Birds are hosts of a stunning diversity of malaria (Plasmodium) and related haemosporidan parasites (Haemoproteus and Leucocytozoon), displaying asexual reproduction in blood or tissues of the vertebrate host, and sexual reproduction in the vector, being an insect such as mosquitoes. A few hundred species have been described morphologically but molecular analyses suggest that the true number of species probably counts in thousands. The highest species diversity is found in the tropics but transmission commonly happens as far north as in Sweden. A particular concern is that with a warmer climate, tropical parasites will expand their ranges and infect European resident species which have not encountered these parasites before, posing substantial threats to bird populations.
Our research span over a broad range of questions from the evolutionary patterns of the distribution of bird malaria parasites to the direct interaction between the hosts and parasites in populations and in individually infected birds. We identify the parasites by DNA sequencing, and connect the molecular identification with taxonomically described species, as well as host distribution, in our freely available database MalAvi. We are presently sequencing the genome of Haemoproteus tartakovskyi, allowing us to address further question which require multiple nuclear genetic markers. With the use of full parasite genomes we also hope to shed light on the enigmatic phylogenetic relationship within the group of Haemosporidian parasites.
To assess direct impact of the parasites on the host and understanding why individual hosts are affected differently by the parasite infections, we carry out controlled infection experiments with birds in captivity. This enables us to monitor the complete infection episode from primary infection to chronic stages, measuring host responses in multiple ways including telomere loss rate and descriptive blood transcriptomes. To understand why individual birds differ in disease resistance and susceptibility, we study the host immune response genes. We also study the impact and dynamics of bird malaria in several species in the wild, particular in a long term study of great reed warblers.