Ecological changes from water resources development projects often affect the epidemiology of water-associated diseases. In order to investigate the occurrence and distribution of freshwater snails ...of medical and veterinary importance in the area of influence of the Serra da Mesa Hydroelectric a survey has been performed since 1997 and revealed the occurrence of well-established populations of Biomphalaria straminea (Dunker, 1848) in the 8 municipalities surrounding the lake. Areas of epidemiologic risk for schistosomiasis were selected and studies of parasite-mollusc compatibility were undertaken using specimens from 19 populations of B. straminea and 3 strains (CM, EC and PB) originally isolated from B. straminea. Among 1,135 specimens used 15 became infected (infection index of 1.3%) and 8 populations were susceptible to the schistosome strains: B. straminea from Campinorte (Castelão, susceptible to CM and EC strains, and Planeta Agua, EC strain), Colinas (Tocantinzinho river, CM and EC strains), Minaçu (Canabrava river, EC strain), Niquelândia (Codemin, CM and PB strains, and Almas river, CM strain), Uruaçu (touristic area, PB strain) and Santa Rita do Novo Destino (Maranhão river, CM and EC strains). These results, associated with marked social and ecological changes occurred, strongly suggest the possibility of B. straminea coming to act as a vector of schistosomiasis in the studied area.
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► Infection by A. cantonensis alters reproductive biology of Biomphalaria glabrata. ► Infection by A. cantonensis induces partial parasitic castration in B. glabrata. ► B. glabrata ...infected with A. cantonensis exhibits a parasitic castration process. ► Infection by A. cantonensis decreases galactogen content in B. glabrata.
This study showed for the first time changes in the reproductive biology of Biomphalaria glabrata experimentally infected with Angiostrongylus cantonensis. The values of all the parameters analyzed (total number of eggs, number of egg masses, number of eggs/mass, number of eggs/snail, percentage of viable eggs and galactogen content in albumen gland) changed with progressive infection. The results indicate the occurrence of partial parasitic castration of B. glabrata by A. cantonensis larvae, probably in response to the depletion of energy reserves, with no injuries to the gonadal tissues.
The activities described here form part of an extensive programme in place in the Região Arqueológica de Central, state of Bahia, Brazil. After malacological and socio-environmental surveys in the ...area, a strategy comprising formal and non-formal education with an emphasis on schistosomiasis prevention was developed, introduced, and evaluated. Interviews were conducted of 142 students and 11 teachers, totalling 11 classes at six primary schools. On the basis of those interviews, four display cases and seven panels were prepared. In addition a table was set up where students could participate directly on the subject, drawing and recognising the factors involved in the schistosomiasis cycle. The exhibition was held at the Museu Arqueológico de Central. The endeavours of this paper underline the importance of health education as well as exhibitions to disease prevention activities.
Introduction Schistosomiasis is a parasitic disease of public health concern in Brazil, and the construction of hydroelectric dams, in addition to increasing permanent human settlement and tourism, ...has created conditions suitable for the establishment of mollusks that can transmit schistosomiasis. Such areas require a number of actions to prevent the establishment of schistosomiasis. This paper reports on a freshwater malacological survey carried out in the geographical area of the Manso Power Plant. Methods Mollusks were collected in 18 municipalities in the State of Mato Grosso between February 2002 and February 2004 (qualitative study) and from April 2009 to February 2011 (quantitative study). Results Thirty-one species of mollusks were collected, including newly recorded species (Antillorbis nordestensis and Burnupia ingae). In addition, the geographic distributions of known species, including Biomphalaria straminea, a snail vector of Schistosoma mansoni, were expanded. A total of 4,507 specimens were collected in the APM Manso reservoir (Usina Hidrelétrica de Aproveitamento Múltiplo de Manso) during the quantitative study, and Biomphalaria amazonica was found in six of the 10 localities analyzed. The Afroasiatic species Melanoides tuberculata, introduced after February 2009, was the dominant species (relative abundance 94.96%). Conclusions The study area is epidemiologically important due to the occurrence of B. straminea and B. amazonica, which are vectors of schistosomiasis, and M. tuberculata, a snail host of Centrocestus formosanus, which is responsible for centrocestiasis transmission. Observations of M. tuberculata and the exotic freshwater clams Corbicula fluminea and Corbicula largillierti raise concerns about biodiversity.
Um levantamento da malacofauna límnina do Campus de Manguinhos, Fundação Oswaldo Cruz, Rio de Janeiro, foi realizado nos últimos dois anos visando comparar as espécies hoje existentes com aquelas ...encontradas no início deste século. Foram pesquisadas 18 coleções hídricas numa extensão de 880.000m², sendo encontradas em 13 delas as seguintes espécies: Antillorbis nordestensis, Biomphalaria glabrata, Biomphalaria straminea, Lymnaea columella, Melanoides tuberculatus, Physa cubensis, Pomacea glauca e Pomacea lineata. Destacam-se o desaparecimento de Biomphalaria tenagophila, registrada por Lutz em 1918, a introdução de B. straminea e da espécie asiática M. tuberculatus. Nenhum molusco apresentou infecção por Schistosoma mansoni.
