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
4 resultados
Resultados de Busca
Agora exibindo 1 - 4 de 4
- 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.
- 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.
- 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.
- One Health approach on human seroprevalence of anti-Toxocara antibodies, Toxocara spp. eggs in dogs and sand samples between seashore mainland and island areas of southern Brazil(2021) DELAI, Ruana Renostro; FREITAS, Aaronson Ramathan; KMETIUK, Louise Bach; MERIGUETI, Yslla Fernanda Fitz Balo; FERREIRA, Isabella Braghin; LESCANO, Susana Angelica Zevallos; GONZALES, William Henry Roldan; BRANDAO, Ana Perola Drulla; BARROS-FILHO, Ivan Roque de; PETTAN-BREWER, Christina; FIGUEIREDO, Fabiano Borges; SANTOS, Andrea Pires dos; PIMPAO, Claudia Turra; SANTAREM, Vamilton Alvares; BIONDO, Alexander WelkerToxocariasis, caused by Toxocara spp. nematodes, is among the top 5 neglected parasitic diseases worldwide; however, no comprehensive study to date has serologically compared infections in people and their dogs and environmentally contaminated soil or sand of mainland and island locations. Accordingly, this study aimed to assess the seroprevalence of anti-Toxocara antibodies in traditional human seashore populations, the presence of eggs in dogs' feces and hair, and the presence of eggs in environmental samples from islands compared to the adjacent mainland of southern Brazil. Overall, 212/328 (64.6%) people were positive for Toxocara spp. antibodies, including 125/190 (65.8%) island and 87/138 (63.0%) mainland residents. For dog samples, 12/115 (10.43%) were positive for the presence of Toxocara spp. eggs, all from dogs living in islands, and 22/104 (21.15%) dog hair samples contained eggs of Toxocara spp. Environmental contamination with Toxocara spp. eggs was observed in 50/130 (38.46%) samples from all sampled sites. No significant association was found between risk factors (age, sex, educational level, monthly income, owning dogs or cats, ingestion of treated water, and consumption of raw or uncooked meat) and Toxocara spp. seropositivity. The present study is the first concurrent report on people, their dogs, and environmental contamination of Toxocara spp. The high prevalence we observed in the seashore populations of both in island and mainland areas may be caused by exposure to contaminated sand and climatic factors favoring frequent exposure to Toxocara spp. In conclusion, seashore lifestyle and living conditions of both island and mainland areas may have predisposed higher contact with infected pets and contaminated soil, favoring the high prevalence of toxocariasis.