Generalist haemosporidian parasites are better adapted to a subset of host species in a multiple host community

Huang, Xi; Ellis, Vincenzo A.; Jönsson, Jörgen; Bensch, Staffan

doi:10.1111/mec.14856

Cited by 29 publications

(37 citation statements)

References 65 publications

(92 reference statements)

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“…Furthermore, a recent work suggests that although a parasite lineage may be found infecting a wide diversity of hosts, they are actually better adapted to key host species as indicated by their infection intensities (Huang et al . ). Collectively, this evidence could indicate that other forces besides vector feeding may limit rates of novel host encounters for parasites.…”

Section: Discussionmentioning

confidence: 97%

Climate variation influences host specificity in avian malaria parasites

et al. 2019

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Parasites with low host specificity (e.g. infecting a large diversity of host species) are of special interest in disease ecology, as they are likely more capable of circumventing ecological or evolutionary barriers to infect new hosts than are specialist parasites. Yet for many parasites, host specificity is not fixed and can vary in response to environmental conditions. Using data on host associations for avian malaria parasites (Apicomplexa: Haemosporida), we develop a hierarchical model that quantifies this environmental dependency by partitioning host specificity variation into region‐ and parasite‐level effects. Parasites were generally phylogenetic host specialists, infecting phylogenetically clustered subsets of available avian hosts. However, the magnitude of this specialisation varied biogeographically, with parasites exhibiting higher host specificity in regions with more pronounced rainfall seasonality and wetter dry seasons. Recognising the environmental dependency of parasite specialisation can provide useful leverage for improving predictions of infection risk in response to global climate change.

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Section: Discussionmentioning

confidence: 97%

Climate variation influences host specificity in avian malaria parasites

et al. 2019

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“…a Cq value was generated but the melting peak corresponded to non-specific amplifications (Additional file 4 : Figure S3). To check and adjust variations between qPCR reactions, three samples with high to low infection intensities (160520: 7.02%; 160514: 0.9%; 160608: 0.4%) were selected as “golden standard samples” [ 7 ] and included in all reactions. To obtain the amplification efficiency in qPCR analyses, each of the golden samples were 4-fold serially diluted to five gradients to generate the standard curves and were equally distributed to several isolated tubes for different PCR reactions to avoid cross-contamination.…”

Section: Methodsmentioning

confidence: 99%

“…Assemblages of parasites and their hosts, estimated by prevalence and infection intensity, can vary both temporally and spatially due to complex and multidimensional environmental conditions [ 5 ], as well as host resistance to parasites [ 6 ], parasite adaptation to certain host species [ 7 ], and whether the host is harbouring two or more different parasites at the same time [ 8 ]. When analysing prevalence and infection intensity of parasites, variations in identification accuracy may lead to biases across studies, further inaccurate estimation of global patterns of host-parasite interactions, and may also lead to biases on how parasites adapt to certain host species under forces of natural selection.…”

Section: Introductionmentioning

confidence: 99%

“…A variety of studies have been carried out on the prevalence of avian haemosporidian parasites in natural communities and variations in relation to a set of environmental factors [ 10 ]. However, studies on infection intensity are still limiting despite the importance in reflecting adaptation of avian haemosporidian parasites, especially in generalist parasites with multiple host species [ 7 ]. Due to differences in host immune systems and host-parasite co-evolutionary history, infection intensity of a given parasite can differ dramatically among different hosts [ 11 ].…”

Section: Introductionmentioning

confidence: 99%

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A new protocol for absolute quantification of haemosporidian parasites in raptors and comparison with current assays

Huang

Liang

et al. 2020

Parasites Vectors

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Background Accurate quantification of infection intensity is essential to estimate infection patterns of avian haemosporidian parasites in order to understand the evolution of host-parasite associations. Traditional microscopy is cost-effective but requires high-quality blood smears and considerable experience, while the widely used semi-quantitative qPCR methods are mostly employed with ideal, laboratory-based golden samples and standard curves, which may limit the comparison of parasitemia from different laboratories. Methods Here we present a digital droplet PCR (ddPCR) protocol for absolute quantification of avian haemosporidians in raptors. Novel primers were designed that target a conserved fragment of a rRNA region of the mitochondrial genome of the parasites. Sensitivity and repeatability were evaluated compared to qPCR and other assays. Results This ddPCR assay enables accurate quantification of haemosporidian parasites belonging to Plasmodium , Haemoproteus and Leucocytozoon with minimum infection quantities of 10 −5 (i.e. one parasite copy in 10 5 host genomes) without the use of standard curves. Quantities assessed by ddPCR were more accurate than qPCR using the same primers through reduction of non-specific amplification in low-intensity samples. The ddPCR technique was more consistent among technical duplicates and reactions, especially when infection intensities were low, and this technique demonstrated equal sensitivity with high correspondence ( R 2 = 0.97) compared to the widely used qPCR assay. Both ddPCR and qPCR identified more positive samples than the standard nested PCR protocol for the cytb gene used for barcoding avian haemosporidians. Conclusions We developed a novel ddPCR assay enabling accurate quantification of avian haemosporidians without golden samples or standard curves. This assay can be used as a robust method for investigating infection patterns in different host-parasite assemblages and can facilitate the comparison of results from different laboratories.

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“…malaria Haemoproteus majoris varies among host species (Huang, Ellis, Jönsson, & Bensch, 2018). Interspecific variation in susceptibility could be a result of variation in resistance and/or tolerance (where resistance refers to variation in the ability to control pathogen replication, while tolerance means variation in ability to limit the damage of a given pathogen load; Råberg, Sim, & Read, 2007).…”

mentioning

confidence: 99%

Comparison of spleen transcriptomes of two wild rodent species reveals differences in the immune response against Borrelia afzelii

Zhong

Lundberg

Råberg

2020

Ecology and Evolution

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Different host species often differ considerably in susceptibility to a given pathogen, but the causes of such differences are rarely known. The natural hosts of the tick‐transmitted bacterium Borrelia afzelii, which is one of causative agents of Lyme borreliosis in humans, include a variety of small mammals like voles and mice. Previous studies have shown that B. afzelii‐infected bank voles (Myodes glareolus) have about ten times higher bacterial load than infected yellow‐necked mice (Apodemus flavicollis), indicating that these two species differ in resistance. In this study, we compared the immune response to B. afzelii infection in these host species by using RNA sequencing to quantify gene expression in spleen. Gene set enrichment analysis (GSEA) showed that several immune pathways were down‐regulated in infected animals in both bank voles and yellow‐necked mice. Moreover, IFNα response was up‐regulated in B. afzelii‐infected yellow‐necked mice, while IL6 signaling and the complement pathway were down‐regulated in infected bank voles; differences in regulation of these three pathways between bank voles and yellow‐necked mice could thus contribute to the difference in resistance to B. afzelii between the species. This study provides knowledge of gene expression induced by a zoonotic pathogen in its natural host, and possible species‐specific regulation of immune responses associated with resistance.

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Generalist haemosporidian parasites are better adapted to a subset of host species in a multiple host community

Cited by 29 publications

References 65 publications

Climate variation influences host specificity in avian malaria parasites

Climate variation influences host specificity in avian malaria parasites

A new protocol for absolute quantification of haemosporidian parasites in raptors and comparison with current assays

Comparison of spleen transcriptomes of two wild rodent species reveals differences in the immune response against Borrelia afzelii

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