| 1. |
- Asghar, Muhammad, et al.
(författare)
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Parallel telomere shortening in multiple body tissues owing to malaria infection
- 2016
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Ingår i: Proceedings of the Royal Society B: Biological Sciences. - : The Royal Society. - 1471-2954 .- 0962-8452. ; 283:1836
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Tidskriftsartikel (refereegranskat)abstract
- Several studies have shown associations between shorter telomere length in blood and weakened immune function, susceptibility to infections, and increased risk of morbidity and mortality. Recently, we have shown that malaria accelerates telomere attrition in blood cells and shortens lifespan in birds. However, the impact of infections on telomere attrition in different body tissues within an individual is unknown. Here, we tested whether malarial infection leads to parallel telomere shortening in blood and tissue samples from different organs. We experimentally infected siskins (Spinus spinus) with the avian malaria parasite Plasmodium ashfordi, and used real-time quantitative polymerase chain reaction (PCR) to measure telomere length in control and experimentally infected siskins. We found that experimentally infected birds showed faster telomere attrition in blood over the course of infection compared with control individuals (repeatedly measured over 105 days post-infection (DPI)). Shorter telomeres were also found in the tissue of all six major organs investigated (liver, lungs, spleen, heart, kidney, and brain) in infected birds compared with controls at 105 DPI. To the best of our knowledge, this is the first study showing that an infectious disease results in synchronous telomere shortening in the blood and tissue cells of internal organs within individuals, implying that the infection induces systemic stress. Our results have far-reaching implications for understanding how the short-term effects of an infection can translate into long-term costs, such as organ dysfunction, degenerative diseases, and ageing.
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| 2. |
- Aželytė, Justė, et al.
(författare)
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A comparative analysis of the dynamics of Plasmodium relictum (GRW4) development in the blood during single and co-infections
- 2022
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Ingår i: Acta Tropica. - : Elsevier BV. - 0001-706X. ; 226
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Tidskriftsartikel (refereegranskat)abstract
- Although co-infections and interactions of parasites are a very common phenomenon in the wild, information received from studies on avian Plasmodium spp. is scarce and fragmented due to its complex nature. Different interactions of parasites and domination of one parasite may have a detrimental effect on transmission success of another pathogen. Untangling these interactions and competitive behavior of malarial parasites may help understanding why some haemosporidian parasites are dominant in certain host species, while others are observed only occasionally. We investigated the development of Plasmodium relictum (genetic lineage GRW4) during single and co-infection with a closely related lineage SGS1, with the aim to determine whether co-infections affect parasite development and condition of experimentally infected Eurasian siskins (Spinus spinus). For the experimental study of these two closely related lineages, a new qPCR protocol was designed to accurately quantify the parasitemia, i.e. the amount of infected red blood cells, during the blood stages of each of the lineages. Our results show that during co-infection, GRW4 parasitemia was transient and disappeared from peripheral blood during acute increases of SGS1. Health parameters of infected birds did not differ between the GRW4 single infected group and the co-infection group. GRW4 induced infection was outcompeted and suppressed by the presence of the lineage SGS1, which is broadly transmitted in Northern Europe. This suggests that double infections and dominating lineages in the area may influence the transmission success of some avian Plasmodium parasites.
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| 3. |
- Bensch, Staffan, et al.
(författare)
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Genomic Resources Notes accepted 1 June 2013-31 July 2013
- 2014
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Ingår i: Molecular Ecology Resources. - : Wiley. - 1755-098X. ; 14:1, s. 218-218
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- This article documents the public availability of (i) raw transcriptome sequence data, assembled contigs and UniProt BLAST hits from common crossbill (Loxia curvirostra) and Plasmodium relictum (lineage SGS1) obtained from a controlled infection experiment; and (ii) raw transcriptome sequence data and 66596 SNPs for the white-tailed deer (Odocoileus virginianus).