A survey for freshwater gastropods carrying trematodes parasites was conducted in Manso Dam and the surrounding areas frequented by tourist, focusing particularly on the Pantanal region. Infected ...snails were recovered from twelve of the eighteen investigated municipalities and forty-one cercaria-snail pairings were recorded. Among these pairings were several first records of snails serving as intermediate hosts for trematodes in Brazil including Biomphalaria amazônica Paraense, 1966, Biomphalaria occidentalis Paraense, 1981, Marisa planogyra Pilsbry, 1933, Pomacea maculata Perry, 1830, Pomacea scalaris (d'Orbigny, 1835) and Gundlachia radiata (Guilding, 1828). Echinostomatidae and Strigeidae were the most common trematode families (ca. 47%) and the greatest diversity of larvae were obtained from Drepanotrema lucidum (Pfeiffer, 1839). Paramphistomatidae, Schistosomatidae or Spirorchiidae and Notocotylidae or Pronocephalidae were recovered in D. lucidum for the first time extending the number of families which use this gastropod as intermediate host. Although no specimens were found harboring larval stages of Schistosoma mansoni Sambon, 1907 other trematode larvae were discovered, including the Schistosomatidae Brevifurcate apharingeate cercaria that can cause dermatitis in humans. Continued studies on the taxonomy and biology of trematodes are essential to better understand the biodiversity of these parasites as well as the epidemiological aspects for control of associated zoonosis.
Os moluscos do gênero Pomacea estão distribuídos no município do Rio de Janeiro e outros municípios vizinhos a este, constituindo uma praga para a agricultura, sobretudo àquelas culturas de ...subsistência, que envolvem os pequenos produtores. Além disto, são incriminados como hospedeiros intermediários para Angiostrongylus cantonensis (Chen, 1935), um nematoide metastrongilídeo parasito de roedores na natureza e que ocasionalmente pode infectar o homem, causando quadros de meningoencefalite eosinofílica, podendo ser fatal, tornando-o um dos mais importantes metastrongilídeos, devido sua importância antropozoonótica. O cálcio é um metal considerado essencial na biologia de moluscos e um dos principais componentes inorgânicos que compõem as conchas desses animais. Pela importância desse íon no sucesso adaptativo de moluscos, o presente estudo teve como objetivo avaliar os efeitos da infecção experimental de A. cantonensis sobre aspectos estruturais da concha do molusco hospedeiro, variações nos conteúdos de cálcio na hemolinfa e de suas reservas na concha de P. maculata durante o período pré-patente (três semanas de infecção). Moluscos do gênero P. maculataforam infectados experimentalmente com 10.000 larvas L1 de A. cantonensis. Semanalmente, por três semanas após a exposição às larvas L1, moluscos tiveram suas conchas retiradas, sem uso de anestesia. Foram realizadas: determinação de cálcio na concha e na hemolinfa e análise das conchas in natura e calcinadas por FTIR. A infecção causou um aumento da concentração de cálcio na hemolinfa de 15,28% na primeira semana de infecção, e redução em 5,36% e 2,90% na segunda e terceira semana de infecção respectivamente. A concentração de cálcio presente na concha de P. maculata sofreu uma redução deste íon de 4,76% na primeira semana de infecção, aumento de 2,5% na segunda semana de infecção, culminando em equilíbrio no final do período pré-patente. Os espectros de FTIR das conchas in natura apresentaram bandas de absorção em regiões típicas de aragonita, diferentemente das conchas calcinadas, que apresentaram bandas de absorção semelhantes às da calcita. Os resultados obtidos até o presente momento evidenciam que P. maculata é um hospedeiro intermediário resistente para A. cantonensis, suportando uma carga larval de 10.000 L1, apresentando apenas uma pequena alteração no seu metabolismo de cálcio durante todo o período de infecção e uma taxa de mortalidade de 13,33%.
O trabalho investiga as percepções de alunos do Ensino Fundamental sobre a espécie Achatinafulica (caramujo africano) e os riscos que esse molusco oferece para a população no município de Barra do ...Piraí (RJ). A pesquisa envolveu a aplicação de questionários, grupos focais e observações de campo, além do estudo parasitológico de exemplares do molusco na localidade. Foi identificada a presença de caramujos infectados com nematódeos de interesse médico-veterinário e evidenciado que os alunos têm uma percepção negativa em relação ao caramujo, havendo predomínio de divergências entre suas percepções e o conhecimento científico. Com base nas contribuições do estudo das percepções e da Teoria da Aprendizagem Significativa, são propostas orientações para o planejamento de estratégias de ensino em contexto escolar.
The study investigates elementary students' perception of the species Achatina fulica (African snail) and the risks this mollusc may pose to the population of Barra do Pirai - in the state of Rio de Janeiro. The research involved questionnaires, focus groups and field observations, besides A. fulica specimens parasitological analysis. The results indicated the presence of snails infected with nematodes of medical and veterinary interest in the locality. The students have a negative perception of the snail, and there is great difference between their perceptions and scientific knowledge. Based on the contributions of the perceptions study and of Meaningful Learning Theory, guidelines are suggested so that strategies for teaching the content regarding the African snail at school environment can be developed.
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