RESUMO
Forest regeneration is becoming a powerful tool to combat land conversion which covers 30 % of the Neotropical territory. However, little is known about the effect of forest regeneration on vector-borne diseases. Here, we describe the haemosporidian lineage composition across a successional gradient within an Atlantic Forest bird community. We test whether forest successional stages, in addition to host life history traits affect haemosporidian infection probability. We sampled birds at 16 sampling units with different successional stages between 2017 and 2018 within a forest remnant located in Antonina, Paraná, Brazil. We captured bird individuals using mist-nets, identified them to the species level, and collected blood samples to detect and identify Plasmodium and Haemoproteus lineages based on molecular analysis. We used a Bayesian phylogenetic linear model with a Bernoulli distribution to test whether the haemosporidian infection probability is affected by nest type, foraging stratum, and forest successional stage. We captured 322 bird individuals belonging to 52 species and 21 families. We found 31 parasite lineages and an overall haemosporidian prevalence of 23.9 %, with most infections being caused by Plasmodium (21.7 % of prevalence). The Plasmodium probability of infection was associated with forest successional stage and bird foraging stratum. Birds from the secondary forest in an intermediate stage of succession are more likely to be infected by the parasites than birds from the primary forests (ß = 1.21, 95 % CI = 0.11 - 2.43), birds from upper strata exhibit a lower probability of infection than birds from lower foraging strata (ß = -1.81, 95 % CI = -3.80 - -0.08). Nest type did not affect the Plasmodium probability of infection. Our results highlight the relevance of forest succession on haemosporidian infection dynamics, which is particularly relevant in a world where natural regeneration is the main tool used in forest restoration.
Assuntos
Doenças das Aves , Aves , Florestas , Haemosporida , Animais , Aves/parasitologia , Haemosporida/isolamento & purificação , Haemosporida/genética , Brasil/epidemiologia , Prevalência , Doenças das Aves/parasitologia , Doenças das Aves/epidemiologia , Plasmodium/isolamento & purificação , Plasmodium/classificação , Filogenia , Infecções Protozoárias em Animais/epidemiologia , Infecções Protozoárias em Animais/parasitologia , Teorema de BayesRESUMO
Avian haemosporidians of the genera Plasmodium and Haemoproteus are a group of widely distributed blood parasites that can negatively affect the fitness of their hosts. Colombia contains the greatest diversity of birds on the planet, but knowledge about the associations between haemosporidian and its avifauna is scarce and fragmented. We collected blood samples from 255 birds (203 residents and 52 neotropical migrants) belonging to 27 families and 108 species. The study was conducted in six localities in the inter-Andean valleys of the Cauca and Magdalena rivers. Parasites of the genera Plasmodium and Haemoproteus were identified in the samples by morphological and molecular analysis of a fragment of the mitochondrial gene cyt b. Among the samples, 9.3% (n = 24) were positive for Plasmodium or Haemoproteus. Co-infection with Plasmodium and Haemoproteus was found in Red-eyed Vireo. Seventeen haemosporidian lineages were identified, five of which were reported for the first time in resident birds (Common Ground Dove, Checker-throated Stipplethroat, Tropical Kingbird, Pale-breasted Thrush, and Ruddy-breasted Seedeater) and one in the Summer Tanager (neotropical migrant). The research results confirm the wide diversity of haemosporidian present in tropical lowlands and the possible role of neotropical migratory birds in dissemination on haemosporidian along their migratory routes.
Assuntos
Doenças das Aves , Aves , Haemosporida , Plasmodium , Infecções Protozoárias em Animais , Animais , Colômbia/epidemiologia , Haemosporida/classificação , Haemosporida/isolamento & purificação , Haemosporida/genética , Aves/parasitologia , Doenças das Aves/parasitologia , Doenças das Aves/epidemiologia , Plasmodium/classificação , Plasmodium/isolamento & purificação , Plasmodium/genética , Infecções Protozoárias em Animais/parasitologia , Infecções Protozoárias em Animais/epidemiologia , Citocromos b/genética , Migração Animal , Filogenia , Coinfecção/parasitologia , Coinfecção/veterinária , Coinfecção/epidemiologiaRESUMO
The order Procellariiformes includes several species of seabirds that perform long-distance migrations crossing all the oceans. These movements may contribute to the dispersal and exchange of hemoparasites, such as haemosporidians. There is a lack of studies regarding the order Haemosporida in Procellariiformes, and, to date, only the genus Plasmodium has been reported. This survey investigated the occurrence of the three genera of haemosporidians, Plasmodium, Haemoproteus, and Leucocytozoon, in samples collected between 2013 and 2022 from 95 individuals of 14 species of Procellariiformes from southern Brazil, including live animals in rehabilitation centers, individuals caught as incidental bycatch, and carcasses found along the coast. A total of 171 samples of blood and fragments of liver and spleen were analyzed, with extracted DNA being subjected to a nested PCR followed by phylogeny analysis. All animals were negative for Plasmodium spp. and Leucocytozoon spp., but one Black-browed Albatross (Thalassarche melanophris) and one Manx Shearwater (Puffinus puffinus) specimen were positive for Haemoproteus spp. The sequences obtained from positive seabirds did not show 100% similarity with other known lineages available in the MalAvi database and thus were probably novel lineages. However, one sequence clustered together with Haemoproteus noctuae, a parasite from Strigiformes, while the other was grouped with Haemoproteus columbae, which is classically related to Columbiformes. These results suggest that both positive animals may have become infected when beached or in rehabilitation centers by a spillover of vectors from local birds. This highlights the importance of surveillance of the health of Procellariiformes regarding the possibility of dissemination of new pathogens in different bird populations.
