Size of gastroesophageal varices: its behavior after the surgical treatment of portal hypertension

The size of gastroesophageal varices is one of the most important factors leading to hemorrhage related to portal hypertension. An endoscopic evaluation of the size of gastroesophageal varices before and after different operations for portal hypertension was performed in 73 patients with schistosomiasis, as part of a randomized trial: proximal splenorenal shunt (PSS n=24), distal splenorenal shunt (DSS n=24), and esophagogastric devascularization with splenectomy (EGDS n=25). The endoscopic evaluation was performed before and up to 10 years after the operations. Variceal size was graded according to Palmer's classification: grade 1 -- up to 3 mm, grade 2 -- from 3 to 6 mm, grade 3 -- greater than 6 mm, and were analyzed in four anatomical locations: inferior, middle or superior third of the esophagus, and proximal stomach. The total number of points in the pre-operative grading minus the number of points in the post-operative grading gave a differential grading, allowing statistical comparison among the surgical groups. Good results, in terms of disappearance or decrease of variceal size, were observed more frequently after PSS than after DSS or EGDS - 95.8%, 83.3%, and 72%, respectively. When differential grading was analyzed, a statistically significant difference was observed between PSS and EGDS, but not between proximal and distal splenorenal shunts. In conclusion, shunt surgeries were more efficient than devascularization in diminishing variceal size.

Dados estatísticos de viscerotomia sobre doenças e condições mórbidas do homem no Brasil: I. Schistosomose Mansônica no período de 1937-1946

Examination of 267.107 liver specimens obtained in Brazil by viscerotomy during from 1937 to 1946 inclusive revealed 5,953 Schistosoma mansoni infe¬ctions. This represents 2.23% ± 0.019 of the total number of livers studied. Data on the incidence of the disease is tabulated by states and municipios. Infected livers were found in all of the states and territories except the Territory of Amapá. Schistosomiasis is widespread in Brazil with highest incidence in the states of the Northeast. The disease is quite common in Espírito Santo and Minas Gerais as well. A study of the age distribution of cases of intestinal schistosomiasis observed among liver specimens obtained in the year 1938 showed a low inci¬dence on young children with a peak of prevalence in the 10 to 19 year age group. The purpose of this contribution is to call attention of the health autho¬rities to the extent and gravity of the problem of intestinal schistosomiasis in Brazil.

Unsusceptibility of Biomphalaria occidentalis to infection with a strain of Schistosoma mansoni

Susceptibility experiments with 1582 specimens of Biomphalaria occidentalis, 3-6 mm in shell diameter, from 10 localities of the states of Mato Groso, Mato Grosso do Sul, Paraná and São Paulo, exposed individually to 5 miracidia of Schistosoma mansoni (SJ2 strain), gave negative results. B. tenagophila from Joinville (Santa Catarina) and Taubaté (São Paulo), used as controls, showed infection rates of 17.9% and 14.8%, respectively. Experiments with other strains of S. mansoni are in progress. If the present results are confirmed, expansion of schistosomiasis toward far-western Brazil through the agency of B. occidentalis becomes less probable.

Immunopathology of Schistosoma mansoni infection in rabbits: (A preliminary report)

Five rabbits infected with Schistosoma mansoni showed marked resistance, which resulted in low worm recovery and low egg production. Pathological changes appeared in liver and intestines as scattered foci of eosinophilic infiltration around immature eggs, with only occasional granulomatous formation. Antibodies to ovular and adult worm structures were demonstrated by immunofluorescence in the sera of rabbits prior to infection (natural antibodies) and specially following infection by S. mansoni. These findings point out to the peculiarities of the immunopathology of schistosomiasis in rabbits.

Characterization of human heterophil hemolysins induced by Schistosoma mansoni infection

Heterophil antibodies could be detected in sera from normal or from patient with chronic schistosomiasis. Their hemolytic activities depend on the integrity of the complement classic pathway. The heterophil antibodies from patient sera presented a higher specificity for Schistosoma mansoni antigen preparations than those detected in normal sera. Most of the hemolytic activity observed in normal sera can be destroyed at 56ºC for 4 min. On the other hand, about 80% of the sera from infected patients are partially or totally resistant to this heat-treatment. The hemolytic activities of sera were eluted from a gel filtration column in different fractions of the first peak.

