Haemocystidium spp., a species complex infecting ancient aquatic turtles of the family Podocnemididae: First report of these parasites in Podocnemis vogli from the Orinoquia

Plasmodium species infecting lizards in the Brazilian Cerrado: Identification and description of a novel species, Plasmodium brasiliensis n. sp

Parasites of the genus Plasmodium, responsible for lizard malaria, are widely distributed and taxonomically diverse. Molecular techniques provide valuable insights into the evolutionary relationships of Plasmodium species and lineages. However, the available data are still scarce, emphasizing the need for taxonomy-focused studies. We investigated the occurrence of Plasmodium infection in free-living lizards in the Brazilian Cerrado using an integrative approach based on the amplification/sequencing of the Plasmodium cytb gene and microscopic analysis. Among 302 lizards screened, 61 (20.2%) tested positive in the molecular screening, including 18 with concordant results in microscopy. We recovered 16 sequences in the first molecular survey of this host group in the biome. Our findings unveil a variety of Plasmodium species, some of which were previously undocumented in this region. We describe new lineages of Plasmodium ouropretensis, P. tropiduri, P. carmelinoi, and also report a new species, herein named as Plasmodium brasiliensis n. sp. The infection by Plasmodium sp. in Hoplocercus spinosus represents the first description of Apicomplexa organisms in this species. Furthermore, our results open remarkable possibilities for extensive studies in a field unexplored for many years.

Hemoparasite occurrence and hematological/serum chemistry variations in Podocnemis vogli turtles: A comparative analysis between wild-residing infected specimens and captive non-infected counterparts

Reptiles show a high occurrence of hemoparasites in the wild; however, little is known about the impact of such infections on their hosts' physiology and health status. Podocnemis vogli is an ancient turtle distributed in South America, frequently infected by blood parasites. Specifically, we analyzed the hematological and serum chemistry parameters of 78 wild turtles. We compared these values with those obtained from non-infected turtles of the same species in ex-situ conditions, considering factors such as sex and coinfections. Two orders of hemoparasites were detected under microscopic analyses: Adelorina, represented by Haemogregarina sp. (98.72 ± 0.28%), and Haemosporida, represented by Haemocystidium sp. (30.77 ± 1.16%), the latter genus being always in coinfection with Haemogregarina. Significant differences were observed in 20 parameters between infected (free living) and uninfected (living in captivity) turtles. The ALP, PCV, Hb, and MCV were significantly different by sex; albumin, cholesterol, creatinine, percentage of heterophils, lymphocytes, and basophils differed in coinfection. This is the first report of reference intervals of P. vogli in the wild and the first study comparing hematological and blood biochemistry values between hemoparasite-infected and uninfected P. vogli turtles. However, the limited knowledge of these parameters in wild reptiles and the wide range of interval values makes it difficult to determine any significant impact on turtle health. Nevertheless, this study highlights the need for more in-depth research to explore the potential effects of blood parasite infections on turtles, including immune response and coevolution studies.

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.

Molecular characterization of haemosporidian and haemogregarine diversity in southwestern Iberian amphibians and reptiles

The knowledge of the diversity and geographic distribution of parasite species is the first step towards understanding processes of global epidemiology and species conservation. Despite recent increases in research on haemosporidian and haemogregarine parasites of reptiles and amphibians, we still know little about their diversity and parasite-host interactions, especially in the Iberian Peninsula, where a few studies have been conducted. In this study, the haemosporidian and haemogregarine diversity and phylogenetic relationships of the parasites in southwestern Iberian amphibians and reptiles were assessed using PCR approaches on blood samples of 145 individuals from five amphibian and 13 reptile species. The amphibians did not present any of both groups of parasites studied. Regarding reptiles, five Hepatozoon, one Haemogregarina, and one Haemocystidum haplotypes were found infecting four different species, revealing new host records for these parasites. Among them, we found one new Haemocystidium haplotype and three new and a previously reported Hepatozoon haplotype from a north African snake. The latter finding suggests that some Hepatozoon parasites may not be host-specific and have large geographic ranges even crossing geographical barriers. These results increased the knowledge about the geographic distribution and the number of known host species of some reptile apicomplexan parasites, highlighting the great unexplored diversity of them in this region.

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.