Assuntos
Doenças das Aves , Haemosporida , Parasitos , Plasmodium , Infecções Protozoárias em Animais , Estrigiformes , Humanos , Animais , Brasil/epidemiologia , Doenças das Aves/epidemiologia , Doenças das Aves/parasitologia , Haemosporida/genética , Plasmodium/genética , Filogenia , Infecções Protozoárias em Animais/epidemiologia , Infecções Protozoárias em Animais/parasitologiaRESUMO
The distribution of avian haemosporidians of the genus Leucocytozoon in the Neotropics remains poorly understood. Recent studies confirmed their presence in the region using molecular techniques alone, but evidence for gametocytes and data on putative competent hosts for Leucocytozoon are still lacking outside highland areas. We combined morphological and molecular data to characterize a new Leucocytozoon species infecting a non-migratory red-legged seriema (Cariama cristata), the first report of a competent host for Leucocytozoon in Brazil. Leucocytozoon cariamae n. sp. is distinguished from the Leucocytozoon fringillinarum group by its microgametocytes that are not strongly appressed to the host cell nucleus. The bird studied was coinfected with Haemoproteus pulcher, and we present a Bayesian phylogenetic analysis based on nearly complete mitochondrial genomes of these 2 parasites. Leucocytozoon cariamae n. sp. morphology is consistent with our phylogenetic analysis indicating that it does not share a recent common ancestor with the L. fringillinarum group. Haemoproteus pulcher and Haemoproteus catharti form a monophyletic group with Haemocystidium parasites of Reptilia, supporting the polyphyly of the genus Haemoproteus. We also discussed the hypothesis that H. pulcher and H. catharti may be avian Haemocystidium, highlighting the need to study non-passerine parasites to untangle the systematics of Haemosporida.
Assuntos
Doenças das Aves , Coinfecção , Genoma Mitocondrial , Haemosporida , Parasitos , Infecções Protozoárias em Animais , Animais , Filogenia , Brasil/epidemiologia , Teorema de Bayes , Infecções Protozoárias em Animais/parasitologia , Doenças das Aves/parasitologia , Haemosporida/genética , Parasitos/genética , AvesRESUMO
The Brazilian Amazon supports an extremely diverse avifauna and serves as the diversification center for avian malaria parasites in South America. Construction of hydroelectric dams can drive biodiversity loss by creating islands incapable of sustaining the bird communities found in intact forest sites. Besides anthropogenic actions, the presence of parasites can also influence the dynamics and structure of bird communities. Avian malaria (Plasmodium) and related haemosporidian parasites (Haemoproteus and Leucocytozoon) are a globally distributed group of protozoan parasites recovered from all major bird groups. However, no study to date has analyzed the presence of avian haemosporidian parasites in fragmented areas such as land bridge islands formed during artificial flooding following the construction of hydroelectric dams. The aim of this study is to assess the prevalence and molecular diversity of haemosporidians in bird communities inhabiting artificial islands in the area of the Balbina Hydroelectric Dam. The reservoir area covers 443,700 ha with 3546 islands on the left bank of the Uatumã River known to contain more than 400 bird species. We surveyed haemosporidian infections in blood samples collected from 445 understory birds, belonging to 53 species, 24 families, and 8 orders. Passeriformes represented 95.5% of all analyzed samples. We found a low overall Plasmodium prevalence (2.9%), with 13 positive samples (two Plasmodium elongatum and 11 Plasmodium sp.) belonging to eight lineages. Six of these lineages were previously recorded in the Amazon, whereas two of them are new. Hypocnemis cantator, the Guianan Warbling Antbird, represented 38.5% of all infected individuals, even though it represents only 5.6% of the sampled individuals. Since comparison with Plasmodium prevalence data prior to construction of Balbina is not possible, other studies in artificially flooded areas are imperative to test if anthropogenic flooding may disrupt vector-parasite relationships leading to low Plasmodium prevalence.
