Acute schistosomiasis: clinical, diagnostic and therapeutic features

Three distinct syndromes caused by schistosomiasis have been described: cercarial dermatitis or swimmer's itch, acute schistosomiasis or Katayama fever, and chronic schistosomiasis. Complications of acute schistosomiasis have also been reported. The absence of a serological marker for the acute stage has hindered early diagnosis and treatment. Recently, an ELISA test using KLH (keyhole limpet haemocyanin) as antigen, has proved useful in differentiating acute from chronic schistosomiasis mansoni. Clinical and experimental evidence indicate that steroids act synergistically with schistosomicides in the treatment of Katayama syndrome. In this paper, clinical, diagnostic and therapeutic features of acute schistosomiasis are updated.

Síntese do anti-helmíntico praziquantel,a partir da glicina

This paper deals mainly with the synthesis of praziquantel, a powerful anti-helminthic used against schistosomiasis, an endemic disease which infest millions of people around the world.

Minsky on "Big Government"

This paper objective is to assess, in light of the main works of Minsky, his view and analysis of what he called the "Big Government" as that huge institution which, in parallels with the "Big Bank" was capable of ensuring stability in the capitalist system and regulate its inherently unstable financial system in mid-20th century. In this work, we analyze how Minsky proposes an active role for the government in a complex economic system flawed by financial instability.

Stability of Schistosoma mansoni progeny to antischistosomal drugs

The susceptibility of the MAP Brazilian strain (F1 to F5 progenies) of S. mansoni to four antischistosomal drugs has been reported in a previous study. In the present investigation, progeny F14 of the same strain, was tested for stability to the same 4 drugs. A new medication, Oltipraz (35,972 RP), was added to the study. Five groups of 12 mice infected with cercariae by tail immersion were treated with hycanthone, oxamniquine, niridazole, praziquantel and Oltipraz. An untreated group was used as control. Schistosomal activity was assessed by the localization of worms in the portal vein system, by oogram changes, and percentage of parasite reduction. The stability of the susceptibility of progeny F14 did not change in relation to generations F1 to F5; the progeny was resistant to hycanthone and oxamniquine; but sensitive to niridazole, praziquantel and Oltipraz. We emphasize the importance of the phenomenon of resistance of the worm in view of the fact that oxamniquine has been widely used in Brazilian areas where mansonic schistosomiasis is endemic.

Morphology and stability of aggregates of an Oxisol according to tillage system and gypsum application

Morphological characterization and aggregate stability is an important factor in evaluating management systems. The aim of this paper is to evaluate the stability and morphology of the aggregates of a dystrophic Oxisol managed with no-tillage and conventional tillage with and without the residual action of gypsum. The experimental design was randomized blocks arranged in split-split plot, where the treatments were two soil management systems (plots) with 0 and 2000 kg ha-1 of gypsum (subplots) and five depths (0-0.05, 0.05-0.10, 0.10-0.15, 0.15-0.20 and 0.20-0.30 m) as the subsubplots, with four replications. The aggregate morphology was determined through images and later evaluated by the Quantporo software. Stability was determined by the wet method. The results showed that the no-tillage system, with or without gypsum residual effect, provided the aggregates with the largest geometric diameters. The combination of no-tillage system and the gypsum residual effect provided rougher aggregates.

Survey on the clinical trial results achieved in Brazil comparing praziquantel and oxamniquine in the treatment of mansoni schistosomiasis

A random, double-blind, parallel group clinical trial program was carried out to compare praziquantel, a recently developed anti-helmintic drug, and oxamniquine, an already established agent for treating mansoni schistosomiasis. Both drugs were administered orally as a single dose, on the average, praziquantel 55 mg/kg and oxamniquine 16 mg/kg BWT. The diagnosis and the parasitological follow-up lasting for a minimum of six months, were based on stool examinations according to Kato/Katz technique. A patient was considered cured if all results were negative and if he had performed at least three post-treatment controls, each one comprising three stool examinations. The finding of a single S. mansoni egg in any stool examination indicated, a therapeutical failure. A total of 267, cases were treated with praziquantel and 272 with oxamniquine. The two groups were homogeneous in regard to patients, age, clinical form of the disease, risk of reinfection and worm burden, relevant factors in the therapeutical response. The incidence and severity of untoward, effects were similar in both groups but abdominal distress and diarrhoea were more frequently reported under praziquantel and dizzines under oxamniquine (p < 0.05). In the former group a marked urticariform reaction was observed whereas in the latter one patient presented convulsion. The laboratory work-up. failed to disclose any significant alteration although the AST, ALT and y-GT mean values revealed a tendence to increase on the 7th day after oxamniquine intake. The overall parasitological cure rates were 75.5% (139/ 184) with praziquantel and 69.8% (134/192) with oxamniquine (p > 0.05). Amongst the noncured aptients a reduction of 88.6% and 74.6% in the mean number of eggs/g of feces Was seen following the treatment with praziquantel and oxamniquine, respectively (p < 0.05). In conclusion, in spite of their different chemical, pharmacological and toxicological profiles as well as mechanisms-of-action, inclusively praziquantel already had proved to be 100% active against S. mansoni strains resistant to oxamniquine, both drugs showed comparable tolerance and therapeutical efficacy.

