Aedes albopictus as a potential vector of arboviruses in catalonia

• Autores: Cristina Santamaría Domínguez
• Directores de la Tesis: Núria Busquets i Marti (dir. tes.), Nonito Pagès Martínez (dir. tes.)
• Lectura: En la Universitat Autònoma de Barcelona ( España ) en 2019
• Idioma: español
• Tribunal Calificador de la Tesis: Miguel Julián Martínez Yoldi (presid.), Francesc Muñoz Muñoz (secret.), Carlos Aranda Pallero (voc.)
• Programa de doctorado: Programa Oficial de Doctorado en Medicina y Sanidad Animales
• Materias:
  • Ciencias de la vida
    • Biología de insectos (entomología)
    • Virología
      • Arbovirus
  • Ciencias médicas
    • Salud publica
• Enlaces
  • Tesis en acceso abierto en: TESEO
• Resumen

  • The Asian tiger mosquito, Aedes albopictus, is widely established in tropical, subtropical, and temperate areas, where is considered a vector for arboviruses like chikungunya and dengue. In the last ten years, autochthonous outbreaks of chikungunya and dengue in Europe have highlighted the risk of arbovirus transmission in areas where Ae. albopictus mosquitoes have become established. To estimate the risk of transmission and spread of arboviruses in Catalonia, we investigate whether local Ae. albopictus mosquitoes are competent to Chikungunya and Dengue viruses (CHIKV and DENV). In this study, we assessed the susceptibility of a Spanish strain of Ae. albopictus for two CHIKV strains (S27 and ITA) at two viral doses (high and low) in environmental conditions mimicking the summer and autumn seasons in Catalonia. These results were compared with previously published data from other European Ae. albopictus populations (Chapter III). The pathogenesis of CHIKV was also investigated in mice deficient in the alpha/beta interferon receptor (IFN-α/β R-/-). In order to study CHIKV infection, the mice were injected subcutaneously with three different doses (low, medium and high) of two CHIKV strains (S27 and ITA) (Chapter IV). To evaluate CHIKV transmission, we employed a mouse model (IFN-α/β R-/-), and an in vitro assay (Chapter V). To evaluate the survival of CHIKV in nature in temperate areas, we assessed the susceptibility of larvae mosquitoes to CHIKV through viral suspension and infected carcasses mosquitoes. The potential contribution of this mechanism to the persistence of CHIKV in an epidemic settle was discussed (Chapter VI). Finally, we assessed the vector competence of a Spanish Ae. albopictus strain for two different DENV strains (serotype 1 and 2). Infection, dissemination, and transmission rates were assessed and compared with previous vector competence studies for DENV in European Ae. albopictus populations (Chapter VII).

    The present study found that environmental conditions had a significant effect on development time, larval and adult survival, and quantity of CHIKV ingested. As shown in previous studies of vector competence for CHIKV, cooler temperatures in the larval and adult stage enhanced CHIKV infection rates relative to warmer temperatures. We found that Ae. albopictus was capable of transmitting the emergent ITA strain (5%). We also observed that mice lacking in the alpha/beta interferon (IFN-α/β -/-) were highly susceptible to CHIKV infection, in congruence with previously published studies. By contrast, we could not demonstrate transstadial transmission (passage of a pathogen from one instar to the next) of CHIKV. We found that the strain of Ae. albopictus tested was susceptible to oral infection with both DENV strains, although was able only to transmit DENV-1 (4.6%).

    In conclusion, the results of this dissertation demonstrated that the Spanish strain of Ae. albopictus tested was competent for CHIKV and DENV. This study confirms the potential of Ae. albopictus to start local transmission cycles in the Mediterranean region. We expect the findings of this study can improve our general understanding of vector competence of Ae. albopictus in Spain.