Assuntos
Doenças das Aves , Haemosporida , Malária Aviária , Parasitos , Passeriformes , Plasmodium , Humanos , Animais , Parasitos/genética , Malária Aviária/parasitologia , Ilhas , Brasil/epidemiologia , Prevalência , Doenças das Aves/epidemiologia , Doenças das Aves/parasitologia , Plasmodium/genética , Haemosporida/genética , Variação GenéticaRESUMO
The relationships between host phylogenetics, functional traits and parasites in wildlife remain poorly understood in the Neotropics, especially in habitats with marked seasonal variation. Here, we examined the effect of seasonality and host functional traits on the prevalence of avian haemosporidians (Plasmodium and Haemoproteus) in the Brazilian Caatinga, a seasonally dry tropical forest. 933 birds were evaluated for haemosporidian infections. We found a high parasitism prevalence (51.2%), which was correlated with phylogenetic relatedness among avian species. Prevalence varied drastically among the 20 well-sampled species, ranging from 0 to 70%. Seasonality was the main factor associated with infections, but how this abiotic condition influenced parasite prevalence varied according to the host-parasite system. Plasmodium prevalence increased during the rainy season and, after excluding the large sample size of Columbiformes (n = 462/933), Plasmodium infection rate was maintained high in the wet season and showed a negative association with host body mass. No association was found between non-Columbiform bird prevalence and seasonality or body mass when evaluating both Plasmodium and Haemoproteus or only Haemoproteus infections. Parasite community was composed of 32 lineages including 7 new lineages. We evidenced that even dry domains can harbour a high prevalence and diversity of vector-borne parasites and pointed out seasonality as a ruling factor.
Assuntos
Doenças das Aves , Haemosporida , Parasitos , Plasmodium , Infecções Protozoárias em Animais , Animais , Filogenia , Prevalência , Brasil/epidemiologia , Plasmodium/genética , Aves/parasitologia , Haemosporida/genética , Florestas , Doenças das Aves/epidemiologia , Doenças das Aves/parasitologia , Infecções Protozoárias em Animais/epidemiologia , Infecções Protozoárias em Animais/parasitologiaRESUMO
Haemosporidia (Apicomplexa, Haemosporida) are protozoa that infect vertebrate blood cells and are transmitted by vectors. Among vertebrates, birds possess the greatest diversity of haemosporidia, historically placed in 3 genera: Haemoproteus, Leucocytozoon and Plasmodium, the causative agent of avian malaria. In South America, existing data on haemosporidia are spatially and temporally dispersed, so increased surveillance is needed to improve the determination and diagnosis of these parasites. During the non-breeding season in 2020 and 2021, 60 common terns (Sterna hirundo) were captured and bled as part of ongoing research on the population health of migratory birds on the Argentinian Atlantic coast. Blood samples and blood smears were obtained. Fifty-eight samples were screened for Plasmodium, Haemoproteus and Leucocytozoon, as well as for Babesia parasites by nested polymerase chain reaction and by microscopic examination of smears. Two positive samples for Plasmodium were found. The cytochrome b lineages detected in the present study are found for the first time, and are close to Plasmodium lineages found in other bird orders. The low prevalence (3.6%) of haemoparasites found in this research was similar to those reported for previous studies on seabirds, including Charadriiformes. Our findings provide new information about the distribution and prevalence of haemosporidian parasites from charadriiforms in the southernmost part of South America, which remains understudied.
