title: Susceptibility of a Brazilian wild rodent isolate of Schistosoma mansoni to praziquantel in mice.
abstract: The therapeutic effects of praziquantel (PZQ) against a Schistosoma mansoni isolate derived from Nectomys squamipes (isolate R) and a susceptible isolate (BH) were analyzed in Swiss mice by fecal egg counting, adult worm reduction and oogram pattern. Infected mice were orally administrated with 62.5mg/kg (group 1), 125mg/kg (group 2), 250mg/kg (group 3) and 500mg/kg (group 4), each dose divided over 3 days (49, 50 and 51 days after infection). The data were analyzed using one-way analysis of variance (ANOVA). In regard to isolate R, no fecal eggs were observed with 250 mg/Kg and 500 mg/kg (p<0.05), whereas BH excretion reached zero with all doses. Mean worm burden reduction was significantly (p<0.05) higher at the two highest concentrations, regardless of isolate. At 62.5mg/kg, the percentage of immature eggs varied from 17% (isolate R) to 38% (isolate BH). At 125 mg/kg, the percentage of immature eggs varied from 20% (isolate R) to 16% (isolate BH). At 250 mg/kg, immature eggs dropped significantly to 1% (isolate R) and 4% (isolate BH). At 500 mg/kg, no immature eggs were found in isolate R, whereas in BH was 8%. No dosage significantly (p>0.05) affected the percentage of mature eggs, regardless of isolate. There was a large increase (p<0.001) in the percentages of dead eggs in all treated groups of 62% and 64% in groups 3 and 4, respectively (isolate R). The percentage of dead eggs rose from 34% (group 1) to 58% (group 3) in isolate BH. Although group 4 showed lowest increase in the percentage of dead eggs (46%), it was higher (p<0.001) compared to the 8% in the control. Our findings indicate that the wild isolate from N. squamipes is susceptible to PZQ.
authors.affiliation: Laboratory of Biology and Parasitology of Wild Mammal Reservoirs, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Av. Brasil 4365, Manguinhos, 21045-900 Rio de Janeiro, Brazil.
authors.forename: Michele
authors.initials: M
authors.lastname: Costa-Silva
authors.forename: Lucas de Andrade
authors.initials: Lde A
authors.lastname: Barros
authors.forename: Juberlan Silva
authors.initials: JS
authors.lastname: Garcia
authors.forename: Renata Heisler
authors.initials: RH
authors.lastname: Neves
authors.forename: Rosângela
authors.initials: R
authors.lastname: Rodrigues-Silva
authors.forename: José Roberto
authors.initials: JR
authors.lastname: Machado-Silva
authors.forename: Arnaldo
authors.initials: A
authors.lastname: Maldonado-Júnior
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000871:Anthelmintics / Q000494:pharmacology* / Q000627:therapeutic use; D001938:Brazil; D004197:Disease Reservoirs; D004305:Dose-Response Relationship, Drug; D005243:Feces / Q000469:parasitology; D005260:Female; D007421:Intestine, Small / Q000469:parasitology; D008297:Male; D051379:Mice; D010270:Parasite Egg Count; D011223:Praziquantel / Q000494:pharmacology* / Q000627:therapeutic use; D012424:Rural Population; D012550:Schistosoma mansoni / Q000187:drug effects*; D012555:Schistosomiasis mansoni / Q000188:drug therapy* / Q000469:parasitology; D016205:Sigmodontinae / Q000469:parasitology*
chemical_list: D000871:Anthelmintics; D011223:Praziquantel