Quantitative and qualitative interferences of pentoxifillyne on hepatic Schistosoma mansoni granulomas: effects on extracellular matrix and eosinophil population

Mast cells and eosinophils actively participate in tissue repair and are prominent components of Schistosoma mansoni granulomas. Since pentoxifillyne (PTX) is an immunomodulatory and antifibrotic substance, we aimed to characterize, by morphological techniques, the effect of this drug on fibrosis developed inside murine hepatic schistosomal granulomatous reaction, beyond the quantification of eosinophil and mast cell populations. The drug (1 mg/100 g animal weight) was administrated from 35 to 90 days post-infection, when the animals were killed. The intragranulomatous interstitial collagen network was analyzed by confocal laser scanning microscopy, the number of eosinophils and mast cells was quantified and the results were validated by t-student test. Treatment did not interfere on the granuloma evolution but caused a significant decrease in the total and involutive number of hepatic granulomas (p = 0.01 and 0.001, respectively), and in the intragranulomatous accumulation of eosinophils (p = 0.0001). Otherwise, the number of mast cells was not significantly altered (p = 0.9); however, it was positively correlated with the number of granulomatous structures (r = 0.955). In conclusion, PTX does not affect development and collagen deposition in S. mansoni murine granuloma, but decreases the intragranulomatous eosinophil accumulation possibly due to its immunomodulatory capability, interfering in cellular recruitment and/or differentiation.

Study of Schistosoma mansoni isolates from patients with failure of treatment with oxamniquine

After three successive treatments with oxamniquine the continuing elimination of Schistosoma mansoni eggs was observed in patients, who came from various regions of Brazil, with different clinical forms of schistosomiasis. The objective of the present study was to determine the experimental behaviour of five different S. mansoni isolates in Swiss Webster mice that were submitted to treatment with the same drug. The experimental group with failure of treatment showed higher mean number of surviving male worms when it was compared to the group without failure of treatment. These date suggest the possibility of resistance to oxamniquine.

Prognosis of schistosomiasis mansoni patients infected with hepatitis B virus

A clinical study on the evolution of patients with schistosomiasis mansoni has been conducted since 1983 at the outpatient clinic of the Infectious and Parasitic Disease Service in the Clementino Fraga Filho University Hospital in Rio de Janeiro, Brazil, comparing prevalence of positive tests for HBsAg, anti-HBsAg, and anti-HBc among patients infected with Schistosoma mansoni coming from various regions of Brazil and with different clinical forms of the disease. A non-significant predominance of HBsAg, anti-HBsAg, and anti-HBc was detected among patients with the hepatosplenic form of schistosomiasis, who presented a more severe clinical evolution with a higher frequency of hematemesis and/or melena, in addition to the development of macronodular cirrhosis and a worse prognosis as compared to patients with the toxemic form, schistosomiasis-infection and the hepatointestinal form.

[Variability of Schistosoma mansoni strains in cercariae production]

A preliminary study showed that B. glabrata infected with strains of S. mansoni isolated from patients with the hepatosplenic form of the disease produced a higher number of cercariae and died sooner than those infected with strains from the intestinal and hepatointestinal forms. However, further studies showed a great variation of the number of cercariae produced by some of those strains in the same system, without relation with the clinical form of the disease.

[Experimental behavior of samples of Schistosoma mansoni in relation to clinical forms of schistosomiasis. I--Study in mice]

Twenty isolates of Schistosoma mansoni were obtained from patients, all males 13 to 30 years old, autochtonous from the Village of Capitão Andrade, municipality of Itanhomi, state of Minas Gerais, where an evolutive study of Mansoni's schistosomiasis is being performed since 1973. The isolates came from six patients with schistosome-infections (type I), six with the hepato-intestinal form (type II), and eight with the hepatosplenic form (type III). Each isolate was inoculated in mice divided in three groups of 16, exposed to 25, 50 and 100 cercariae, respectively. Controls were 12 uninfected mice. After 90 days adult worms were recovered from the portal by perfusion, from four mice of each experimental groups. Mice dying at various intervals and half of the rest f mice in each group sacrificed on the 90th and the 180th days were studied according to the following parameters: weight of liver, spleen, lung and intestine; egg count in the small intestine (proximal and medial) and large intestine (distal). The average numbers of worms obtained by perfusion from groups I, II and III were 21.9%, 22% and 17.8% respectively. The average natural mortality rates of mice submitted to infection with 25, 50 and 100 cercariae were, respectively, 12.4%, 23.2% and 40.2% for group I, 4.7%, 19.5% and 22.2% for group II and 11.4%, 29.5% and 41.6% for group III, being therefore proportional to the inocula.(ABSTRACT TRUNCATED AT 250 WORDS)

