OLOF HELLGREN results 13
· Newest (Page 1/1, per page 25)
Author: OLOF HELLGREN ×Clear All Filters
Search Results
During an infection, the genetic composition of the pathogen population in the host might range from clonal to genetically diverse, depending on the genetic variation of the inoculum, mutation events, genetic drift, and host selection during the course of the infection. Variation in the genetic diversity of avian malaria parasites, both within and between individual hosts, is not well documented. To shed light on this, we used...
Climate‐Driven Increase in Transmission of a Wildlife Malaria Parasite Over the Last Quarter CenturyNARA Subscribed
Climate warming is expected to influence the prevalence of vector‐transmitted parasites. Understanding the extent to which this is ongoing, or has already occurred, requires empirical data from populations monitored over long periods of time, but these studies are sparse. Further, vector‐disease research involving human health is often influenced by disease control efforts that supersede natural trends. By screening for malari...
Aim The increasing spread of vector‐borne diseases has resulted in severe health concerns for humans, domestic animals and wildlife, with changes in land use and the introduction of invasive species being among the main possible causes for this increase. We explored several ecological drivers potentially affecting the local prevalence and richness of avian malaria parasite lineages in native and introduced house sparrows ( Pas...
Immune gene expression in the mosquito vector Culex quinquefasciatus during an avian malaria infectionNARA Subscribed
Plasmodium relictum is the most widespread avian malaria parasite in the world. It is listed as one of the 100 most dangerous invasive species, having been responsible for the extinction of several endemic bird species, and the near‐demise of several others. Here we present the first transcriptomic study focused on the effect of P. relictum on the immune system of its vector (the mosquito Culex quinquefasciatus ) at different...
Global drivers of avian haemosporidian infections vary across zoogeographical regionsNARA Subscribed
Aim Macroecological analyses provide valuable insights into factors that influence how parasites are distributed across space and among hosts. Amid large uncertainties that arise when generalizing from local and regional findings, hierarchical approaches applied to global datasets are required to determine whether drivers of parasite infection patterns vary across scales. We assessed global patterns of haemosporidian infection...
Major shifts in gut microbiota during development and its relationship to growth in ostrichesNARA Subscribed
The development of gut microbiota during ontogeny is emerging as an important process influencing physiology, immunity and fitness in vertebrates. However, knowledge of how bacteria colonize the juvenile gut, how this is influenced by changes in the diversity of gut bacteria and to what extent this influences host fitness, particularly in nonmodel organisms, is lacking. Here we used 16S rRNA gene sequencing to describe the suc...
The transcriptome of the avian malaria parasite Plasmodium ashfordi displays host‐specific gene expressionNARA Subscribed
Malaria parasites ( Plasmodium spp.) include some of the world's most widespread and virulent pathogens. Our knowledge of the molecular mechanisms these parasites use to invade and exploit their hosts other than in mice and primates is, however, extremely limited. It is therefore imperative to characterize transcriptome‐wide gene expression from nonmodel malaria parasites and how this varies across individual hosts. Here, we u...
Avian migration and the distribution of malaria parasites in New World passerine birdsNARA Subscribed
Aim Migrating birds transport their parasites, often over long distances, but little is known about the transfer of these parasites to resident hosts in either the wintering or breeding ranges of the migratory host populations. We investigated the haemosporidian parasite faunas of migratory and resident birds to determine connections among distant parasite faunas, plausibly brought about by migratory host populations. Location...
A jack‐of‐all‐trades and still a master of some: prevalence and host range in avian malaria and related blood parasitesNARA Subscribed
A parasite's ability to be a specialist vs. a generalist may have consequences for its prevalence within one or more if its host species. In this study we investigated the relationship between host specialization and prevalence in the highly species diverse avian blood parasites of the genera Plasmodium and Haemoproteus . Contrary to trade‐off hypotheses that may explain host specialization, within both genera the parasites wi...
Poster abstractsNARA Subscribed
Detecting shifts of transmission areas in avian blood parasites — a phylogenetic approachNARA Subscribed
We investigated the degree of geographical shifts of transmission areas of vector‐borne avian blood parasites ( Plasmodium , Haemoproteus and Leucocytozoon ) over ecological and evolutionary timescales. Of 259 different parasite lineages obtained from 5886 screened birds sampled in Europe and Africa, only two lineages were confirmed to have current transmission in resident bird species in both geographical areas. We used a phy...
Previous1Next