Global health at local level: characterization of tropical diseases in northern Portugal, 2020-2024

Abstract Background The escalating global prevalence and geographic spread of tropical diseases pose significant global health risks worldwide, with local implications. In Portugal, these diseases require mandatory notification. Concerns were raised following the detection of Aedes albopictus mosquitoes in mainland Portugal in 2017, alongside a Dengue outbreak in Madeira in 2012. Despite Portugal being declared malaria-free, the detection of Anopheles mosquitoes also raises concerns. This study aims at characterizing notified cases of tropical diseases in two cities in Northern Portugal since 2020. Methods A retrospective study of Malaria, Dengue, Zika, and Chikungunya cases in the Maia & Valongo’s Public Health Unit included data from the National Epidemiological Surveillance System covering January 2020 to April 2024. Descriptive analysis was conducted using SPSS IBM for iOS® v29. Results are presented as mean ± standard deviation for continuous variables and proportions for categorical ones. Results Five malaria cases were reported, predominantly affecting males (80%), with an average age of 34±16.96 years. Four were Portuguese and one Angolan. All cases were imported, mostly from Angola (80%). Etiological analysis revealed two cases of Plasmodium malariae and three of Plasmodium falciparum. All were hospitalized, no deaths. Four dengue cases were documented, 50% in males, averaged 33±24.73 years. Three were Portuguese and one Mozambican. One was hospitalized with no deaths. All cases were imported from Brazil, Cuba, Indonesia, and islands of Saint Martin/Saint-Barthélemy. No Zika or Chikungunya confirmed cases were identified during this period. Conclusions The increasing incidence of Dengue and Malaria underscores the critical connection between infectious diseases, vector ecology, and global health security. This study highlights the risk of imported Dengue and Malaria cases, emphasizing the imperative for surveillance and preventive actions to protect public health. Key messages • Dengue and Malaria cases in Portugal underline the importance of international collaboration and robust strategies. • Stepped-up surveillance is key to protecting vulnerable groups from imported infections.