Renal Infection by a New Coccidian Genus in Big Brown Bats (Eptesicus fuscus)

Abstract

A novel coccidian parasite from the kidney of big brown bats (Eptesicus fuscus) is described. This coccidian (Nephroisospora eptesici nov. gen., n. sp.) was associated with a generally mild, focal or multifocal, well-demarcated cortical renal lesion less than 1 mm in diameter. The lesion represented cystic, dilated tubules with hypertrophied tubular epithelial cells and was present in the kidneys of 29 of 590 bats. Numerous coccidian parasites in various stages of development were present within the tubular epithelial cells and within the cyst lumina. Oocysts were collected from cystic dilated tubules. Thin-walled, sporulated ellipsoidal oocysts measuring an average of 18.9 x 20.8 microm were present in kidney tissue. The oocysts contained 2 sporocysts with 4 sporozoites. A polar body and a prominent oocyst residuum were present in the oocysts, but no micropyle, sporocyst residuum, or Stieda bodies were detected. Analysis of the 18S rRNA gene sequence put the parasite in the Sarcocystidae. The parasite is closely related to Besnoitia, Hammondia, Neospora, and Toxoplasma. Ultrastructural features, such as the presence of an apical complex in merozoites, support the identification of a coccidian. A new genus and species, Nephroisospora eptesicii, is proposed for this unusual coccidian in which the entire cycle is completed in the kidney of a single host; it has a membrane-like oocyst wall, sporogony occurs in the host rather than in the abiotic environment, and the positioning of the parasite by nucleic acid sequence indicates it to be closely allied to Sarcocystis and Besnoitia.

Diseases in free-ranging bats from Germany

“…Of the 486 bats examined in the current study, 11 individuals belonging to 6 different species revealed renal coccidiosis. Histo-pathological lesions were consistent with reports from Gruber et al [10] and Wünschmann et al [12], while the reported macroscopically visible white foci on the external surface of the kidneys were only seen in 2 animals we examined. Inflammatory cell response was observed in one of these cases and was associated with a cystic cavity filled with amorphous necrotic material.…”

“…Renal coccidiosis has sporadically been reported in free-ranging bats [10,12,33]. In European bat species, infection was observed in 4 animals of 4 different vespertilionid species found in Germany [10].…”

“…Combined pathological investigations and pathogen detection in free-ranging bats are sparse [6-9] and often limited by small sample sizes. Most reports describe disease incidents in single bats or small numbers of animals caused by parasitic [10-12], bacterial [13,14] or viral infections [15,16]. In Europe, all bat species are registered in the IUCN Red list of endangered species and legislation for nature conservation prohibits invasive sampling of free-ranging individuals for research purposes.…”

Chiroptera

“…Renal coccidiosis is reported in a few bat species, including Eptesicus fuscus, Pipistrellus pipistrellus, Myotis mystacinus, M. nattereri, M. sodalis, Nyctalus noctula, Hipposideros caffer, and Rhinolophus sp. (Gruber et al, 1996;Kusewitt et al, 1977;Wünschmann et al, 2010). Early reports in M. sodalis presumptively identified the coccidia morphologically as Klossiella sp.…”

“…(Kusewitt et al, 1977). The name Nephroisospora eptesici has been proposed for the organism in E. fuscus (Wünschmann et al, 2010). White foci up to 2 mm diameter may be visible on the renal capsular surface (Fig.…”