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.

Natural Schistosoma mansoni Infection in the Wild Reservoir Nectomys squamipes Leads to Excessive Lipid Droplet Accumulation in Hepatocytes in the Absence of Liver Functional Impairment

“…mansoni isolated from N . squamipes is susceptible to the therapeutic effects of praziquantel [46], the most used chemotherapy to treat human schistosomiasis [1]. …”

From field to laboratory: isolation, genetic assessment, and parasitological behavior of Schistosoma mansoni obtained from naturally infected wild rodent Holochilus sciureus (Rodentia, Cricetidae), collected in Northeastern Brazil

“…These rodents are highly susceptible to S. mansoni infection (Souza et al 1992; Maldonado et al 1994;Miranda et al 2019), showing a high number of viable eggs in feces (Piva 1966;Dias et al 1978;Picot 1992;Souza et al 1992), persistent infections (Souza et al 1992) and good pathological tolerance (Silva and Andrade 1989;Amaral et al 2016;Miranda et al 2019). Furthermore, previous experimental studies using S. mansoni from naturally infected N squamipes and H. sciureus demonstrated distinct morphological and biological characteristics between parasite strains isolated from wild rodents and humans, including differences in morphological aspects of adult worms (Machado- , pathogenicity in mice (Bastos et al 1984, Silva andAndrade 1989), compatibility/virulence in Biomphalaria snails (Bastos et al 1982) and sensitivity to praziquantel (PZQ) (Costa- Silva et al 2012). However, to advance the knowledge pertaining to the pathology and genetics of schistosomes from Brazilian wild rodents, it is important to isolate and maintain the parasite under laboratory conditions.…”