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| 4. |
- Bensch, Staffan, et al.
(författare)
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How can we determine the molecular clock of malaria parasites?
- 2013
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Ingår i: Trends in Parasitology. - : Elsevier BV. - 1471-5007 .- 1471-4922. ; 29:8, s. 363-369
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Forskningsöversikt (refereegranskat)abstract
- The association of contemporary hosts and their parasites might reflect either cospeciation or more recent shifts among existing hosts. Cospeciation implies that lineages of hosts and parasites diverge in parallel at the same time, but testing this prediction requires time-calibrated phylogenies, which are particularly difficult to obtain in organisms that leave few fossils. It has successively become clear that host shifts have been frequent in the evolutionary history of malaria parasites, but dating these host shifts cannot be done without calibrated phylogenies. Hence, it remains unresolved how long contemporary hosts and vectors have been coevolving with their malaria parasites. This review addresses conflicting rate estimates of molecular evolution and suggests research directions to aid dating diversification events in malaria parasites.
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| 5. |
- Bensch, Staffan, et al.
(författare)
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The genome of Haemoproteus tartakovskyi and its relationship to human malaria parasites
- 2016
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Ingår i: Genome Biology and Evolution. - : Oxford University Press (OUP). - 1759-6653. ; 8:5, s. 73-1361
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Tidskriftsartikel (refereegranskat)abstract
- The phylogenetic relationships among hemosporidian parasites, including the origin of Plasmodium falciparum, the most virulent malaria parasite of humans, have been heavily debated for decades. Studies based on multiple-gene sequences have helped settle many of these controversial phylogenetic issues. However, denser taxon sampling and genome-wide analyses are needed to confidently resolve the evolutionay relationships among hemosporidian parasites. Genome sequences of several Plasmodium parasites are available but only for species infecting primates and rodents. To root the phylogenetic tree of Plasmodium, genomic data from related parasites of birds or reptiles are required. Here, we use a novel approach to isolate parasite DNA from microgametes and describe the first genome of a bird parasite in the sister genus to Plasmodium, Haemoproteus tartakovskyi Similar to Plasmodium parasites, H. tartakovskyi has a small genome (23.2 Mb, 5,990 genes) and a GC content (25.4%) closer to P. falciparum (19.3%) than to Plasmodium vivax (42.3%). Combined with novel transcriptome sequences of the bird parasite Plasmodium ashfordi, our phylogenomic analyses of 1,302 orthologous genes demonstrate that mammalian-infecting malaria parasites are monophyletic, thus rejecting the repeatedly proposed hypothesis that the ancestor of Laverania parasites originated from a secondary host shift from birds to humans. Genes and genomic features previously found to be shared between P. falciparum and bird malaria parasites, but absent in other mammal malaria parasites, are therefore signatures of maintained ancestral states. We foresee that the genome of H. tartakovskyi will open new directions for comparative evolutionary analyses of malarial adaptive traits.
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| 6. |
- Dimitrov, Dimitar, et al.
(författare)
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Plasmodium spp.: An experimental study on vertebrate host susceptibility to avian malaria.