Assuntos
Doenças das Aves , Charadriiformes , Haemosporida , Malária Aviária , Parasitos , Plasmodium , Infecções Protozoárias em Animais , Animais , Malária Aviária/epidemiologia , Malária Aviária/parasitologia , Doenças das Aves/epidemiologia , Doenças das Aves/parasitologia , Plasmodium/genética , Haemosporida/genética , Aves/parasitologia , América do Sul/epidemiologia , Prevalência , Filogenia , Infecções Protozoárias em Animais/epidemiologia , Infecções Protozoárias em Animais/parasitologiaRESUMO
Morphological traits from blood stages have been the gold standard for determining haemosporidian parasite species. However, the status of some taxa and the value of such traits in parasites from reptiles remain contentious. The scarce sampling of these species worsens the situation, and several taxa lack molecular data. A survey was performed in the Magdalena Department in Colombia, where 16 species of reptiles were captured. A peculiar haemosporidian parasite was found in the Turnip-tailed gecko Thecadactylus rapicauda. This haemosporidian does not show malarial pigment in blood stages under light microscopy; thus, it fits the Garnia genus's characters belonging to the Garniidae. However, the phylogenetic analyses using a partial sequence of cytochrome b and the mitochondrial DNA placed it within the Plasmodium clade. Our findings suggest that many putative Garnia species belong to the genus Plasmodium, like the one reported here. This study either shows that visible malarial pigment in blood stages is not a diagnostic trait of the genus Plasmodium or malarial pigment might be present in an undetectable form under a light microscope. In any case, the current taxonomy of haemosporidian parasites in reptiles requires revision. This study highlights the importance of using molecular and morphological traits to address taxonomic questions at the species and genus levels in haemosporidian parasites from reptiles.
Assuntos
Brassica napus , Haemosporida , Lagartos , Parasitos , Plasmodium , Animais , Filogenia , Plasmodium/genética , Serpentes , Haemosporida/genéticaRESUMO
Espinilho savanna ("seasonal steppe savanna") is a unique vegetation formation of the Pampas biome that is found near the tri-border of Brazil, Uruguay, and Argentina. The Yellow Cardinal (Gubernatrix cristata) is a flagship species of this ecosystem, but it is classified as "critically endangered" in Brazil due to habitat loss and poaching for the illegal trade. Population supplementation through the release of individuals that were captive-bred or apprehended by authorities from the illegal trade has been considered as a conservation strategy for this species; however, the risk of pathogen introduction is a critical concern. We used microscopy and molecular methods to investigate the occurrence of blood parasites in wild passerines (n = 64, including three Yellow Cardinals) at Espinilho State Park, Rio Grande do Sul, Brazil, and in captive Yellow Cardinals (n = 30) at three facilities in Brazil. Haemosporidian parasites were detected in the blood smears of 10.9% of the wild passerines, comprising the morphospecies Haemoproteus erythrogravidus in Rufous-collared Sparrow (Zonotrichia capensis), H. quiscalus in Grayish Baywing (Agelaioides badius), and H. tyranni in Great Kiskadee (Pitangus sulphuratus); these are the southernmost records for these morphospecies and their first record for the Pampas biome. No haemosporidian parasites were detected in the blood smears of the Yellow Cardinals, wild or captive. Microfilariae were detected in the blood smears of 14.1% of the wild passerines, including all wild Yellow Cardinals, and in 43.3% of captive Yellow Cardinals. Trypanosoma sp. was detected in the blood smear of one captive Yellow Cardinal. Nested PCR and gene sequencing of the cyt-b gene of Haemoproteus/Plasmodium was used to test a subset of wild passerines and captive Yellow Cardinals, allowing for the molecular barcoding of H. quiscalus lineage AGEBAD04 and H. tyranni lineage PITSUL01; additionally, DNA identical to that of lineage PITSUL01 was detected in the blood of one captive Yellow Cardinal. This study provides valuable data to support the conservation management of the Yellow Cardinal and other threatened passerines from the Pampas and highlights the need for further studies on the epidemiology and pathology of filarioid worms and trypanosomes in passerines from this biome.
Assuntos
Doenças das Aves , Haemosporida , Lepidópteros , Parasitos , Infecções Protozoárias em Animais , Pardais , Animais , Doenças das Aves/parasitologia , Brasil , Suplementos Nutricionais , Ecossistema , Haemosporida/genética , Parasitos/genética , Filogenia , Infecções Protozoárias em Animais/epidemiologia , Infecções Protozoárias em Animais/parasitologiaRESUMO
Migratory birds are implicated in dispersing haemosporidian parasites over great geographic distances. However, their role in sharing these vector-transmitted blood parasites with resident avian host species along their migration flyway is not well understood. We studied avian haemosporidian parasites in 10 localities where Chilean Elaenia, a long-distance Neotropical austral migrant species, spends part of its annual cycle to determine local parasite transmission among resident sympatric host species in the elaenia's distributional range across South America. We sampled 371 Chilean Elaenias and 1,818 birds representing 243 additional sympatric species from Brazilian wintering grounds to Argentinian breeding grounds. The 23 haemosporidian lineages found in Chilean Elaenias exhibited considerable variation in distribution, specialization, and turnover across the 10 avian communities in South America. Parasite lineage dissimilarity increased with geographic distance, and infection probability by Parahaemoproteus decreased in localities harbouring a more diverse haemosporidian fauna. Furthermore, blood smears from migrating Chilean Elaenias and local resident avian host species did not contain infective stages of Leucocytozoon, suggesting that transmission did not take place in the Brazilian stopover site. Our analyses confirm that this Neotropical austral migrant connects avian host communities and transports haemosporidian parasites along its distributional range in South America. However, the lack of transmissive stages at stopover site and the infrequent parasite lineage sharing between migratory host populations and residents at breeding and wintering grounds suggest that Chilean Elaenias do not play a significant role in dispersing haemosporidian parasites, nor do they influence local transmission across South America.
