Abstract
Migratory birds wintering in tropical Africa are each year bringing a large number of species of avian malaria parasites to breeding areas in N Europe. Most of these parasites do not have transmission at our latitudes despite circulating in the blood of the tropical migrant birds and abundance of presumably suitable vectors. The reason for the failure of transmission is believed to be our cool summer climate, preventing the parasite to successfully develop in the vector. Phylogenetic analyses based on the parasite mtDNA, including both African and European transmitted Plasmodium lineages, demonstrate that area of transmission has changed repeatedly in the course of evolution. Hence, with the large number of tropical avian malaria parasites each year “knocking on the door”, suggests that tropical malaria parasites, rarely but regularly, will establish in Northern Europe. With increasing summer temperatures due to ongoing climatic change, this scenario of changing transmission area will be even more likely. Host shifts are often associated with change in virulence, suggesting that novel hosts may suffer substantial fitness costs when infected, with potentially strong effects on the population size of such species. The aim of the present study is to assess the risk and to evaluate the consequences of transmission of tropical malaria species to resident European bird populations. In this project we will combine explicit infection experiments with detailed studies of vectors.
Sweden