Human schistosomiasis in the post mass drug administration era.

Profound changes are occurring in the epidemiology of schistosomiasis, a neglected tropical disease caused by a chronic infection with parasitic helminths of the genus Schistosoma. Schistosomiasis currently affects 240 million people worldwide, mostly in sub-Saharan Africa. The advent and proliferation of mass drug administration (MDA) programmes using the drug praziquantel is resulting in substantial increases in the number of people, mainly children aged 6-14 years, being effectively treated, approaching the point where most people in endemic areas will receive one or more treatments during their lifetimes. Praziquantel treatment not only cures infection but also frees the host from the powerful immunomodulatory action of the parasites. The treatment simultaneously enhances exposure to key parasite antigens, accelerating the development of protective acquired immunity, which would take many years to develop naturally. At a population level, these changes constitute a substantial alteration to schistosome ecology in that the parasites are more likely to be exposed not only to praziquantel directly but also to hosts with altered immune phenotypes. Here, we consider the consequences of this for schistosome biology, immunoepidemiology, and public health. We anticipate that there could be substantial effects on chronic pathology, natural immunity, vaccine development strategies, immune disorders, and drug efficacy. This makes for a complex picture that will only become apparent over decades. We recommend careful monitoring and assessment to accompany the roll-out of MDA programmes to ensure that the considerable health benefits to populations are achieved and sustained.

Cerebral and spinal schistosomiasis.

Cerebral schistosomiasis and spinal schistosomiasis are severe underrecognized complications of Schistosoma sp. infection, and can occur at any time during the parasitic infection. Neuroschistosomiasis has been increasingly reported not only in endemic areas but also in Western countries owing to immigration and international travel. Immunogenic interaction between schistosome egg deposition and the delayed hypersensitivity reaction of the host are the main neuropathogenic mechanisms involved. Eggs induce a periovular granulomatous reaction in the tissues. In some cases, schistosome adult worms may aberrantly migrate to the central nervous system via the vertebral venous plexus and place the ova at an ectopic site. Headache and seizures are common in cerebral schistosomiasis, and intracranial hypertension and hydrocephalus may occur in tumour-like and cerebellar schistosomiasis. Spinal schistosomiasis may manifest itself as acute myelitis and/or myeloradiculopathy. Recognition of neuroschistosomiasis is important so that early treatment with praziquantel and steroids can be started in an attempt to prevent severe disability.

Correlação interobservador das alterações morfológicas das vias biliares em pacientes com esquistossomose mansoni pela colangiorressonância magnética / Evaluation of morphological changes of the biliary tree by magnetic resonance cholangiography in patients with schistosomiasis mansoni: interobserver agreement

OBJETIVO: Descrever as alterações das vias biliares pela colangiografia por ressonância magnética (CPRM) na esquistossomose hepatoesplênica e avaliar a concordância interobservador da CPRM na detecção de colangiopatia esquistossomótica. MATERIAIS E MÉTODOS: Estudo prospectivo e transversal em 24 pacientes com a forma hepatoesplênica da esquistossomose mansoni e em 6 pacientes sadios, como grupo controle, com avaliação da via biliar pela CPRM. As alterações da via biliar consideradas foram: distorção, afilamento, estenose, dilatação e irregularidade. Foi calculada a concordância interobsevador para alteração da via biliar com o teste de McNemar e o índice kappa (κ). RESULTADOS: A concordância interobservador na caracterização de distorção e afilamento da via biliar foi quase perfeita (κ = 0,867; intervalo de confiança [IC] 95 por cento [0,512-1,0] e κ = 0,865; IC 95 por cento [0,51-1,0], respectivamente). A concordância foi substancial para a estenose (κ = 0,78; IC 95 por cento [0,424-1,0]), moderada para dilatação (κ = 0,595; IC 95 por cento [0,247-0,942]) e regular para afilamento (κ = 0,229; IC 95 por cento [0,095-0,552]). CONCLUSÃO: As alterações observadas nas vias biliares foram, em ordem decrescente de ocorrência: distorção, afilamento, estenose, dilatação e irregularidade. A concordância interobservador para sinais de colangiopatia esquistossomótica foi quase perfeita para distorção e afilamento e substancial para estenose.