A survey of planorbid molluscs in the Amazonian region of Brazil

A survey of the plarnorbid fauna in the Brazilian states of the Amazonian river basin revealed the occurence of 14 species, 8 of the genus Biomphalaria, 4 of Drepanotrema, 1 of Antillorbis and 1 of Plesiophysa, besides a naturalized puopulation of Helisoma duryi at Santa Rosa, municipality of Formosa, state of Goiás. The following is the distribution of the species by genera, in decreasing order of frequency (number of localities in parenthesis): 1. Biomphalaria straminea (50): Acre, Amazonas, Distrito Federal, Goiás, Maranhão, Mato Grosso, Mato Grosso do Sul, Pará and Roraima; 2. B. occidentalis (30): Acre, Amazonas, Mato Grosso and Mato Grosso do Sul; 3. B. schrammi (22); Distrito Federal, Goiás, Maranhão, Mato Grosso, Mato Grosso do Sul and Pará; 4. B. amazonica (14): Acre, Amazonas and Rondônia; 5. B. glabrata (13): Distrito Federal, Goiás, Maranhão and Pará; 6. B. peregrina (4): Distrito Federal, Goiás and Mato Grosso do Sul; 7. B. tenagophila (2): Distrito Federal and Goiás; 8. B. oligoza (2): Mato Grosso do Sul; 9. Drepanotrema lucidium (72): Acre, Amapá, Amazonas, Distrito Federal, Goiás, Maranhão, Mato Grosso, Mato Grosso do Sul, Pará, Rondônia and Roraima; 10. D. anatinum (41): Acre, Amazonas, Distrito Federal, Goiás, Maranhão, Mato Grosso do Sul, Pará, Rondônia and Roraima; 11. D. depressissimum (19): Acre, Amazonas, Distrito Federal, Goiás, Maranhão, Mato Grosso, Mato Grosso do Sul and Pará; 12. D. cimex (15): Acre, Amazonas, Distrito Federal, Goiás, Mato Grosso, Mato Grosso do Sul and Pará; 13. Antillorbis nordestensis (3): Distrito Federal, Maranhão and Pará; 14. Plesiophysa ornata (1): Goiás. B. glabrata is responsibel for transmission of schistosomiasis mansoni in northeastern Pará, northern Marnhão and central Goiás including the Distrito Fedreal. B. tenagophila, although susceptible to experimental infection with Schistosoma mansoni, has not been found naturally infected so far in the area. B. straminea has been incriminated as...

Schistosomal glomerular disease (a review)

In this review paper schistosomal glomerulopathy is defined as an immune-complex disease. The disease appears in 12-15 per cent of the individuals with hepatosplenic schistosomiasis. Portal hypertension with collateral circulation helps the by pass of the hepatic clearance process and the parasite antigens can bind to antibodies in the circulation and be trapped in the renal glomerulus. Chronic membranousproliferative glomerulonephritis is the most commom lesion present and the nephrotic syndrome is the usual form of clinical presentation. The disease can be experimentally produced, and schistosomal antigens and antibodies, as well as complement, can be demonstrated in the glomerular lesions. Specific treatment of schistosomiasis does not seem to alter the clinical course of schistosomal nephropathy.

Further experiments on susceptibility of Biomphalaria amazonica to Schistosoma mansoni

A sample of Biomphalaria amazonica from Porto Velho, Rondônia state, was exposed to miracidia of Schistosoma mansoni (SJ2 strain) from São José dos Campos, São Paulo state (five miracidia per snail). Water freshly taken from the snails' breeding place was used to make sure that its quality was compatible with hatching of miracidia and their penetration into the snails. The resulting infection rate was 3.5%, as against 45% in B. tenagophila controls. In comparison with the controls, B. amazonica, besides a lower infection rate, showed a longer prepatent period and a lower cercarial production. These characteristics seem to indicate that it is a poor host of S. mansoni, like B. straminea, but it should be considered that, this notwithstanding, the latter is admittedly a good vector of the parasite in hyperendemic areas of northeastern Brazil. These results point to the possibility of introduction of schistosomiasis mansoni into the western Amazonian region, where B. amazonica is widespread.

The changing pattern of pathology due to Schistosoma mansoni infection

A survey of the autopsy data on hepatosplenic schistosomiasis during periods, before and after the advent of new chemotherapeutic drugs, revealed that: a) the pathological presentation was the same for the two periods; b) the number of cases in the last five years is progressively decreasing; c) hepatosplenic disease due to schistosomiasis is becoming rare in young people. These data represent a change in the pattern of pathology in schistosomiasis, probably related to new chemotherapy.

Latex of "Coroa de Cristo" (Euphorbia Splendens): an effective molluscicide

An aqueous solution of the latex of "coroa de cristo" (Euphorbia splendens var. hislopii) showed molluscicide action (LD90) at a concentration lower than 0.5 ppm on Biomphalaria glabrata and B. tenagophila reared in laboratory and at a concentration lower than 4.0 ppm for field B. tenagophila.

