SUSANA ANGELICA ZEVALLOS LESCANO
Projetos de Pesquisa
Unidades Organizacionais
Departamento de Moléstias Infecciosas e Parasitárias, Faculdade de Medicina
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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- BEHAVIORAL CHANGES IN Rattus norvegicus COINFECTED BY Toxocara canis AND Toxoplasma gondii(2013) QUEIROZ, Maisa Leite de; VIEL, Tania Araujo; PAPA, Cassio Henrique Gomide; LESCANO, Susana A. Zevallos; CHIEFFI, Pedro PauloUsing an elevated plus maze apparatus and an activity cage, behavioral changes in Rattus norvegicus concomitantly infected by Toxocara canis and Toxoplasma gondii were studied, during a period of 120 days. Rats infected by Toxocara canis or Toxoplasma gondii showed significant behavioral changes; however, in the group coinfected by both parasites a behavioral pattern similar to that found in the group not infected was observed thirty days after infection, suggesting the occurrence of modulation in the behavioral response.
- Migration pattern of Toxocara canis larvae in experimentally infected male and female Rattus norvegicus(2017) SANTOS, Sergio Vieira dos; SANTOS, Felipe Henrique Yazawa; LESCANO, Susana Angelica Zevallos; SANTOS, Daniel Mauricio dos; TIAGO, Erico da Silva; FONSECA, Gabriela Rodrigues e; RIBEIRO, Manoel Carlos Sampaio de Almeida; CHIEFFI, Pedro PauloIntroduction: Migration of Toxocara canis larvae was investigated in male and female Rattus norvegicus. Methods: Eighteen male and 18 female R. norvegicus were infected with 300 T. canis eggs. Three male and three female rats were euthanized at 3, 7, 10, 15, 30, and 60 days post-infection, and T. canis larvae were recovered by means of organ and tissue digestion. Results: Female rats showed a greater number of larvae in the liver than males. Conclusions: Paratenic host sex influences the migration pattern of T. canis larvae.
- Human Toxocariasis: 2010 to 2020 Contributions from Brazilian Researchers(2021) CHIEFFI, Pedro Paulo; LESCANO, Susana Angelica Zevallos; FONSECA, Gabriela Rodrigues e; SANTOS, Sergio Vieira dosThis is a review of the published contributions made by Brazilian researchers between 2010 and 2020 on the natural history of human toxocariasis and the effects of human toxocariasis on nonhuman paratenic hosts.
- Experimental toxocariasis in BALB/c mice: relationship between parasite inoculum and the IgG immune response(2017) FONSECA, Gabriela Rodrigues e; SANTOS, Sergio Vieira dos; CHIEFFI, Pedro Paulo; PAULA, Fabiana Martins de; GRYSCHEK, Ronaldo Cesar Borges; LESCANO, Susana Angelica ZevallosBALB/c mice were inoculated with 5-500 Toxocara canis infective eggs, and bled at 15-120 days post infection (dpi) to evaluate the dynamics of IgG antibody response and larvae distribution. Positive results were observed in all occasions for every inoculum, and a direct proportional relationship between antibody detection and the parasitic load was observed. In samples collected at 60 dpi, detection of IgG was more intense, especially with the 50 and 500 egg doses; also, a correlation between antibody level and egg count was observed with these two inocula. At 120 dpi, a decrease in antibody titer was observed for all groups; and at the end of the experiment, larvae were recovered from carcass, liver and brain. In the liver, larvae were only found in mice inoculated with 500 T. canis eggs. In carcasses, these were recovered in all groups, and the group inoculated with 50 eggs showed the highest percentage of larvae in the brain.
bookPart Ancilostomíase(2013) LESCANO, Susana Angélica Zevallos; CHIEFFI, Pedro Paulo- EFFICACY OF NITAZOXANIDE AGAINST Toxocara canis: LARVAL RECOVERY AND HUMORAL IMMUNE RESPONSE IN EXPERIMENTALLY INFECTED MICE(2015) LESCANO, Susana A. Zevallos; SANTOS, Sergio Vieira dos; ASSIS, Jesiel Mauricio Lemos; CHIEFFI, Pedro PauloThe efficacy of nitazoxanide (NTZ) against toxocariasis was investigated in an experimental murine model and results were compared to those obtained using mebendazole. Sixty male BALB/c mice, aged six to eight weeks-old, were divided into groups of 10 each; fifty were orally infected with 300 larvaed eggs of T. canis and grouped as follows, G I: infected untreated mice; G II: infected mice treated with MBZ (15 mg/kg/day) 10 days postinfection (dpi); G III: infected mice treated with NTZ (20 mg/kg/day) 10 dpi; G IV: infected mice treated with MBZ 60 dpi; G V: infected mice treated with NTZ 60 dpi; GVI: control group comprising uninfected mice. Mice were bled via retro-orbital plexus on four occasions between 30 and 120 dpi. Sera were processed using the ELISA technique to detect IgG anti-Toxocara antibodies. At 120 dpi, mice were sacrificed for larval recovery in the CNS, liver, lungs, kidneys, eyes and carcass. Results showed similar levels of anti-Toxocara IgG antibodies among mice infected but not submitted to treatment and groups treated with MBZ or NTZ, 10 and 60 dpi. Larval recovery showed similar values in groups treated with NTZ and MBZ 10 dpi. MBZ showed better efficacy 60 dpi, with a 72.6% reduction in the parasite load compared with NTZ, which showed only 46.5% reduction. We conclude that administration of these anthelmintics did not modify the humoral response in experimental infection by T. canis. No parasitological cure was observed with either drug; however, a greater reduction in parasite load was achieved following treatment with MBZ.