Assuntos
Doenças das Aves , Haemosporida , Parasitos , Passeriformes , Plasmodium , Animais , Prevalência , Chile/epidemiologia , Doenças das Aves/epidemiologia , Doenças das Aves/parasitologia , Haemosporida/genética , FilogeniaRESUMO
Great-tailed Grackles (Quiscalus mexicanus) are a social, polygamous bird species whose populations have rapidly expanded their geographic range across North America over the past century. Before 1865, Great-tailed Grackles were only documented in Central America, Mexico, and southern Texas in the USA. Given the rapid northern expansion of this species, it is relevant to study its role in the dynamics of avian blood parasites. Here, 87 Great-tailed grackles in Arizona (a population in the new center of the range) were screened for haemosporidian parasites using microscopy and PCR targeting the parasite mitochondrial cytochrome b gene. Individuals were caught in the wild from January 2018 until February 2020. Haemosporidian parasite prevalence was 62.1% (54/87). A high Plasmodium prevalence was found (60.9%, 53/87), and one grackle was infected with Haemoproteus (Parahaemoproteus) sp. (lineage SIAMEX01). Twenty-one grackles were infected with P. cathemerium, sixteen with P. homopolare, four with P. relictum (strain GRW04), and eleven with three different genetic lineages of Plasmodium spp. that have not been characterized to species level (MOLATE01, PHPAT01, and ZEMAC01). Gametocytes were observed in birds infected with three different Plasmodium lineages, revealing that grackles are competent hosts for some parasite species. This study also suggests that grackles are highly susceptible and develop chronic infections consistent with parasite tolerance, making them competent to transmit some generalist haemosporidian lineages. It can be hypothesized that, as the Great-tailed Grackle expands its geographic range, it may affect local bird communities by increasing the transmission of local parasites but not introducing new species into the parasite species pool.
Assuntos
Doenças das Aves , Haemosporida , Malária Aviária , Parasitos , Passeriformes , Plasmodium , Animais , Doenças das Aves/epidemiologia , Haemosporida/genética , Humanos , Malária Aviária/epidemiologia , Filogenia , Plasmodium/genética , Prevalência , TexasRESUMO
South America has different biomes with a high richness of wild bird species and Diptera vectors, representing an ideal place to study the influence of habitat on vector-borne parasites. In order to better understand how different types of habitats do or do not influence the prevalence of haemosporidians, we performed a new analysis of two published datasets comprising wild birds from the Brazilian Savanna (Cerrado) as well as wild birds from the Venezuelan Arid Zone. We investigated the prevalence and genetic diversity of haemosporidian parasites belonging to two genera: Plasmodium and Haemoproteus. We evaluated data from 676 wild birds from the Cerrado and observed an overall prevalence of 49%, whereas, in the Venezuelan Arid Zone, we analyzed data from 527 birds and found a similar overall prevalence of 43%. We recovered 44 lineages, finding Plasmodium parasites more prevalent in the Cerrado (15 Plasmodium and 12 Haemoproteus lineages) and Haemoproteus in the Venezuelan Arid Zone (seven Plasmodium and 10 Haemoproteus lineages). No difference was observed on parasite richness between the two biomes. We observed seven out of 44 haemosporidian lineages that are shared between these two distinct South American biomes. This pattern of parasite composition and prevalence may be a consequence of multiple factors, such as host diversity and particular environmental conditions, especially precipitation that modulate the vector's dynamics. The relationship of blood parasites with the community of hosts in large and distinct ecosystems can provide more information about what factors are responsible for the variation in the prevalence and diversity of these parasites in an environment.