Treatment of patients with Schistosomiasis mansoni: a double blind clinical trial comparing praziquantel with oxamniquine

A double-blind clinical trial involving 120 patients with chronic schistosomiasis was carried out to compare the tolerability and efficacy of praziquantel and oxamniquine. The patients were randomly allocated into two groups. One was treated with praziquantel, 55 mg/kg of body weight CBWT), and the other one with oxamniquine, 15mg/kg bwt, administered in a single oral dose. The diagnosis and the parasitological follow-up was based on stool examinations by quantitative Kato-Katz method and on rectal biopsies. Side-effects — mainly dizziness, sleepness, abdominal distress, headache, nausea and diarrhea — were observed in 87% of the cases. Their incidence, intensity and duration were similar for both drugs but abdominal pain was significantly more frequent after praziquantel intake and severe dizziness was more commonly reported after oxamniquine. A significant increase of alanine-aminotransferase and y-glutamyltransferase was found with the latter drug and of total bilirubin with the former one. A total of 48 patients treated with praziquantel and 46 with oxamniquine completed with negative findings the required three post-treatment parasitological controls — three slides of each stool sample on the first, third and sixth month. The achieved cure rates were 79.2% and 84.8%, respectively, a difference without statistical significance. The non-cured cases showed a mean reduction in the number of eggs per gram of feces of 93.5% after praziquantel and of 84.1% after oxamniquine. This diference also was not significant. Five patients retreated with praziquantel were cured but only one out of three treated a second time with oxamniquine. These findings show that both drugs — despite their different chemical structures, pharmacological properties and mechanisms-of-action — induce similar side-effects as well as a comparable therapeutical efficacy, in agreement with the results reported from analogous investigations.

Therapeutical evaluation of different dose regimens of praziquantel in schistosomiasis mansoni, based on the quantitative oogram technique

A clinical trial involving 80 patients of both sexes, from ages 15 to 55, with chronic intestinal or hepatointestinal schistosomiasis mansoni, was carried out to evaluate the therapeutical efficacy of different dose regimens of praziquantel. The patients were randomly allocated into four groups with an equal number of cases and were then treated with one of the following dosages: 60 mg/kg for 1 day; 60 mg/kg daily for 2 days; 60 mg/kg daily for 3 days; and 30 mg/kg daily for 6 days. The assessment of parasitological cure was based on the quantitative oogram technique through rectal mucosa biopsies which were undertaken prior to, as well as, 1,2,4 and 6 months post-treatment. Concurrently, stool examinations according to the qualitative Hoffman, Pons & Janer (HPJ) and the quantitative Kato-Katz (K-K) methods were also performed. The best tolerability was observed with 30 mg/kg daily for 6 days whereas the highest incidence of side-effects (mainly dizziness and nausea) was found with 60 mg/kg daily for 3 days. No serious adverse drug reaction has occurred. The achieved cure rates were: 25% with 60 mg/kg for 1 day; 60% with 60 mg/kg daily for 2 days; 89.5% with 60 mg/kg daily for 3 days; and 90% with 30 mg/kg daily for 6 days. At the same time there has been a downfall of 64%, 73%, 87% and 84% respectively, in the median number of viable S. mansoni ova per gram of tissue. Thus, a very clear direct correlation between dose and effect could be seen. The corresponding cure rates according to stool examinations by HPJ were 39%, 80%, 100% and 95%; by K-K 89%, 100%, 100% and 100%. This discrepancy in results amongst the three parasitological methods is certainly due to their unequal accuracy. In fact, when the number of viable eggs per gram of tissue fell below 5,000 the difference in the percentage of false negative findings between HPJ (28%) and K-K (80%) became significative. When this number dropped to less than 2,000 the percentage of false negative results obtained with HPJ (49%) turned significant in relation to the oogram as well. In conclusion, it has been proven that praziquantel is a highly efficacious agent against S. mansoni infections. If administered at a total dose of 180 mg/kg divided into either 3 or 6 days, it yields a 90% cure rate. Possibly, one could reach 100% by increasing the total dose to 240 mg/kg. Furthermore, it was confirmed that the quantitative oogram technique is the most reliable parasitological method when evaluating the efficacy of new drugs in schistosomiasis mansoni.