- IgG ANTIBODY RESPONSES IN MICE COINFECTED WITH Toxocara canis AND OTHER HELMINTHS OR PROTOZOAN PARASITES(2012) LESCANO, Susana A. Zevallos; NAKHLE, Maria Cristina; RIBEIRO, Manoel Carlos S. A.; CHIEFFI, Pedro PauloThe immune response expressed by IgG antibodies in BALB/c mice experimentally infected with Toxocara canis, was studied with the aim of verifying the possible in vivo cross-reactivity between antigens of T. canis and other parasites (Ascaris suum, Taenia crassiceps, Schistosoma mansoni, Strongyloides venezuelensis and Toxoplasma gondii). Experiments included three groups of mice: one infected only by T. canis, another with one of the other species of parasites and a third concomitantly infected with T. canis and the other species in question. Animals were bled by orbital plexus at 23, 38 and 70 days post infection (p.i.). Sera were analyzed for anti-Toxocara antibodies by ELISA and Immunoblotting, using excretion-secretion antigens (ES), obtained from culture of third-stage larvae of T. canis. For all experiments a control group comprised by ten non-infected mice was used. Only in the case of A. suum infection, in these experimental conditions, the occurrence of cross-reactivity with T. canis was observed. However, in the case of co-infection of T. canis - S. mansoni, T. canis - S. venezuelensis and T. canis - T. crassiceps the production of anti-Toxocara antibodies was found at levels significantly lower than those found in mice infected with T. canis only. Co-infection with S. mansoni or S. venezuelensis showed lower mortality rates compared to what occurred in the animals with single infections. Results obtained in mice infected with T. canis and T. gondii showed significant differences between the mean levels of the optical densities of animals infected with T. canis and concomitantly infected with the protozoan only in the 23rd day p.i.
bookPart Esquistossomose(2013) GRYSCHEK, Ronaldo César; CHIEFFI, Pedro Paulo; LESCANO, Susana Angélica Zevallos- Seroprevalence of Toxocara spp. in children with atopy(2014) GRAMA, Daliane Faria; LESCANO, Susana Zevallos; MOTA, Kelem Cristina Pereira; PULTZ, Brunna dos Anjos; MIRANDA, Juliana Silva; SEGUNDO, Gesmar Rodrigues Silva; TAKETOMI, Ernesto Akio; FERNANDES, Karla Pereira; LIMONGI, Jean Ezequiel; PAULA, Fabiana Martins de; CHIEFFI, Pedro Paulo; CURY, Marcia CristinaBackground: Epidemiological studies around the world suggest that infection with Toxocara spp. can contribute to the development or worsening of atopic diseases, especially in children. This study investigated the seroprevalence of toxocariasis in atopic children treated at the pediatric clinic of the Federal University of Uberlandia Clinical Hospital, identifying possible relationships with risk factors. Methods: The study was conducted between November 2011 and March 2013. Blood samples were collected from 173 children aged 6 to 15 years, who were first subjected to clinical exams and then to a skin-prick test to determine the presence or absence of atopy. Risk factors for toxocariasis were analyzed based on a questionnaire. Serum samples were tested for the presence of IgG antibodies to Toxocara spp. by means of enzyme-linked immunosorbent assay. Results: The seroprevalence of Toxocara spp. was 19.6% (24/122) in atopic children and 15% (8/51) in non-atopic children, with no statistical difference. No significant association was found between infection and possible risk factors in atopic and non-atopic children. Conclusions: Although no statistical association was found between human toxocariasis and atopy, this study revealed a high seroprevalence of Toxocara spp. in children that may indicate environmental contamination with the parasite's eggs in the area where these children live.
- BEHAVIORAL AND MEMORY CHANGES IN Mus musculus COINFECTED BY Toxocara canis AND Toxoplasma gondii(2014) CORREA, Flavia Motta; CHIEFFI, Pedro Paulo; LESCANO, Susana A. Zevallos; SANTOS, Sergio Vieira dosSeveral researchers have stated that parasites can alter the behavior of their hosts, in order to increase the transmission rate, principally when prey-predator relationships are a reliable way of infection transmission. The aim of this study was to verify the occurrence of changes in anxiety and short-term memory patterns in experimentally infected Mus musculus by Toxocara canis and/or Toxoplasma gondii. Forty male Mus musculus (Balb/c) eight-week-old were divided into four groups of 10 mice each. One group was infected with 300 eggs of Toxocara canis; a second group was submitted to infection with 10 cysts of Toxoplasma gondii; a third group was concomitantly infected with both parasites with the same inoculums and the last group was maintained without infection. The anxiety levels were evaluated using an elevated plus maze and an actometer; the short-term memory was determined by a two-way active avoidance equipment. The determination of anxiety levels were conducted 40 and 70 days after infection and the short-term memory was evaluated 140 days after infection. Mice chronically infected by Toxoplasma gondii showed impaired learning and short-term memory, but no significant differences were found in mice infected by Toxocara canis or concomitantly infected by Toxocara canis and Toxoplasma gondii when compared to non infected mice.