Rate of action of schistosomicides in mice infected with Schistosoma mansoni

Katz, Naftale; Dias, Emmanuel; Souza, Cecília Pereira de; Bruce, J. I.; Coles, G.C.

doi:10.1590/s0037-86821989000400004

Cited by 8 publications

(5 citation statements)

References 5 publications

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“…This confirms the findings of previous studies showing that disappearance of S. haematobium egg excretion after PZQ treatment is rather slow (Tchuem‐Tchuenté et al. 2004) compared to the rapid reduction in S. mansoni egg counts after treatment (Katz et al. 1989).…”

Section: Resultssupporting

confidence: 91%

Praziquantel efficacy and long-term appraisal of schistosomiasis control in Pemba Island

Гуиди

Andolina

Makame

et al. 2010

Tropical Medicine &Amp; International Health

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Summaryobjective To determine whether praziquantel (PZQ) has retained its efficacy against Schistosoma haematobium on Pemba Island after 20 years of mass administration -albeit discontinuous-and to analyse retrospectively the performance of schistosomiasis control programmes.methods A sample of Pemba schoolchildren was examined before and after PZQ treatment by urine filtration, macro-and micro-haematuria and viability of excreted eggs.results Although 5% of treated children continued to pass some eggs in the urine up to the seventh week after PZQ administration, none of these eggs was viable, indicating an effective schistosomicidal activity followed by a slow release of dead eggs from host tissues.conclusion No signs of PZQ resistance could be detected in the population under study. An overall retrospective analysis of schistosomiasis control activities in Pemba Island revealed that mass drug administration is clearly effective in reducing infection prevalence, but soon after interruption of drug distribution prevalence returns rapidly to pre-intervention levels.

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Section: Resultssupporting

confidence: 91%

Praziquantel efficacy and long-term appraisal of schistosomiasis control in Pemba Island

Гуиди

Andolina

Makame

et al. 2010

Tropical Medicine &Amp; International Health

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“…To assess the utility of in vivo imaging to test antischistosome therapeutics, infected mice were first treated with the drug of choice for treating the infection, PZQ (32). One week after treatment, in vivo imaging was performed on all mice, including an untreated, infected control group and an uninfected, control group, and the results of these analyses are illustrated in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Worms were recovered from infected mice 5‐8 wk after infection by vascular perfusion (31) and were cultured in RPMI medium supplemented with 10 mM HEPES, 2 mM glutamine, 5% fetal calf serum, and antibiotics (100 U/ml penicillin and 100 μg/ml streptomycin) at 37°C, in an atmosphere of 5% CO 2 . To clear an S. mansoni infection, mice (infected with 120 cercariae 7 wk previously) were treated with praziquantel (PZQ) in liquid formulation (500 mg/kg in 2.5% Cremophor El) by gavage (32).…”

Section: Methodsmentioning

confidence: 99%

Imaging schistosomes in vivo

Krautz‐Peterson

Ndegwa

Vasquez³

et al. 2009

FASEB j.

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Schistosomes are intravascular, parasitic helminths that cause a chronic, often debilitating disease afflicting over 200 million people in over 70 countries. Here we describe novel imaging methods that, for the first time, permit visualization of live schistosomes within their living hosts. The technology centers on fluorescent agent uptake and activation in the parasite's gut, and subsequent detection and signal quantitation using fluorescence molecular tomography (FMT). There is a strong positive correlation between the signal detected and parasite number. Schistosoma mansoni parasites of both sexes recovered from infected experimental animals exhibit vivid fluorescence throughout their intestines. Likewise, the remaining important human schistosome parasites, S. japonicum and S. hematobium, also exhibit gut fluorescence when recovered from infected animals. Imaging has been used to efficiently document the decline in parasite numbers in infected mice treated with the antischistosome drug praziquantel. This technology will provide a unique opportunity both to help rapidly identify much-needed, novel antischistosome therapies and to gain direct visual insight into the intravascular lives of the major schistosome parasites of humans.

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“…The low cure rates at threeweeks post-treatment, compared with the significantly higher cure rates at six-and nine-weeks post-treatment, suggest that either worms are killed very slowly or, more likely, that eggs continue to be released from tissues after worm death. In mice infected with S. mansoni, it has been shown that PZQ completes its antischistosomal action in one week, 14 and a similar rate of action may well apply to S. haematobium. The idea of a slowly tapering egg excretion is indirectly reinforced by the much lower cures rates (at three weeks) in heavily infected children (< 25%) compared with children with low infection levels (58%).…”

Section: Discussionmentioning

confidence: 97%

Efficacy of Praziquantel Against Schistosoma Haematobium Infection in Children

Tchuenté¹,

Shaw²,

Polla³

et al. 2004

The American Journal of Tropical Medicine and Hygiene

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A study was performed to determine the efficacy of praziquantel (PZQ) against Schistosoma haematobium. Children (n = 592) infected with S. haematobium received either a single treatment with PZQ (40 mg/kg) or two or three treatments with PZQ at three-week intervals after the initial treatment and efficacy was monitored for nine weeks. Cure rates at three-weeks post-treatment were low (< 50%), suggesting either that worms are killed very slowly or, more likely, that eggs continue to be released from tissues after worm death. Interestingly, a single dose of PZQ showed high efficacy (cure rate > 83% and egg reduction rate > 98%) when assessed from six weeks post-treatment onward. There were no significant differences in cure rates or intensity of infection between the three cohorts at any point in the study, despite the different treatment regimens. Since children were in contact with transmission sites during the study period, the results suggest good efficacy of PZQ against all stages of S. haematobium, including the immature worms.

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Rate of action of schistosomicides in mice infected with Schistosoma mansoni

Cited by 8 publications

References 5 publications

Praziquantel efficacy and long-term appraisal of schistosomiasis control in Pemba Island

Praziquantel efficacy and long-term appraisal of schistosomiasis control in Pemba Island

Imaging schistosomes in vivo

Efficacy of Praziquantel Against Schistosoma Haematobium Infection in Children

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