Schistosoma mansoni granulomas in the skeletal striated muscles in the murine model of neuroschistosomiasis: histological findings

Schistosomiasis mansoni presents many clinical manifestations during migration of schistosomes in their hosts, including diarrhea, hepatomegaly, splenomegaly, liver abscesses, skinlesions, brain tumors and myeloradiculopathy. No lesions have been reported in skeletal striated muscles due to schistosomiasis mansoni in the literature. This short communication reports the histopathological findings on skeletal musculature in a murine model of neuroeschistosomiasis mansoni. Lesions were found in the tongue, masseter muscle, buccinator muscle, digastric muscle and temporalis muscle. Worm recovery was carried out to confirm the infection. We describe here, for the first time in the literature, injuries in the skeletal musculature due to Schistosoma mansoni nfection.

Parasitological and histological aspects of Holochilus sciureus naturally infected by Schistosoma mansoni / Aspectos parasitológicos e histológicos de Holochilus sciureus naturalmente infectados por Schistosoma mansoni

Abstract Schistosomiasis is a neglected disease that affects millions of people around the world, being common in the state of Maranhão. A total of 225 rodents of the Holochilus sciureus species from the Western Lowland Maranhão were studied, of which 144 animals (64%) exhibited Schistosoma eggs in their feces samples. Macroscopic lesions characterized as well-defined whitish areas on the liver and spleen surfaces were observed. Histopathological examination revealed multifocal granulomas in the esophagus, liver, spleen, pancreas and duodenum, with structures compatible with Schistosoma mansoni eggs, as well as severe hepatic micro-vacuolar degeneration, multifocal and coalescent, with proliferation of random bile ducts and associated epithelial hyperplasia to areas of fibrosis. Adult forms of the parasite were observed in the blood vessels of the portal space. The lungs exhibited moderate and diffuse interstitial pneumonia with intralesional S. mansoni eggs. In the kidneys, hyaline cylinders were observed in the pelvis and diffuse hemorrhage. In conclusion, H. sciureus displays a pathological picture similar to human being. This rodent plays a role as sentinel in Baixada Maranhense.

Resumo A esquistossomose é uma doença negligenciada que afeta milhões de pessoas em todo o mundo, sendo comum no estado do Maranhão. Um total de 225 roedores da espécie Holochilus sciureus da Planície Ocidental do Maranhão foram estudados, dos quais 144 animais (64%) apresentaram ovos de Schistosoma em suas fezes. Lesões macroscópicas caracterizadas como áreas esbranquiçadas bem definidas nas superfícies do fígado e baço foram observadas. O exame histopatológico revelou granulomas multifocais no esôfago, fígado, baço, pâncreas e duodeno, com estruturas compatíveis com ovos de Schistosoma mansoni, degeneração micro-vacuolar hepática grave, multifocal e coalescente, com proliferação de ductos biliares aleatórios e hiperplasia epitelial associada a áreas de fibrose. Formas adultas do parasito foram observadas nos vasos sanguíneos do espaço portal. Os pulmões exibiram pneumonia intersticial moderada e difusa com ovos de S. mansoni intralesionais. Nos rins, foram observados cilindros hialinos na pelve e hemorragia difusa. Em conclusão, H. sciureus apresenta um quadro patológico semelhante ao ser humano. Este roedor desempenha um papel de sentinela na Baixada Maranhense.

Characterisation of ocular involvement in an experimental model of neuroschistosomiasis mansoni

The Global Burden of Disease Study 2010 listed schistosomiasis among the leading 100 causes of death in Brazil, responsible for 3.6% of the estimated total of deaths globally. Eye and adnexa are very rarely affected by schistosomiasis mansoni, with limited documentation of ocular pathology in this setting. This short communication reports ocular histolopathological findings in a murine model of neuroschistosomiasis mansoni. Lesions were found in the bulbar conjunctiva, lacrimal gland, choroid and corneoscleral limbus.