Efficacy of oxamniquine, praziquantel and a combination of both drugs in schistosomiasis mansoni in Brazil

A randomized clinical trial was carried out to compare the efficacy of a low-dosage combination of oxamniquine (7.5 mg/kg) plus praziquantel (20 mg/kg) against either agent, oxamniquine (15 mg/kg) or praziquantel (40 mg/kg) alone, in the treatment of schistosomiasis mansoni in the Brazilian north-east. The drugs were randomly administered per os to 91 patients. Six and twelve months after treatment 89% of those admitted to the trial were reexamined by Kato-Katz method (ten slides) and MIF technique (one gram of stool) The achieved cure rates, as defined by absence of S. mansoni eggs in the faeces of individual patients at all points during the parasitological follow-up, were 81.8%, 81.2% and 67.6% for praziquantel, oxamniquine and the combination respectively. The reduction of eggs excretion in non cured patients six months after therapy ranged from 93.8-96.8% with praziquantel, 32.5-97% with oxamniquine and 76.9-99.5% with the combination. It is concluded that, at the used dosages, the three therapeutical regimens give similar and satisfactory results in the treatment of uncomplicated S. mansoni infection in Brazil.

Egg excretion in the initial phase of experimental murine schistosomiasis mansoni: stability and association with worm burden

Stability of faecal egg excretion and correlation with results related to worm burden at the initial phase of schistosomiasis mansoni were observed in two groups of mice infected with different Schistosoma mansoni cercarial burdens, by means of analysis of quantitative parasitological studies and schistosome counts after perfusion. Thus, it may be stated that few quantitative parasitological stool examinations could be sufficient to express the infection intensity at the initial phase, on the same grounds that it was already demonstrated at the chronic phase. Furthermore, it is confirmed that the use of the number of eggs passed in the faeces as a tool to estimate the worm burden at the initial phase of schistosome infection is adequate.

Schistosomiasis haematobia: histopathological course determined by cystoscopy in a patient in whom praziquantel treatment failed

Schistosomiasis haematobia or urinary schistosomiasis is one of the main public health problems in Africa and the Middle East. A single dose of 40 mg praziquantel per kg body weight continues to be the treatment of choice for this infection. The aims of this follow-up were to study the post-treatment course of a patient infected with S. haematobium and not submitted to re-exposure, and to identify complications of the disease and/or therapeutic failure after praziquantel treatment by histopathological analysis. Treatments were repeated under medical supervision to ensure the correct use of the drug. In view of the suspicion of lesions in cystoscopy, the patient was submitted to bladder biopsy. The histopathological characteristics observed in biopsies obtained, after each treatment, indicated viability of parasite eggs and activity of granulomas.

Evaluation of WGA and Concanavalin A (Con A) lectin as biomarkers of hepatosplenic schistosomiasis in human biopsies with no evidence of egg-granuloma system

Introduction: Colonic lesions are predominant in patients with schistosomiasis. However, carbohydrate alterations in colonic schistosomiasis remain unclear. Lectin-ligands allow us to identify changes in the saccharide patterns of cells. Methods: Biopsies of descending and rectosigmoid colon of patients were submitted to WGA and Con A lectin histochemistry. Results: WGA stained stroma and gland cells of descending colon and rectosigmoid tissues in a granular strong cytoplasmatic pattern in schistosomiasis specimens differing from normal control and Con A failing to recognize all samples analyzed. Conclusions: WGA ligands are expressed differently in patients with hepatosplenic schistosomiasis and no evidence of egg-granuloma system.

Reduction of morbidity in hepatosplenic Schistosomiasis mansoni after treatment with praziquantel: a long term study

Forty-two with hepatosplenic patients treated with praziquantel and followed up for 5 years. One half of the patients received a single 30 mg/kg dose and the other half, two doses of 25 mg/kg given 4 hrs apart. According to Hoffman and Kato-Katz stool exams, an 83.3% cure rate, was observed after twelve months. Stool egg counts in cases of incomplete cure were greatly reduced. Liver function, as assessed by serum levels of aspartate aminotransferase, alanine aminotransferase, gamma glutamyltransferase and alkaline phosphatase activities as well as albumin and gamma globulin showed marked improvement after one year. Hepatomegaly was reduced in 81.0% of patients and splenomegaly in 78.8%. Spleen regression was complete in 15.1% of the total, and in 18.5% of those with compensated hepatosplenic disease. As a result of these observations, the authors recomend early treatment with anti-schistosomal medication, either oxamniquine or praziquantel, to halt progression of disease and reduce splenomegaly.

Clinical and ultrasound findings before and after praziquantel treatment among Venezuelan schistosomiasis patients

Abdominal ultrasound can be a useful tool for diagnosing periportal fibrosis related to Schistosoma mansoni infection, and also for planning and monitoring the evolution of hepatic morbidity following control measures. We evaluated the standardized ultrasound methodology proposed by the World Health Organization for detecting periportal fibrosis and portal hypertension, among patients from an endemic area in Venezuela, and the impact of praziquantel treatment 3-5 years later. After chemotherapy, complete reversal of periportal lesions was observed in 28.2% of the cases and progression of the disease in 5.1%. Improvement in the hepatic disease started with a reduction in the periportal thickening followed by a decrease in the size of the left hepatic lobe, spleen and mesenteric and spleen veins. Ultrasound confirmed the clinical findings after chemotherapy among the patients with reversal of the disease. However, in patients with more advanced disease, these findings were contradictory. There was no correlation between evolution of the disease seen on ultrasound and age, intensity of infection or serological findings.