WILLIAM HENRY ROLDAN GONZALES
Projetos de Pesquisa
Unidades Organizacionais
LIM/06 - Laboratório de Imunopatologia da Esquistossomose e outras Parasitoses, Hospital das Clínicas, Faculdade de Medicina
13 resultados
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- Diagnostic accuracy of somatic and excretory-secretory antigens from Strongyloides venezuelensis infective larvae for the immunodiagnosis of human strongyloidiasis(2021) GONZALES, William Henry Roldan; MEISEL, Dirce Mary Correia Lima; PAULA, Fabiana Martins de; GRYSCHEK, Ronaldo Cesar BorgesTo evaluate the diagnostic accuracy of three types of antigenic preparations from Strongyloides venezuelensis infective larvae for detection of serum IgG anti-Strongyloides antibodies by enzyme-linked immunosorbent assay (ELISA). Soluble somatic fractions (SSF) and membrane somatic fractions (MSF) and excretory-secretory (E/S) products from S. venezuelensis infective larvae were evaluated against 71 sera from individuals with strongyloidiasis, 105 sera from healthy individuals, and 84 sera from individuals with other helminth infections. Using an ELISA cut-off for 100% sensitivity, E/S products were 97.88% specific followed by MSF (93.12%) and then by SSF (85.2%). The occurrence of cross-reactivity with other helminths was 4.76% (4/84) with E/S products, 8.33% (7/84) with MSF, and 17.86% (15/84) with SSF. For a cut-off for 100% specificity, E/S products showed a sensitivity of 88.73% whereas MSF and SSF showed sensitivities of 59.15% and 53.52%, respectively. In conclusion, E/S products were the best antigenic option for the serodiagnosis of human strongyloidiasis.
- Culture isolation and molecular identification of Blastocystis sp. in Brazilian human isolates: preliminary results(2020) MELO, Gessica Baptista de; ROLDAN, William; MALTA, Fernanda de Mello; LESCANO, Susana Angelica Zevallos; CASTILHO, Vera Lucia; GONCALVES, Elenice Messias Do Nascimento; PAULA, Fabiana Martins de; GRYSCHEK, Ronaldo Cesar BorgesBlastocystis sp. is a protist commonly found in stool samples of humans and animals. Biological and genetic factors of this organism remain controversial. The present study aimed to develop and implement the Blastocystis in vitro culture of Brazilian human isolates for routine use. The fecal isolates (n = 20) were maintained in our laboratory by several passages in Pavlova's medium. Cultures were monitored every 72 h by light microscopy. Genomic DNA was extracted to identify the subtypes (STs). In most isolates, the vacuolar form was prevalent. The amoeboid, granular and cystic forms were observed during in vitro cultivation. STs 1, 2, 3. 4 and 7 were identified. Our preliminary results show the generation time and forms present in the in vitro culture of Blastocystis subtypes isolated from Brazilian human isolates. Therefore, we emphasize the use of in vitro culture as a tool in future studies for the better understanding of the biological aspects of Blastocystis sp.
- Serosurvey of anti-Toxocara canis antibodies in people experiencing homelessness and shelter workers from Sao Paulo, Brazil(2022) SANTAREM, Vamilton Alvares; COUTO, Anahi Chechia do; LESCANO, Susana Zevallos; ROLDAN, William Henry; DELAI, Ruana Renostro; GIUFFRIDA, Rogerio; KMETIUK, Louise Bach; BIONDO, Alexander Welker; DANGOUDOUBIYAM, Sriveny; SANTOS, Andrea Pires DosBackground: Despite being one of the most prevalent helminth parasitic zoonoses worldwide and particularly in socioeconomically vulnerable populations, toxocariasis remains to be fully investigated in persons experiencing homelessness. Accordingly, the present study has aimed to assess the seroprevalence and associated risk factors of Toxocara spp. exposure in persons experiencing homelessness and shelter workers from a day-shelter in Sao Paulo city, Brazil. Methods: Anti-Toxocara IgG antibodies were detected by enzyme-linked immunosorbent assay (ELISA). Univariable and multivariable logistic regression models were performed to assess the risks for toxocariasis. Results: Overall, anti-Toxocara IgG antibodies were detected in 89/194 (45.9%, 95% CI: 39.0-52.9%) persons experiencing homelessness, twice as high (OR =2.2; 95% CI = 1.245-3.873; P= 0.0089) than the frequency of 22/79 (27.8%, 95% CI: 19.2-38.6) in shelter workers. College education was the only protective factor for Toxocara spp. exposure (OR: 0.23; P= 0.018) revealed by logistic regression. Conclusions: Although indicating a multifactorial origin of toxocariasis, the present study has assessed a highly vulnerable population with high disease risks and premature death. Thus, the living conditions of the homeless population have influenced the high prevalence of anti-Toxocara antibodies verified here compared with domiciled shelter workers. Despite being less exposed, shelter and other outdoor workers may present an occupational risk to toxocariasis. Future studies should establish whether such environmental exposure might occur in persons experiencing homelessness in other regions worldwide.