Correlation between the values of circulating blood elements with the size of spleen in the presence of schistosomal splenomegaly

Abstract Purpose: To evaluate a possible relationship between the size of the spleen and values of circulating blood elements in patients with schistosomatic splenomegaly. Methods: ixty one patients with hepatosplenic schistosomiasis mansoni underwent a clinical exam and peripheral venous blood was collected for a hemogram. The erythrocyte, hemoglobin, hematocrit, leukocyte, and platelet values were determined. All patients underwent abdominal ultrasound to measure the spleen. The hematological test results were compared to the size of the spleen. Results: The size of the spleen varied from 14.0 to 28.4 (19.9 ± 3.7) cm according to the ultrasound image. Thrombocytopenia was observed 58 (95%) patients, leukopenia in 55 (90%) patients, and anemia in 32 (52.4%) patients. Leukopenia was proportional to splenomegaly. Conclusion: Schistosomal splenomegaly leads to leukopenia in direct proportion to the size of the spleen.

Ectopic forms of schistosomiasis mansoni in the second macroregion of Alagoas: case series report and review of the literature

Abstract INTRODUCTION Ectopic forms of schistosomiasis are those in which the parasitic element is localized outside the portal system, the natural habitat of the helminth. Although the prevalence rates of schistosomiasis are high in Brazil, clinical and epidemiological data on ectopic forms of the disease are still scarce. METHODS Cross-sectional, retrospective and descriptive epidemiological study in which cases with a confirmed histopathological diagnosis of an ectopic form of schistosomiasis were analyzed. The cases were selected from a database of the anatomic pathology files of a referral center. RESULTS Of the 21 cases identified, seven affected the female genital tract and five the male genital tract; four cases were identified in the peritoneum; two cases involved lymph nodes and two involved adipose tissue; and renal involvement was detected in one case. CONCLUSIONS The lack of knowledge of the clinical presentation of ectopic forms of schistosomiasis makes the early identification and treatment of this form difficult, with direct implications in the reduction of morbidity and mortality in endemic areas.

Cutaneous ectopic schistosomiasis: diagnostic challenge

Abstract Cutaneous schistosomiasis is a rare clinical manifestation of schistosomiasis, an infectious and parasitic disease, caused in Brazil by the trematode Schistosoma mansoni. The lesions are due to the deposition of eggs or, rarely, adult worms, usually involving the genital and groin areas. Extra-genital lesions occur mainly on the torso as papules of zosteriform appearance. The case of a patient with ectopic cutaneous schistosomiasis is reported in this article, due to the rarity of its occurrence and its difficult clinical diagnosis.

Low transformation growth factor-β1 production and collagen synthesis correlate with the lack of hepatic periportal fibrosis development in undernourished mice infected with Schistosoma mansoni

Undernourished mice infected (UI) submitted to low and long-lasting infections by Schistosoma mansoni are unable to develop the hepatic periportal fibrosis that is equivalent to Symmers’ fibrosis in humans. In this report, the effects of the host’s nutritional status on parasite (worm load, egg viability and maturation) and host (growth curves, biology, collagen synthesis and characteristics of the immunological response) were studied and these are considered as interdependent factors influencing the amount and distribution of fibrous tissue in hepatic periovular granulomas and portal spaces. The nutritional status of the host influenced the low body weight and low parasite burden detected in UI mice as well as the number, viability and maturation of released eggs. The reduced oviposition and increased number of degenerated or dead eggs were associated with low protein synthesis detected in deficient hosts, which likely induced the observed decrease in transformation growth factor (TGF)-β1 and liver collagen. Despite the reduced number of mature eggs in UI mice, the activation of TGF-β1 and hepatic stellate cells occurred regardless of the unviability of most miracidia, due to stimulation by fibrogenic proteins and eggshell glycoproteins. However, changes in the repair mechanisms influenced by the nutritional status in deficient animals may account for the decreased liver collagen detected in the present study.

Brain schistosomiasis in mice experimentally infected with Schistosoma mansoni

Introduction Human neuroschistosomiasis has been reported in the literature, but the possibility of modeling neuroschistosomiasis in mice is controversial. Methods In two research laboratories in Brazil that maintain the Schistosoma mansoni life cycle in rodents, two mice developed signs of brain disease (hemiplegia and spinning), and both were autopsied. Results S. mansoni eggs, both with and without granuloma formation, were observed in the brain and meninges of both mice by optical microscopy. Conclusions This is the first description of eggs in the brains of symptomatic mice that were experimentally infected with S. mansoni. An investigation of experimental neuroschistosomiasis is now feasible. .

