Alan Fecchio

Structure and organization of an avian haemosporidian assemblage in a Neotropical savanna in Brazil.

Studies on avian haemosporidia are on the rise, but we still lack a basic understanding of how ecological and evolutionary factors mold the distributions of haemosporidia among species in the same bird community. We studied the structure and organization of a local avian haemosporidian assemblage (genera Plasmodium and Haemoproteus) in the Cerrado biome of Central Brazil for 5 years. We obtained 790 blood samples from 54 bird species of which 166 (21%) were infected with haemosporidians based on molecular diagnostics. Partial sequences of the parasite cytochrome b gene revealed 18 differentiated avian haemosporidian lineages. We also analysed the relationship of life-history traits (i.e., nesting height, migration status, nest type, sociality, body mass, and embryo development period) of the 14 most abundant bird species with the prevalence of avian haemosporidia. It was found that host species that bred socially presented a higher prevalence of Haemoproteus (Parahaemoproteus) than bird species that bred in pairs. Thus, aspects of host behaviour could be responsible for differential exposure to vectors. The assemblage of avian haemosporidia studied here also confirms a pattern that is emerging in recent studies using molecular markers to identify avian haemosporidians, namely that many lineages are host generalists.

High prevalence of blood parasites in social birds from a neotropical savanna in Brazil

Abstract Blood parasites play a fundamental role in the ecology and evolution of passerine birds because they are able to affect the fitness and survival of their hosts. The prevalence of avian malarial parasites among host species can vary from 0 to 100% but the ecological and evolutionary reasons for this variation are not clear. In this study we tested if height or type of nest, body mass or social system, which we believe are variables associated with exposure of hosts to vectors, could explain the variation in the prevalence of blood parasites in a bird community from the Cerrado biome of central Brazil. We found a significant positive correlation between nest-height and prevalence of Haemoproteus, which is consistent with the hypothesis linking prevalence of blood parasites with nesting stratum in North American birds. We also found evidence for increased levels of parasitism by Haemoproteus in neotropical birds that live in groups and breed cooperatively and increased levels of parasitism by Plasmodium in species that nest in cavities or closed cups. We suggest that reproductive and behavioural parameters of hosts may be responsible for their differential exposure to vectors and that these parameters may therefore be able to indicate interspecific variation in the prevalence of blood parasites in other bird communities.

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

Species 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).

A new real-time PCR protocol for detection of avian haemosporidians

BackgroundBirds possess the most diverse assemblage of haemosporidian parasites; including three genera, Plasmodium, Haemoproteus, and Leucocytozoon. Currently there are over 200 morphologically identified avian haemosporidian species, although true species richness is unknown due to great genetic diversity and insufficient sampling in highly diverse regions. Studies aimed at surveying haemosporidian diversity involve collecting and screening samples from hundreds to thousands of individuals. Currently, screening relies on microscopy and/or single or nested standard PCR. Although effective, these methods are time and resource consuming, and in the case of microscopy require substantial expertise. Here we report a newly developed real-time PCR protocol designed to quickly and reliably detect all three genera of avian haemosporidians in a single biochemical reaction.MethodsUsing available DNA sequences from avian haemosporidians we designed primers R330F and R480RL, which flank a 182 base pair fragment of mitochondrial conserved rDNA. These primers were initially tested using real-time PCR on samples from Malawi, Africa, previously screened for avian haemosporidians using traditional nested PCR. Our real time protocol was further tested on 94 samples from the Cerrado biome of Brazil, previously screened using a single PCR assay for haemosporidian parasites. These samples were also amplified using modified nested PCR protocols, allowing for comparisons between the three different screening methods (single PCR, nested PCR, real-time PCR).ResultsThe real-time PCR protocol successfully identified all three genera of avian haemosporidians from both single and mixed infections previously detected from Malawi. There was no significant difference between the three different screening protocols used for the 94 samples from the Brazilian Cerrado (χ2 = 0.3429, df = 2, P = 0.842). After proving effective, the real-time protocol was used to screen 2113 Brazilian samples, identifying 693 positive samples.ConclusionsOur real-time PCR assay proved as effective as two widely used molecular screening techniques, single PCR and nested PCR. However, the real-time protocol has the distinct advantage of detecting all three genera in a single reaction, which significantly increases efficiency by greatly decreasing screening time and cost. Our real-time PCR protocol is therefore a valuable tool in the quickly expanding field of avian haemosporidian research.

