A novel Haemosporida clade at the rank of genus in North American cranes (Aves: Gruiformes)

Novel phylogenetic clade of avian Haemoproteus parasites (Haemosporida, Haemoproteidae) from Accipitridae raptors, with description of a new Haemoproteus species

Avian haemosporidian parasites (order Haemosporida, phylum Apicomplexa) are blood and tissue parasites transmitted by blood-sucking dipteran insects. Three genera (Plasmodium, Haemoproteus and Leucocytozoon) have been most often found in birds, with over 270 species described and named in avian hosts based mainly on the morphological characters of blood stages. A broad diversity of Haemoproteus parasites remains to be identified and characterized morphologically and molecularly, especially those infecting birds of prey, an underrepresented bird group in haemosporidian parasite studies. The aim of this study was to investigate and identify Haemoproteus parasites from a large sample comprising accipitriform raptors of 16 species combining morphological and new molecular protocols targeting the cytb genes of this parasite group. This study provides morphological descriptions and molecular characterizations of two Haemoproteus species, H. multivacuolatus n. sp. and H. nisi Peirce and Marquiss, 1983. Haemoproteus parasites of this group were so far found in accipitriform raptors only and might be classified into a separate subgenus or even genus. Cytb sequences of these parasites diverge by more than 15% from those of all others known avian haemosporidian genera and form a unique phylogenetic clade. This study underlines the importance of developing new diagnostic tools to detect molecularly highly divergent parasites that might be undetectable by commonly used conventional tools.

Origin and diversity of malaria parasites and other Haemosporida

Symbionts, including parasites, are ubiquitous in all world ecosystems. Understanding the diversity of symbiont species addresses diverse questions, from the origin of infectious diseases to inferring processes shaping regional biotas. Here, we review the current approaches to studying Haemosporida's species diversity and evolutionary history. Despite the solid knowledge of species linked to diseases, such as the agents of human malaria, studies on haemosporidian phylogeny, diversity, ecology, and evolution are still limited. The available data, however, indicate that Haemosporida is an extraordinarily diverse and cosmopolitan clade of symbionts. Furthermore, this clade seems to have originated with their vertebrate hosts, particularly birds, as part of complex community level processes that we are still characterizing.

Haemosporidian Parasites of White-Breasted Waterhens (Amaurornis phoenicurus), with a Report and Molecular Characterization of Haemoproteus gallinulae in Thailand

Haemosporidian parasites are vector-borne parasites infecting terrestrial vertebrates as well as avian species, such as the White-breasted Waterhen, a Gruiformes waterbird found in lowlands near wetlands and distributed throughout Thailand. However, information regarding haemosporidia infection in this species is lacking. To establish regional information, 17 blood samples were collected from White-breasted Waterhens. Four haemoparasite lineages were identified in six blood samples: Haemoproteus gallinulae, Plasmodium collidatum, Plasmodium elongatum, and an unidentified Plasmodium species. H. gallinulae was characterized with morphological features in White-breasted Waterhens for the first time; the morphological characteristics were consistent with previous descriptions. H. gallinulae was more closely related to Haemoproteus species of Passeriformes birds than to those of Gruiformes birds. The Plasmodium parasites infecting these White-breasted Waterhens previously caused severe avian malaria in other host species. The unidentified Plasmodium species had rarely been documented, although it was reported in the Culex vector and was possibly associated with specialist parasites either as host or habitat. Our findings reveal multiple haemosporidian species reflecting the role of this avian host as a carrier of haemosporidians. This study offers species records and molecular materials that may provide critical information for further targeted research into these haemosporidia.

Haemosporidians in Non-Passerine Birds of Colombia: An Overview of the Last 20 Years of Research

The Neotropics are highly diverse in avian species. Neotropical countries contribute a large part of the estimated diversity of haemosporidian parasites reported for the planet’s tropical zones. However, sampling is limited and biased, illustrated by only 30% of the genetic records (barcodes) from non-passerines, most of them not linked to a nominal species. This paper aimed to perform the molecular and morphological characterization of the haemosporidians that infect non-passerine birds from Colombia deposited in the biological collection named “Grupo de Estudio Relación Parásito Hospedero (GERPH)”. We analyzed 1239 samples from twelve biomes and two animal care facilities. Phylogenetic relationships using barcodes and mitochondrial genomes were estimated. In addition, the reports of haemosporidian infections in non-passerine birds from the Neotropics recorded after 1978 were summarized. We reported the presence of thirteen morphological haemosporidian species, four potential new species deposited in GERPH, a host range expansion for two Plasmodium species, and a barcode sequence for Haemoproteus caprimulgi. We confirmed the species associated with 56 molecular lineages reported in other neotropical countries at the genus level. Thus, biological collections and curated databases such as MalAvi are essential to support integrative approaches demanded in modern taxonomy.