Correlation beteeen platelet count and both livr fibrosis and spleen diameter in patients with schistosomiasis mansnni / Correlação entre o número de plaquetas e o grau de fibrose hepática e o tamanho do baço em pacientes com Esquistossomose mansoni

Context Studies have described the correlation between platelet count and the stages of fibrosis in chronic viral hepatitis, but few publications have studied this correlation in Schistosomiasis mansoni. Objectives Therefore, this study aimed to correlate platelet count with both the periportal fibrosis pattern and spleen diameter evaluated by ultrasound exam in patients with Schistosomiasis mansoni. Methods Patients with Schistosomiasis mansoni were evaluated by abdominal ultrasound by a single examiner for the determination of periportal fibrosis pattern (Niamey classification) and spleen diameter. Platelet counts were performed in an automated cell counter. Results One hundred eighty-seven patients with Schistosomiasis mansoni (mean age: 50.2 years) were included in the study, 114 of whom (61%) were women. Based on the Niamey classification, the ultrasound analysis revealed that 37, 64, 64 and 22 patients exhibited patterns C, D, E and F, respectively. In these four groups, the mean number of platelets was 264, 196, 127 and 103 x 109/L and mean spleen diameter was 9.2, 11.9, 14.9 and 16.2 centimeters, respectively. A reduction in platelet count was significantly associated with both the progression of the periportal fibrosis and the increase in spleen size. Conclusions Platelet count in patients with Schistosomiasis mansoni was inversely correlated with the severity of periportal fibrosis and spleen diameter. .

Contexto Estudos vem descrevendo correlação entre o número de plaquetas e o grau de fibrose hepática na hepatite viral crônica, mas poucas publicações estudaram esta correlação em pacientes com Esquistossomose mansoni. Objetivos Correlacionar a contagem de plaquetas com o padrão de fibrose periportal e com o diâmetro do baço, avaliados pela ultrassonografia em pacientes com Esquistossomose mansoni. Métodos Os pacientes com Esquistossomose mansoni foram avaliados pela ultrassonografia abdominal, por um único examinador, para determinação do padrão de fibrose periportal (classificação de Niamey) e do diâmetro do baço. A contagem de plaquetas foi realizada em contador automatizado. Resultados Cento e oitenta e sete pacientes com Esquistossomose mansoni com média de idade de 50,2 anos foram incluídos no estudo, 114 (61%) dos quais eram mulheres. De acordo com a classificação de Niamey, a ultrassonografia revelou que 37, 64, 64 e 22 pacientes exibiam padrões C, D, E e F, respectivamente. Nestes quatro grupos, o número médio de plaquetas foi 264, 196, 127 e 103 x 109/L, respectivamente, e o diâmetro médio do baço foi 9,2, 11,9, 14,9 e 16,2 centímetros, respectivamente. Observou-se, portanto, redução significativa na contagem de plaquetas associada à progressão da fibrose periportal e ao aumento do tamanho do baço. Conclusões Neste estudo verificou-se que a contagem de plaquetas foi inversamente correlacionada com o padrão de fibrose periportal, como também com o diâmetro do baço nos pacientes com Esquistossomose mansoni. .

Biochemical and histological changes in liver of Nectomys squamipes naturally infected by Schistosoma mansoni / Alterações na bioquímica e histologia do fígado de Nectomys squamipes naturalmente infectado por Schistosoma mansoni

The South American water rat Nectomys squamipes is a wild mammal reservoir of Schistosoma mansoni in Brazil. In the present study, wild rodents were collected in the field and categorized into two groups: infected and uninfected by S. mansoni. Blood was collected to analyze changes in the serum glucose level (mg/dL) and liver fragments were used to determine the hepatic glycogen content (mg of glucose/g tissue). The histological examination showed inflammatory granulomatous lesions in different phases of development in the liver of rodents naturally infected with S. mansoni, in some cases with total or partial occlusion of the vascular lumen. Early lesions were characterized by the presence of inflammatory infiltrate around morphologically intact recently deposited eggs. Despite the significance of these histological lesions, the biochemical changes differed in extent. N. squamipes naturally infected by S. mansoni showed no variation in hepatic glycogen reserves. These findings were accompanied by a significant increase in plasma glucose contents, probably as a consequence of amino acids deamination, which are degraded, resulting in the formation of intermediates used as precursors for the glucose formation, without compromising the reserves of liver glycogen. In the wild, naturally infected N. squamipes can maintain S. mansoni infections without undergoing alterations in its carbohydrate metabolism, which minimizes the deleterious effects of S. mansoni.

