Fascioliasis: a worldwide parasitic disease of importance in travel medicine.

Fascioliasis is a foodborne zoonotic disease caused by the two parasite species Fasciola hepatica and Fasciola gigantica. This trematodiasis has never been claimed special relevance for travellers and migrants. However, the situation has drastically changed in the last two decades, in a way that fascioliasis should today be included in the list of diseases to be enhanced in Travel Medicine. Different kind of travellers have been involved in human infection reports: business travellers, tourists, migrants, expatriated workers, military personnel, religious missionaries, and refugees. Europe is the continent where more imported cases have been reported in many countries. More cases would have been probably reported in Europe if fascioliasis would be a reportable disease. In the Americas, most of the reports concern cases diagnosed in USA. Relative few patients have been diagnosed in studies on travellers performed in Asia. In Africa, most cases were reported in Maghreb countries. Blood eosinophilia and the ingestion of watercress or any other suggestive freshwater plant in anamnesis are extremely useful in guiding towards a fascioliasis diagnosis in a developed country, although may not be so in human endemic areas of developing countries. Several suggestive clinical presentation aspects may be useful, although the clinical polymorphism may be misleading in many cases. Non-invasive techniques are helpful for the diagnosis, although images may lead to confusion. Laparoscopic visualization should assist and facilitate procurement of an accurately guided biopsy. Endoscopic retrograde cholangiopancreatography (ERCP) is the first choice in patients in the chronic phase. ERCP and sphincterotomy are used to extract parasites from the biliary tree. Fluke egg finding continues to be the gold standard and enables for burden quantification and establishing of the drug dose. Many serological and stool antigen detection tests have been developed. Immunological techniques present the advantages of being applicable during all periods of the disease, but fundamentally during the invasive or acute period, as well as to other situations in which coprological techniques may present problems. Triclabendazole is the drug of choice at present, although the spread of resistance to this drug is challenging. Prevention mainly concerns measures to avoid individual infection by considering the different human infection sources.

Revisão taxonômica e elaboração de mapas de distribuição geográfica de espécies brasileiras da família Lymnaeidae Rafinesque, 1815 (Gastropoda, Basommatophora)

Moluscos da família Lymnaeidae Rafinesque, 1815, atuam como hospedeiros intermediários do trematódeo Fasciola hepatica Linnaeus, 1758, agente etiológico da fasciolose, doença parasitária de importância médica e veterinária. As áreas mais críticas onde a doença representa um problema de saúde pública estão localizadas nos países Andinos (Bolívia, Peru, Chile, Equador), região do Caribe (Cuba), norte da África (Egito) e Europa ocidental (Portugal, França e Espanha). Estima-se que mais de 20 milhões de pessoas encontram-se infectadas em todo o mundo. A variabilidade na morfologia da concha e a uniformidade na anatomia interna são características de vários gêneros e espécies da família as quais dificultam a determinação específica. Os objetivos do presente trabalho foram: 1) Analisar a morfologia de espécimes tipo outopótipos das espécies Galba viatrix d'Orbigny, 1835, G. truncatula (Müller, 1774), G.cubensis Pfeiffer, 1839, Lymnaea rupestris Paraense, 1982 e Pseudosuccinea columella(Say, 1817) e compará-las com limneídeos procedentes do Brasil; 2) Elucidar alocalidade tipo de P. columella; 3) Refinar e definir novos caracteres morfológicos que possam ser utilizados na identificação; 4) Rever e retificar a taxonomia dos limneídeos do acervo da coleção Fiocruz-CMM; 5) Elaborar mapas de distribuição geográfica dos limneídeos brasileiros.

Através das análises dos topótipos e de exemplares coletados no Brasil foram confirmadas a presença de G. viatrix, G. truncatula, G. cubensis e P.columella. Um neótipo é proposto para P. columella, considerando o desconhecimento da localidade tipo e a invalidade da série tipo para essa espécie. As diferenças evidenciadas entre as espécies de limneídeos foram encontradas principalmente na concha (microescultura e formato), sistema digestivo (estômago e glândulas salivares) e sistema reprodutor (oviduto, próstata, complexo peniano, vesicular seminal e ovotestis). Após avaliação e retificação, o acervo Fiocruz-CMM ficou composto por sete espécies em um total de 98 pontos de coleta, sendo 64 (65.3%) identificados com exemplares da espécie P. columella, 14 (14.3%) com G. truncatula, oito (8.2%) com G. cubensis, sete(7.1%) com G. viatrix, dois (2%) com L. diaphana King, 1830, dois (2%) com L. peregra (Müller, 1774) e um (1%) com L. stagnalis (Linnaeus, 1758). Após o levantamento da ocorrência das espécies no Brasil registrou-se: P. columella em 400 municípios (95,7%), G. viatrix em 10 (2,4%), G. cubensis em seis (1,4%), G. truncatulaem três (0,7%) e L. rupestris em um (0,2%). Pela primeira vez, foi elaborado mapas de distribuição de limneídeos no Brasil.