Keys to the avian Haemoproteus parasites (Haemosporida, Haemoproteidae)

BACKGROUND

Haemoproteus is a sister genus to malaria parasites (Plasmodium), which both belong to the order Haemosporida (Apicomplexa). Parasites of both genera are flourishing in birds, however, Haemoproteus species are noticeably less investigated. This is unfortunate because knowledge about close relatives of malaria pathogens is important for better understanding the evolutionary origin and basic biological features of the entire group of haemosporidian infections. Moreover, recent findings show that Haemoproteus species can cause severe damage of various bird organs due to megalomeronts and other exo-erythrocytic stages. These haemosporidians are remarkably diverse, but remain neglected partly due to difficulties in species identification. Hundreds of Haemoproteus genetic lineages have been reported in birds, and numerous new lineages are found each year, but most remain unidentified to the species level. Numerous new Haemoproteus pathogens were described during the past 20 years. However, keys for their identification are absent. Identification of Haemoproteus species remains a difficult task and is an obstacle for better understanding of the distribution and epidemiology of these parasites. This study aimed to develop comprehensive keys for the identification of described avian Haemoproteus species using morphological features of their blood stages (gametocytes).

METHODS

Type and voucher preparations of avian Haemoproteus species were accessed in museums in Europe, Australia and the USA. Gametocytes of most described species were examined, and these data formed a background for this study. The data also were considered from published articles containing parasite species descriptions. The method of dichotomous keys was applied. The most difficult steps in the keys were accompanied with references to the corresponding parasite pictures.

RESULTS

In all, 201 published articles were included in this review. Morphological diagnostic features of gametocytes of all described Haemoproteus species were analysed and compared. Illustrated keys for identification of these parasite species were developed. Available information about the molecular characterization of Haemoproteus parasites was provided.

CONCLUSION

This review shows that 177 described species of avian Haemoproteus can be distinguished and identified in blood films using morphological characters of their gametocytes and host cells. These species were incorporated in the keys. Information about possible morphologically cryptic parasites was provided. Molecular markers are available for only 42% of the described Haemoproteus parasites, calling for researchers to fill this gap.

A new haemosporidian parasite from the Red-legged Seriema Cariama cristata (Cariamiformes, Cariamidae)

Haemoproteids (Haemosporida, Haemoproteidae) are a diverse group of avian blood parasites that are transmitted by hematophagous dipterans. In this study, we describe Haemoproteus pulcher sp. nov. from a Red-legged Seriema (Cariama cristata) in southeast Brazil. Analysis of the mitochondrial cytb gene indicates this parasite is closely related to Haemoproteus catharti (from Turkey Vulture, Cathartes aura) and the unidentified haemosporidian lineages PSOOCH01 (from Pale-winged Trumpeter, Psophia leucoptera) and MYCAME08 (from Wood Stork, Mycteria americana). This group of parasites appears to represent an evolutionary lineage that is distinct from other Haemoproteus spp., being instead more closely related to Haemocystidium spp. (from reptiles), Plasmodium spp. (from reptiles, birds, and mammals) and other mammal-infecting haemosporidians (Nycteria, Polychromophilus, and Hepatocystis). Current evidence suggests that parasites of this newly discovered evolutionary lineage may be endemic to the Americas, but further studies are necessary to clarify their taxonomy, life cycle, vectors, hosts, geographic distribution and host health effects. Additionally, it should be borne in mind that some PCR protocols targeting the cytb gene might not reliably detect H. pulcher due to low primer affinity.

