This paper presents the results of an extensive survey of freshwater mollusks in the Simplício Queda Única Hydroelectric Development area, Southeast Brazil.
Mollusks were collected between 2008 and ...2013. All specimens were examined for the presence of larval trematodes.
In total, 12,507 specimens classified into 16 genera were obtained. Known snail vectors of schistosomiasis and fascioliasis and exotic species were identified, and new records are reported.
No specimens parasitized by larval trematodes of medical interest were detected. However, the results reinforce the importance of surveillance in study areas vulnerable to the occurrence of schistosomiasis transmission.
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► Infection by Angiostrongylus cantonensis alters metabolism of Biomphalaria glabrata. ► The ALT and AST activities in the hemolymph of B. glabrata infected with A. cantonensis ...increase. ► The total proteins content in the hemolymph of B. glabrata infected with A. cantonensis is reduced. ► Infection by A. cantonensis induces changes in the levels of nitrogen products in B. glabrata.
The effect of infection by Angiostrongylus cantonensis on the activity of the enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and the concentration of total proteins, uric acid and urea in the hemolymph of Biomphalaria glabrata were investigated. The snails were dissected after 1, 2 and 3weeks of infection to collect the hemolymph. The infection by A. cantonensis induced severe changes in the host snail’s metabolism, triggering physiological mechanisms to minimize the deleterious effects caused by the larvae. There was a significant decrease in the concentration of total proteins in the infected snails, which occurred gradually as the infection advanced. This change was accompanied by an increase in the concentrations of urea and a decrease in the levels of uric acid in the hemolymph, suggesting that in this model the infection induces proteolysis and inversion of the excretion pattern of the infected snails. Besides this, variations in the activities of the aminotransferases were observed, with significantly higher levels in the infected groups than in the control group. These results indicate an increase in the protein metabolism of the infected snails, since there was an increase in nitrogen catabolites such as urea.
Angiostrongylus cantonensis, which causes the zoonosis Eosinophilic Meningitis (EM), has become increasingly widespread in Brazil. Terrestrial mollusks, especially the exotic giant African snail ...Achatina fulica, have being found naturally infected with this nematode besides some few freshwater species. In this study, we collected several terrestrial and one freshwater mollusks from five different localities in the city of Manaus, in the Brazilian Amazon Region. One hundred and eighteen specimens from nine different species were obtained. In all, 49 specimens were analyzed parasitologically, including A. fulica (42 specimens), Bulimulus sp. (one specimen) and the freshwater species Pomacea dolioides (five specimens). The other specimens died or were represented by shells. Specimens of A. fulica from one locality were found naturally infected with A. cantonensis, which was confirmed by phylogenetic analysis of mitochondrial MT-CO1 gene sequences. A recent case of EM reported in the Amazon region, in the city of Macapá, reinforces the need of effective surveillance of areas in which the parasite is known to occur, as well as raising the awareness of local populations at risk of infection. We highlight both the role of A. fulica in the transmission of A. cantonensis and the need for effective measures to control the spreading of EM in Brazil.
KEY WORDS: Mollusk; neural angiostrongyliasis; neurotropic parasite; intermediate host
The rat lungworm Angiostrongylus cantonensis is a
worldwide-distributed zoonotic nematode that can cause human
eosinophilic meningoencephalitis. Here, for the first time, we report
the isolation of ...A. cantonensis from Achatina fulica from two
Brazilian states: Rio de Janeiro (specifically the municipalities of
Barra do Piraí, situated at the Paraiba River Valley region and
São Gonçalo, situated at the edge of Guanabara Bay) and Santa
Catarina (in municipality of Joinville). The lungworms were identified
by comparing morphological and morphometrical data obtained from adult
worms to values obtained from experimental infections of A. cantonensis
from Pernambuco, Brazil, and Akita, Japan. Only a few minor
morphological differences that were determined to represent
intra-specific variation were observed. This report of A. cantonensis
in South and Southeast Brazil, together with the recent report of the
zoonosis and parasite-infected molluscs in Northeast Brazil, provide
evidence of the wide distribution of A. cantonensis in the country. The
need for efforts to better understand the role of A. fulica in the
transmission of meningoencephalitis in Brazil and the surveillance of
molluscs and rodents, particularly in ports, is emphasized.
Abstract The activity of lactate dehydrogenase and the concentrations of glucose in the hemolymph and of glycogen in the digestive gland and cephalopedal mass of Biomphalaria glabrata experimentally ...infected with Angiostrongylus cantonensis were evaluated. Additionally, high performance liquid chromatography (HPLC) was used to determine the hemolymph concentrations of some carboxylic acids (oxalic, piruvic, lactic and succinic). After one, two and three weeks of infection, the snails were dissected to collect the hemolymph and separate the tissues. A significant reduction of the levels of glucose in the hemolymph was observed as of the first week of infection in relation to the control group. The lactate dehydrogenase activity of the infected group was significantly higher than the average of the control group. This increase was accompanied by a reduction of the levels of piruvic acid and an increase in the levels of lactic acid in the hemolymph of the parasited snails, confirming the acceleration of the anaerobic metabolism, necessary for the host to obtain energy and maintain its redox balance. In parallel, there was a decrease in the glycogen content of the storage tissues, with that reduction being significantly greater in the cephalopedal mass than the digestive gland, demonstrating that in this interaction system, the mobilization of glycogen was not sufficient to maintain and reestablish the normal glycemia of the infected snails.