Nectomys squamipes é um mamífero silvestre reservatório de Schistosoma mansoni no Brasil. No presente estudo, os roedores silvestres, colhidos no campo, foram classificados em dois grupos: infectado e não infectado por S. mansoni. O sangue foi colhido para análise da alteração no nível de glicose sérico (mg/dL) e fragmentos de fígado foram usados para determinar o conteúdo de glicogênio hepático (mg de glicose/g tecido). A análise histológica demonstrou lesões granulomatosas em diferentes fases de desenvolvimento no tecido hepático dos roedores naturalmente infectados com S. mansoni, localizados principalmente na região periportal, com total ou parcial oclusão do lúmen vascular. As lesões foram caracterizadas por presença de infiltrado inflamatório ao redor de ovos morfologicamente intactos recentemente depositados. Apesar da grande significância das lesões histológicas, as alterações bioquímicas não diferiram no mesmo grau. N. squamipes naturalmente por S. mansoni não apresentaram variação na reserva de glicogênio hepático. Esses achados foram acompanhados pelo aumento significativo nos conteúdos de glicose plasmática, provavelmente como consequência ao processo desaminativo de aminoácidos, que passam a ser degradados notadamente para a formação de glucose, sem contudo comprometer a reserva de glicogênio hepático. Em condições naturais a infecção de S. mansoni pode ser mantida usando N. squamipes como hospedeiro definitivo, sem alterações significativas nos conteúdos de glicogênio hepático, minimizando os efeitos deletérios causados por S. mansoni nos roedores N. squamipes naturalmente infectados.

Schistosoma mansoni granuloma in late evolutive phase, in a case of tumoral form in man / Granuloma equistossomótico em fase evolutiva tardia, em um caso de forma tumoral no homem

INTRODUCTION: Authors describe human schistosomal granuloma in late chronic phase, from the morphological and evolutionary viewpoints. METHODS: The study was based on a histological analysis of two fragments obtained from a surgical biopsy of peritoneum and large intestine of a 42-year-old patient, with a pseudotumoral form mimicking a peritoneal carcinomatosis associated to the schistosomiasis hepatointestinal form. RESULTS: Two hundred and three granulomas were identified in the pseudotumor and 27 in the intestinal biopsy, with similar morphological features, most in the late chronic phase, in fibrotic healing. A new structural classification was suggested for granulomas: zone 1 (internal), 2 (intermediate) and 3 (external). CONCLUSIONS: Regarding granuloma as a whole, we may conclude that fibrosis is likely to be controlled by different and independent mechanisms in the three zones of the granuloma. Lamellar fibrosis in zone 3 seems to be controlled by matrix mesenchymal cells (fibroblasts and myoepithelial cells) and by inflammatory exudate cells (lymphocytes, plasmocytes, neutrophils, eosinophils). Annular fibrosis in zone 2, comprising a dense fibrous connective tissue, with few cells in the advanced phase, would be controlled by epithelioid cells involving zone 1 in recent granulomas. In zone 1, replacing periovular necrosis, an initialy loose and tracery connective neoformation, housing stellate cells or with fusiform nuclei, a dense paucicellular nodular connctive tissue emerges, probably induced by fibroblasts. In several granulomas, one of the zones is missing and granuloma is represented by two of them: Z3 and Z2, Z3 and Z1 or Z2 and Z1 and, ultimately, by a scar.