Is Haemoproteus gabaldoni a valid species? An approach from morphology and molecular tools applied to parasites of Anseriformes

Currently, there are three recognized species of haemoproteids infecting Anseriformes: Haemoproteus nettionis, H. macrovacuolatus, and H. greineri. Unfortunately, genetic information associated with a morphotype is available only for H. macrovacuolatus. We recently found a parasite morphologically compatible with Haemoproteus gabaldoni, a species Bennet (1993) described in a Cairina moschata (Muscovy duck) from Venezuela. This species was synonymized to H. nettionis by Valkiūnas (2005), arguing not enough morphological differentiation between them; it was said that H. greineri could be as well a synonym of H. nettionis. In this study, we aimed to provide evidence to determine if Haemoproteus gabaldoni is a different species of H. nettionis and help to clarify other species status. We first performed morphological and morphometrical analyses and compared this information against the parahapantotypes of H. greineri, H. gabaldoni and material diagnosed as H. nettionis provided by the International Reference center for Avian Haematozoa (IRCAH), and H. macrovacuolatus from the Host-Parasite Relationship Study Group (GERPH, in Spanish Grupo de Estudio Relación Parásito Hospedero) biological collection. We used Principal Component Analysis (PCA) of dimensionless standard morphometrical variables from gametocytes. Furthermore, we amplified a small fragment of cytochrome b (cyt b) to compare the sequence with information in GenBank and Malavi through phylogenetic analyses and haplotype networks. PCA analyses revealed the presence of three distinct groups in the samples studied, supported in the morphological traits of each parasite species analyzed; phylogenetic analyses grouped parasite lineages separately according to the host and continent of provenance. Such results indicate that, H. gabaldoni, is a different species from H. nettionis. One more time, it is demonstrated the importance of linking barcode surveys to morphological studies. Finally, it is highlighted the importance of biological collections as repositories of worldwide biodiversity.

Haemosporidia of grey crowned cranes in Rwanda

Grey crowned cranes (Balearica regulorum) have been facing significant and long-term population declines in East Africa. Studies of Haemosporidian infections are essential to gain insight into pathogenic threats and help infer vector-host relationships, resolve parasite relationships, and support conservation efforts. As part of a program to reintroduce captive cranes in Rwanda back to their natural habitats, through health checks and initial microscopic examination, 120 grey crowned cranes were selected under suspicion of harboring Haemosporidian infections following initial peripheral blood smear examinations. Of these, 104 were infected with Haemoproteus and 3 were coinfected with Leucocytozoon as detected by PCR and microscopy. Sequencing allowed us to identify 2 distinct unreported lineages of Haemoproteus antigonis and one lineage of Leucocytozoon in the subspecies of Grey Crowned Cranes endemic to East Africa, B. r. gibbericeps. Molecularly, our two lineages of Haemoproteus antigonis differ by 32 base pairs and matched with about 95 percent identity to previously reported sequences of H. antigonis found in other species of cranes. No visible morphologic differences were found when compared to images of H. antigonis from previous studies. Our work demonstrates not only a need for increased testing within the family Gruidae, but also to investigate the possibility of cryptic speciation within the morphospecies Haemoproteus antigonis.

Neglected parasite reservoirs in wetlands: Prevalence and diversity of avian haemosporidians in waterbird communities in Northeast China

The diversity of waterbirds is threatened, and haemosporidian parasite infection is considered one of the most important causative factors. However, to date, only a few studies focusing on specific parasite species have been carried out, which cannot reflect the general patterns at the community level. To test whether the reported haemosporidian diversity in waterbirds is underestimated, we estimated the prevalence and lineage diversity of avian haemosporidian parasites in 353 waterbirds from 26 species in the Tumuji National Nature Reserve, Northeast China, as well as the host-parasite associations. According to the molecular analysis of cytochrome b (cyt b) barcode sequences, 28.3% of the birds were infected by 49 distinct parasite lineages, including 11 Plasmodium, 12 Haemoproteus, and 26 Leucocytozoon lineages, of which 39 were novel. The highest prevalence was contributed by Leucocytozoon (13.31%), followed by Plasmodium (13.03%) and Haemoproteus (4.25%), which suggested that waterbirds were infected to a lesser extent by Haemoproteus than by the other two genera. Among the most sampled birds, species belonging to Anatidae appeared to be susceptible to Leucocytozoon but resistant to Plasmodium, while Rallidae presented the opposite pattern. On the phylogenetic tree, most of the Leucocytozoon lineages detected in Anatidae clustered together and formed two well-supported clades, while lineages restricted to Gruidae were distantly related to other parasites in all three genera. SW5 was the most abundant lineage and therefore might be a major threat to waterbirds; among the hosts, the common coot harboured the highest diversity of parasite lineages and thus could act as a reservoir for potential transmission. This is the first study of avian haemosporidian infections in a wild waterbird community in Asia. Our findings have doubled the number of lineages recorded in waterbirds, broadened our understanding of host-parasite associations, and addressed the importance of studying haemosporidian infections in wild waterbird conservation.

