| Abstract [eng] |
Avian malaria parasites are widespread pathogens of wild birds that may cause severe disease and mortality in susceptible hosts. Although microbiota are increasingly recognized as important factors in host–pathogen interactions, the role of vertebrate and vector microbial communities in avian malaria infections remains insufficiently understood. This dissertation investigated alterations of host and vector microbiota during avian malaria infections, their impact on parasite sporogonic development, and parasite responses to changing vertebrate host environments. Experimental studies were carried out using 16S rRNA amplicon sequencing and transcriptomic analyses. The study revealed that avian malaria parasites alter the composition, assembly, and stability of gut microbial communities in both vertebrate hosts and mosquito vectors, affecting bacterial interactions, network structure, and colonization resistance. For the first time, it was shown that host-derived antibodies can modulate vector microbiota and negatively affect Plasmodium relictum sporogonic development, highlighting a previously unrecognized link between vertebrate immunity, vector microbiota, and parasite infectivity. In addition, transcriptomic analyses demonstrated that Plasmodium homocircumflexum initially retained donor-host transcriptional profiles after transmission and subsequently adjusted gene expression to the conditions of the new host environment. The obtained findings emphasize the importance of microbiota-driven processes and parasite transcriptional plasticity in shaping avian malaria infection dynamics, parasite transmission, and adaptation to changing host environments. |
