Nematopsis temporariae (Gregarinasina, Apicomplexa, Alveolata) intracellular infectious agent of tadpole livers

Amphibians are in decline as a result of habitat destruction, climate change and infectious diseases. Tadpoles are thought susceptible to infections because they are dependent on only an innate immune system (e.g. macrophages). This is because the frog adaptive immune system does not function until later stages of the life cycle. In 1920, Nöller described a putative infectious agent of tadpoles named Nematopsis temporariae, which he putatively assigned to gregarine protists (Apicomplexa). Here, we identify a gregarine infection of tadpoles using both microscopy and ribosomal DNA sequencing of three different frog species (Rana temporaria, R. dalmatina, and Hyla arborea). We show that this protist lineage belongs to the subclass Gregarinasina Dufour 1828 and is regularly present in macrophages located in liver sinusoids of tadpoles, confirming the only known case of a gregarine infection of a vertebrate. This article is protected by copyright. All rights reserved.Marie Curie Intra-European and EMBO Long-Term Fellowships . Grant Number: FP7-PEOPLE-2011-IEF-299815-PARAFROGS and ATL-1069-2011. Czech Science Foundation . Grant Number: GBP505/12/G112-ECI