Browsing by Author "Nascimento, M. S. J."
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- Characterization of histopathologic lesions in gastroenteritis associated to norovirus in a model of studyPublication . Vala, Helena; Mesquita, JR.; Nascimento, M. S. J.Background: Human noroviruses are the major cause of nonbacterial epidemic gastroenteritis worldwide. Although noroviruses have been absent from the list of gastrointestinal infectious agents in dogs, recently several studies emphasized their role in the aetiology of gastroenteritis, suggesting the possibility of a novel model for human infection. The aim of this study was to evaluate the histopathological lesions in gastroenteritis, associated to canine norovirus, in order to contribute to the knowledge of its pathogenic features and the role of apoptotic events in the noroviruses pathogenesis. Material and methods: Samples of small intestine were collected from 2 adult dogs (2-year-old cross-bred and a 6 year-old cocker spaniel) housed in a kennel where CaNoV had been diagnosed. Samples of small intestine were collected and fixed (10% neutral buffered formalin) for a maximum of 48 hours, dehydrated (graded ethanol series) and embedded in paraffin wax. Apoptosis studies combined the immunohistochemical detection of cytochrome c (anti-cytochrome C sc-8385 antibody, Santa Cruz Biotechnology) and the DNA fragmentation by TUNEL assay (In Situ Cell Death Detection Kit, Roche, Germany). Samples were examined by light microscopy (Microscope Zeiss Mod. Axioplan 2), by two independent observers. All procedures were performed in accordance with the European Communities Council Directive 86/609/ECC. Results: The microscopic findings revealed severe epithelial detachment, mucosal loss and hypertrophy of all small intestinal layers. Also, an intense mononuclear inflammatory infiltrate within lamina propria of small intestine proximal segments were seen, very similar to IBD lesional pattern. Discussion and Conclusions: Canine inflammatory bowel disease (IBD) is a heterogeneous group of chronic gastrointestinal disorders with unknown aetiology, immunologically-mediated, similar to human IBD. With this study it is tempting to hypothesize that canine norovirus could be significantly evolved in the complex aetiopathogenesis of IBD, identically in human Crohn disease - an example of human IBD, which could highlight the relevance of norovirus, in its role of in the aetiopathogenesis of this chronic condition.
- Hepatitis E Virus in Sylvatic and Captive Wild Boar from PortugalPublication . Mesquita, João R.; Oliveira, R. M. S.; Coelho, Catarina; Vieira-Pinto, M.; Nascimento, M. S. J.Hepatitis E virus (HEV) is a zoonotic agent today considered a major Public Health issue in industrialized countries. HEV strains belonging to zoonotic genotype 3 are widely present in swine, being today considered important reservoirs for human disease. Unlike in swine, only scarce data are available on the circulation of HEV in wild boar. This study describes the detection and molecular characterization of HEV in livers from sylvatic wild boar hunted in Portugal and destined for consumption. Additionally, the detection of HEV in stools of a confined wild boar population also destined for consumption is also described. A total of 80 liver samples collected during the hunting season of 2011/2012 and 40 stools collected in February 2012 from a wild boar breeding farm in Portugal were tested by a nested broad-spectrum RT-PCR assay targeting open reading frame (ORF) 1. Twenty livers (25.0%) and 4 stools (10%) were positive for HEV. Phylogenetic analysis showed that all strains clustered with sequences classified as HEV genotype 3 subgenotype e. To our knowledge, this is the first report documenting the occurrence and molecular analysis of HEV in sylvatic and captive wild boar destined for human consumption in Portugal. This report demonstrates for the first time the circulation of HEV in wildlife reservoirs of Portugal adding knowledge to the epidemiology of HEV in wild boar populations.
