Low prevalence of haemosporidian parasites in the introduced house sparrow (Passer domesticus) in Brazil

2010 ◽  
Vol 55 (4) ◽  
Author(s):  
Marcos Lima ◽  
Lucy Simpson ◽  
Alan Fecchio ◽  
Cynthia Kyaw
Keyword(s):  
Fixed Effects ◽  
Passer Domesticus ◽  
Parasite Prevalence ◽  
Host Population ◽  
Enemy Release ◽  
Negative Effects ◽  
House Sparrows ◽  
Central Brazil ◽  
Native Birds ◽  
Low Prevalence

AbstractSpecies that are introduced to novel environments can lose their native pathogens and parasites during the process of introduction. The escape from the negative effects associated with these natural enemies is commonly employed as an explanation for the success and expansion of invasive species, which is termed the enemy release hypothesis (ERH). In this study, nested PCR techniques and microscopy were used to determine the prevalence and intensity (respectively) of Plasmodium spp. and Haemoproteus spp. in introduced house sparrows and native urban birds of central Brazil. Generalized linear mixed models were fitted by Laplace approximation considering a binomial error distribution and logit link function. Location and species were considered as random effects and species categorization (native or non-indigenous) as fixed effects. We found that native birds from Brazil presented significantly higher parasite prevalence in accordance with the ERH. We also compared our data with the literature, and found that house sparrows native to Europe exhibited significantly higher parasite prevalence than introduced house sparrows from Brazil, which also supports the ERH. Therefore, it is possible that house sparrows from Brazil might have experienced a parasitic release during the process of introduction, which might also be related to a demographic release (e.g. release from the negative effects of parasites on host population dynamics).

scholarly journals Epigenetic Potential in Native and Introduced Populations of House Sparrows (Passer domesticus)

2020 ◽  
Vol 60 (6) ◽  
pp. 1458-1468 ◽  
Author(s):  
Haley E Hanson ◽  
Bilal Koussayer ◽  
Holly J Kilvitis ◽  
Aaron W Schrey ◽  
J Dylan Maddox ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Phenotypic Plasticity ◽  
Statistical Power ◽  
Passer Domesticus ◽  
House Sparrows ◽  
Cpg Sites ◽  
Introduced Populations ◽  
Introduced Birds ◽  
The Individual ◽  
Native Birds

Synopsis Epigenetic potential, defined as the capacity for epigenetically-mediated phenotypic plasticity, may play an important role during range expansions. During range expansions, populations may encounter relatively novel challenges while experiencing lower genetic diversity. Phenotypic plasticity via epigenetic potential might be selectively advantageous at the time of initial introduction or during spread into new areas, enabling introduced organisms to cope rapidly with novel challenges. Here, we asked whether one form of epigenetic potential (i.e., the abundance of CpG sites) in three microbial surveillance genes: Toll-like receptors (TLRs) 1B (TLR1B), 2A (TLR2A), and 4 (TLR4) varied between native and introduced house sparrows (Passer domesticus). Using an opportunistic approach based on samples collected from sparrow populations around the world, we found that introduced birds had more CpG sites in TLR2A and TLR4, but not TLR1B, than native ones. Introduced birds also lost more CpG sites in TLR1B, gained more CpG sites in TLR2A, and lost fewer CpG sites in TLR4 compared to native birds. These results were not driven by differences in genetic diversity or population genetic structure, and many CpG sites fell within predicted transcription factor binding sites (TFBS), with losses and gains of CpG sites altering predicted TFBS. Although we lacked statistical power to conduct the most rigorous possible analyses, these results suggest that epigenetic potential may play a role in house sparrow range expansions, but additional work will be critical to elucidating how epigenetic potential affects gene expression and hence phenotypic plasticity at the individual, population, and species levels.

scholarly journals Epigenetic potential affects immune gene expression in house sparrows

2021 ◽  
Vol 224 (6) ◽  
pp. jeb238451
Author(s):  
Haley E. Hanson ◽  
Cedric Zimmer ◽  
Bilal Koussayer ◽  
Aaron W. Schrey ◽  
J. Dylan Maddox ◽  
...  
Keyword(s):  
Gene Expression ◽  
Natural Infection ◽  
Passer Domesticus ◽  
Immune Gene ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
House Sparrows ◽  
Native Birds ◽  
Fine Tune ◽  
Increase Gene Expression