A phylogenetic study of Haemocystidium parasites and other Haemosporida using complete mitochondrial genome sequences

Haemosporida are diverse vector-borne parasites associated with terrestrial vertebrates. Driven by the interest in species causing malaria (genus Plasmodium), the diversity of avian and mammalian haemosporidian species has been extensively studied, relying mostly on mitochondrial genes, particularly cytochrome b. However, parasites from reptiles have been neglected in biodiversity surveys. Reptilian haemosporidian parasites include Haemocystidium, a genus that shares morphological features with Plasmodium and Haemoproteus. Here, the first complete Haemocystidium mitochondrial DNA (mtDNA) genomes are studied. In particular, three mtDNA genomes from Haemocystidium spp. sampled in Africa, Oceania, and South America, are described. The Haemocystidium mtDNA genomes showed a high A + T content and a gene organization, including an extreme fragmentation of the rRNAs, found in other Haemosporida. These Haemocystidium mtDNA genomes were incorporated in phylogenetic and molecular clock analyses together with a representative sample of haemosporidian parasites from birds, mammals, and reptiles. The recovered phylogeny supported Haemocystidium as a monophyletic group apart from Plasmodium and other Haemosporida. Both the phylogenetic and molecular clock analyses yielded results consistent with a scenario in which haemosporidian parasites radiated with modern birds. Haemocystidium, like mammalian parasite clades, seems to originate from host switches by avian Haemosporida that allowed for the colonization of new vertebrate hosts. This hypothesis can be tested by investigating additional parasite species from all vertebrate hosts, particularly from reptiles. The mtDNA genomes reported here provide baseline data that can be used to scale up studies in haemosporidian parasites of reptiles using barcode approaches.

Haemosporidian Parasites of Chilean Ducks: The Importance of Biogeography and Nonpasserine Hosts

Biogeography is known to have shaped the diversity and evolutionary history of avian haemosporidian parasites across the Neotropics. However, a paucity of information exists for the temperate Neotropics and especially from nonpasserine hosts. To understand the effect of biogeography in the temperate Neotropics on haemosporidians of nonpasserine hosts we screened ducks (Anseriformes) from central Chile for the presence of these parasites. Forty-two individuals of 4 duck species (Anas flavirostris, Anas georgica, Mareca sibilatrix, Spatula cyanoptera cyanoptera) were collected and assessed for haemosporidian parasite infections by real-time polymerase chain reaction screening and subsequent sequencing of the mitochondrial cytochrome b gene. Haemoproteus (subgenus Haemoproteus) and Plasmodium were detected in 2 host species, A. georgica and S. c. cyanoptera, with no Leucocytozoon found. Overall haemosporidian prevalence was low (14.2%), with the prevalence of Plasmodium (11.9%) being substantially greater than that of Haemoproteus (4.8%). Six haemosporidian cytochrome b lineages were recovered, 2 Haemoproteus and 4 Plasmodium, with all 6 lineages identified for the first time. In phylogenetic reconstruction, the Chilean Plasmodium lineages were more closely related to South American lineages from passerine birds than to known lineages from anseriforms. The subgenus Haemoproteus known from nonpasseriformes has never been identified from any anseriform host; however, we recovered 2 lineages from this subgenus, one from each A. georgica and S. c. cyanoptera. Further work is needed to determine if this presents true parasitism in ducks or only a spillover infection. The results of phylogenetic reconstruction demonstrate a unique evolutionary history of these Chilean parasites, differing from what is known for this host group. The unique geography of Chile, with a large part of the country being relatively isolated by the Atacama Desert in the north and the Andes in the east and south, would present opportunities for parasite diversification. Further work is needed to investigate how strongly the biogeographical isolation has shaped the haemosporidian parasites of this area. Our results add to the growing body of evidence that nonpasserine hosts support unique lineages of haemosporidian parasites, while also demonstrating the role of biogeography in haemosporidian parasite diversity in the temperate Neotropics.

