Browsing by Author "Martins, S."
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- Genetic and virulence characterization of Toxoplasma gondii strains isolated from pigeons in Lisbon regionPublication . Vilares, Anabela; Gargate, M.J.; Ferreira, I.; Martins, S.; Waap, H.; Ângelo, H.habitat with cats and humans, bands are observed in recreational areas such as urban parks, playgrounds and parks. The interaction between cats, birds and human population is quite evident favoring the fecal-oral transmission of T. gondii between the definitive host and intermediate hosts, in the urban cycle of the parasite. The results of the inoculation in vivo of the brain homogenates showed pigeon isolation rates (58.5%) significantly higher when compared with previous studies, including the preliminary study in 2006 that the isolation rate in mice was 39,1% (9/23) (Waap 2008) and another that was not achieved any isolation in mouse (Godoi 2010). The genotypic analysis revealed a majority of strains of type II, which is consistent with what has been described in Portugal, the rest of Europe and the USA (Ajzenberg 2005, Fazaeli 2000, Honoré 2000, Howe 1997, Waap 2008) . We also isolated strains of type III and type I. The identification of type III strains in animals have been reported by other authors, but the type I have been rarely found in animals has not been previously described in Portugal except in a preliminary study of our team at the 2008 (Waap 2008). The type I strains are usually associated with high virulence in laboratory mice, leading to death within days. This strain was identified by molecular biology and has not been isolated in vivo. The difficulty in isolation of strain may be related to the small number of cysts of the type I strains can develop, these type strains are considered low cystogenic. Genetic characterization of strains of T. gondii is far from its terminus, more sequences of different genes should be studied to help the understanding of the molecular epidemiology and genetic characterization of T. gondii, a relevant parasite for which these data are lacking. The combination of data from humans and animals, through the use of high resolution genetic characterization should improve our perceptive of T. gondii, which will be ultimately beneficial for the control of T. gondii transmission.
- Isolation and molecular characterization of Toxoplasma gondii isolated from pigeons and stray cats in Lisbon, PortugalPublication . Vilares, A.; Gargaté, M.J.; Ferreira, I.; Martins, S.; Júlio, C.; Waap, H.; Angelo, H.; Gomes, João PauloCats and pigeons are important factors in the epidemiology of Toxoplasma gondii as felidsare the only definitive hosts that can excrete environmentally resistant oocysts, andpigeons share the same places of cats and humans constituting a good model and indicatorof the ground field contamination. We aimed to study the virulence and genotypes ofT. gondii isolated from pigeons and stray cats in Lisbon, Portugal. Fresh samples of brainfrom 41 pigeons and 164 cats revealing antibodies to T. gondii were inoculated in mice.Three isolates (one isolated from a cat and two isolated from pigeons) were virulent in themouse model. Sag2-based genotyping of T. gondii was achieved in 70.7% (29/41) of samplesisolated from pigeons (26 samples were type II, two were type III, and one strain was type I).From the cat brain samples, 50% (82/164) yielded Sag2 positive results, where 72 belongedto genotype II and 10 were no type III (it was not possible to discriminate between typeI and II). Further genotyping was obtained by multiplex PCR of 5 microsatellites (TUB2,TgM-A, W35, B17, B18), allowing the identification of two recombinant strains that hadbeen previously identified as type II by Sag2 amplification (one isolated from cat brain andthe other from pigeon brain). This is the first evidence of recombinant strains circulatingin Portugal and the first report of T. gondii genotyping from cats in this country. This studyalso highlights the importance of environmental contamination in the synanthropic cycleconstituting a potential source of human infection.
- Origin and spread of a common deletion causing mucolipidosis type II: insights from patterns of haplotypic diversityPublication . Coutinho, Maria Francisca; Encarnação, M.; Gomes, R.; Da Silva Santos, L.; Martins, S.; Sirois-Gagnon, D.; Bargal, R.; Filocamo, M.; Raas-Rothschild, A.; Tappino, B.; Laprise, C.; Curyg, G.K.; Schwartz, I.; Artigalás, O.; Prata, M.; Alves, SandraMucolipidosis II (ML II alpha/beta), or I-cell disease, is a rare genetic disease in which activity of the uridine diphosphate (UDP)-N-acetylglucosamine:lysosomal enzyme N-acetylglucosamine-1-phosphotransferase (GlcNAc-phosphotransferase) is absent. GlcNAc-phosphotransferase is a multimeric enzyme encoded by two genes, GNPTAB and GNPTG. A spectrum of mutations in GNPTAB has been recently reported to cause ML II alpha/beta. Most of these mutations were found to be private or rare. However, the mutation c.3503_3504delTC has been detected among Israeli and Palestinian Arab-Muslim, Turkish, Canadian, Italian, Portuguese, Irish traveller and US patients. We analysed 44 patients who were either homozygous or compound heterozygous for this deletion (22 Italians, 8 Arab-Muslims, 1 Turk, 3 Argentineans, 3 Brazilians, 2 Irish travellers and 5 Portuguese) and 16 carriers (15 Canadians and 1 Italian) for three intragenic polymorphisms: c.-41_-39delGGC, c.18G>A and c.1932A>G as well as two microsatellite markers flanking the GNPTAB gene (D12S1607 and D12S1727). We identified a common haplotype in all chromosomes bearing the c.3503_3504delTC mutation. In summary, we showed that patients carrying the c.3503_3504delTC deletion presented with a common haplotype, which implies a common origin of this mutation. Additionally, the level of diversity observed at the most distant locus indicates that the mutation is relatively ancient (around 2063 years old), and the geographical distribution further suggests that it probably arose in a peri-Mediterranean region.
- Towards a risk assessment for Giardia sp. and Cryptosporidium sp. in Portuguese fluvial beaches: a seasonal sampling over two yearsPublication . Júlio, C.; Ferreira, I.; Martins, S.; Sá, C.; Ângelo, H.; Guerreiro, J.; Tenreiro, R.Abstract background: Waterborne outbreaks of diarrhoeal illness reported worldwide are mostly associated with Cryptosporidium sp. and Giardia sp. Lake and river waters contaminated with (oo)cysts are major routes of human exposure making essential the development of preventive strategies for water safety. Since monitoring of water contamination with (oo)cysts is not routinely performed in Portugal, this study aims to unveil the possible associations between Portuguese fluvial beach characteristics and risk for public health caused by different genotypes of Giardia sp. and Cryptosporidium sp.. Abstract Methods: Nineteen beaches were selected according to land use and environmental parameters and sampled, on winter and summer, for the presence of Giardia sp. and Cryptosporidium sp., as well as faecal indicators and physicochemical parameters. Immunomagnetic separation was performed according the US EPA Method 1623 with Dynal procedure (Dynabeads), followed by detection of (oo)cysts by immunofluorecence microscopy after staining with FICT-labelled monoclonal antibody. Cysts viability was also confirmed by nucleic acid dye (DAPI) staining. Abstract Results: The results show that Giardia cysts are present at least in 83% of the sampled beaches. Presence of Cryptosporidium oocysts was not lower than 74%. Additionally, seasonal differences on (oo)cysts amount were perceived. A dendrogram analysis highlighted different clusters which evidence patterns among the sampled beaches. Principal Component Analysis also indicates distinct weights for land use, physical-chemical and microbiological parameters in these different clusters. Abstract Conclusions: The results of the present study indicate that Giardia sp. and Cryptosporidium sp. are widely distributed and should be considered as a public health issue. Moreover, beach clusters turn out to be a helpful tool to assess the public health risk.