Avaliação terapêutica duplo-cega baseada na técnica do oograma quantitativo, comparando praziquantel com oxamniquine na esquistossomose mansônica humana

Abstract

SUMMARYA total of 54 adult patients with chronic intestinal or hepato-intestinal schis tosomiasis mansoni were included into a double-blind clinical trial to compare praziquantel and oxamniquine. Following a randomized allocation, 27 patients received praziquantel -65 mg/kg bwt -and 27 oxamniquine -18 mg/kg bwtin a single oral dose divided into two intakes. The incidence, severity and du ration of side-effects were similar for the two drugs.The assessment of therapeutical efficacy was based on the quantitative oogram technique via biopsy of the rectal mucosa, performed at the end of 1, 2, 4 and 6 months after treatment. At these same occasions, stool examinations according to Hoffman, Pons & Janer (HPJ) and Kato-Katz (K-K) methods were undertaken to confront their results with the oogram findings. In order to evaluate the immediate effect of the therapy upon the egg laying activity of the parasite, a limited number of patients was submitted to rectal biopsies on the 6th. and 18th. days subsequent to the drug administration.Both drugs proved to be active anti-schistosomal agents as their coefficients of variation, determined from the oograms made immediatly following the treat ment, were above 60%. Furthermore, out of 27 patients in each group, 24 treated with praziquantel and 22 with oxamniquine have completed the required six months parasitological follow up period. The respective cure rates in accordance with the oogram, HPJ and K-K findings were: 29.2%, 50% and 91.7% for praziquan tel; 22.7%, 50% and 86.3% for oxamniquine. Despite a quite low cure rate, a sharp fall (-83%) in the mean number of living eggs per gram of tissue was ob served in the post-treatment oograms.These results indicated that both anti-schistosomal agents were similarly effi cacious On the other hand, a striking difference in the cure rates amongst the three parasitological control methods became evident. The oogram was the most accu rate one, followed by HPJ and lastly by K-K. Since there was a direct correla tion between the number of living eggs in the oogram and the positivity of the stool examinations, the percentage of false-negative results has augmented remar kably after treatment reaching 47.3% with HPJ and 92.9% with K-K. Prior to therapy they were 0% and 64,8%, respectively. The authors infer that the different accuracy of the applied methodology to assess therapeutical efficacy may explain the discrepancy between the cure rate achieved in this clinical trial and those reported by other investigations with either praziquantel or oxamniquine.

Schistosomiasis is more prevalent than previously thought: what does it mean for public health goals, policies, strategies, guidelines and intervention programs?

“…The information provided above regarding the use of the “confirmatory” UCP-CAA assay would indicate that this is perhaps a problem with some of trace readings, but not the majority of them. Number 4 in the Table reflects the finding that upon treatment with PZQ some worms are damaged and experience temporary suppression of oviposition but can subsequently rebound and produce viable eggs, even months later [41]. Do female worms go through menopause, or decline significantly in their ability to produce eggs, while remaining long-lived, as hypothesized in no.…”

Efeito Do Extrato De Piper Tuberculatum Sobre Adultos De Schistosoma Mansoni: Testes in Vitro E in Vivo

“…Sixty days after the infection, the mice were euthanized by cervical displacement in order to recover the worms from the mesenteric-portal system, confirming the presence of the worms in the intra-hepatic branches of the portal vein, the portal vein itself and the mesenteric veins. After the worms were removed, a segment of the ileum of each mouse was used for oogram tests (Cunha & Carvalho, 1966), in order to count and compare the stages of development and the viability of the eggs (Pellegrino & Faria, 1965). At this time, the numbers of granuloma in the liver and eggs in the feces were also confirmed (Zanotti- Magalhães et al, 1993).…”

Estudo de atividade de Phyllanthus amarus L. contra o Schistosoma mansoni linhagem BH

“…A OXQ foi por muito tempo o fármaco escolhido para o tratamento no controle de endemias. A ação apenas na espécie e vários casos de resistência e de percentuais de curas muito baixos, restringiu o uso da OXQ (Batista, 2006;Bonesso Sabadini, 1995;Cunha, 1982), deixando assim o PZQ como o fármaco de escolha no tratamento da esquistossomose, uma vez que o mesmo tem ação contra todas as espécies de e pouco efeito colateral (Picca Mattoccia & Cioli, 2004).…”