Revisão taxonômica e elaboração de mapas de distribuição geográfica de espécies brasileiras da família Lymnaeidae Rafinesque, 1815 (Gastropoda, Basommatophora) / Taxonomic revision and preparation of distribution maps geographic Brazilian species of Lymnaeidae family Rafinesque, 1815 (Gastropoda, Basommatophora)

Moluscos da família Lymnaeidae Rafinesque, 1815, atuam como hospedeiros intermediários do trematódeo Fasciola hepatica Linnaeus, 1758, agente etiológico da fasciolose, doença parasitária de importância médica e veterinária. As áreas mais críticas onde a doença representa um problema de saúde pública estão localizadas nos países Andinos (Bolívia, Peru, Chile, Equador), região do Caribe (Cuba), norte da África (Egito) e Europa ocidental (Portugal, França e Espanha). Estima-se que mais de 20 milhões de pessoas encontram-se infectadas em todo o mundo. A variabilidade na morfologia da concha e a uniformidade na anatomia interna são características de vários gêneros e espécies da família as quais dificultam a determinação específica. Os objetivos do presente trabalho foram: 1) Analisar a morfologia de espécimes tipo outopótipos das espécies Galba viatrix d'Orbigny, 1835, G. truncatula (Müller, 1774), G.cubensis Pfeiffer, 1839, Lymnaea rupestris Paraense, 1982 e Pseudosuccinea columella(Say, 1817) e compará-las com limneídeos procedentes do Brasil; 2) Elucidar alocalidade tipo de P. columella; 3) Refinar e definir novos caracteres morfológicos que possam ser utilizados na identificação; 4) Rever e retificar a taxonomia dos limneídeos do acervo da coleção Fiocruz-CMM; 5) Elaborar mapas de distribuição geográfica dos limneídeos brasileiros...

Através das análises dos topótipos e de exemplares coletados no Brasil foram confirmadas a presença de G. viatrix, G. truncatula, G. cubensis e P.columella. Um neótipo é proposto para P. columella, considerando o desconhecimento da localidade tipo e a invalidade da série tipo para essa espécie. As diferenças evidenciadas entre as espécies de limneídeos foram encontradas principalmente na concha (microescultura e formato), sistema digestivo (estômago e glândulas salivares) e sistema reprodutor (oviduto, próstata, complexo peniano, vesicular seminal e ovotestis). Após avaliação e retificação, o acervo Fiocruz-CMM ficou composto por sete espécies em um total de 98 pontos de coleta, sendo 64 (65.3%) identificados com exemplares da espécie P. columella, 14 (14.3%) com G. truncatula, oito (8.2%) com G. cubensis, sete(7.1%) com G. viatrix, dois (2%) com L. diaphana King, 1830, dois (2%) com L. peregra (Müller, 1774) e um (1%) com L. stagnalis (Linnaeus, 1758). Após o levantamento da ocorrência das espécies no Brasil registrou-se: P. columella em 400 municípios (95,7%), G. viatrix em 10 (2,4%), G. cubensis em seis (1,4%), G. truncatulaem três (0,7%) e L. rupestris em um (0,2%). Pela primeira vez, foi elaborado mapas de distribuição de limneídeos no Brasil...

Direct and indirect affection of the central nervous system by Fasciola infection.

Fascioliasis is a worldwide, zoonotic disease caused by the liver trematodes Fasciola hepatica and Fasciola gigantica. Neurological fascioliasis has been widely reported in all continents, affecting both sexes and all ages. Two types of records related to two physiopathogenic mechanisms may be distinguished: cases in which the neurological symptoms are due to direct effects of a migrating juvenile present in the brain or neighboring organ and with cerebral lesions suggesting migration through the brain; and cases with neurological symptoms due to indirect immuno-allergic and toxic effects at distance from flukes in the liver. Neurological manifestations include minor symptoms, mainly cephalalgias, and major symptoms which are nonspecific, extremely diverse, varying from one patient to another and even within the same patient, and comprising meningeal manifestations and impressive neurological manifestations. The puzzling neurological polymorphism leads to confusion with cerebral tumors, multiple sclerosis, lesions of the brainstem, or cerebro-meningeal hemorrhages. Only blood eosinophilia and information on infection source guide toward correct diagnosis by appropriate coprological and/or serological techniques. Although neurological patients usually recover after fasciolicide treatment or surgical worm extraction, sequelae, which are sometimes important, remain in several patients. The need to include possible neurological complications within the general frame of fascioliasis becomes evident.