Evolutionary ecology, taxonomy, and systematics of avian malaria and related parasites

Haemosporidian parasites of the genera Plasmodium, Leucocytozoon, and Haemoproteus are one of the most prevalent and widely studied groups of parasites infecting birds. Plasmodium is the most well-known haemosporidian as the avian parasite Plasmodium relictum was the original transmission model for human malaria and was also responsible for catastrophic effects on native avifauna when introduced to Hawaii. The past two decades have seen a dramatic increase in research on avian haemosporidian parasites as a model system to understand evolutionary and ecological parasite-host relationships. Despite haemosporidians being one the best studied groups of avian parasites their specialization among avian hosts and variation in prevalence amongst regions and host taxa are not fully understood. In this review we focus on describing the current phylogenetic and morphological diversity of haemosporidian parasites, their specificity among avian and vector hosts, and identifying the determinants of haemosporidian prevalence among avian species. We also discuss how these parasites might spread across regions due to global climate change and the importance of avian migratory behavior in parasite dispersion and subsequent diversification.

Mode and Rate of Evolution of Haemosporidian Mitochondrial Genomes: Timing the Radiation of Avian Parasites

Haemosporidians are a diverse group of vector-borne parasitic protozoa that includes the agents of human malaria; however, most of the described species are found in birds and reptiles. Although our understanding of these parasites’ diversity has expanded by analyses of their mitochondrial genes, there is limited information on these genes’ evolutionary rates. Here, 114 mitochondrial genomes (mtDNA) were studied from species belonging to four genera: Leucocytozoon, Haemoproteus, Hepatocystis, and Plasmodium. Contrary to previous assertions, the mtDNA is phylogenetically informative. The inferred phylogeny showed that, like the genus Plasmodium, the Leucocytozoon and Haemoproteus genera are not monophyletic groups. Although sensitive to the assumptions of the molecular dating method used, the estimated times indicate that the diversification of the avian haemosporidian subgenera/genera took place after the Cretaceous–Paleogene boundary following the radiation of modern birds. Furthermore, parasite clade differences in mtDNA substitution rates and strength of negative selection were detected. These differences may affect the biological interpretation of mtDNA gene lineages used as a proxy to species in ecological and parasitological investigations. Given that the mitochondria are critically important in the parasite life cycle stages that take place in the vector and that the transmission of parasites belonging to particular clades has been linked to specific insect families/subfamilies, this study suggests that differences in vectors have affected the mode of evolution of haemosporidian mtDNA genes. The observed patterns also suggest that the radiation of haemosporidian parasites may be the result of community-level evolutionary processes between their vertebrate and invertebrate hosts.

Molecular detection and genetic diversity of avian haemosporidian parasites in Iran

Background

The mobility of birds across or between continents exposes them to numerous vectors that have the potential to transmit pathogens and spread them into new regions. A combination of rich species diversity of birds along with the small amount of molecular studies in Iran makes observing the blood parasite distribution in wild avian populations indispensable for further estimation and administration of blood parasites.

Methodology/Principal findings

In order to evaluate the infection rate and molecular context of avian blood parasites, bird samples were collected (passerine = 316 and non-passerine = 14) in eight provinces of northern Iran between June to September 2015 and 2016. All bird samples were examined for haematoprotozoan infections by morphological screening using light microscope and mtDNA cytb gene amplification. A total of 115 birds were positive for blood parasites by molecular approach (34.84% overall infection). The infection rate of Haemoproteus, Plasmodium, and Leucocytozoon were 33.03%, 1.21%, and 0.6%, respectively. Sequences analysis has detected 43 lineages in Iranian birds’ hosts. Lineages were attributed to three genera Haemoproteus (n = 37), Plasmodium (n = 4), and Leucocytozoon (n = 2), of which 23 lineages fully matched previously recorded sequences in GenBank and MalAvi data reciprocities. Five lineages of ACDUM1, ACDUM2, PARUS1, PYERY01, and SISKIN1 were detected in multiple hosts’ species from dissimilar families. In Bayesian tree, all sequences were clustered in three main monophyletic clades as Haemoproteus, Plasmodium, and Leucocytozoon genera.

