Hemolivia species infecting Central American wood turtles (Rhinoclemmys pulcherrima manni) and problems with differential diagnosis within the genus Hemolivia

Blood parasites of the genus Hemolivia Petit, Landau, Baccam and Lainson, 1990 (Adeleorina: Karyolysidae) are hemogregarines of ectothermic vertebrates, such as lizards, chelonians, and toads. Only five species of Hemolivia from vertebrate hosts and one from their tick vector have been described so far. In the present study, Central American wood turtles (Rhinoclemmys pulcherrima manni) originating from Southern Nicaragua were screened for the presence of hemogregarines. Ten out of 30 specimens (33.3%) were positive for Hemolivia using both approaches - microscopy and PCR-based analyses. Phylogenetic analyses based on the 18S rRNA gene revealed the presence of two haplotypes, both placed as sister taxa in the Hemolivia clade. Their phylogenetic position was supported by high bootstrap values and high posterior probabilities, suggesting that there are at least two new distinct haplotypes corresponding to two distinct species. However, the specimens of each haplotype were microscopically indistinguishable from each other based on the gamont morphology, therefore, only a single species could be described and named, as Hemolivia pulcherrima n. sp. We consider that the uniform morphology of the most common blood stages of species of the genus Hemolivia complicates their differential diagnosis. Sequence divergence and different host spectra, therefore, remain the only differentiating tools.

Molecular Screening of Haemogregarine Hemoparasites (Apicomplexa: Adeleorina: Haemogregarinidae) in Populations of Native and Introduced Pond Turtles in Eastern Europe

Haemogregarines (Apicomplexa: Adeleorina) are the most common and widespread reptilian blood parasites. Haemogregarina stepanowi was the first haemogregarine described from a reptile, the European pond turtle Emys orbicularis, and initial assessments indicated it was widespread across different pond turtle host species across much of Europe, the Middle East and North Africa. However, recent molecular assessments have indicated the presence of multiple genetically distinct forms in North Africa and the Iberian Peninsula, and extensive mixed infections which may be associated with a negative impact on the hosts. Here, we screened two native species, E. orbicularis and Mauremys rivulata, and the introduced Trachemys scripta from Serbia and North Macedonia for haemogregarines by amplifying and sequencing part of the 18S rRNA gene of these parasites, and used a standard DNA barcoding approach to identify leeches, the final host, attached to pond turtles. Our results again demonstrate the occurrence of considerable diversity of parasites in the analysed pond turtle species, and that T. scripta are likely infected by local haemogregarine parasites, and not those that are found in its native range. Leeches were identified as Placobdella costata, part of a lineage from Northern Europe. Mixed infections within pond turtles were again common. Current haemogregarine taxonomy does not reflect the genetic diversity identified, and a full taxonomic reassessment is needed.

Characterization and identification of haemogregarine hemoparasites (Apicomplexa: Adeleina: Hepatozoidae) in natural populations of Mauremys leprosa leprosa and M. leprosa saharica from Morocco

Distribution, prevalence and parasitaemia of apicomplexan parasites of the genus Haemogregarina were studied in 858 freshwater turtles (735 Mauremys leprosa leprosa and 123 Mauremys leprosa saharica) throughout 30 localities from Morocco. Blood smears were collected from the turtles and partial 18S rRNA sequence data used to infer genetic diversity and phylogenetic relationships. Of the 858 individuals analyzed by microscopy 22.7% were infected, from 16 M. leprosa leprosa localities. Individuals of M. leprosa saharica sampled south of the High Atlas Mountains were not infected, probably due to the absence or rarity of the leech vectors in these localities. Within M. leprosa leprosa, we did not identify any patterns between geography and prevalence, which varied between 10% (Oued Nfiss) to 100% (Oued Tassaout). Five distinct genetic lineages were identified, indicating the likely presence of multiple species of haemogregarines, one of which probably corresponds to Haemogregarina stepanowi. Mixed infections were also detected. Additional studies are needed to better understand the ecology and epidemiology of this parasite in turtles, as well as the host-parasite relationship with their definitive hosts, leeches.

Haemogregarines and Criteria for Identification

Simple Summary

Taxonomic classification of haemogregarines belonging to Apicomplexa can become difficult when the information about the life cycle stages is not available. Using a self-reporting, we record different haemogregarine species infecting various animal categories and exploring the most systematic features for each life cycle stage. The keystone in the classification of any species of haemogregarines is related to the sporogonic cycle more than other stages of schizogony and gamogony. Molecular approaches are excellent tools that enabled the identification of apicomplexan parasites by clarifying their evolutionary relationships.

Abstract

Apicomplexa is a phylum that includes all parasitic protozoa sharing unique ultrastructural features. Haemogregarines are sophisticated apicomplexan blood parasites with an obligatory heteroxenous life cycle and haplohomophasic alternation of generations. Haemogregarines are common blood parasites of fish, amphibians, lizards, snakes, turtles, tortoises, crocodilians, birds, and mammals. Haemogregarine ultrastructure has been so far examined only for stages from the vertebrate host. PCR-based assays and the sequencing of the 18S rRNA gene are helpful methods to further characterize this parasite group. The proper classification for the haemogregarine complex is available with the criteria of generic and unique diagnosis of these parasites.