Assuntos
Doenças das Aves , Haemosporida , Malária , Parasitos , Plasmodium , Animais , Parasitos/genética , Ecossistema , Prevalência , Doenças das Aves/epidemiologia , Plasmodium/genética , Haemosporida/genética , Malária/epidemiologia , Brasil/epidemiologia , Aves/parasitologiaRESUMO
Haemosporidian parasites are common in birds but are seldom reported in seabirds. The absence of vectors or genetic resistance to infection have been proposed to explain this pattern. However, screening of blood parasites in many seabirds has been done only by visual inspection of blood smears, which can miss low-intensity infections, and molecular detection of blood parasites must be supported by detection in blood smears to confirm the presence of haemosporidians and avoid false positive cases. Here, we tested for the presence of blood parasites of the genera Plasmodium, Haemoproteus and Leucocytozoon, combining inspection of blood smears and PCR-based detection methods in a highly philopatric colony of blue-footed boobies (Sula nebouxii) in the Tropical North Pacific. Our results indicate that adults in this colony are likely free of these blood parasites, probably due to unsuitable conditions for insect vectors in booby breeding sites, although potential genetic resistance of blue-footed boobies to infection deserves examination. Apparent absence of blood parasites in Isla Isabel boobies indirectly adds to the growing evidence of variation in parasite infections among avian host species that coexist locally.
Assuntos
Haemosporida , Malária Aviária , Parasitos , Animais , Aves/parasitologia , Cruzamento , Haemosporida/genética , Malária Aviária/parasitologiaRESUMO
Avian haemosporidian from the genera Haemoproteus and Plasmodium are a diverse and widely distributed group of vector-borne blood parasites. These parasites can have negative effects on bird survival by influencing several aspects of their life cycle, causing different clinical signs and even death. Colombia has the widest range of bird richness throughout the globe; however, the associations between haemosporidian parasites and wild birds in different ecosystems remain poorly explored. Within this frame of reference, the objective of the present study was to identify and understand haemosporidian associated with resident and migratory wild birds and their lineages in northeast Orinoquia region, Colombia. Birds were captured in 8 localities and blood samples were collected, identifying the presence of haemosporidian parasites through morphological and molecular analysis of the mitochondrial cytochrome b gene. Blood samples from 233 wild birds (86 species) were analyzed for haemosporidian parasites. Sixteen individuals (6.9%) from 15 resident and migratory species were positive for Haemoproteus or Plasmodium. Fourteen haemosporidian lineages were identified, five of them reported for the first time. These new lineages are reported in four resident birds and one boreal migratory bird (Parkesia noveboracensis). This study is the first developed in the department of Arauca and contributes to the knowledge of haemosporidian lineages and their interaction with wild birds in the Colombian Orinoquia region and South America.
Assuntos
Doenças das Aves , Haemosporida , Parasitos , Plasmodium , Infecções Protozoárias em Animais , Animais , Animais Selvagens , Doenças das Aves/epidemiologia , Doenças das Aves/parasitologia , Aves/parasitologia , Colômbia/epidemiologia , Ecossistema , Haemosporida/genética , Humanos , Filogenia , Plasmodium/genética , Prevalência , Infecções Protozoárias em Animais/epidemiologia , Infecções Protozoárias em Animais/parasitologiaRESUMO
The order Piroplasmida, including the genera Babesia, Cytauxzoon, and Theileria is often referred to as piroplasmids and comprises of dixenous hemoprotozoans transmitted by ticks to a mammalian or avian host. Although piroplasmid infections are usually asymptomatic in wild animals, in domestic animals, they cause serious or life-threatening consequences resulting in fatalities. Piroplasmids are particularly notorious for the enormous economic loss they cause worldwide in livestock production, the restrictions they pose on horse trade, and the negative health impact they have on dogs and cats. Furthermore, an increasing number of reported human babesiosis cases are of growing concern. Considerable international research and epidemiological studies are done to identify existing parasite species, reveal their phylogenetic relationships, and develop improved or new drugs and vaccines to mitigate their impact. In this review, we present a compilation of all piroplasmid species, isolates, and species complexes that infect domestic mammals and which have been well defined by molecular phylogenetic markers. Altogether, 57 taxonomic piroplasmid entities were compiled, comprising of 43 piroplasmid species, 12 well-defined isolates awaiting formal species description, and two species complexes that possibly mask additional species. The extrapolation of the finding of at least 57 piroplasmid species in only six domestic mammalian groups (cattle, sheep, goat, horse, dog, and cat) allows us to predict that a substantially higher number of piroplasmid parasites than vertebrate host species exist. Accordingly, the infection of a vertebrate host species by multiple piroplasmid species from the same and/or different phylogenetic lineages is commonly observed. Molecular phylogeny using 18S rRNA genes of piroplasmids infecting domestic mammals results in the formation of six clades, which emerge due to an anthropocentric research scope, but not due to a possibly assumed biological priority position. Scrutinizing the topology of inferred trees reveals stunning insights into some evolutionary patterns exhibited by this intriguing group of parasites. Contrary to expectations, diversification of parasite species appears to be dominated by host-parasite cospeciation (Fahrenholz's rule), and, except for piroplasmids that segregate into Clade VI, host switching is rarely observed. When only domestic mammalian hosts are taken into account, Babesia sensu lato (s.l.) parasites of Clades I and II infect only dogs and cats, respectively, Cytauxzoon spp. placed into Clade III only infect cats, Theileria placed into Clade IV exclusively infect horses, wheras Theileria sensu stricto (s.s.) of Clade V infects only cattle and small ruminants. In contrast, Babesia s.s. parasites of Clade VI infect all farm and companion animal species. We outline how the unique ability of transovarial transmission of Babesia s.s. piroplasmids of Clade VI facilitates species diversification by host switching to other host vertebrate species. Finally, a deterioration of sequence fidelity in databases is observed which will likely lead to an increased risk of artifactual research in this area. Possible measures to reverse and/or avoid this threat are discussed.