ABSTRACTEpigenetic mechanisms may play a central role in mediating phenotypic plasticity, especially during range expansions, when populations face a suite of novel environmental conditions. Individuals may differ in their epigenetic potential (EP; their capacity for epigenetic modifications of gene expression), which may affect their ability to colonize new areas. One form of EP, the number of CpG sites, is higher in introduced house sparrows (Passer domesticus) than in native birds in the promoter region of a microbial surveillance gene, Toll-like Receptor 4 (TLR4), which may allow invading birds to fine-tune their immune responses to unfamiliar parasites. Here, we compared TLR4 gene expression from whole blood, liver and spleen in house sparrows with different EP, first challenging some birds with lipopolysaccharide (LPS), to increase gene expression by simulating a natural infection. We expected that high EP would predict high inducibility and reversibility of TLR4 expression in the blood of birds treated with LPS, but we did not make directional predictions regarding organs, as we could not repeatedly sample these tissues. We found that EP was predictive of TLR4 expression in all tissues. Birds with high EP expressed more TLR4 in the blood than individuals with low EP, regardless of treatment with LPS. Only females with high EP exhibited reversibility in gene expression. Further, the effect of EP varied between sexes and among tissues. Together, these data support EP as one regulator of TLR4 expression.

scholarly journals Prevalence and evolutionary relationships of haematozoan parasites in native versus introduced populations of common myna Acridotheres tristis

2005 ◽  
Vol 273 (1586) ◽  
pp. 587-594 ◽  
Author(s):  
Farah Ishtiaq ◽  
Jon S Beadell ◽  
Allan J Baker ◽  
Asad R Rahmani ◽  
Yadvendradev V Jhala ◽  
...  
Keyword(s):  
Parasite Prevalence ◽  
Oceanic Islands ◽  
Enemy Release Hypothesis ◽  
Malarial Parasite ◽  
Enemy Release ◽  
Common Myna ◽  
Introduced Populations ◽  
Native Populations ◽  
Acridotheres Tristis ◽  
Low Prevalence

The success of introduced species is frequently explained by their escape from natural enemies in the introduced region. We tested the enemy release hypothesis with respect to two well studied blood parasite genera ( Plasmodium and Haemoproteus ) in native and six introduced populations of the common myna Acridotheres tristis . Not all comparisons of introduced populations to the native population were consistent with expectations of the enemy release hypothesis. Native populations show greater overall parasite prevalence than introduced populations, but the lower prevalence in introduced populations is driven by low prevalence in two populations on oceanic islands (Fiji and Hawaii). When these are excluded, prevalence does not differ significantly. We found a similar number of parasite lineages in native populations compared to all introduced populations. Although there is some evidence that common mynas may have carried parasite lineages from native to introduced locations, and also that introduced populations may have become infected with novel parasite lineages, it may be difficult to differentiate between parasites that are native and introduced, because malarial parasite lineages often do not show regional or host specificity.

scholarly journals Temporal and spatial variation in prevalence of the parasite Syngamus trachea in a metapopulation of house sparrows (Passer domesticus)

Parasitology ◽  
2013 ◽  
Vol 140 (10) ◽  
pp. 1275-1286 ◽  
Author(s):  
HÅKON HOLAND ◽  
HENRIK JENSEN ◽  
JARLE TUFTO ◽  
BERNT-ERIK SÆTHER ◽  
THOR HARALD RINGSBY
Keyword(s):  
Evolutionary Dynamics ◽  
Natural Populations ◽  
Passer Domesticus ◽  
Parasite Prevalence ◽  
Fragmented Landscape ◽  
Fundamental Parameter ◽  
Time And Space ◽  
House Sparrows ◽  
Demographic Groups ◽  
Syngamus Trachea

SUMMARYWhen investigating parasite–host dynamics in wild populations, a fundamental parameter to investigate is prevalence. This quantifies the percentage of individuals infected in the population. Investigating how prevalence changes over time and space can reveal interesting aspects in the parasite–host relationship in natural populations. We investigated the dynamic between a common avian parasite (Syngamus trachea) in a host metapopulation of house sparrows (Passer domesticus) on the coast of Helgeland in northern Norway. We found that parasite prevalence varied in both time and space. In addition, the parasite prevalence was found to be different between demographic groups in the local populations. Our results reveal just how complex the dynamic between a host and its parasite may become in a fragmented landscape. Although temperature may be an important factor, the specific mechanisms causing this complexity are not fully understood, but need to be further examined to understand how parasite–host interactions may affect the ecological and evolutionary dynamics and viability of host populations.

scholarly journals From Africa to Europe: evidence of transmission of a tropical Plasmodium lineage in Spanish populations of house sparrows

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Martina Ferraguti ◽  
Josué Martínez-de la Puente ◽  
Luz García-Longoria ◽  
Ramón Soriguer ◽  
Jordi Figuerola ◽  
...  
Keyword(s):  
Avian Malaria ◽  
Passer Domesticus ◽  
Malaria Parasites ◽  
House Sparrows ◽  
Current Transmission ◽  
Spanish Populations ◽  
Current Scenario ◽  
Low Prevalence ◽  
Natural Dispersal ◽  
Avian Malaria Parasites