INTRODUÇÃO: Os autores descrevem o granuloma esquistossomótico no homem, na fase crônica tardia, do ponto de vista morfológico e evolutivo. MÉTODOS: O estudo baseou-se na análise histológica de dois fragmentos obtidos de biópsia cirúrgica do peritônio e do intestino grosso de um paciente de 42 anos de idade, com a forma pseudotumoral mimetizando carcinomatose peritoneal associada à forma hepatointestinal da esquistossomose. RESULTADOS: Foram identificados 203 granulomas no pseudotumor e 27 na biópsia intestinal, com aspectos morfológicos semelhantes, a maioria na fase crônica tardia, em cura por fibrose. Foi sugerida nova classificação estrutural para os granulomas: zona 1 (interna), zona 2 (intermediária) e zona 3 (externa). CONCLUSÕES: Considerando o granuloma como um todo, concluímos que, provavelmente, a fibrose é comandada por mecanismos diferentes e independentes nas três zonas do granuloma. A fibrose lamelar na zona 3 parece ser comandada pelas células mesenquimais da matriz (fibroblastos e células mioepiteliais) e pelas células do exsudato inflamatório (linfócitos, plasmócitos, neutrófilos, eosinófilos). A fibrose anular na zona 2, composta por conjuntivo fibroso denso, pouco celular na fase avançada, seria comandada pelas células epitelioides que envolvem a zona 1 nos granulomas recentes. Na zona 1, substituindo a necrose periovular, a neoformação conjuntiva inicialmente frouxa, rendilhada, albergando células estreladas ou com núcleos fusiformes, surge um conjuntivo denso, paucicelular, nodular, provavelmente induzido pelos fibroblastos. Em muitos granulomas falta uma das zonas descritas e o granuloma é representado apenas por duas delas: Z3 e Z2, Z3 e Z1 ou Z2 e Z1 e, no final, por uma cicatriz.

Ultrasound and magnetic resonance imaging findings in Schistosomiasis mansoni: expanded gallbladder fossa and fatty hilum signs / Achados da ultrassonografia e da ressonância magnética na esquistossomose mansônica: sinais da expansão da fossa da vesícula e do hilo gorduroso

INTRODUCTION: There is no study relating magnetic resonance imaging (MRI) to ultrasound (US) findings in patients with Schistosomiasis mansoni. Our aim was to describe MRI findings inpatients with schistosomal liver disease identified by US. METHODS: Fifty-four patients (mean age 41.6±13.5years) from an area endemic for Schistosomiasis mansoni were selected for this study.All had US indicating liver schistosomal fibrosis and were evaluated with MRI performed witha 1.5-T superconducting magnet unit (Sigma). RESULTS: Forty-seven (87%) of the 54 patientsshowing signs of periportal fibrosis identified through US investigation had confirmed diagnosesby MRI. In the seven discordant cases (13%), MRI revealed fat tissue filling in the hilar periportalspace where US indicated isolated thickening around the main portal vein at its point of entryto the liver. We named this the fatty hilum sign. One of the 47 patients with MRI evidence ofperiportal fibrosis had had his gallbladder removed previously. Thirty-five (76.1%) of the other46 patients had an expanded gallbladder fossa filled with fat tissue, whereas MRI of the remainingeleven showed pericholecystic signs of fibrosis. CONCLUSIONS: Echogenic thickening of thegallbladder wall and of the main portal vein wall heretofore attributed to fibrosis were frequentlyidentified as fat tissue in MRI. However, the gallbladder wall thickening shown in US (expandedgallbladder fossa in MRI) is probably secondary to combined hepatic morphologic changes inschistosomiasis, representing severe liver involvement.

INTRODUÇÃO: Não existem estudos que correlacionam os achados da ressonância magnética (RM) aos da ultrassonografia (US) em pacientes com esquistossomose mansônica. O objetivodeste estudo foi descrever os achados da imagem por RM em pacientes com doença hepática esquistossomótica identificada por US. MÉTODOS: Selecionaram-se 54 pacientes com idade média de 41,6±13,5 anos, provenientes de área endêmica para a esquistossomose mansônica. Todos apresentavam US indicativa de fibrose hepática esquistossomótica, e foram avaliados com imagens por RM, realizadas com uma unidade magnética supercondutora de 1,5-T(Sigma). RESULTADOS: Quarenta e sete (87%) entre 54 pacientes com sinais ultrassonográficosde fibrose periportal esquistossomótica tiveram este diagnóstico confirmado pela RM. Nos sete(13%) casos discordantes, a RM revelou tecido adiposo preenchendo o espaço periportal hilaronde a US indicava espessamento isolado da parede da veia porta em seu ponto de entrada no fígado. Este achado foi nomeado sinal do hilo gorduroso. Um dos 47 pacientes com evidência de fibrose periportal RM era colecistectomizado. Trinta e quatro (76,1%) dos 46 pacientes restantes apresentavam expansão da fossa da vesícula, que se encontrava preenchida portecido adiposo. Nos outros sete, a RM revelou sinais de fibrose pericolecística. CONCLUSÕES: Os espessamentos ecogênicos central da parede da veia porta, e da parede da vesícula biliar, até o momento, atribuídos à fibrose, foram frequentemente identificados como tecido adiposopela RM. Entretanto, o espessamento da parede da vesícula identificado pela US (expansão da fossa da vesícula na RM) é provavelmente secundário a alterações morfológicas hepáticas na esquistossomose, e representa comprometimento grave do fígado.

