Piroplasms of New Zealand seabirds

A novel variant of Babesia sp. (Piroplasmida) as a hemoparasite in procellariiform seabirds

Procellariiformes includes pelagic seabirds that only use land for breeding; and also, these sites mostly occur in insular habitats. These peculiar habits make the investigation of hemoparasites a challenging issue. Thus, the data on the blood parasites of Procellariiformes are still scarce. In the order Piroplasmida, 16 species of Babesia have been described in terrestrial birds and seabirds. However, there is no register for Babesia spp. in procellariiform seabirds. Hence, the objective of this survey was to investigate the occurrence of Babesia spp. in these seabirds. A total of 220 tissue samples from 18 different seabird species were analyzed; the samples comprised blood and fragments of liver and spleen. The samples were obtained from live rescued animals and carcasses found along the southern coast of Brazil. Polymerase chain reaction (PCR) was conducted, followed by phylogenetic analysis. Only one blood sample yielded a positive result, from an adult female Thalassarche chlororhynchos (Atlantic yellow-nosed albatross). The sequence obtained showed the highest identity with sequences of Babesia spp. of birds from the South Pacific, and the isolate was named Babesia sp. strain Albatross. In the phylogenetic analysis, the sequence was grouped within the Babesia sensu stricto group, and further still into a subgroup including Babesia spp. of the Kiwiensis clade (parasites from birds). The phylogenetic analysis also showed that Babesia sp. strain Albatross clustered apart from the Peircei group, a clade that includes Babesia spp. from seabirds. As far as it is known, this is the first report of Babesia sp. in procellariiform seabirds. Babesia sp. strain Albatross may constitute a novel variant of tick-borne piroplasmids associated with the Procellariiformes order.

Potential Role of Avian Populations in the Epidemiology of Rickettsia spp. and Babesia spp

Birds often are carriers of hard and/or soft ticks harboring pathogens of humans and veterinary concern. Migratory avian species, which cover long distance by their flight, may deeply influence the ticks’ distribution worldwide; in particular, they can introduce in a given geographic area new tick species and related tick-borne pathogens. Studies about the detection of tick-borne agents in birds are not numerous, whereas more attention has been turned to the presence of these microorganisms in ticks carried by birds. The present review focused on the role of avian populations in the epidemiology of rickettsioses and babesioses, which represent two severe problems for the health of humans and other mammals.

Characterization and diversity of Babesia sp. YLG, a new member of the Peircei group infecting Mediterranean yellow-legged gulls (Larus michahellis)

Avian infecting piroplasms are largely under-studied compared to other hemoparasites, and this paucity of information has blurred our phylogenetic and biological comprehension of this important group as a whole. In the present study, we detected and characterized Babesia from yellow-legged gull (Larus michahellis) chicks from a colony in southern France. Based on morphological and molecular characterizations, a new Babesia species belonging to the Peircei group, a clade of avian-specific piroplasms, was identified. Due to the complexity of species delineations and the low number of parasites characterized in this clade to date, a species name was not yet attributed; we refer to it for now as Babesia sp. YLG (Yellow-Legged Gull). High prevalence (85% and 58% in 2019 and 2020, respectively) and high parasitemia (up to 20% of parasitized erythrocytes) were recorded in chicks, without any obvious clinical signs of infection. Although the 16 isolates examined had identical 18S rRNA gene sequences, six genetic variants were described based on partial cox1 sequencing, with evidence of chicks co-infected by two variants. Transmission of Babesia sp. YLG via the soft tick Ornithodoros maritimus is discussed.

Babesia Life Cycle - When Phylogeny Meets Biology

Although Babesia represents an important worldwide veterinary threat and an emerging risk to humans, this parasite has been poorly studied as compared to Plasmodium, its malaria-causing relative. In fact, Babesia employs highly specific survival strategies during its intraerythrocytic development and its intricate journey through the tick vector. This review introduces a substantially extended molecular phylogeny of the order Piroplasmida, challenging previous taxonomic classifications. The intriguing developmental proficiencies of Babesia are highlighted and compared with those of other haemoparasitic Apicomplexa. Molecular mechanisms associated with distinctive events in the Babesia life cycle are emphasized as potential targets for the development of Babesia-specific treatments.