[Morbidity of schistosomiasis mansoni in Brazil. Developmental study in an endemic area over a 10-year period]

Four cross sectional studies on morbidity of schistosomiasis mansoni were carried out respectively in 1973, 1974, 1979 and 1983 in the Village of Capitão Andrade, District of Itanhomi, State of Minas Gerais, Brazil, through clinical and fecal examination of the population. In addition a comparison was made of the dinamic and infection rate of the snails and the man-water contact between 1973-1974. The present study compares the prevalence of the human infection by S. mansoni and the evolutive pattern of the disease in the area from 1973 to 1983. Besides 190 persons infected with S. mansoni and 134 non-infected, were followed-up during this period. The infection rate was 60.8% among 1,234 persons examined in 1973, decreasing to 36.2% of the 1,269 examined in 1983. However, the intense migration of the population in the area and the specific treatment of 7% of persons by their own decision may be partially responsible for this reduction. Although there was a decrease of more than 50% in the mean egg output of S. mansoni, there was no change in the morbidity of the disease and in the proportion of the different clinical forms. The incidence of S. mansoni infection among 134 persons followed-up during the ten years was 40.3% (annual average of 4%), with 61.9% in males. The incidence of the clinical forms was 51.8% for type I (intestinal form), 38.9% for type II (hepatointestinal) and 9.3% for type III (hepatoesplenic). The clinical evolutive pattern of 190 patients followed-up during the mentioned period showed that 75.3% had no change, 12.1% deteriorated and 12.6% improved. Two thirds of those which improved (8.4%) had received specific treatment.

[Morbidity of schistosomiasis mansoni in Brazil. II. - Study in 4 field areas in the States of Minas Gerais, Sergipe and Paraiba]

Os autores fazem um estudo comparativo sobre a morbidade da esquistossomose mansoni em 4 áreas de campo no Brasil, duas na região Sudeste (Capitão Andrade, município de Inhomi e Padre Paraíso, ambas no Estado de Minas Gerais) e duas outras na região nordeste (Riachuelo, no Estado de Sergipe e Alhandra, no Estado da Paraíba). A população total estudada nas 4 áreas foi de 4.870 pessoas, das quais 1.369 em Capitão Andrade (área 1), 850 em Riachuelo (área 2), 1.736 em Padre Paraíso (área 3) e 915 em alhandra (área 4). Na área 1, com uma população de 1.480 habitantes, foi tentado um estudo de toda a pupulação. Nas áreas 2, 3 e 4, devido ao grande número de habitantes, foi estudada uma amostra sistemática por conglomerado de aproximadamente 25% da população (grupamento familiar de uma em cada 4 residências). O estudo constou e uma avaliação das condições econômicas e sanitárias da população, do seu contacto com os focos locais de transmissão da esquistossomose, dos índices e intensidade da infecção pelo S. mansoni e das relações da carga parasitária com as diversas formas clínicas da doença em diferentes grupos etários. Paralelamente, foi feito um estudo dos hospedeiros intermediários de cada área e dos seus índices de infecção com cercárias de S. mansoni. Demonstrou-se uma prevalência de 60,8, 50,5, 63,1 e 46,6% de infecção ativa pelo S. mansoni para as áreas 1, 2, 3 e 4, com a mediana de eliminação de ovos de 207, 77,6, 391 e 211 respectivamente. Verificou-se, ainda, nas áreas da região Sudeste um aumento mais tardio dos parâmetros mencionados. Outras correlações com grupos etários, sexo, cor dos pacientes, bem como os índices de infecção dos planorbídeos com a forma clínica da doença foram feitas.