Not only are we still discovering new species of parasites, sometimes we're finding whole new genera. Today's parasite is one such example. Nephroisospora eptesici is a new species of coccidian parasite that was recently found in the kidneys of big brown bats (Eptisecus fuscus) in Minnesota. Bats that had been submitted for rabies testing were found to have macroscopic lesions on their kidneys (shown in photo) and subsequent analyses using histology of the lesions as well as DNA sequencing confirmed that they were coccidia. However, these parasites are very unusual in that they appear to undergo their entire life cycle in just one host - all of their relatives use two hosts. The discovery of sporocysts within the kidneys also was perplexing to the authors as other relatives (Isospora, Eimeria, Toxoplama) need oxygen to produce these stages.The original species description, where the photo is from can be found here.
Not so perplexing. For one side, there are several renal Eimeria species in birds although they are a minimal part of the genus, and on the other side, the sister Toxoplasma genus can also complete the entire life cycle in the gut of the definitive host, and multiply in renal tissues too, so this does not prove that an intermediate host cannot exist, only the the cyst phase in the intermediate host is unknown (and maybe existed or exist). However, the esporulation in renal tissues is indeed a peculiar case.
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