Assuntos
Babesia , Babesiose , Doenças do Gato , Doenças do Cão , Haemosporida , Piroplasmida , Theileria , Animais , Babesiose/parasitologia , Gatos , Bovinos , Doenças do Cão/parasitologia , Cães , Fazendas , Haemosporida/genética , Cavalos , Mamíferos , Filogenia , RNA Ribossômico 18S/genética , Ovinos/genética , Theileria/genéticaRESUMO
Parasites of the genus Haemoproteus have been reported in almost all avian clades and zoogeographic regions, except Antarctica. However, despite the large number of reports worldwide, they are poorly studied in the Neotropical region, which includes the Atlantic Forest, a biodiversity hotspot with more than 890 bird species, of which 24% are endemic. Haemoproteus (Haemoproteus) paramultipigmentatus was described by morphological and molecular analyses in 2013 infecting Columbiform birds in Mexico. However, since the original description this parasite has not been studied in detail. Here, we investigate the prevalence of Haemoproteus spp. in Brazilian Columbiformes and conducted a taxonomic integrative study of the species Haemoproteus (Haemoproteus) paramultipigmentatus, including new morphological and molecular data from a Brazilian population. Moreover, we provide discussions about the geographic distribution and phylogenetic relationships between different lineages of this parasite. Our findings demonstrated a high prevalence of Haemoproteus spp. infection in Brazilian Columbiformes, which is in accordance with previous studies. Morphological characterization of H. paramultipigmentatus revealed minor differences from the original description. Through molecular and phylogenetic analyses we identified a new lineage of H. paramultipigmentatus that was added to the genetic databases. Our findings also suggest a new geographical distribution for this hemoparasite, including South American countries, and raise discussions about its current distribution.
Assuntos
Doenças das Aves/epidemiologia , Columbidae , Haemosporida/classificação , Interações Hospedeiro-Parasita , Infecções Protozoárias em Animais/epidemiologia , Animais , Animais Selvagens , Doenças das Aves/parasitologia , Brasil , Citocromos b/análise , Haemosporida/genética , Haemosporida/isolamento & purificação , Prevalência , Infecções Protozoárias em Animais/parasitologia , Proteínas de Protozoários/análiseRESUMO
The specialist versus generalist strategies of hemoparasites in relation to their avian host, as well as environmental factors, can influence their prevalence, diversity and distribution. In this paper we investigated the influence of avian host species, as well as the environmental and geographical factors, on the strategies of Haemoproteus and Plasmodium hemoparasites. We determined prevalence and diversity by targeting their cytochrome b (Cytb) in a total of 2,590 passerine samples from 138 localities of Central and South America, and analysed biogeographic patterns and host-parasite relationships. We found a total prevalence of 23.2%. Haemoproteus presented a higher prevalence (15.3%) than Plasmodium (4.3%), as well as a higher diversity and host specificity. We determined that Plasmodium and Haemoproteus prevalences correlated positively with host diversity (Shannon index) and were significantly influenced by bird diversity, demonstrating a possible "amplification effect". We found an effect of locality and the avian family for prevalences of Haemoproteus and Plasmodium. These results suggest that Haemoproteus is more specialist than Plasmodium and could be mostly influenced by its avian host and the Andes Mountains.