Rangelia vitalii and Hepatozoon canis coinfection in pampas fox Lycalopex gymnocercus from Santa Catarina State, Brazil

Rangelia vitalii is a haemoparasite that infects erythrocytes, white blood cells and the cytoplasm of endothelial cells of blood capillaries of canids in South America, and has been detected in both domestic dogs and sylvatic canids. Hepatozoon canis is a parasite that infects neutrophils and monocytes of many mammalian hosts. This study reports the infection of Lycalopex gymnocercus from Santa Catarina, Brazil, with R. vitalii and H. canis. The piroplasm was observed on both blood smears and molecular tests. Many large piroplasms were detected inside the erythrocytes, with round, oval, or teardrop-shaped organism, that occurred singly or in pairs. They had an abundant, pale blue cytoplasm and decentral dark red small nucleus. The animal was also infected with H. canis that was detected only by molecular tests. The majority of haematological and biochemistry parameters were within the reference values for domestic dog and wild canids.

Arthropod-borne agents in wild Orinoco geese (Neochen jubata) in Brazil

Although Orinoco goose (Neochen jubata) is an anatid species widely distributed in South America, scarce are the reports on the occurrence of arthropod-borne pathogens in this avian species. The present work aimed to verify, by serological and molecular methods, the occurrence of haemosporida piroplasmids and Anaplasmataceae agents in wild Orinoco geese captured in Brazil. Between 2010 and 2014, 62 blood samples were collected from free-living geese captured in the Araguaia River, Goiás State, Brazil. Six geese (10%) were seropositive for Anaplasma phagocytophilum, showing titers ranging from 40 and 80. Twenty out of 62 blood samples (32.25%) were positive in nested PCR for hemosporidia (cytochrome b gene). Fifteen and five sequences shared identity with Haemoproteus and Plasmodium, respectively. Six out of 62 blood samples (9.68%) were positive in nested PCR for Babesia spp. (18S rRNA gene); one sequence showed to be closely related to Babesia vogeli. Thirty (48.38%) out of 62 Orinoco geese blood samples were positive in nested cPCR assays for Anaplasmataceae agents (16S rRNA gene): three for Anaplasma spp. and 27 for Ehrlichia. Six geese were simultaneously positive to Haemoproteus and Ehrlichia; three animals were co-positive to different Ehrlichia species/genotypes; and one goose sample was positive for both Anaplasma and Ehrlichia. The present work showed the occurrence of Ehrlichia, Anaplasma, Babesia, Plasmodium, and Haemoproteus species in free-living N. jubata in Brazil. The threat of these arthropod-borne pathogens in Orinoco goose's fitness, especially during the breading season, should be assessed in the future.

Molecular characterization of Babesia peircei and Babesia ugwidiensis provides insight into the evolution and host specificity of avian piroplasmids

There are 16 recognized species of avian-infecting Babesia spp. (Piroplasmida: Babesiidae). While the classification of piroplasmids has been historically based on morphological differences, geographic isolation and presumed host and/or vector specificities, recent studies employing gene sequence analysis have provided insight into their phylogenetic relationships and host distribution and specificity. In this study, we analyzed the sequences of the 18S rRNA gene and ITS-1 and ITS-2 regions of two Babesia species from South African seabirds: Babesia peircei from African penguins (Spheniscus demersus) and Babesia ugwidiensis from Bank and Cape cormorants (Phalacrocorax neglectus and P. capensis, respectively). Our results show that avian Babesia spp. are not monophyletic, with at least three distinct phylogenetic groups. B. peircei and B. ugwidiensis are closely related, and fall within the same phylogenetic group as B. ardeae (from herons Ardea cinerea), B. poelea (from boobies Sula spp.) and B. uriae (from murres Uria aalge). The validity of B. peircei and B. ugwidiensis as separate species is corroborated by both morphological and genetic evidence. On the other hand, our results indicate that B. poelea might be a synonym of B. peircei, which in turn would be a host generalist that infects seabirds from multiple orders. Further studies combining morphological and molecular methods are warranted to clarify the taxonomy, phylogeny and host distribution of avian piroplasmids.

•

Babesia peircei (Bp) infects penguins and B. ugwidiensis (Bu) infects cormorants.

•

Gene sequences of Bp and Bu were analyzed from birds sampled in South Africa.

•

Phylogenetic analysis reveals at least three paraphyletic groups of avian Babesia.

•

Bp and Bu form a phylogenetic group along with other Babesia from aquatic birds.

•

Avian Babesia might not be host-specific at the order level as previously thought.