Abstract Background Avian malaria parasites are a highly diverse group that commonly infect birds and have deleterious effects on their hosts. Some parasite lineages are geographically widespread and infect many host species in many regions. Bird migration, natural dispersal, invasive species and human-mediated introductions into areas where competent insect vectors are present, are probably the main drivers of the current distribution of avian malaria parasites. Methods A total of 412 and 2588 wild house sparrows (Passer domesticus) were captured in 2012 and 2013 in two areas of the Iberian Peninsula (central and southern Spain, respectively). Genomic DNA was extracted from blood samples; parasite lineages were sequenced and identified by comparing with GenBank and/or MalAvi databases. Results Thirteen Plasmodium lineages were identified in house sparrows corresponding to three major clades. Five individuals were infected by the African Plasmodium lineage PAGRI02, which has been proposed to actively circulate only in Africa. Conclusions Despite the low prevalence of PAGRI02 in sparrows in Spain, our results suggest that the area of transmission of this parasite is more widespread than previously thought and covers both Africa and Europe. Further studies of the global distribution of Plasmodium lineages infecting wild birds are required to identify the current transmission areas of these parasites. This is vital given the current scenario of global change that is providing new opportunities for avian malaria transmission into areas where parasites were previously absent.

Haemosporidian parasites missed the boat during the introduction of common waxbills (Estrilda astrild) in Iberia

Parasitology ◽  
2018 ◽  
Vol 145 (11) ◽  
pp. 1493-1498 ◽  
Author(s):  
Ricardo J. Lopes ◽  
Joana Correia ◽  
Helena Batalha ◽  
Gonçalo C. Cardoso
Keyword(s):  
Exotic Species ◽  
Parasite Prevalence ◽  
Sub Saharan Africa ◽  
Enemy Release ◽  
Haemosporidian Parasite ◽  
Haemosporidian Parasites ◽  
Geographic Differences ◽  
Sub Saharan ◽  
The 1960S ◽  
Low Prevalence

AbstractExotic species can experience fast expansion in new environments, especially if they left their pathogens behind (Enemy Release hypothesis) or brought novel pathogens to the native competitors (Novel Weapon hypothesis). Common waxbills (Estrilda astrild) are native to sub-Saharan Africa and invaded west Iberia since the 1960s. Past haemosporidian parasite surveys at four locations in Portugal showed that waxbills can be infected with parasites, though with very low prevalence. However, it is not known if this pattern generalizes across their distribution range, or if there are geographic differences in parasite prevalence. It is also not discussed if this is a case of Enemy Release, as opposed to waxbills being also little parasitized in their native range. We screened 617 waxbills in 23 sites in Portugal and detected nine parasite lineages, most of them only known to the Palearctic. Only ten individuals were parasitized, and there was no significant geographical pattern on the prevalence. Overall, this population shows very low prevalence of haemosporidians (1.6% prevalence), which contrasts with significantly higher prevalence in native grounds, as compiled from the literature. These data support Enemy Release as the most likely hypothesis, which may have been important for their success as an exotic species.

scholarly journals Mediating distributive politics: political alignment and electoral business cycle effects on municipality financing in Greece

2021 ◽  
Author(s):  
Anastasios Kitsos ◽  
Antonios Proestakis
Keyword(s):  
Business Cycle ◽  
Fixed Effects ◽  
Central Government ◽  
Intergovernmental Transfers ◽  
Negative Effects ◽  
National Elections ◽  
Data Set ◽  
Resource Misallocation ◽  
Run Up ◽  
Political Alignment

AbstractWe examine the role of political alignment and the electoral business cycle on municipality revenues in Greece for the period 2003–2010. The misallocation of resources for political gain represents a waste of resources with significant negative effects on local growth and effective decentralization. The focus of our analysis is municipality mayors since they mediate the relationship between central government and voters and hence can influence the effectiveness of any potential pork-barrelling activity. A novel panel data set combining the results of two local and three national elections with annual municipality budgets is used to run a fixed-effects econometric model. This allows us to identify whether the political alignment between mayors and central government affects municipality financing. We examine this at different stages of local and national electoral cycles, investigating both direct intergovernmental transfers (grants) and the remaining sources of local revenues (own revenues, loans). We find that total revenues are significantly higher for aligned municipalities in the run-up to elections due to higher intergovernmental transfers. We also find evidence that the 2008 crisis has reduced such pork-barrelling activity. This significant resource misallocation increases vertical networking dependency and calls for policy changes promoting greater decentralization and encouraging innovation in local revenue raising.

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