Assuntos
Doenças das Aves , Haemosporida , Malária Aviária , Parasitos , Plasmodium , Infecções Protozoárias em Animais , Animais , Doenças das Aves/epidemiologia , Haemosporida/genética , Malária Aviária/epidemiologia , Filogenia , Plasmodium/genética , PrevalênciaRESUMO
The transmission of vector-borne protozoa such as parasites of the Order Haemosporida is dependent on both biotic and abiotic factors such as host life history traits and environmental conditions. This study aimed to identify the variables that determine haemosporidian prevalence, parasitaemia and aggregation within the context of elevation and avian life history traits in Central Veracruz, Mexico. We sampled 607 birds from 88 species; we used microscopy and the mtDNA cytochrome b gene to detect parasites. We found an overall prevalence of 32.3%. Haemosporidian prevalence was 21.6% in tropical sub-deciduous forest (at sea level), 38% in tropical deciduous forest (265 m above sea level (asl)), 19.4% in montane cloud forest (1630 m asl), and 51.7% in pine-oak forest (2790 m asl). The prevalence of each parasite genus was strongly influenced by elevation (a proxy of habitat type). Plasmodium showed the highest prevalence at low elevation. Haemoproteus increased in prevalence with elevation. Leucocytozoon displayed the highest prevalence at the highest elevation (pine-oak forest). Haemoproteus spp. and Leucocytozoon spp. prevalences were higher in open cup than in closed nests. Haemoproteus prevalence and haemosporidian parasitaemia were lower in solitary birds than birds with pairing and gregarious behavior. Haemosporidian aggregation decreased with elevation, yielding the significantly lowest values at the pine-oak forest. Elevation distribution patterns of prevalence for each genus were similar to those previously reported in other geographical areas (e.g., South America, Europe).
Assuntos
Doenças das Aves , Haemosporida , Características de História de Vida , Animais , Doenças das Aves/epidemiologia , Aves , DNA de Protozoário/genética , Haemosporida/genética , Filogenia , PrevalênciaRESUMO
Studies contrasting parasite prevalence and host-parasite community structure between pristine and disturbed environments will improve our understanding of how deforestation affects disease transmission and parasite extinction. To determine how infection rates of a common and diverse group of avian blood parasites (Plasmodium and Haemoproteus) respond to changes in avian host composition after mining, we surveyed 25 bird communities from pristine forests (two forest types: plateau and hillside) and reforested sites in Northeast Amazonia. Infection rates and both parasite and avian host community structure exhibited considerable variation across the deforestation gradient. In opposition to the emerging pattern of lower avian haemosporidian prevalence in disturbed tropical forests in Africa, we show that secondary forests had higher haemosporidian prevalence in one of the largest mining areas of Amazonia. The dissimilarity displayed by bird communities may explain, in part, the higher prevalence of Haemoproteus in reforested areas owing to the tolerance of some bird species to open-canopy forest habitat. On the other hand, deforestation may cause local extinction of Plasmodium parasites due to the loss of their avian hosts that depend on closed-canopy primary forest habitats. Our results demonstrate that forest loss induced by anthropogenic changes can affect a host-parasite system and disturb both parasite transmission and diversity.
Assuntos
Apicomplexa/isolamento & purificação , Doenças das Aves/epidemiologia , Interações Hospedeiro-Parasita , Animais , Apicomplexa/genética , Biodiversidade , Doenças das Aves/parasitologia , Doenças das Aves/transmissão , Aves , Brasil/epidemiologia , Código de Barras de DNA Taxonômico/veterinária , Ecossistema , Florestas , Geografia , Haemosporida/genética , Haemosporida/isolamento & purificação , Mineração , Plasmodium/genética , Plasmodium/isolamento & purificação , PrevalênciaRESUMO
A number of evolutionary hypotheses can be tested by comparing selective pressures among sets of branches in a phylogenetic tree. When the question of interest is to identify specific sites within genes that may be evolving differently, a common approach is to perform separate analyses on subsets of sequences and compare parameter estimates in a post hoc fashion. This approach is statistically suboptimal and not always applicable. Here, we develop a simple extension of a popular fixed effects likelihood method in the context of codon-based evolutionary phylogenetic maximum likelihood testing, Contrast-FEL. It is suitable for identifying individual alignment sites where any among the K≥2 sets of branches in a phylogenetic tree have detectably different ω ratios, indicative of different selective regimes. Using extensive simulations, we show that Contrast-FEL delivers good power, exceeding 90% for sufficiently large differences, while maintaining tight control over false positive rates, when the model is correctly specified. We conclude by applying Contrast-FEL to data from five previously published studies spanning a diverse range of organisms and focusing on different evolutionary questions.