAZARI, Carolina dos Santos; SILVA, Fernanda Ferreira da; NAKANISHI, Erika Shimoda; NISIDA, Isabelle Vichr; FREITAS, Angela Carvalho; GRYSCHEK, Ronaldo Borges; LAGONEGRO, Eduardo Ronner; LAZERA, Marcia; SHIKANAI-YASUDA, Maria AparecidaCryptococcosis is a severe life-threatening disease and a major cause of mortality in people with advanced AIDS and CD4 <= 100 cells/ mu L. Considering the knowledge gap regarding the benefits of routine application of antigenemia tests in HIV-infected patients with 100-200 CD4 cells/mu L for the prevention of cryptococcal meningitis (CM), we aimed to evaluate the prevalence of positive antigenemia through lateral flow assay (LFA) and associated factors in HIV-infected patients with CD4 < 200 cells/ mu L. Our findings of 3.49% of positive LFA (LFA+) patients with CD4 < 100 cells/mu L and 2.24% with CD4 between 100-200 cells/mu L have been included in a Bayesian analysis with 12 other studies containing similar samples worldwide. This analysis showed a proportion of 3.6% LFA+ patients (95% credible interval-Ci [2.5-5.7%]) with CD4 < 100 cells/mu L and 1.1% (95%Ci [0.5-4.3%]) with CD4 between 100-200 cells/mu L, without statistical difference between these groups. The difference between mortality rates in LFA+ and negative LFA groups was e = 0.05013. Cryptococcoma and CM were observed in the LFA+ group with 100-200 and <100 CD4 cells/mu L, respectively. Considering the benefits of antifungal therapy for LFA+ patients, our data reinforced the recommendation to apply LFA as a routine test in patients with 100-200 CD4 cells/ mu L aiming to expand cost-effectiveness studies in this group.