40 research outputs found
First records of molluscs naturally infected with Angiostrongylus cantonensis (Nematoda: Metastrongyloidea) in Northeastern Brazil, including new global records of natural intermediate hosts
Human neural angiostrongyliasis is an emerging infectious disease caused by nematode Angiostrongylus cantonensis. The present study investigated the presence of Angiostrongylus spp. in terrestrial molluscs collected from the following areas in the Metropolitan Region of Aracaju, Sergipe State, Brazil: Barra dos Coqueiros, Nossa Senhora do Socorro, Sao Cristovao and Aracaju. In total, 703 specimens representing 13 mollusc species were screened for Angiostrongylus spp. Larvae of Angiostrongylus spp. were found in three species. Larvae recovered from Achatina fulica were used for experimental infection in Wistar rats (Rattus norvegicus). For specific identification of nematodes, the mitochondrial cytochrome c oxidase subunit I (COI) was sequenced from both larvae and adults recovered from molluscs and rats, respectively. Infection with A. cantonensis was detected in all municipalities and in the following three host species: Bulimulus tenuissimus, Cyclodontina fasciata (Barra dos Coqueiros), and A. fulica (Aracaju, Nossa Senhora do Socorro and Sao Cristovao). Coinfections were also found with Caenorhabditis sp. and Strongyluris sp. larvae. This is the first study of the helminth fauna associated with the terrestrial malacofauna in Sergipe State, and confirms that these three snail species are involved in the transmission of A. cantonensis in the state. In addition, B. tenuissimus and C. fasciata are newly reported natural hosts of the parasite
Pharmacological inhibition of lysine-specific demethylase 1 (LSD1) induces global transcriptional deregulation and ultrastructural alterations that impair viability in Schistosoma mansoni
Treatment and control of schistosomiasis still rely on only one effective drug, praziquantel (PZQ) and, due to mass treatment, the increasing risk of selecting for schistosome strains that are resistant to PZQ has alerted investigators to the urgent need to develop novel therapeutic strategies. The histone-modifying enzymes (HMEs) represent promising targets for the development of epigenetic drugs against Schistosoma mansoni. In the present study, we targeted the S. mansoni lysine-specific demethylase 1 (SmLSD1), a transcriptional corepressor, using a novel and selective synthetic inhibitor, MC3935, which was used to treat schistosomula and adult worms in vitro. By using cell viability assays and optical and electron microscopy, we showed that treatment with MC3935 affected parasite motility, egg-laying, tegument, and cellular organelle structures, culminating in the death of schistosomula and adult worms. In silico molecular modeling and docking analysis suggested that MC3935 binds to the catalytic pocket of SmLSD1. Western blot analysis revealed that MC3935 inhibited SmLSD1 demethylation activity of H3K4me1/2. Knockdown of SmLSD1 by RNAi recapitulated MC3935 phenotypes in adult worms. RNA-Seq analysis of MC3935-treated parasites revealed significant differences in gene expression related to critical biological processes. Collectively, our findings show that SmLSD1 is a promising drug target for the treatment of schistosomiasis and strongly support the further development and in vivo testing of selective schistosome LSD1 inhibitors
SHORT COMMUNICATION - Susceptibility of Biomphalaria straminea (Dunker, 1848) from Serra da Mesa Dam, Goiás, Brazil to Infection with Three Strains of Schistosoma mansoni Sambon, 1907
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
Água, 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
Susceptibility of Biomphalaria straminea from Peixe Angical dam, Tocantins, Brazil to infection with three strains of Schistosoma mansoni
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
Infection by Schistosoma mansoni sambon 1907 in the first four months of life of Biomphalaria straminea (Dunker, 1848) in Brazil
Compatibility between Schistosoma mansoni and Biomphalaria straminea when exposed to the parasite on the first four months of age was assessed for five parasitological aspects: indices of infection and mortality, duration of precercarial and cercarial periods, and rate of cercarial emission. Infections were made on molluscs from laboratory colonies, at the following ages: 8, 13, 18, 21, 53, 83 and 114 days. Two B. straminea colonies were used (Camorim, PE and Picos, PI), and one B. glabrata colony (Ressaca, MG) was used as control. The main results are as follows: (I) infection was significantly associated with mollusc age, being proportionally higher in sexually immature than in mature molluscs for the three colonies; (II) for B. straminea from Camorim, mortality did not differ significantly between infected and non-infected snails; for B. straminea from Picos significantly more deaths occurred among infected than among non-infected snails, while the opposite was observed for B. glabrata from Ressaca; (III) for the three colonies, the precercarial period was significantly shorter for immature molluscs than for mature ones; (IV) the duration of the cercarial period was extremely variable for the three colonies; (V) sexual maturity did not influence cercarial emission for the three colonies