Resistance of Biomphalaria occidentalis from Varzea das Flores dam, Minas Gerais, to Schistosoma mansoni infection detected by low stringency polymerase chain reaction

Biomphalaria occidentalis Paraense, 1981 from Varzea das Flores dam, MG, Brazil, was exposed to infection with Schistosoma mansoni. Individual infection was performed with 140 B. occidentalis and 100 B. glabrata snails using LE and SJ strains. Two groups of B. occidentalis were killed after seven day-miracidia exposure to detect S. mansoni DNA, through the low stringency polymerase chain reaction (LS-PCR), and were negative. The infection rates were 69.2 percent (LE strain) and 96.7 percent (SJ strain) for B. glabrata and 0 percent for B. occidentalis. LS-PCR enabled early resistance diagnosis

Suscetibilidade aos agentes quimioterápicos de isolados de Schistosoma mansoni oriundos de pacientes tratados com oxamniquine e praziquantel e näo curados / Susceptibility to the chemotherapeutical compounds of Schistosoma mansoni from patients treated with oxamniquine and praziquantel and not cured ones

Ten inhabitants of Itaquara, Bahia, Brazil treated with oxamniquine and subsequently praziquantel were not cured. Schistosoma mansoni isolates derived from these patients were studied. Snails were infected with miracidia derived from the feces of these patients and the cercariae produced used to infect albino mice. The animals were then treated with a single oral dose of oxamniquine (25, 50 and 100mg/kg) or praziquantel (100, 200 and 400 mg/kg). The response to chemotherapy was significantly different in some of the isolates although it was not possible to characterize any of them as resistant. In addition, DNA analysis of the isolates by means of ®Random Amplified Polymorphic DNA® indicated a low degree of variability as compared with a laboratory strain, LE. Thus, it was not possible to characterize these organisms at a genetic level as a distinct strain.