- Importance of the canine norovirus in the etiopathogenesis of enteritis like IBDPublication . Vala, Helena; Mesquita, J.; Ortiz, A. L.; Nascimento, M. S. J.Background: Recent studies stated that canine norovirus (caNoV) infection is an endemic and highly contagious disease in the dog population in Portugal, with peak shedding in winter months. Previous studies reported caNoV as a potentially important zoonotic virus with increased importance since dogs are an integral part of household, potentially, affecting both owners and small animal veterinarians. However, despite the impact of norovirus-induced disease, the pathogenic features of infection are not well understood. The aim of this study was to evaluate the histopathological lesions in gastroenteritis, associated to CaNoV, in order to contribute to the knowledge of its pathogenic features. Material and methods: Samples of small intestine from 2 diarrheic dogs housed in a kennel, previously diagnosed with caNoV, were collected and fixed (10% neutral buffered formalin) for a maximum of 48 hours, embedded in paraffin wax, and 3µm sections were stained for routine histopathological evaluation. Results: The microscopic findings revealed a more notorious mononuclear inflammatory infiltrate within lamina propria of small intestine proximal segments, with increasing numbers of lymphocytes and plasma cells, changing from severe to moderate, from the duodenum to jejunum, respectively, like IBD pattern. Discussion and Conclusions: The histopathological features led to the hypothesis that caNoV could be significantly involved in the complex aetiopathogenesis of IBD, as reported with murine norovirus and human norovirus, the later having an important role exacerbating or complicating other diseases, like human Crohn disease - an example of human IBD, which highlights the relevance of norovirus, in its role of indirect infectious agent.
- Outbreak of Porcine Epidemic Diarrhea Virus in Portugal, 2015Publication . Mesquita, J. R.; Hakze-van der Honing, R.; Almeida, A.; Lourenço, M.; van der Poel, W. H. M.; Nascimento, M. S. J.An outbreak of porcine epidemic diarrhea virus (PEDV) in the South of Portugal in January 2015 and the spread of PEDV northwards in the territory are described. Comparative analysis of the amplified sequences showed a very high (99.0%) identity with the PEDV variant most recently reported in the United States and also show complete (100%) identity to the strains recently reported in Germany, supporting the hypothesis that a unique strain is currently circulating in Europe. The origin of this PEDV variant still needs to be elucidated and further studies in the remaining European countries may contribute to the knowledge.
- Persistence of rubella and mumps antibodies, following changes in the recommended age for the second dose of MMR vaccine in PortugalPublication . Gonçalves, G.; Frade, J.; Nascimento, M. S. J.; Mesquita, João R.; Nunes, C.In Portugal, the recommended age for the second dose of MMR (MMR2) was changed from 10-13 years to 5-6 years for those born in 1994 and afterwards. This study aimed to assess if MMR schedule and time elapsed from the last dose are associated with the concentration of rubella and mumps IgG antibodies. Three Portuguese birth cohorts (convenience samples) were selected for this study (66, 59 and 41 participants born respectively in 1990-1993, 1994-1995 and 2001-2003). Geometric mean concentrations (GMC) for mumps IgG were respectively 36, 30 and 38 RU/ml (P = 0·236) and for rubella IgG were 18, 20 and 17 IU/ml (P = 0·641). For both specific antibodies, no differences were observed with time since MMR2. Receiving MMR2 at 5-6 or 10-13 years was not associated with concentration of both antibodies. The GMC of rubella IgG was lower in males (P = 0·029). Taking into account previous evidence and the logistics needed to change vaccination schedules, it seems reasonable that sustaining very high coverage with two doses of MMR is currently the most pragmatic way to control mumps and rubella rather than any changes to the schedule.
- Prevalence of hepatitis E virus antibodies in workers occupationally exposed to swine in PortugalPublication . Teixeira, J.; Mesquita, J. R.; Pereira, S. S.; Oliveira, R. M. S.; Abreu-Silva, Joana; Rodrigues, A.; Myrmel, M.; Stene-Johansen, K.; Øverbø, J.; Gonçalves, G.; Nascimento, M. S. J.The concept of zoonotic hepatitis E in industrialized countries has emerged with the discovery of swine strains of hepatitis E virus (HEV) genotype 3, closely related to human HEV. Different routes of zoonotic HEV transmission have been recognized, including contact with infected pigs. Workers occupationally exposed to swine (WOES) have been considered a risk group for HEV infection, but contradictory results have been reported. In the present study, we searched for anti-HEV IgG in WOES (butchers, slaughterhouse workers, veterinarians and pig farmers; n = 114) and in the general population (n = 804) in order to investigate the potential occupational risk of zoonotic HEV infection in this work group. A significantly higher (p = 0.008) anti-HEV IgG seroprevalence was found in WOES (30.7 %) when compared with the general population (19.9 %). Multivariate analysis showed that having professions with exposure to pigs for more than 16.5 years was a risk factor for being positive for anti-HEV IgG (aOR of 5.4, 95 % CI 1.9-15.6, p = 0.002). To our knowledge, this is the first study on the prevalence of anti-HEV IgG in WOES in Portugal, also showing increased probability for infection in this group.