- A simple method for purification of Strongyloides venezuelensis eggs from rat faeces(2020) ROLDAN, W. H.; PAULA, F. Martins de; GRYSCHEK, R. C. B.The aim of this study was to develop a simple method to purify Strongyloides eggs from rat faeces using a sucrose gradient centrifugal-flotation technique. This procedure is simple, rapid and possesses a high efficiency in recovering Strongyloides eggs without faecal detritus in less than one hour, thus eliminating the use of complex apparatus and different chemical substances. The possibility of working with pure and live Strongyloides eggs opens up a wide range of future studies on the biology of this parasite. This study constitutes the first report in the scientific literature on purifying Strongyloides eggs using a sucrose density gradient.
- Kinetics and avidity of anti-Toxocara antibodies (IgG) in rabbits experimentally infected with Toxocara canis(2016) BIN, Lundia Luara Cavalcante; SANTAREM, Vamilton Alvares; LAPOSY, Cecilia Braga; RUBINSKY-ELEFANT, Guita; ROLDAN, William Henry; GIUFFRIDA, RogerioAn evaluation was made of the kinetics and avidity of anti-Toxocara antibodies (IgG) in rabbits experimentally infected with embryonated Toxocara canis eggs. Seventeen four month old New Zealand White rabbits were distributed into two groups. In the experimental group, twelve rabbits were infected orally with 1,000 embryonated T. canis eggs. A second group (n = 5), uninfected, was used as a control. Serum samples were collected for analysis on days 7, 14, 21, 28 and 60 post-infection (DPI). An indirect ELISA test was performed to evaluate the reactivity index (RI) of IgG anti-T. canis antibodies and to calculate the avidity index (AI). The animals showed seroconversion from the 14th DPI, with high AI (over 50%) except for one animal, which presented an intermediate AI. At 60 DPI, all the animals were seropositive and maintained a high AI. The data indicated that specific IgG antibodies formed early (14 DPI) in rabbits infected with T. canis, with a high avidity index that persisted throughout the course of the infection.
- Risk factors for toxocariasis during incarceration: the One Health intervention approach(2023) SANTAREM, Vamilton Alvares; PINTO, Gabriel Luis Brucinski; SOUZA FILHO, Roberto Teixeira de; FERREIRA, Isabella Braghin; LESCANO, Susana Angelica Zevallos; GONZALES, William Henry Roldan; KOSLOSKI, Jully; RIBEIRO, Juliano; GIUFFRIDA, Rogerio; SANTOS, Andrea Pires dos; KMETIUK, Louise Bach; BIONDO, Alexander WelkerDespite potential exposure to soil-transmitted helminths, especially when stray dogs and cats are present, toxocariasis in inmate populations remains to be established. Accordingly, the present study assessed the seroprevalence and associated risk factors of toxocariasis at the Women's State Penitentiary of Parana, Brazil. A total of 234/370 (63.2%; 95% CI 58.2-68.0) women inmates and 28/87 (32.2%; 95% CI 23.3-42.6) correctional officers were seropositive for anti-Toxocara spp. IgG by ELISA, with inmates 2.62-fold more likely positive (p = 0.00000026). The univariate model has identified that non-white (OR = 1.58, p = 0.047) and older than 39 years (OR = 1.28, p = 0.032) inmates were associated with mild but significant odds for seropositivity. Elementary or higher educational level was considered a protective factor for seropositivity. The presence of Toxocara spp. eggs was observed in 10/15 (66.7%) collected soil samples by centrifuge-flotation in Zinc Sulfate, and molecular analysis by PCR identified only Toxocara cati in these eggs. An intervention program was established with regular trap-neuter-release, with gradual removal for adoption (donation campaigns), treatment, and euthanasia when necessary (particularly due to advanced sporotrichosis). In addition, an educational awareness agenda was proposed, aiming to reduce soil contamination and accidental intake by the incarcerated population. A total of 40 feral cats were trapped, 20 males and 20 females, mostly adults. After trapping, 36 cats were neutered, treated, and microchipped in the Veterinary Teaching Hospital (VTH) at the Federal University of Parana. Five trapped feral cats were euthanized, four diagnosed with advanced sporotrichosis, and one already neutered cat (not herein) with complications due to feline immunodeficiency virus (FIV). Female inmates presented higher seroprevalence for Toxocara spp. antibodies when compared to correctional officers, significantly associated with age, selfdeclared ethnicity (non-white), and lack of formal education. Despite the non-natural scenario of a state penitentiary, the One Health approach of Toxocara spp. has highlighted the interdisciplinary nature of the study and its relevance in understanding the complex interactions between human, animal, and environmental factors, particularly impacting female inmates. Further studies should establish the rate of inmate infection over time while deprived of liberty.