Behavior of Biomphalaria glabrata, the intermediate host snail of Schistosoma mansoni, at different depths in water in laboratory conditions

Using three columns of different depths (1.10m, 8.40m and 10.40m), we investigated the possibility of Biomphalaria glabrata moving towards deep regions. In the 1.10m column, we noted that locomotion can occur in two manners: 1) when the foot is in contact with the substrate: a) sliding descent; b) sliding ascent; c) creeping descent; d) creeping ascent, 2) when the foot is not in contact with the substrate: a) sudden descent without emission of air bules; b) sudden descent with emission of air bules; c) sudden ascent. In the 8.40m column containing food on the bottom (experimental group), the snails remained longer at this depth when compared to those of the group which received no food (control). The sliding behavior was characteristic of locomotion occurring at 0 to 1m both in upward and downward directions. Creeping behavior was typical for the ascent of the snails that reached deeper levels. When the snails were creeping, the shell remained hanging as if it were heavier, a fact that may have been due to water entering the pulmonary chamber. In the 10.40m column, the snails slid downward to a depth of 4m or descended suddenly all the way to the bottom. Ascent occurred by creeping from the bottom to the surface. In the 8.40m and 10.40m columns, copulation, feeding and oviposition occurred at the deepest levels.

Cell-matrix interactions in Schistosomal portal fibrosis: a dynamic event

In recent years, one of the most significant progress in the understanding of liver diseases was the demonstration that liver fibrosis is a dynamic process resulting from a balance between synthesis and degradation of several matrix components, collagen in particular. Thus, fibrosis has been found to be a very early event during liver diseases, be it of toxic, viral or parasitic origin, and to be spontaneously reversible, either partially or totally. In liver fibrosis cell matrix interactions are dependent on the existence of the many factors (sometimes acting in combination) which produce the same events at the cellular and molecular levels. These events are: (i) the recruitment of fiber-producing cells, (ii) their proliferation, (iii) the secretion of matrix constituents of the extracellular matrix, and (iv) the remodeling and degradation of the newly formed matrix. All these events represent, at least in principle, a target for a therapeutic intervention aimed at influencing the experimentally induced hepatic fibrosis. In this context, hepatosplenic schistosomiasis is of particular interest, being an immune cell-mediated granulomatous disease and a model of liver fibrosis allowing extensive studies in human and animals as well as providing original in vitro models.

Esquistossomose mansônica: dinâmica da transmissão

The following remarks were addressed at the round table that discussed the alternative approaches to schistosomiasis control. The address begins with a short analysis of the progressive spread of the area of distribution of the disease, and of the difficulties faced by those in charge of control programs, conventional or otherwise. A model was sketched, taking into consideration the distinct classes of factors involved in the dynamics of transmission: biological, immunological, ecological, socio-cultural, and economical. The true significance and pertinence of such a model was analysed, and the relevant questions that must be answered before a true representative model can be constructed, were listed.

The intermediate snail-host: an agenda for future study

The strategy for the control of schistosomiasis has shifted from one directed towards the interruption of transmission to one of reducing morbidity. As a consequence of this change, it appears prudent to reassess the role of the malacologist and malacology and identify the future direction to be taken by the discipline. The present paper addresses these concerns; first, by reviewing the role of the snail-hosts in the epidemiology and control of schistosomiasis, and, secondly, by suggesting areas for future study. The possible application of newer methods in biotechnology for the resolution of malacological problems are discussed.

Congenital and nursing effects on the evolution of Schistosoma mansoni infection in mice

Modification of the immune response to schistosomal infection in children or offspring born to mother R infected with Schistosoma mansoni has been demonstrated in human and in experimental schistosomiasis. One of the hypothesis to explain this fact could be the transfer of circulating antigens and antibodies from mother to foetus through the placenta or from mother to child by milk. The results of this spontaneous transference are controversial in the literature. In an attempt to investigate these questions, we studied one hundred and twenty offspring (Swiss mice), sixty born to infected-mothers (group A) and sixty born to non-infected mothers (group B). These were percutaneously infected with 50 cercariae/mouse, and divided in six sub-groups (20 mice/sub-group), according to the following schedule: after birth (sub-groups A.I and B.I), 10 days old (sub-groups A.II and B.II) and 21 days old (sub-groups A.III and B.III). After the exposure period, the young mice returned to their own mothers for nursing. Six weeks later, the mice were killed. We obtained the following results: 1) There is transference of antibody to cercariae (CAP), adult worms (SWAP) and egg antigens (SEA) from the infected mothers to the offspring, probably through placenta and milk; 2) Offspring born to infected mothers exhibit much less coagulative hepatic necrosis and show a lower number of eggs in the small intestine and a less intense and predominant exsudative stage of the hepatic granulomas when compared with the exsudative-productive stage of the control groups. The findings suggest that congenital and nursing factors can interfere on the development of the schistosomiasis infection, causing an hyporesponse to the eggs.