INTRODUCTION Risk of schistosomiasis expansion to semi-arid northeastern Brazil under the influence of the Integration Project of the São Francisco River (IPSFR) was assessed.
Stool examinations of ...schoolchildren, epidemiological investigation, and survey of the local host snail Biomphalaria straminea were performed in five IPSFR municipalities. RESULTS Six of 4,770 examined schoolchildren were egg-positive for Schistosoma mansoni. Biomphalaria straminea was widespread, but not naturally infected with S. mansoni. Snails experimentally exposed to two laboratory S. mansoni strains yielded infection indices of 1-4.5%.
There is evidence of active schistosomiasis transmission in the area; thus, intensive surveillance actions are required.
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.
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).
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%).
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.
Environmental changes from water resource developmental projects affect
the epidemiology of water-associated diseases, as well as malaria and
schistosomiasis. Aiming to investigate the occurrence and ...distribution
of freshwater snails of medical and veterinary importance in the area
of inf luence of the Peixe Angical hydroelectric dam, a survey has been
conducted over four years (2004-2008). The study has revealed the
occurrence of populations of Biomphalaria straminea (Dunker) in all
municipalities surrounding the lake. Studies on parasite-mollusc
compatibility were undertaken using 35 populations of B. straminea,
descendants of specimens obtained from that area and three strains of
Schistosoma mansoni (Sambon) (BH, CM and CMO). The main results are
as follows: (i) among the 1,314 specimens used, eight had been infected
(infection index of 0.6%) with only the BH strain, (ii) for B.
straminea populations, the mortality index was 6.8% and, depending on
the strain used, the indexes were 4.6%, 8.49% and 19% with BH, CM and
CMO strains, respectively, (iii) the infection indexes varied according
to the B. straminea populations, ranging from 0-12.5% and (iv) the
duration of the precercarial period varied from 25-49 days. These
results, in addition to environmental and social changes that took
place in the Peixe Angical dam region, indicate the possibility of B.
straminea emerging as a schistosomiasis vector in this area.
The Baixada Maranhense Microregion currently has the highest prevalence of schistosomiasis in the State of Maranhão, likely because this parasitosis is characterized as an occupational disease, and ...increased contact with water increases the risk of infection by Schistosoma mansoni. This paper reports the results of the first comprehensive freshwater malacological survey performed in the Baixada Maranhense Microregion.
Freshwater mollusks were collected from the twenty-one municipalities of the Baixada Maranhense Microregion and from Bacurituba and Cajapió and were evaluated for infection by trematodes.
A total of 9,129 mollusks were collected (sixteen species), which included the first records of six species in the State of Maranhão: Gundlachia radiata, G. ticaga, Hebetancylus moricandi, Plesiophysa guadeloupensis, Pomacea bridgesii diffusa and Omalonyx sp. Biomphalaria glabrata was found in five municipalities, whereas B. straminea was found in nine. Biomphalaria glabrata and B. straminea were observed in syntopy in Pinheiro and São Bento. Of the 990 specimens of B. glabrata and the 2,109 specimens of B. straminea that were exposed to and/or analyzed for the presence of larval trematodes, only a single specimen of B. glabrata (0.1%) from São Bento shed S. mansoni. Other larval trematodes were first observed in mollusks from the State of Maranhão.
These results indicate that the study area is epidemiologically important due to the presence of two natural vectors of schistosomiasis and the active transmission of schistosomiasis, which was confirmed in the infected specimen that was collected in this study.
Resumo Objetivo: descrever a distribuição geográfica dos hospedeiros intermediários do Schistosoma mansoni em cinco estados brasileiros. Métodos: estudo transversal; foram selecionados municípios dos ...estados do Paraná (78), Minas Gerais (120), Bahia (82), Pernambuco (51) e Rio Grande do Norte (98), nos anos de 2012 a 2014; esses municípios foram escolhidos por não possuírem registros atualizados da presença de caramujos hospedeiros intermediários de S. mansoni; moluscos foram capturados, taxonomicamente identificados e examinados para verificação de cercárias de S. mansoni. Resultados: os trabalhos foram realizados em 427 municípios (99,5% dos 429 selecionados); foi registrada presença de moluscos em 300 (70,2%) municípios e a ocorrência de Biomphalaria glabrata em 62 (21%) municípios, B. straminea em 181 (60%), B. tenagophila em três (1%); associação de B. glabrata/B. straminea foi encontrada em 53 (18%), e de B. glabrata/B. tenagophila em um (0,3%). Conclusão: os registros de B. glabrata, B. straminea e B. tenagophila estão de acordo com a distribuição conhecida.
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