Production and characterization of a monoclonal antibody against recombinant saposin-like protein 2 of Fasciola gigantica.

A monoclonal antibody (MoAb) against recombinant Fasciola gigantica saposin-like protein 2 (rFgSAP-2) was produced by hybridoma technique using spleen cells from BALB/c mice immunized with rFgSAP-2. This MoAb is an IgG1, κ light chain isotype. By immunoblotting and indirect ELISA, the MoAb reacted specifically with rFgSAP-2, the natural FgSAP-2 at 10kDa in whole body (WB) and excretory-secretory (ES) fractions of F. gigantica. It did not cross react with antigens in WB fractions from other parasites, including Opisthorchis viverrini, Schistosoma mansoni which are human parasites, Haemonchus placei, Setaria labiato-papillosa, Eurytrema pancreaticum, Cotylophoron cotylophorum, Fischoederius cobboldi, Gigantocotyle explanatum, Gastrothylax crumenifer, and Paramphistomum cervi which are ruminant parasites. By immunohistochemistry, the FgSAP-2 protein was localized only in the cytoplasm of caecal epithelial cells of 4-week-old juvenile and adult stages, but not in metacercariae, newly excysted juvenile (NEJ), 2- and 3-week-old juveniles. This finding indicated that FgSAP-2 is an abundantly expressed parasite protein that is released into the ES, hence SAP-2 and its MoAb may be used for immunodiagnosis of ruminant and human fasciolosis.

[Proteases in helminthic parasites]. / Les protéases chez les helminthes.

Proteases catalyse the cleavage of internal peptide bonds within peptides and proteins. They are classified into four major classes and are involved in a broad range of eukaryotic processes. Proteases have also been found to play a number of critical roles in the virulence of pathogenic agents, particularly of nematode parasites. Parasitic proteases are involved in different aspects of host-parasite interactions. They facilitate the invasion of host tissues and allow nutrition as well as the survival of the parasite in its host. Proteases also participate in the parasite's evasion from the host's immune response. The functional diversity and complexity of these enzymes are described in this review, with a particular focus on the principally identified proteases of four helminths: Schistosoma sp., Fasciola sp., Taenia sp. and Haemonchus sp. Some of these proteases, especially the cysteine proteases secreted by the parasitic trematode Fasciola hepatica, have been successfully tested in experimental immunodiagnosis. Proteases identified in different parasites are currently under study for a use as recombinant vaccines. In this respect, proteases are proposed as major potential targets for immunotherapy and chemotherapy against parasitic diseases.

Studies on the viability of metacercariae of Fasciola gigantica.

The viability of metacercariae of Fasciola gigantica was tested by in vitro and in vivo methods. In vitro testing was based upon the motility of juvenile flukes within the inner cyst as examined under the light microscope. In vivo testing was undertaken through experimental infections of rabbits (two groups) and natural definitive hosts, lambs (one group). In the first group, out of six rabbits each given 25 metacercariae, worm establishment only took place in one rabbit with a single fluke recovery on 60 days post infection. In the second group of six rabbits each given 200 metacercariae, five were infected, with two or three flukes per host. All the lambs given 250 metacercariae became infected showing prevalences of 7.2-40% in comparison with rabbits in which low prevalences (0-4%) were recorded. The results indicated that even viable metacercariae which were already tested in vitro could not readily establish in rabbits. Such variability in worm establishment suggests that immunological and chemotherapeutic studies in rabbits infected with F. gigantica are likely to be unreliable.

On the viability of Fasciola gigantica metacercariae ingested by Lymnaea auricularia.

The effect of ingestion by Lymnaea auricularia on the viability and infectivity of Fasciola gigantica metacercariae was studied. The cyst wall was unaffected by the snail's digestive processes. Two rabbits, each infected with 50 ingested metacercariae, died at 83 and 87 days post-infection. Eight and 10 immature flukes were recovered from the livers, indicating that the metacercariae had remained infective after passing through the intestine of the snail.

Infectivity and pathogenicity of Fasciola gigantica in West African dwarf sheep and goats.

The infectivity and pathogenicity of Fasciola gigantica for sheep and goats were investigated in animals infected with single doses of between 200 and 2,000 metacercariae. Acute fascioliasis occurred in sheep infected with 1,000 to 2,000 cysts in which 10 to 17% of the cysts became established. The infected animals died 80 to 90 days after infection. In goats given the same infective doses death from acute fascioliasis occurred earlier (70 to 83 days after infection) and 12 to 38% of cysts became established. Subacute fascioliasis could occur in both hosts with an infective dose of 200 cysts, the animals surviving for more than 100 days. It therefore appears that F. gigantica is more infective for goats and that the disease was more severe in this host than in sheep.