- 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.
- Entamoeba gingivalis and Trichomonas tenax: Protozoa parasites living in the mouth(2023) SANTOS, Juliana Oliveira; ROLD, William HenryObjective: This review article aims to summarize the existing data on the history, biology and potential patho-genicity of Entamoeba gingivalis and Trichomonas tenax in periodontal disease, as well as the available techniques for laboratory diagnosis.Design: A detailed review of scientific literature available up to October 1, 2022 in three databases (PubMed, Scopus and Web of Science) was performed relevant to biology, biochemistry, epidemiology, and experimental studies on infection by E. gingivalis and T. tenax, as well as laboratory techniques for the diagnosis of both protozoa in periodontal diseases.Results: Accumulated evidence over the decades indicates that the protozoa E. gingivalis and T. tenax are able to interact with host cells and induce inflammation in the periodontal tissue by promoting the expression of pro -inflammatory molecules and the recruitment of neutrophils, contributing to the periodontal disease process. Among the available techniques for the laboratory diagnosis, culture and molecular assays seems to be the best tools for detection of both protozoan parasites.Conclusions: E. gingivalis and T. tenax are potentially pathogens that colonize the oral cavity of humans and may cause periodontal disease.
- Serosurvey and associated risk factors of anti-Toxocara spp. antibodies in bovines from slaughterhouses of southeastern Brazil(2021) GIUDICE, Paula Andreia Fabris; LESCANO, Susana Angelica Zevallos; GONZALES, William Henry Roldan; GIUFFRIDA, Rogerio; BANDEIRA, Fernanda Nobre; KMETIUK, Louise Bach; SANTOS, Andrea Pires dos; BIONDO, Alexander Welker; SANTAREM, Vamilton AlvaresBackground: Toxocariasis, caused by a nematode species of the genus Toxocara, has been described as one of the most prevalent zoonotic helminthiases worldwide. Human transmission may occur by ingesting Toxocara spp. larvae from raw or undercooked meat or organs; however, no comprehensive serosurvey study has been conducted to date investigating the role of cattle as paratenic hosts. The aim of the study reported here was to assess the prevalence of anti-Toxocara spp. antibodies and associated risk factors in bovines from two slaughterhouses located in Presidente Prudente, southeastern Brazil. Methods: Blood samples were collected and tested by indirect enzyme-linked immunosorbent assay (ELISA). Cattle farmers voluntarily responded to an epidemiologic questionnaire. Results: Overall, 213 of the 553 (38.5%) bovine samples were assessed as seropositive for anti-Toxocara spp. antibodies by indirect ELISA. Multivariate analysis revealed that the source of beef cattle and the presence of dogs or cats at the farm were associated with seropositivity. The use of feedlot systems was associated with lower likelihood of seropositivity. Conclusions: These results indicate a high level of anti-Toxocara seropositivity in slaughterhouse cattle, with potentially contaminated meat posing an infection risk to humans. In addition, the presence of dogs and cats where the slaughtered beef cattle were raised was statistically associated with bovine seropositivity, probably due to the overlapping environment at the farm and the lack of pet deworming. The use of feedlot systems was a protective factor likely due to the absence of dog and cat contact, elevated feeding troughs that avoid contact with contaminated soil or grass, and younger age at slaughter of feedlot cattle. In summary, bovines may be used as environmental sentinels of Toxocara spp. contamination, and high seropositivity of slaughterhouse cattle may indicate a potential risk of human toxocariasis through the ingestion of raw or undercooked contaminated meat.
- Deglycosylation of Toxocara excretory-secretory antigens improves the specificity of the serodiagnosis for human toxocariasis(2015) ROLDAN, W. H.; ELEFANT, G. R.; FERREIRA, A. W.Serodiagnosis of human toxocariasis is difficult in tropical areas where other helminthiasis are endemic. Many studies have shown that glycans from helminths may be the responsible for cross-reactions in the immunoassays. In this study, we have evaluated the deglycosylation of the Toxocara canis excretory-secretory (TES) antigens for the detection of IgG antibodies using a panel of 228 serum samples (58 patients with toxocariasis, 75 patients with other helminth infections and 95 healthy individuals) by ELISA and Western blot assays. Our results showed that the deglycosylation of TES antigens resulted in a single fraction of 26 kDa (dTES) and was able to detect IgG antibodies with a sensitivity and specificity of 100% in both above-mentioned assays. The rate of cross-reactions, observed in ELISA with TES (133%), was significantly reduced (53%) when the dTES antigens were used. Likewise, the cross-reactivity observed with the fractions of 32, 55 and 70 kDa of the TES antigens was totally eliminated when the dTES were used in the Western blot. All these results showed that the deglycosylation of the TES antigens really improves the specificity of the serodiagnosis of human toxocariasis in endemic areas for helminth infections.