The genetic diversity of blood parasites within the freshwater turtles Mauremys leprosa and Emys orbicularis in Tunisia reveals coinfection with Haemogregarina spp

Hemoparasite Analysis and Hematological Parameters of Four Freshwater Turtle Species (Testudines: Podocnemididae) from the Brazilian Amazon

METHODS

Sampling was performed at three sites in the Tapajós River mouth, Pará State, Brazil, and an aliquot of blood was collected from each turtle by post-occipital dorsal vein puncture. The aliquots were used for the determination of hematological parameters and for the study of hemoparasites in the blood samples.

RESULTS

A total of 37 turtles were sampled: 21 Podocnemis expansa, three P. sextuberculata, nine P. unifilis, and four P. erythrocephala. Parasitological analyses showed inclusions in erythrocytes compatible with Haemogregarina sp., representing an overall prevalence of parasitized animals of 64.8% with an average of 94,789 parasites/ml of blood. In this study, the evolutionary forms of Haemogregarina spp. from trophozoites, pre-meronts, meronts, and mature and immature gamonts were observed in three species of freshwater turtle species, and one morphotype of the parasite with high similarity to Haemogregarina podocnemis has been observed.

CONCLUSION

Despite recent research on freshwater turtles, this study provides new information on the intensity of blood parasite infection and hematological parameters of free-living animals, highlighting the need for studies on infected and uninfected animals from the same population.

Placobdella nabeulensis sp. nov. (Hirudinea: Glossiphoniidae), a new glossiphoniiform leech from Palearctic North Africa

BACKGROUND

Herein, we describe a new species of turtle blood-feeding leech, Placobdella nabeulensis sp. nov. from Palearctic North Africa (Tunisia and Algeria). The new species is described based on detailed morphological analyses using light and scanning electron microscopes.

RESULTS

Apart from the detailed morphology of the atrium, morphological features alone do not sufficiently separate the species from congeners due to the absence of distinct diagnostic characters. Therefore, we turned to molecular data to better distinguish this new species from other members of the genus and establish a basis for its genetic separation. Four DNA fragments were successfully amplified, including mitochondrial COI and 12S rDNA, as well as nuclear 28S rDNA and histone H3. We then provided the molecular descriptor of the taxon, based on redundant diagnostic nucleotide combinations in DNA sequence alignment within the Folmer region. Results of the phylogenetic analysis and species delimitation methods (ABGD, ASAP, and bPTP) based on the COI locus support the species rank of the Tunisian-Algerian Placobdella.

CONCLUSIONS

The new species is most closely related to the European species Placobdella costata (Fr. Müller, 1846) and the present study indicates that Placobdella nabeulensis sp. nov. has likely been confused with the European counterpart in several previous studies. This article is registered at www.zoobank.org under urn:lsid:zoobank.org:pub:4A4B9C1D-2556-430F-8E4B-0CE99F2012F5.

Molecular Phylogenies of Leeches and Haemoparasites Infecting Freshwater Turtles in Aquatic Ecosystems of Northern Africa Suggest Phylogenetic Congruence between Placobdella costata Sensu Lato and Haemogregarina stepanowi Sensu Lato

Haemogregarines are blood parasites with a life-cycle involving a vertebrate as the intermediate host and an invertebrate as the definitive host and vector. Extensive phylogenetic investigations based on 18S-rRNA gene sequences have shown that Haemogregarina stepanowi (Apicomplexa: Haemogregarinidae) is able to infest a large diversity of freshwater turtle species, including the European pond turtle Emys orbicularis, the Sicilian pond turtle Emys trinacris, the Caspian turtle Mauremys caspica, the Mediterranean pond turtle Mauremys leprosa, and the Western Caspian turtle Mauremys rivulata, among others. From the same molecular markers, H. stepanowi is further considered to be a complex of cryptic species predisposed to infect the same host species. While Placobdella costata is known to be the unique vector of H. stepanowi, it is only recently that independent lineages within P. costata have been illustrated-suggesting the presence of at least five unique leech species across Western Europe. The aims of our study were therefore to investigate from mitochondrial markers (COI) the genetic diversity within haemogregarines and leeches infecting freshwater turtles of the Maghreb, in order to identify processes of parasite speciation. We showed that H. stepanowi consists of at least five cryptic species in the Maghreb, while two Placobella species were identified in the same area. Although an Eastern-Western speciation pattern was apparent for both leeches and haemogregarines, we cannot make definitive conclusions regarding co-speciation patterns between parasites and vectors. However, we cannot reject the hypothesis of a very strict host-parasite specificity within leeches.

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.

Cytochrome c oxydase I phylogenetic analysis of Haemogregarina parasites (Apicomplexa, Coccidia, Eucoccidiorida, Haemogregarinidae) confirms the presence of three distinct species within the freshwater turtles of Tunisia

Species of Haemogregarina are apicomplexan blood parasites that use vertebrates as intermediate hosts. Due to limited interspecific morphological characters within the genus during the last decade, 18S rRNA gene sequences were widely used for species identification. As coinfection patterns were recently reported from nuclear molecular data for two sympatric freshwater turtles Mauremys leprosa and Emys orbicularis from Tunisia, our objectives were to design COI specific primers to confirm the presence of three distinct species in both host species. Blood samples were collected from 22 turtles, from which DNAs were extracted and used as templates for amplification. Following different rounds of PCR and nested PCR, we designed specific Haemogregarina COI primers that allowed the sequencing of nine distinct haplotypes. Phylogenetic Bayesian analysis revealed the occurrence of three well-differentiated sublineages that clustered together into a single clade. Based on pairwise genetic distances (p-distance), we confirmed the occurrence of three distinct but phylogenetically closely related species coinfecting M. leprosa and E. orbicularis in the same aquatic environments. Our results demonstrate that the use of fast evolving genes within Haemogregarina will help to investigate the parasite diversity within both intermediate vertebrate and definitive invertebrate hosts, and to assess the evolution, historical biogeography and specificity of haemogregarines.