Occurrence of blood parasites in seabirds admitted for rehabilitation in the Western Cape, South Africa, 2001-2013

Blood parasites are generally uncommon in seabirds, and knowledge on their epidemiology is further limited by the fact that they often inhabit remote locations that are logistically difficult or expensive to study. We present a long term data set of blood smear examinations of 1909 seabirds belonging to 27 species that were admitted to a rehabilitation centre in Cape Town (Western Cape, South Africa) between 2001 and 2013. Blood parasites were detected in 59% of species (16/27) and 29% of individuals examined (551/1909). The following blood parasites were recorded: Babesia ugwidiensis, Babesia peircei, Babesia sp., Plasmodium sp., Leucocytozoon ugwidi, Hepatozoon albatrossi, Haemoproteus skuae and Spirochaetales. Several of the records are novel host-parasite associations, demonstrating the potential of rehabilitation centres for parasite and disease surveillance, particularly for species infrequently sampled from which no host-specific parasites have been described.

Mitochondrial Genome Sequences and Structures Aid in the Resolution of Piroplasmida phylogeny

The taxonomy of the order Piroplasmida, which includes a number of clinically and economically relevant organisms, is a hotly debated topic amongst parasitologists. Three genera (Babesia, Theileria, and Cytauxzoon) are recognized based on parasite life cycle characteristics, but molecular phylogenetic analyses of 18S sequences have suggested the presence of five or more distinct Piroplasmida lineages. Despite these important advancements, a few studies have been unable to define the taxonomic relationships of some organisms (e.g. C. felis and T. equi) with respect to other Piroplasmida. Additional evidence from mitochondrial genome sequences and synteny should aid in the inference of Piroplasmida phylogeny and resolution of taxonomic uncertainties. In this study, we have amplified, sequenced, and annotated seven previously uncharacterized mitochondrial genomes (Babesia canis, Babesia vogeli, Babesia rossi, Babesia sp. Coco, Babesia conradae, Babesia microti-like sp., and Cytauxzoon felis) and identified additional ribosomal fragments in ten previously characterized mitochondrial genomes. Phylogenetic analysis of concatenated mitochondrial and 18S sequences as well as cox1 amino acid sequence identified five distinct Piroplasmida groups, each of which possesses a unique mitochondrial genome structure. Specifically, our results confirm the existence of four previously identified clades (B. microti group, Babesia sensu stricto, Theileria equi, and a Babesia sensu latu group that includes B. conradae) while supporting the integration of Theileria and Cytauxzoon species into a single fifth taxon. Although known biological characteristics of Piroplasmida corroborate the proposed phylogeny, more investigation into parasite life cycles is warranted to further understand the evolution of the Piroplasmida. Our results provide an evolutionary framework for comparative biology of these important animal and human pathogens and help focus renewed efforts toward understanding the phylogenetic relationships within the group.

First Molecular Characterization of Theileria ornithorhynchi Mackerras, 1959: yet Another Challenge to the Systematics of the Piroplasms

Piroplasms, tick-transmitted Apicomplexa of the genera Theileria, Babesia and Cytauxzoon, are blood-borne parasites of clinical and veterinary importance. The order Piroplasmida shows a puzzling systematics characterized by multiple clades, soft polytomies and paraphyletic/polyphyletic genera. In the present study, screening of platypuses (Ornithorhynchus anatinus), was performed to infer the parasite molecular phylogeny. DNA was extracted from blood, ectoparasites and tick eggs and the 18S rRNA- hsp70-genes were used for the phylogenetic reconstructions. Microscopic analyses detected pleomorphic intra-erythrocytic organisms and tetrads consistent with previous descriptions of Theileria ornithorhynchi Mackerras, 1959, but observation of possible schizonts could not be confirmed. DNA sequences obtained from blood and ticks allowed resolving the systematics of the first piroplasm infecting a monotreme host. Molecularly, T. ornithorhynchi formed a novel monophyletic group, basal to most known piroplasms' clades. The ancestral position of this clade, isolated from an ancient lineage of mammalian host appears particularly fascinating. The present paper discusses the inadequacies of the current molecular systematics for the Piroplasmida and the consequences of incomplete sampling, morphology-based classification and ambiguous microscopic identifications. Likely when the current sampling bias is rectified and more sequence data is made available, the phylogenetic position of T. ornithorhynchi will be further contextualized without ambiguity.