Publicação
Epidemiological and molecular characterization of hepatitis A strains circulating in Portugal
| Resumo: | Hepatitis A (HA) is an acute liver infection caused by the hepatitis A virus (HAV), primarily transmitted through the fecal-oral route. Despite the high effectiveness of the HA vaccine, it remains a global public health concern. In very low endemicity countries, such as Portugal, the population remains susceptible due to limited exposure, and reported cases are associated with non-immune travelers returning from endemic regions or outbreaks within high-risk groups. This study aimed to characterize HAV strains from anti-HAV IgM-positive confirmed cases reported in Portugal between September 2024 and June 2025. Molecular characterization and phylogenetic analysis were performed to identify circulating subgenotypes and strains, and their association with both sporadic infections and outbreak-related clusters. During the study period, specimens from 391 cases were received, of which 347 (89%) were successfully genotyped. Most samples were from male individuals (75%), predominantly within the 18–44 age group (61%). Geographically, most cases were reported from the Norte region (n = 147). Among the 347 genotyped strains, 13 unique strains were identified, including seven of subgenotype IA, one strain of subgenotype IIA, four of subgenotype IB, and one of subgenotype IIIA. Seven outbreaks and six sporadic cases were detected, with two major ongoing outbreaks: one affecting the GBMSM community (n = 205), and another linked to the Roma population (n = 117). Phylogenetic analysis revealed a diverse profile of strains associated with travel to endemic countries such as Angola, the Dominican Republic, Morocco, and India, while others had no identifiable source of infection. These findings highlight the diversity of HAV strains imported to Portugal and underscore the importance of molecular surveillance to identify potential outbreaks and implement adequate control measures when needed. The results also reinforce the value of vaccination for travelers to endemic regions and susceptible populations. |
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| Autores principais: | Lucas, Mafalda Brites de Araújo |
| Assunto: | Hepatitis A virus hepatitis A molecular surveillance genotyping outbreak |
| Ano: | 2025 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso embargado |
| Instituição associada: | Universidade Nova de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório Institucional da UNL |
| Resumo: | Hepatitis A (HA) is an acute liver infection caused by the hepatitis A virus (HAV), primarily transmitted through the fecal-oral route. Despite the high effectiveness of the HA vaccine, it remains a global public health concern. In very low endemicity countries, such as Portugal, the population remains susceptible due to limited exposure, and reported cases are associated with non-immune travelers returning from endemic regions or outbreaks within high-risk groups. This study aimed to characterize HAV strains from anti-HAV IgM-positive confirmed cases reported in Portugal between September 2024 and June 2025. Molecular characterization and phylogenetic analysis were performed to identify circulating subgenotypes and strains, and their association with both sporadic infections and outbreak-related clusters. During the study period, specimens from 391 cases were received, of which 347 (89%) were successfully genotyped. Most samples were from male individuals (75%), predominantly within the 18–44 age group (61%). Geographically, most cases were reported from the Norte region (n = 147). Among the 347 genotyped strains, 13 unique strains were identified, including seven of subgenotype IA, one strain of subgenotype IIA, four of subgenotype IB, and one of subgenotype IIIA. Seven outbreaks and six sporadic cases were detected, with two major ongoing outbreaks: one affecting the GBMSM community (n = 205), and another linked to the Roma population (n = 117). Phylogenetic analysis revealed a diverse profile of strains associated with travel to endemic countries such as Angola, the Dominican Republic, Morocco, and India, while others had no identifiable source of infection. These findings highlight the diversity of HAV strains imported to Portugal and underscore the importance of molecular surveillance to identify potential outbreaks and implement adequate control measures when needed. The results also reinforce the value of vaccination for travelers to endemic regions and susceptible populations. |
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