Low prevalence of blood parasites in Cerrado birds, Central Brazil

O objetivo do presente estudo foi determinar a prevalencia de hemoparasitos de aves silvestres em uma area de Cerrado do Brasil Central. Para isso foram examinados 508 individuos pertencentes a 26 especies e nove familias de Passeriformes capturados entre abril de 2005 e marco de 2006 em cinco fitofisionomias da Estacao Ecologica de Aguas Emendadas, DF, Brasil. Apenas 35 individuos (6,9%) estavam parasitados pelos generos Haemoproteus ou Plasmodium . Apenas tres familias se encontraram parasitadas: Emberizidae (9,9%), Tyrannidae (6,8%) e Furnariidae (2,2%). Seis especies de aves sao descritas pela primeira vez como hospedeiras de Haemoproteus ou Plasmodium . Nao foram encontradas diferencas significativas nas prevalencias de parasitismo entre as estacoes seca (7,2%) e chuvosa (6,3%). A prevalencia durante a estacao reprodutiva foi similar a da estacao nao reprodutiva. Especies migratorias nao diferiram das especies residentes na prevalencia de infeccoes por ambos os generos de hemoparasitos. A baixa prevalencia de hemoparasitos encontrada na area de Cerrado estudada e uma das menores ja registrada para comunidades de aves silvestres na regiao Neotropical e no mundo, confirmando os padroes encontrados em estudos anteriores realizados no Brasil e na regiao Neotropical. Palavras-chave: Haemoproteus , malaria aviaria, Passeriformes, Plasmodium , regiao Neotropical.

Host community similarity and geography shape the diversity and distribution of haemosporidian parasites in Amazonian birds

Identifying the mechanisms driving the distribution and diversity of parasitic organisms and characterizing the structure of parasite assemblages are critical to understanding host-parasite evolution, community dynamics, and disease transmission risk. Haemosporidian parasites of the genera Plasmodium and Haemoproteus are a diverse and cosmopolitan group of bird pathogens. Despite their global distribution, the ecological and historical factors shaping the diversity and distribution of these protozoan parasites across avian communities and geographic regions remains unclear. Here we used a region of the mitochondrial cytochrome b gene to characterize the diversity, biogeographical patterns and phylogenetic relationships of Plasmodium and Haemoproteus infecting Amazonian birds. Specifically, we asked whether, and how, host community similarity and geography (latitude and area of endemism) structure parasite assemblages across 15 avian communities in the Amazon Basin. We identified 265 lineages of haemosporidians recovered from 2661 sampled birds from 330 species. Infection prevalence varied widely among host species, avian communities, areas of endemism, and latitude. Composition analysis demonstrated that both malarial parasites and host communities differed across areas of endemism and as a function of latitude. Thus, areas with similar avian community composition were similar in their parasite communities. Our analyses, within a regional biogeographic context, imply that host switching is the main event promoting diversification in malarial parasites. Although dispersal of haemosporidian parasites was constrained across six areas of endemism, these pathogens are not dispersal-limited among communities within the same area of endemism. Our findings indicate that the distribution of malarial parasites in Amazonian birds is largely dependent on local ecological conditions and host evolutionary relationships. This article is protected by copyright. All rights reserved.

Plumage coloration, body condition and immunological status in Yellow-billed Cardinals (Paroaria capitata)