Pharmacodynamics of mefloquine and praziquantel combination therapy in mice harbouring juvenile and adult Schistosoma mansoni

Praziquantel (PZQ) is currently the only drug widely used for the treatment of schistosomiasis, but the antimalarial drug mefloquine (Mef) possesses interesting antischistosomal properties. Combination therapy with these two drugs has been suggested as a strategy for transmission control, as PZQ is active against adult worms and Mef is active against schistosomula. To examine the efficacy of combination therapy, Schistosoma mansoni-reinfected mice were separated into seven groups: untreated (I), treated with PZQ in doses of 200 mg/kg (II) or 1,000 mg/kg (III), treated with Mef in doses of 200 mg/kg (IV) or 400 mg/kg (V); each dose was divided equally and given on two consecutive days. Group VI was treated with doses of PZQ + Mef as in groups II and IV, respectively, while group VII was treated with PZQ + Mef as in groups III and V, respectively. PZQ + Mef at the reduced doses of 200 mg/kg each enhanced the therapeutic efficacy over the reduced PZQ dose alone as shown by a very high reduction in the total numbers of mature worms (95 percent vs. 49 percent), immature worms (96 percent vs. 29 percent) and the complete eradication of immature females, mature females and immature eggs. The reduction in worm burden was associated with the healing of hepatic granulomatous lesions and the normalisation of all liver enzymes. Therefore, the use of Mef with PZQ is more effective than PZQ alone and should be considered for clinical trials in humans as a potential treatment regimen to prevent treatment failures in areas with high rates of schistosomiasis.

Schistosomal glomerulopathy and changes in the distribution of histological patterns of glomerular diseases in Bahia, Brazil

Distinct patterns of glomerular lesions, including membranoproliferative glomerulonephritis and focal segmental glomerulosclerosis, are associated with infection by Schistosoma mansoni or Schistosoma japonicum. Evidence suggests that immune complex deposition is the main mechanism underlying the different forms of schistosomal glomerulonephritis and that immune complex deposition may be intensified by portal hypertension. The relationship between focal segmental glomerulosclerosis and schistosomiasis remains poorly understood. A clinicopathologic classification of schistosomal glomerulopathies was proposed in 1992 by the African Association of Nephrology. In Brazil, mass treatment with oral medications has led to a decrease in the occurrence of schistosomal glomerulopathy. In a survey of renal biopsies performed in Salvador, Brazil, from 2003-2009, only 24 (4 percent) patients were identified as positive for S. mansoni infection. Among these patients, only one had the hepatosplenic form of the disease. Focal segmental glomerulosclerosis was found in seven patients and membranoproliferative glomerulonephritis was found in four patients. Although retrospective studies on the prevalence of renal diseases based on kidney biopsies may be influenced by many patient selection biases, a change in the distribution of glomerulopathies associated with nephrotic syndrome was observed along with a decline in the occurrence of severe forms of schistosomiasis.