- 2015
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Ingår i: Experimental Parasitology. - : Elsevier BV. - 0014-4894. ; 148, s. 1-16
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Tidskriftsartikel (refereegranskat)abstract
- The interest in experimental studies on avian malaria caused by Plasmodium species has increased recently due to the need of direct information about host-parasite interactions. Numerous important issues (host susceptibility, development of infection, the resistance and tolerance to avian malaria) can be answered using experimental infections. However, specificity of genetically different lineages of malaria parasites and their isolates is largely unknown. This study reviews recent experimental studies and offers additional data about susceptibility of birds to several widespread cytochrome b (cyt b) lineages of Plasmodium species belonging to four subgenera. We exposed two domesticated avian hosts (canaries Serinus canaria and ducklings Anas platyrhynchos) and also 16 species of common wild European birds to malaria infections by intramuscular injection of infected blood and then tested them by microscopic examination and PCR-based methods. Our study confirms former field and experimental observations about low specificity and wide host-range of Plasmodium relictum (lineages SGS1 and GRW11) and P. circumflexum (lineage TURDUS1) belonging to the subgenera Haemamoeba and Giovannolaia, respectively. However, the specificity of different lineages and isolates of the same parasite lineage differed between species of exposed hosts. Several tested Novyella lineages were species specific, with a few cases of successful development in experimentally exposed birds. The majority of reported cases of mortality and high parasitaemia were observed during parasite co-infections. Canaries were susceptible mainly for the species of Haemamoeba and Giovannolaia, but were refractory to the majority of Novyella isolates. Ducklings were susceptible to three malaria infections (SGS1, TURDUS1 and COLL4), but parasitaemia was light (<0.01%) and transient in all exposed birds. This study provides novel information about susceptibility of avian hosts to a wide array of malaria parasite lineages, outlining directions for future experimental research on various aspects of biology and epidemiology of avian malaria.
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| 7. |
- Dolnik, Olga V., et al.
(författare)
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Individual Oocysts Of Isospora (Apicomplexa: Coccidia) Parasites From Avian Feces: From Photo To Sequence
- 2009
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Ingår i: The Journal of Parasitology. - 0022-3395. ; 95:1, s. 169-174
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Tidskriftsartikel (refereegranskat)abstract
- Numerous microscopic studies of coccidian oocysts from avian feces have become the basis for species identification. In contrast, molecular studies of wild birds' Coccidia are still in their infancy and are mostly based on DNA extracted from the blood stages of these parasites. Linking microscopic and molecular data requires a method that reliably extracts DNA from single oocysts with parallel detailed morphological examination of the same cell. We offer a thorough manual of isolating, photographing, and trapping single oocysts from avian feces, followed by extraction of parasite DNA and amplification of mitochondrial DNA from the same cells. In 39 single oocysts from 6 wild blackcaps, we combined microscopic studies of individual cells with studies on their mitochondrial haplotype. In 72% of the single oocysts sampled, we detected unambiguous sequences. From feces and blood of investigated birds, we obtained 6 different haplotypes of Isospora sp. (iSATI-iSAT 6), finding both the same haplotype in different host individuals and various haplotypes in the same host individual. Our described methodology enables linking the huge amount of morphological data with innovative gene analysis. This method expands the scope of genetic studies conducted on Isospora species, including routine molecular analysis of single oocysts isolated from fecal samples.
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| 8. |
- Ellis, Vincenzo A., et al.
(författare)
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Genomic sequence capture of Plasmodium relictum in experimentally infected birds
- 2022
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Ingår i: Parasites and Vectors. - : Springer Science and Business Media LLC. - 1756-3305. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Sequencing parasite genomes in the presence of host DNA is challenging. Sequence capture can overcome this problem by using RNA probes that hybridize with the parasite DNA and then are removed from solution, thus isolating the parasite DNA for efficient sequencing. Methods: Here we describe a set of sequence capture probes designed to target 1035 genes (c. 2.5 Mbp) of the globally distributed avian haemosporidian parasite, Plasmodium relictum. Previous sequence capture studies of avian haemosporidians from the genus Haemoproteus have shown that sequencing success depends on parasitemia, with low-intensity, chronic infections (typical of most infected birds in the wild) often being difficult to sequence. We evaluate the relationship between parasitemia and sequencing success using birds experimentally infected with P. relictum and kept under laboratory conditions. Results: We confirm the dependence of sequencing success on parasitemia. Sequencing success was low for birds with low levels of parasitemia (< 1% infected red blood cells) and high for birds with higher levels of parasitemia. Plasmodium relictum is composed of multiple lineages defined by their mitochondrial DNA haplotype including three that are widespread (SGS1, GRW11, and GRW4); the probes successfully isolated DNA from all three. Furthermore, we used data from 25 genes to describe both among- and within-lineage genetic variation. For example, two samples of SGS1 isolated from different host species differed by 11 substitutions across those 25 genes. Conclusions: The sequence capture approach we describe will allow for the generation of genomic data that will contribute to our understanding of the population genetic structure and evolutionary history of P. relictum, an extreme host generalist and widespread parasite. Graphical Abstract: [Figure not available: see fulltext.].