Plumage coloration deriving from carotenoid and melanin pigments can be a quality signal in birds, and can be under conspecific inspection in social interactions. For example, parasite load and immune system status can be inferred through plumage color intensity, and can influence the choice of sexual partners. Here, we evaluated two plumage ornaments in the Yellow-billed Cardinal [Paroaria capitata (d’Orbigny & Lafresnaye 1837)]: the carotenoid-based coloration of the cap and the melanin-based coloration of the bib. We evaluated whether these ornaments were related to blood parasite burden, immunological status and body condition, and whether they could reveal individual sex and age. Cardinals were mist-netted in a Brazilian wetland, and 12 individuals were infected with malaria parasites. Both carotenoid and melanin colorations were related to age, but only carotenoids reflected immunological status. Adult cardinals presented redder caps and darker bibs in comparison to juveniles, and redder caps were associated with low values of heterophil to lymphocyte ratio (H/L, indicating lower stress level). Plumage coloration did not indicate individual sex or parasite infection. Taken together, these results demonstrated that both melanin- and carotenoid-based coloration in cardinals can potentially reflect significant information for social interactions, such as individual age and experience, but apparently only carotenoid coloration is condition-dependent and could reliably indicate quality.

Host associations and turnover of haemosporidian parasites in manakins (Aves: Pipridae)

Parasites of the genera Plasmodium and Haemoproteus (Apicomplexa: Haemosporida) are a diverse group of pathogens that infect birds nearly worldwide. Despite their ubiquity, the ecological and evolutionary factors that shape the diversity and distribution of these protozoan parasites among avian communities and geographic regions are poorly understood. Based on a survey throughout the Neotropics of the haemosporidian parasites infecting manakins (Pipridae), a family of Passerine birds endemic to this region, we asked whether host relatedness, ecological similarity and geographic proximity structure parasite turnover between manakin species and local manakin assemblages. We used molecular methods to screen 1343 individuals of 30 manakin species for the presence of parasites. We found no significant correlations between manakin parasite lineage turnover and both manakin species turnover and geographic distance. Climate differences, species turnover in the larger bird community and parasite lineage turnover in non-manakin hosts did not correlate with manakin parasite lineage turnover. We also found no evidence that manakin parasite lineage turnover among host species correlates with range overlap and genetic divergence among hosts. Our analyses indicate that host switching (turnover among host species) and dispersal (turnover among locations) of haemosporidian parasites in manakins are not constrained at this scale.

Avian malaria, ecological host traits and mosquito abundance in southeastern Amazonia

Avian malaria is a vector transmitted disease caused by Plasmodium and recent studies suggest that variation in its prevalence across avian hosts is correlated with a variety of ecological traits. Here we examine the relationship between prevalence and diversity of Plasmodium lineages in southeastern Amazonia and: (1) host ecological traits (nest location, nest type, flocking behaviour and diet); (2) density and diversity of avian hosts; (3) abundance and diversity of mosquitoes; and (4) season. We used molecular methods to detect Plasmodium in blood samples from 675 individual birds of 120 species. Based on cytochrome b sequences, we recovered 89 lineages of Plasmodium from 136 infected individuals sampled across seven localities. Plasmodium prevalence was homogeneous over time (dry season and flooding season) and space, but heterogeneous among 51 avian host species. Variation in prevalence among bird species was not explained by avian ecological traits, density of avian hosts, or mosquito abundance. However, Plasmodium lineage diversity was positively correlated with mosquito abundance. Interestingly, our results suggest that avian host traits are less important determinants of Plasmodium prevalence and diversity in southeastern Amazonia than in other regions in which they have been investigated.

First Record of Leucocytozoon (Haemosporida: Leucocytozoidae) in Amazonia: Evidence for Rarity in Neotropical Lowlands or Lack of Sampling for This Parasite Genus?

Abstract Birds harbor an astonishing diversity of haemosporidian parasites belonging to the genera Haemoproteus, Leucocytozoon, and Plasmodium. Currently there are more than 250 morphologically described avian haemosporidian species and 2,828 unique lineages found in virtually all avian clades and zoogeographic regions, except for Antarctica. Our report is based on PCR and microscopic screening of 1,302 individual avian samples from Brazil to detect the underrepresented genus Leucocytozoon. This survey primarily focuses on passerine birds collected from Amazonia, the Atlantic Rain Forest, and Pantanal. We also summarize studies conducted in Brazil that report haemosporidian prevalence using both microscopy and molecular tools and present for the first time a record of Leucocytozoon infecting an avian host population in Amazonia. Based on our findings, we suggest that high average temperatures may be constraining both the distribution and diversity of Leucocytozoon in lowland tropical South America.