Conclusions/Significance

As the first study outlining the molecular detection of hematozoa of passerines from Iran, the current study has recorded 20 new lineages for three genera of Haemoproteus, Plasmodium, and Leucocytozoon. Additional investigations into these taxa in the avifauna for the other parts of Iran may provide extra information on blood parasites, hosts relationships and distribution patterns.

Combining morphological and molecular data to reconstruct the phylogeny of avian Haemosporida

The traditional classification of avian Haemosporida is based mainly on morphology and life history traits. Recently, molecular hypotheses have challenged the traditional classification, leading to contradictory opinions on whether morphology is phylogenetically informative. However, the morphology has never been used to reconstruct the relationships within the group. We inferred the phylogeny of avian Haemosporida from 133 morphological characters present in blood stages. We included all species with at least one mitochondrial gene characterized (n = 93). The morphological hypothesis was compared with the one retrieved from mitochondrial DNA (mtDNA) nucleotide sequences and a hypothesis that used a combination of morphological and molecular data (i.e., total evidence). In order to recover the evolutionary history and identify phylogenetically and taxonomically informative characters, they were mapped on the total evidence phylogeny. The morphological hypothesis presented more polytomies than the other two, especially within Haemoproteus. In the molecular hypothesis, the two Haemoproteus subgenera are paraphyletic, and some relationships within Parahaemoproteus were resolved. By combining the morphological and molecular data, we were able to resolve the majority of polytomies and posterior probabilities increased. We identified a unique combination of morphological traits, clearly differentiating avian Haemosporida genera, sub-genera of Leucocytozoon and Haemoproteus, and some Plasmodium sub-genera. Plasmodium had the highest number of synapomorphies. Furthermore, 86% of the species presented a unique combination of taxonomically informative characters. A limiting factor was the mismatch of traits characterized in species descriptions, leading to a morphological matrix with a considerable amount of missing data, particularly for the stages of early young and young gametocytes (67% of all missing data). Characters lacking information for the majority of species included the colour of pigment granules, the cytoplasm appearance, and the presence and dimensions of vacuoles. According to our results, the combination of morphology and mtDNA proved to be a robust alternative to reconstruct the relationships among avian Haemosporida, obtaining a resolution and support similar to that obtained using full mitochondrial genome sequences for over 100 lineages.

Malaria parasites and related haemosporidians cause mortality in cranes: a study on the parasites diversity, prevalence and distribution in Beijing Zoo

Background

Malaria parasites and related haemosporidian parasites are widespread and may cause severe diseases in birds. These pathogens should be considered in projects aiming breeding of birds for purposes of sustained ex situ conservation. Cranes are the ‘flagship species’ for health assessment of wetland ecosystems, and the majority of species are endangered. Malaria parasites and other haemosporidians have been reported in cranes, but the host-parasite relationships remain insufficiently understood. Morbidity of cranes due to malaria has been reported in Beijing Zoo. This study report prevalence, diversity and distribution of malaria parasites and related haemosporidians in cranes in Beijing Zoo and suggest simple measures to protect vulnerable individuals.

Methods

In all, 123 cranes (62 adults and 61 juveniles) belonging to 10 species were examined using PCR-based testing and microscopic examination of blood samples collected in 2007–2014. All birds were maintained in open-air aviaries, except for 19 chicks that were raised in a greenhouse with the aim to protect them from bites of blood-sucking insects. Bayesian phylogenetic analysis was used to identify the closely related avian haemosporidian parasites.

Results

Species of Plasmodium (5 lineages), Haemoproteus (1) and Leucocytozoon (2) were reported. Malaria parasites predominated (83% of all reported infections). The overall prevalence of haemosporidians in juveniles was approximately seven-fold higher than in adults, indicating high susceptibility of chicks and local transmission. Juvenile and adult birds hosted different lineages of Plasmodium, indicating that chicks got infection from non-parent birds. Plasmodium relictum (pSGS1) was the most prevalent malaria parasite. Mortality was not reported in adults, but 53% of infected chicks died, with reports of co-infection with Plasmodium and Leucocytozoon species. All chicks maintained in the greenhouse were non-infected and survived. Species of Leucocytozoon were undetectable by commonly used PCR protocol, but readily visible in blood films.

