Avian Malaria and Related Blood Parasites: Molecular Diversity, Ecology and Evolution

Research output: ThesisDoctoral Thesis (compilation)

Abstract

Malaria-like parasites consist of a large group of species that infects primates, rodents, bats, lizard and birds. I have focused on parasites from the genera Haemoproteus, Plasmodium and Leucocytozoon that are infecting birds. By using molecular methods to identify parasites from avian blood samples, I have found a diversity, based on the cytochrome b gene, that greatly exceeds the diversity previously known when identification was based on morphological characters. By phylogenetic analyses we have shown that the morphological identification system of these parasites represent, to a large degree, consists of monophyletic groups and that parasite lineages obtained by molecular identification consists of non-recombining lineages.

Using a phylogenetic approach, including ~6000 samples from 139 bird species, we investigated how common it is that parasites are introduced into resident bird faunas in Europe and Africa, two areas linked by an immense amount of migrating birds each year. For Haemoproteus spp. and Leucocytozoon spp. such introductions are rare events that happen over an evolutionary time scale, whereas parasites belonging to the genera Plasmodium seem to be less restricted to a specific transmission area. This might be a consequence of the lower host-specificity of Plasmodium lineages. Detailed analysis of the host specificity of Plasmodium and Haemoproteus showed that lineages that could develop in many different host-species over a large taxonomic range, also exhibited among the highest prevalence in single bird species. Hence, being a generalist did not prevent it to be highly successful in single hosts.

A crucial part of the parasite life-cycle takes place inside the blood feeding vector. By using wild-caught and blood-feed blackflies, the main vectors for Leucocytozoon spp., we could successfully determine both which animal they had been feeding on and which parasite each host was carrying and potentially could be transmitted. We found that blackfly species had either a preference for birds or for mammals. Moreover, among blackfly species attacking birds there was also a finer specificity with preferences for e.g. ducks, grouse, passerines, cranes. This host specificity shaped the distribution of the parasites in the different blackfly species such as the same or similar parasite lineages ended up in the same blackfly species or in species with a similar host preference. Hence, the host-preferences of the blackflies could then potentially act as an ecological transmission barrier for parasites between different bird host species.

Details

Authors
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Biological Sciences

Keywords

  • diversity, Plasmodium, bird-migration, transmission, blackfly, host-specificity, host-preference, cytochrome b, DHFR-TS, recombination, phylogeny, Ecology, Ekologi, Genetics, cytogenetics, Genetik, cytogenetik, Parasitology (human and animal), Haemoproteus, Leucocytozoon, Parasitologi (människa och djur), Animal ecology, Djurekologi, Natural science, Naturvetenskap
Original languageEnglish
QualificationDoctor
Awarding Institution
Supervisors/Assistant supervisor
Award date2006 Dec 15
Publisher
  • Department of Ecology, Lund University
Print ISBNs91-7105-244-5
Publication statusPublished - 2006
Publication categoryResearch

Bibliographic note

Defence details Date: 2006-12-15 Time: 13:00 Place: Blå hallen, Ecology building, Sölvegatan 37, Lund External reviewer(s) Name: Ricklefs, Robert E. Title: Professor Affiliation: Department of Biology, University of Missouri at St. Louis ---