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| 9. |
- Ferraguti, Martina, et al.
(författare)
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Environmental, geographical and time-related impacts on avian malaria infections in native and introduced populations of house sparrows (Passer domesticus), a globally invasive species
- 2023
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Ingår i: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 32:5, s. 809-823
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Tidskriftsartikel (refereegranskat)abstract
- 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 (Passer domesticus) populations. Location: Global. Time period: 2002–2019. Major taxa studied: Avian Plasmodium parasites in house sparrows. Methods: We analysed data from 2,220 samples from 69 localities across all continents, except Antarctica. The influence of environment (urbanization index and human density), geography (altitude, latitude, hemisphere) and time (bird breeding season and years since introduction) were analysed using generalized additive mixed models (GAMMs) and random forests. Results: Overall, 670 sparrows (30.2%) were infected with 22 Plasmodium lineages. In native populations, parasite prevalence was positively related to urbanization index, with the highest prevalence values in areas with intermediate urbanization levels. Likewise, in introduced populations, prevalence was positively associated with urbanization index; however, higher infection occurred in areas with either extreme high or low levels of urbanization. In introduced populations, the number of parasite lineages increased with altitude and with the years elapsed since the establishment of sparrows in a new locality. Here, after a decline in the number of parasite lineages in the first 30 years, an increase from 40 years onwards was detected. Main conclusions: Urbanization was related to parasite prevalence in both native and introduced bird populations. In invaded areas, altitude and time since bird introduction were related to the number of Plasmodium lineages found to be infecting sparrows.
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| 10. |
- Hellgren, Olof, et al.
(författare)
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Global phylogeography of the avian malaria pathogen Plasmodium relictum based on MSP1 allelic diversity
- 2015
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Ingår i: Ecography. - : Wiley. - 1600-0587 .- 0906-7590. ; 38:8, s. 842-850
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Tidskriftsartikel (refereegranskat)abstract
- Knowing the genetic variation that occurs in pathogen populations and how it is distributed across geographical areas is essential to understand parasite epidemiology, local patterns of virulence, and evolution of host-resistance. In addition, it is important to identify populations of pathogens that are evolutionarily independent and thus free' to adapt to hosts and environments. Here, we investigated genetic variation in the globally distributed, highly invasive avian malaria parasite Plasmodium relictum, which has several distinctive mitochondrial haplotyps (cyt b lineages, SGS1, GRW11 and GRW4). The phylogeography of P. relictum was accessed using the highly variable nuclear gene merozoite surface protein 1 (MSP1), a gene linked to the invasion biology of the parasite. We show that the lineage GRW4 is evolutionarily independent of GRW11 and SGS1 whereas GRW11 and SGS1 share MSP1 alleles and thus suggesting the presence of two distinct species (GRW4 versus SGS1 and GRW11). Further, there were significant differences in the global distribution of MSP1 alleles with differences between GRW4 alleles in the New and the Old World. For SGS1, a lineage formerly believed to have both tropical and temperate transmission, there were clear differences in MSP1 alleles transmitted in tropical Africa compared to the temperate regions of Europe and Asia. Further, we highlight the occurrence of multiple MSP1 alleles in GRW4 isolates from the Hawaiian Islands, where the parasite has contributed to declines and extinctions of endemic forest birds since it was introduced. This study stresses the importance of multiple independent loci for understanding patterns of transmission and evolutionary independence across avian malaria parasites.
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