Pan-American Trypanosoma (Megatrypanum) trinaperronei n. sp. in the white-tailed deer Odocoileus virginianus Zimmermann and its deer ked Lipoptena mazamae Rondani, 1878: morphological, developmental and phylogeographical characterisation

Background

The subgenus Megatrypanum Hoare, 1964 of Trypanosoma Gruby, 1843 comprises trypanosomes of cervids and bovids from around the world. Here, the white-tailed deer Odocoileus virginianus (Zimmermann) and its ectoparasite, the deer ked Lipoptena mazamae Rondani, 1878 (hippoboscid fly), were surveyed for trypanosomes in Venezuela.

Results

Haemoculturing unveiled 20% infected WTD, while 47% (7/15) of blood samples and 38% (11/29) of ked guts tested positive for the Megatrypanum-specific TthCATL-PCR. CATL and SSU rRNA sequences uncovered a single species of trypanosome. Phylogeny based on SSU rRNA and gGAPDH sequences tightly cluster WTD trypanosomes from Venezuela and the USA, which were strongly supported as geographical variants of the herein described Trypanosoma (Megatrypanum) trinaperronei n. sp. In our analyses, the new species was closest to Trypanosoma sp. D30 from fallow deer (Germany), both nested into TthII alongside other trypanosomes from cervids (North American elk and European fallow, red and sika deer), and bovids (cattle, antelopes and sheep). Insights into the life-cycle of T. trinaperronei n. sp. were obtained from early haemocultures of deer blood and co-culture with mammalian and insect cells showing flagellates resembling Megatrypanum trypanosomes previously reported in deer blood, and deer ked guts. For the first time, a trypanosome from a cervid was cultured and phylogenetically and morphologically (light and electron microscopy) characterised.

Conclusions

In the analyses based on SSU rRNA, gGAPDH, CATL and ITS rDNA sequences, neither cervids nor bovids trypanosomes were monophyletic but intertwined within TthI and TthII major phylogenetic lineages. One host species can harbour more than one species/genotype of trypanosome, but each trypanosome species/genotype was found in a single host species or in phylogenetically closely related hosts. Molecular evidence that L. mazamae may transmit T. trinaperronei n. sp. suggests important evolutionary constraints making tight the tripartite T. trinaperronei-WTD-deer ked association. In a plausible evolutionary scenario, T. trinaperronei n. sp. entered South America with North American white-tailed deer at the Pliocene-Pleistocene boundary following the closure of the Panama Isthmus.

Haematological values of post-laying Arrau turtle (Podocnemis expansa) in the Orinoco River, Venezuela

The Arrau turtle (Podocnemis expansa) is an endangered species, as a result of long-lasting, unsustainable exploitation. To obtain reference haematological values from the wild Podocnemis expansa during post-laying, 20 turtles were captured in the Orinoco River. Blood was obtained from the dorsal cervical sinus in lithium heparin tubes. Red blood cells (RBC), white blood cells (WBC), thrombocytes (TC), packed cell volume (PCV), plasmatic protein (PP), haemoglobin (Hgb), mean corpuscular volume (MCV) and differential leukocyte count were determined. Haematological values were: RBC 0.9×10(9)/L, WBC 5.7×10(9)/L, TC 5.4×10(9)/L, PCV 35.6%, PP 4.2g/dL, Hgb 11.8g/dL, MCV 411fL. The differential leukocyte count comprised: 71% heterophils, 23% lymphocytes, 3% eosinophils, 1.6% basophils, and 1% monocytes. The reports of reference haematology values for the wild P. expansa are limited; therefore, the results presented herein contrast with those values obtained in captivity. This study represents a contribution to the referential haematological values of the wild P. expansa.