Esquistossomose mansônica: aspectos gerais, imunologia, patogênese e história natural: [revisão] / Schistosomiasis mansoni: general aspects, immunology, pathogenesis and natural history: [review]

JUSTIFICATIVA E OBJETIVOS: A esquistossomose mansônica ainda hoje é um grave problema de saúde pública no país. Sua patogênese é dependente da interação do parasita e do hospedeiro podendo acometer diferentes órgãos e sistemas. O objetivo deste estudo foi trazer ao leitor uma visão geral da etiologia e da patogênese da esquistossomose, seus aspectos patológicos, determinantes de maior importância para seu desenvolvimento e manifestações clínicas. Foram utilizadas as palavras esquistossomose mansônica, etiologia, imunologia, patogênese e história natural como descritores na pesquisa de dados nas bases Scielo (Scientific Eletronic Library Online) e Pubmed (U. S. National Library of Medicine), assim como livros-texto relacionados ao tema. CONTEÚDO: O S. mansoni, apresenta alguns mecanismos de "escape" contra o sistema imunológico do hospedeiro dentre os quais alterações morfológicas e bioquímicas. Um dos eventos patogênicos mais importantes na esquistossomose é a formação do granuloma hepático e a fibrose hepática peri-portal. A formação dos granulomas em diferentes órgãos explica as manifestações da doença, como a hipertensão porta, a forma pseudotumoral, aneurológica e vásculo-pulmonar. CONCLUSÃO: A esquistossomose aguda é representada por manifestações pruriginosas na pele, de duração geralmente transitória e cedendo quase sempre espontaneamente. Em relação à sua fase crônica, pode se apresentar de maneira polimórfica, sendo a forma hepatointestinal a mais frequentemente observada,representando a fase intermediária na evolução da doença para aforma hepatoesplênica.

BAC KGROUND AND OBJECTIVES: The schistosomiasis mansoni is still regarded today as a grave public health problem for this country. Its pathogenesis is dependable on the host parasite interaction making it possible to affect different organs and systems. The aim of this article is to bring to the reader a general view of the etiology and pathogenesis of schistosomiasis,its pathological aspects, determinant and of major importance for its development and clinical manifestations. There have beenused the words schistosomiasis mansoni, etiology, immunology, pathogenesis and natural history as descriptions for the data researchon these databases: Scielo (Scientific Electronic Library Online) and Pubmed (U. S. National Library of Medicine), as much as textbooks related to the theme. CONTENTS : The Schistosoma mansoni presents some evasion mechanisms against the host's immunological system including morphological and biochemical modifications. One of the most important pathogenical events on the schistosomiasis is the formation of hepatic granuloma and periportal hepatic fibrosis.The formations of granulomas on different organs explain the manifestations of the disease, such as the portal hypertension,the pseudotumoral form, and the neurological and vascular lung forms. CONCLUSION: The acute schistosomiasis is represented by prickly skin manifestations, of generally transitory duration. They almost always give away spontaneously. In relation with its chronic phase this can present itself on a polymorphic manner.The hepatointestinal is the most frequently observed, representing the intermediate phase on the disease evolution towards the hepatosplenic form.

Immunological and parasitological parameters after treatment with dexamethasone in murine Schistosoma mansoni

This work aimed to evaluate the effect of diphenyl dimethyl bicarboxylate (DDB) and dexamethasone alone and in combination with praziquantel on various parasitological, immunological and pathological parameters reflecting disease severity and morbidity in murine schistosomiasis. DDB and dexamethasone had no effect on worm burden but altered tissue egg distribution. This indicates that, under the schedule used, neither drug interfered with the development of adult worms or oviposition, but both can modulate liver pathology. Dexamethasone resulted in a greater reduction in granuloma size than did DDB. Dexamethasone-treated mice also showed lower levels of serum gamma interferon (IFN-γ), interleukin-12 (IL-12) and IL-4, together with higher IL-10 levels, than infected untreated control animals. These data suggest that dexamethasone is a convenient and promising coadjuvant agent that results in decreased morbidity in murine schistosomiasis.

Manson's schistosomiasis in the undernourished mouse: some recent findings

This paper deals with current knowledge of the interrelationships between Schistosoma infection and malnutrition. It emphasizes the relevance of these investigations in the face of dynamic and evolving changes occurring in population diets and changes in the epidemiological patterns of schistosomiasis in endemic countries. The paper further discusses the basis for continuing the studies on this subject and the reasons why it represents a misunderstood association. This review also focuses on the cellular and humoral immune responses in the undernourished mouse model infected with Schistosoma mansoni, with updated information on the immune response in wild-type and iNOS knockout mice concerning soluble egg antigen specific antibodies and kinetics of IFN-ã, IL-4, IL-10 and IL-13 cytokines, in the chronic phase of Manson's schistosomiasis. There is indication that schistosome-infected undernourished mice are able to develop a humoral immune response, but antibody titres are much lower than in the control animals. Cytokine production (IFN-ã, IL-4, IL-10) is lower in the undernourished mice, but as infection progresses to the chronic phase its kinetics run an antagonistic course when compared to that of well-nourished animals. Marked variation in the secretion of IL-13 (a fibrogenic cytokine) could explain why undernourished mice do not develop liver "pipe-stem" fibrosis described in previous papers on well-nourished animals.

