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Percorrer por autor "Silva, Susana"

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  • Rubella in Sub-Saharan Africa and sensorineural hearing loss: a case control study
    Publication . Caroça, Cristina; Vicente, Vera; Campelo, Paula; Chasqueira, Maria; Caria, Helena; Silva, Susana; Paixão, Paulo; Paço, João
    Background - Rubella infection can affect several organs and cause birth defects that are responsible for congenital rubella syndrome (CRS). Congenital hearing loss is the most common symptom of this syndrome, occurring in approximately 60% of CRS cases. Worldwide, over 100 000 babies are born with CRS every year. There is no specific treatment for rubella, but the disease is preventable by vaccination. Since 1969, the rubella vaccine has been implemented in many countries, but in Africa, only a few countries routinely immunize against rubella. The aim of this study was to estimate the rate of infection from the wild-type rubella virus in São Tomé and Príncipe by determining rubella seroprevalence with a DBS method. The goal of this study was to reinforce the need for implementation of the rubella vaccine in this country. As secondary objectives, the validation of a DBS method was first attempted and an association between seroprevalence and hearing loss was assessed. Methods - We collected samples from individuals observed during humanitarian missions in São Tomé and Príncipe. All individuals underwent an audiometric evaluation, and a drop of blood was collected for the dried blood spot (DBS). We define two groups: the case group (individuals with unilateral or bilateral hearing loss (HL)) and the control group (individuals with two normal ears). Patients were excluded if they suffered from conductive HL, if they showed evidence of possible causes of HL, if they had developmental delay or if they refused to participate in the study. Results - Among the 315 subjects, we found 64.1% individuals with IgG for the rubella virus, 32.1% without immunity for the rubella virus and 3.8% who were borderline. In the control group, 62.6% were positive for the rubella IgG, whereas in the case group, 72% were positive. Analyzing both groups, with ages ranging from 2 to 14 years of age and from 15 to 35 years of age, we found a seroprevalence of 50.3% to rubella in the younger group and 82.1% in the older group, with a significant difference between cases and control group noted within the younger patients (p = 0.025). Conclusions - Rubella is a disease that can be prevented. Rubella infections are still very common in São Tomé and Príncipe, and women of child-bearing age are still at risk for rubella infection during pregnancy, justifying the urgency of vaccination against rubella. A statistically significant association between the group of children under 14 years of age with HL and immunity for rubella was observed in this country, although this study did not allow us to establish a cause-effect relationship between rubella infection and SNHL.
    2017-02Artigo científico Acesso aberto Ver mais
  • Sand quality on Portuguese blue flagged beaches: fungal and faecal contamination across two bathing seasons
    Publication . Silva, Ana Margarida; Sarioglou, Konstantina; Silva, Susana; Viegas, Carla; Ribeiro, Edna; Rebelo, Maria Teresa; Brandão, João
    There is growing concern about the quality of beach sand, as users tend to spend most of their time on the sand rather than in the water. Numerous pathogenic agents have reportedly been isolated from sand, including bacteria, nematodes, and opportunistic fungi. The ability of sand to retain pollutants and facilitate the transmission of pathogens raises public health concerns. We analysed sand-monitoring data from the 2024 and 2025 bathing seasons on Blue Flag beaches to find trends and patterns in total fungal counts, enterococci, and E. coli. The values recorded for microorganisms showed considerable variability, which may reflect the combined influence of multiple climatic, environmental, and anthropogenic factors on their presence in beach sand. Our findings suggest that the total fungal count on coastal beaches may be influenced by periods of rainfall, which increases the fungal load in the sand. Values recorded from inland beaches vary considerably between beaches, which may reflect the influence of local environmental characteristics, particularly vegetation and beach morphology, although the smaller number of inland samples also makes it difficult to define clear patterns and consistent reference values for this parameter. Bacterial indicators may be particularly influenced by occasional anthropogenic disturbances and contamination events. This study adds significantly to the understanding of the microbiological quality of beach sand, encouraging the integration of sand monitoring into environmental surveillance and management programmes.
    2026-05Artigo científico Acesso aberto Ver mais