OBJECTIVE: To describe changes of the biliary tree demonstrated by magnetic resonance cholangiography (MRC) in patients with the hepatosplenic presentation of schistosomiasis mansoni, and evaluating the interobserver agreement in the detection of schistosomal cholangiopathy. MATERIALS AND METHODS: Prospective, cross-sectional study involving 24 patients with hepatosplenic schistosomiasis and 6 healthy patients (control group) submitted to biliary tree evaluation by MRC. The following changes of the biliary tree were considered: distortion, thinning, stenosis, dilation and irregularity. The interobserver agreement in the detection of biliary tree changes was calculated with the McNemar's test and the kappa index of agreement (κ). RESULTS: The interobserver agreement in the detection of distortion and thinning of the biliary tree was almost perfect (κ = 0.867; confidence interval [CI] 95 percent [0.512-1.0] and κ = 0.865; CI 95 percent [0.51-1.0], respectively). There was a substantial agreement for stenosis (κ = 0.78; CI 95 percent [0.424-1.0]), moderate agreement for dilation (κ = 0.595; CI 95 percent [0.247-0.942]) and mild agreement for thinning (κ = 0.229; CI 95 percent [0.095-0.552]). CONCLUSION: In a decreasing order of frequency, the changes of the biliary tree were observed: distortion, thinning, stenosis, dilation and irregularity. The interobserver agreement for signs of schistosomal cholangiopathy was almost perfect for distortion and thinning, and substantial for stenosis.

Parasitic central nervous system infections: echinococcus and schistosoma.

Central nervous system (CNS) manifestations of Echinococcus and Schistosoma infections occur throughout the world, with incidence increasing in developed regions. A detailed literature review generated a current summary on epidemiology, parasitology, pathology, clinical manifestations, imaging studies, diagnosis, and treatment of neuroechinococcosis and neuroschistosomiasis. Recent advancements have been made in diagnosis, treatment, and prevention of these parasitic CNS infections. Ongoing advancements in neuroimaging and diagnostic studies, as well as efforts to better understand the parasite genome and host-parasite relationships, will likely continue to improve patient management.

Worms take the 'phyto' out of 'phytochelatins'.

Phytochelatin synthase is the enzyme responsible for the synthesis of heavy-metal-binding peptides (phytochelatins) from glutathione and related thiols. It has recently been determined that it is not only restricted to plants and some fungi, as was once thought, but also has an essential role in heavy-metal detoxification in the model nematode Caenorhabditis elegans. These findings and others that demonstrate phytochelatin synthase-coding sequences in the genomes of several other invertebrates, including pathogenic nematodes, schistosomes and roundworms, herald a new era in phytochelatin research, in which these novel post-translationally synthesized peptides will not only be investigated in the context of phytoremediation but also from a clinical parasitological standpoint.

Estudo da resposta linfoproliferativa de pacientes com diferentes formas clínicas de esquistossomose mansônica / Study of proliferative response of patients with different clinical forms of schistosomiasis mansoni

O objetivo deste trabalho foi avaliar a resposta linfoproliferativa "in vitro" de células do baço e do sangue periférico de pacientes infectados com ::"chistosoma mansoni com diferentes formas clínicas e/ou intensidade de infecção aos seguintes antígenos: antígeno ovular solúvel (SEA), triose fosfato isomerase recombinante (rTPI), peptídeo sintético P4 derivado do rTPI, derivado protéico purificado (PPO) e mitógeno fitohemaglutinina. Os pacientes foram classificados em três grupos: 1- Hepatoíntestinal, 2- Hepatoesplênico e 3- Tratados e Curados. A resposta linfoproliferativa a estes antígenos foi testada em células mononucleares do sangue periférico de pacientes com as três formas clínicas. Também foi avaliada a resposta linfoproliferativa de células povenientes do baço de pacientes com a forma hepatoesplênica e que haviam sido submetidos a esplenectomia terapêutica. As células mononucleares do sangue periférico dos pacientes com a forma hepatointestinal e dos pacientes tratados e curados responderam ao antígeno SEA, sendo maior o nível de resposta observado neste último grupo. As células mononucleares do sangue periférico e do baço de pacientes com a forma hepatoespiênica mostraram uma resposta linfoproliferativa ao antígeno SEA inferior às células dos pacientes dos demais grupos. Não foi observada resposta linfoproliferativa estatisticamente significante aos antígenos P4 e rTPl em nenhum dos grupos estudados.