RESISTANCE TO OXAMNIQUINE OF A Schistosoma mansoni STRAIN ISOLATED FROM PATIENT SUBMITTED TO REPEATED TREATMENTS

Abstract

A strain of Schistosoma mansoni (R1) was isolated from patient previously submitted to four treatments with oxamniquine, and to another one with praziquantel. The results obtained with chemotherapeutic test, by using oxamniquine in mice infected with the strains R1 and LE (standard), showed an evident resistance to the drug in worms of the strain R1. Thus, at the dose of 250 mg/kg oxamniquine, all mice (17) infected with the LE strain did not show surviving worms, whereas 12 out of 17 mice infected with the R1 strain presented surviving worms. At the dose of 200 mg/kg, the LE strain showed recovery rates of 1.06% and 20.58%, whereas the R1 strain presented 18.57% and 61.14%, for male and female worms, respectively. At the dose of 100 mg/kg, the recovery of male worms was 2.6% for the LE strain, and 29.9% for the R1 strain. At the same dose, the recovery of females did not show statistically significant differences between the two strains (LE = 76.38%, R1 = 79.12%). Praziquantel showed similar antischistosomal activity against both studied strains, when administered at the dose of 500 mg/kg.

A comparative parasitologic study on Biomphalaria glabrata snail and C3H/He mice infected with human and murine isolates of Schistosoma mansoni derived from Sumidouro, Rio de Janeiro, Brazil

“…It is widely known that Schistosoma mansoni geographical strains exhibit variability related to infectivity, prepatent period, fecal egg excretion, liver or intestinal egg counts and altered response to schistosomicidal drugs in rodent models (Kassim et al 1979, Coelho et al 1997, Incani et al 2001, Yoshioka et al 2002, Bonesso-Sabadini & Dias 2002. However, little attention has been paid to the biological characteristics of sympatric human and murine strains.…”

Schistosomiasis mansoni in Bananal (State of São Paulo, Brazil): I. Efficiency of diagnostic and treatment procedures

“…The effects of such factors can be serious when only one fecal sample is collected from each subject. Oxamniquine resistant worms, mentioned by Cioli et al (1978), Coura et al (1980), Prata et al (1980), Bina and Prata (1980), Dias et al (1982), Kloetzel (1982) and Coelho et al (1997) also set important limits on the evaluation of prevalence, parasite burden, and risk of infection. All such drawbacks notwithstanding, given the fact that the parasitological surveys were comprehensive, it can be concluded that the prophylactic measures introduced in Bananal succeeded in reducing schistosomiasis prevalence.…”

Surgical hepatosplenic mansonic schistosomiasis in adolescents: repercussions of the post-treatment schistosomotic burden on the hepatic functional reserve

“…It has been reported strains of S. mansoni resistant to oxamniquine (Coelho et al 1997). On the other hand, the dose of this drug has varied from treatment to treatment.…”