Conclusion

Crane chicks often die due to malaria and Leucocytozoon infections, which they likely gain from wild free-living birds in Beijing Zoo. Molecular diagnostics of crane Leucocytozoon parasites needs improvement. Because the reported infections are mainly chick diseases, the authors recommend maintaining of juvenile birds in vector-free facilities until the age of approximately 6 months before they are placed in open-air aviaries.

Electronic supplementary material

The online version of this article (10.1186/s12936-018-2385-3) contains supplementary material, which is available to authorized users.

The polyphyly of Plasmodium: comprehensive phylogenetic analyses of the malaria parasites (order Haemosporida) reveal widespread taxonomic conflict

The evolutionary relationships among the apicomplexan blood pathogens known as the malaria parasites (order Haemosporida), some of which infect nearly 200 million humans each year, has remained a vexing phylogenetic problem due to limitations in taxon sampling, character sampling and the extreme nucleotide base composition biases that are characteristic of this clade. Previous phylogenetic work on the malaria parasites has often lacked sufficient representation of the broad taxonomic diversity within the Haemosporida or the multi-locus sequence data needed to resolve deep evolutionary relationships, rendering our understanding of haemosporidian life-history evolution and the origin of the human malaria parasites incomplete. Here we present the most comprehensive phylogenetic analysis of the malaria parasites conducted to date, using samples from a broad diversity of vertebrate hosts that includes numerous enigmatic and poorly known haemosporidian lineages in addition to genome-wide multi-locus sequence data. We find that if base composition differences were corrected for during phylogenetic analysis, we recovered a well-supported topology indicating that the evolutionary history of the malaria parasites was characterized by a complex series of transitions in life-history strategies and host usage. Notably we find that Plasmodium, the malaria parasite genus that includes the species of human medical concern, is polyphyletic with the life-history traits characteristic of this genus having evolved in a dynamic manner across the phylogeny. We find support for multiple instances of gain and loss of asexual proliferation in host blood cells and production of haemozoin pigment, two traits that have been used for taxonomic classification as well as considered to be important factors for parasite virulence and used as drug targets. Lastly, our analysis illustrates the need for a widespread reassessment of malaria parasite taxonomy.

Parasitaemia data and molecular characterization of Haemoproteus catharti from New World vultures (Cathartidae) reveals a novel clade of Haemosporida

Background

New World vultures (Cathartiformes: Cathartidae) are obligate scavengers comprised of seven species in five genera throughout the Americas. Of these, turkey vultures (Cathartes aura) and black vultures (Coragyps atratus) are the most widespread and, although ecologically similar, have evolved differences in morphology, physiology, and behaviour. Three species of haemosporidians have been reported in New World vultures to date: Haemoproteus catharti, Leucocytozoon toddi and Plasmodium elongatum, although few studies have investigated haemosporidian parasites in this important group of species. In this study, morphological and molecular methods were used to investigate the epidemiology and molecular biology of haemosporidian parasites of New World vultures in North America.

Methods

Blood and/or tissue samples were obtained from 162 turkey vultures and 95 black vultures in six states of the USA. Parasites were identified based on their morphology in blood smears, and sequences of the mitochondrial cytochrome b and nuclear adenylosuccinate lyase genes were obtained for molecular characterization.

Results

No parasites were detected in black vultures, whereas 24% of turkey vultures across all sampling locations were positive for H. catharti by blood smear analysis and/or PCR testing. The phylogenetic analysis of cytochrome b gene sequences revealed that H. catharti is closely related to MYCAMH1, a yet unidentified haemosporidian from wood storks (Mycteria americana) in southeastern USA and northern Brazil. Haemoproteus catharti and MYCAMH1 represent a clade that is unmistakably separate from all other Haemoproteus spp., being most closely related to Haemocystidium spp. from reptiles and to Plasmodium spp. from birds and reptiles.

Conclusions

Haemoproteus catharti is a widely-distributed parasite of turkey vultures in North America that is evolutionarily distinct from other haemosporidian parasites. These results reveal that the genetic diversity and evolutionary relationships of avian haemosporidians are still being uncovered, and future studies combining a comprehensive evaluation of morphological and life cycle characteristics with the analysis of multiple nuclear and mitochondrial genes will be useful to redefine the genus boundaries of these parasites and to re-evaluate the relationships amongst haemosporidians of birds, reptiles and mammals.

Electronic supplementary material

The online version of this article (10.1186/s12936-017-2165-5) contains supplementary material, which is available to authorized users.