Efficacy of praziquantel against Schistosoma mekongi and Opisthorchis viverrini: a randomized, single-blinded dose-comparison trial - PubMed (original) (raw)

Randomized Controlled Trial

doi: 10.1371/journal.pntd.0001726. Epub 2012 Jul 24.

Tippi K Mak, Khampheng Phongluxa, Phonepasong Ayé Soukhathammavong, Youthanavanh Vonghachack, Jennifer Keiser, Penelope Vounatsou, Marcel Tanner, Christoph Hatz, Jürg Utzinger, Peter Odermatt, Kongsap Akkhavong

Affiliations

Randomized Controlled Trial

Efficacy of praziquantel against Schistosoma mekongi and Opisthorchis viverrini: a randomized, single-blinded dose-comparison trial

Leonore Lovis et al. PLoS Negl Trop Dis. 2012.

Abstract

Background: Schistosomiasis and opisthorchiasis are of public health importance in Southeast Asia. Praziquantel (PZQ) is the drug of choice for morbidity control but few dose comparisons have been made.

Methodology: Ninety-three schoolchildren were enrolled in an area of Lao PDR where Schistosoma mekongi and Opisthorchis viverrini coexist for a PZQ dose-comparison trial. Prevalence and intensity of infections were determined by a rigorous diagnostic effort (3 stool specimens, each examined with triplicate Kato-Katz) before and 28-30 days after treatment. Ninety children with full baseline data were randomized to receive PZQ: the 40 mg/kg standard single dose (n = 45) or a 75 mg/kg total dose (50 mg/kg+25 mg/kg, 4 hours apart; n = 45). Adverse events were assessed at 3 and 24 hours posttreatment.

Principal findings: Baseline infection prevalence of S. mekongi and O. viverrini were 87.8% and 98.9%, respectively. S. mekongi cure rates were 75.0% (95% confidence interval (CI): 56.6-88.5%) and 80.8% (95% CI: 60.6-93.4%) for 40 mg/kg and 75 mg/kg PZQ, respectively (P = 0.60). O. viverrini cure rates were significantly different at 71.4% (95% CI: 53.4-84.4%) and 96.6% (95% CI: not defined), respectively (P = 0.009). Egg reduction rates (ERRs) against O. viverrini were very high for both doses (>99%), but slightly lower for S. mekongi at 40 mg/kg (96.4% vs. 98.1%) and not influenced by increasing diagnostic effort. O. viverrini cure rates would have been overestimated and no statistical difference between doses found if efficacy was based on a minimum sampling effort (single Kato-Katz before and after treatment). Adverse events were common (96%), mainly mild with no significant differences between the two treatment groups.

Conclusions/significance: Cure rate from the 75 mg/kg PZQ dose was more efficacious than 40 mg/kg against O. viverrini but not against S. mekongi infections, while ERRs were similar for both doses.

Trial registration: Controlled-Trials.com ISRCTN57714676.

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Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Figure 1

Figure 1. Flowchart of subjects with cure and egg reduction rates.

Cure and egg reduction rates are presented for O. viverrini and S. mekongi infections following 40 mg/kg and 75 mg/kg (50 mg/kg+25 mg/kg 4 hours apart) PZQ treatment considering (a) the maximum sampling effort (3×3, 3 stool specimens with triplicate Kato-Katz thick smears per specimen); (b) the minimum sampling effort (1×1, single Kato-Katz thick smear from the first stool specimen).

Figure 2

Figure 2. Cumulative prevalence according to the sampling effort.

Cumulative infection prevalences for (a) S. mekongi and (b) O. viverrini by the number over consecutive days of stool specimen collection (x-axis). Each point on a curve represents a cumulative prevalence value for each sampling effort (number of Kato-Katz thick smears per stool specimen). At baseline (day 0), n = 90; after treatment (days 28–30), n = 66.

Figure 3

Figure 3. Geometric mean fecal egg counts according to the sampling effort.

Geometric mean fecal egg counts before and after PZQ treatment, by the number of days of stool specimen collection (x-axis), based on children diagnosed “infected” following maximum Kato-Katz thick smear sampling effort. (a) S. mekongi infected at baseline (day 0), n = 79; days 28–30 after treatment, n = 14; and (b) O. viverrini infected at baseline (day 0), n = 89; days 28–30 after treatment, n = 11. Each point on a curve represents the geometric mean fecal egg count for each sampling effort (number of Kato-Katz thick smears examined per stool specimen).

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