Imaging techniques and histology in the evaluation of liver fibrosis in hepatosplenic schistosomiasis mansoni in Brazil: a comparative study

Few publications have compared ultrasound (US) to histology in diagnosing schistosomiasis-induced liver fibrosis (LF); none has used magnetic resonance (MR). The aim of this study was to evaluate schistosomal LF using these three methods. Fourteen patients with hepatosplenic schistosomiasis admitted to hospital for surgical treatment of variceal bleeding were investigated. They were submitted to upper digestive endoscopy, US, MR and wedge liver biopsy. The World Health Organization protocol for US in schistosomiasis was used. Hepatic fibrosis was classified as absent, slight, moderate or intense. Histology and MR confirmed Symmers' fibrosis in all cases. US failed to detect it in one patient. Moderate agreement was found comparing US to MR; poor agreement was found when US or MR were compared to histology. Re-classifying LF as only slight or intense created moderate agreement between imaging techniques and histology. Histomorphometry did not separate slight from intense LF. Two patients with advanced hepatosplenic schistosomiasis presented slight LF. Our data suggest that the presence of the characteristic periportal fibrosis, diagnosed by US, MR or histology, associated with a sign of portal hypertension, defines the severity of the disease. We conclude that imaging techniques are reliable to define the presence of LF but fail in grading its intensity.

Angiogenesis and schistosomiasis

Angiogenesis has been recognised as a precursor of fibrosis in several pathologic conditions. Its participation has been demonstrated in schistosomiasis, both during periovular granuloma formation and in the genesis of schistosomal periportal fibrosis. Paradoxically, proliferation of new blood vessels, accompanied by production of vascular-endothelial growth factor, appeared prominent during fibrosis regression months after curative treatment of schistosomiasis. Thus, angiogenesis in schistosomiasis seems to have a two-way mode of action, participating both in fibrogenesis and in fibrosis degradation. Morphological observations presented here are in keeping with the possibility that, in the first case, angiogenesis allows pericytes to come in great numbers to the site of lesions and be detached from capillary walls and transformed into myofibroblasts, which are important extra-cellular matrix forming cells. During post-curative fibrosis regression, actin-containing pericytes appeared at various foci of tissue remodelling, especially at sites of repair of vascular lesions. The molecular and cell factors involved in both situations seem to be important subjects in need of further investigations and the schistosomiasis model certainly will be of great avail in this regard.

Omental and pleural milky spots: different reactivity patterns in mice infected with Schistosoma mansoni reveals coelomic compartmentalisation

In vertebrate animals, pleural and peritoneal cavities are repositories of milky spots (MS), which constitute an organised coelom-associated lymphomyeloid tissue that is intensively activated by Schistosoma mansoni infection. This study compared the reactive patterns of peritoneal MS to pleural MS and concluded from histological analysis that they represent independent responsive compartments. Whole omentum, lungs and the entire mediastinum of 54 S. mansoni-infected mice were studied morphologically. The omental MS of infected animals were highly activated, modulating from myeloid-lymphocytic (60 days of infection) to lymphomyeloid (90 days of infection) and lymphocytic or lymphoplasmacytic (160 days of infection) types. The non-lymphoid component predominated in the acute phase of infection and was expressed by monocytopoietic, eosinopoietic and neutropoietic foci, with isolated megakaryocytes and small foci of late normoblasts and mast cells. Nevertheless, pleural or thoracic MS of infected mice were monotonous, consisting of small and medium lymphocytes with few mast and plasma cells and no myeloid component. Our data indicate that compartmentalisation of the MS response is dependent on the lymphatic vascularisation of each coelomic cavity, limiting the effects or consequences of any stimulating or aggressive agents, as is the case with S. mansoni infection.