Isosporan Oocysts in the Faeces of Bank Voles (Myodes glareolus; Arvicolinae, Rodentia): Real Parasites, or Pseudoparasites?

Gut protozoa of wild rodents - a meta-analysis

Protozoa are well-known inhabitants of the mammalian gut and so of the gut microbiome. While there has been extensive study of a number of species of gut protozoa in laboratory animals, particularly rodents, the biology of the gut protozoa of wild rodents is much less well-known. Here we have systematically searched the published literature to describe the gut protozoa of wild rodents, in total finding records of 44 genera of protozoa infecting 228 rodent host species. We then undertook meta-analyses that estimated the overall prevalence of gut protozoa in wild rodents to be 24%, with significant variation in prevalence among some host species. We investigated how host traits may affect protozoa prevalence, finding that for some host lifestyles some protozoa differed in their prevalence. This synthesis of existing data on wild rodent gut protozoa provides a better understanding of the biology of these common gut inhabitants and suggests directions for their future study.

Isospora and Lankesterella Parasites (Eimeriidae, Apicomplexa) of Passeriform Birds in Europe: Infection Rates, Phylogeny, and Pathogenicity

Wild birds are common hosts to numerous intracellular parasites such as single-celled eukaryotes of the family Eimeriidae (order Eucoccidiorida, phylum Apicomplexa). We investigated the infection rates, phylogeny, and pathogenicity of Isospora and Lankesterella parasites in wild and captive passerine birds. Blood and tissue samples of 815 wild and 15 deceased captive birds from Europe were tested using polymerase chain reaction and partial sequencing of the mitochondrial cytochrome b and cytochrome c oxidase I and the nuclear 18S rRNA gene. The infection rate for Lankesterella in wild birds was 10.7% compared to 5.8% for Isospora. Chromogenic in situ hybridization with probes targeting the parasites' 18S rRNA was employed to identify the parasites' presence in multiple organs, and hematoxylin-eosin staining was performed to visualize the parasite stages and assess associated lesions. Isospora parasites were mainly identified in the intestine, spleen, and liver. Extraintestinal tissue stages of Isospora were accompanied by predominantly lymphohistiocytic inflammation of varying severity. Lankesterella was most frequently detected in the spleen, lung, and brain; however, infected birds presented only a low parasite burden without associated pathological changes. These findings contribute to our understanding of Isospora and Lankesterella parasites in wild birds.

Morphological and molecular characterization of Isospora elliotae n. sp. (Apicomplexa: Eimeriidae) from the Australian magpie Gymnorhina tibicen (Latham, 1801) (Passeriformes: Artamidae) in Western Australia

A new coccidian species, Isospora elliotae n. sp., from the Australian magpie Gymnorhina tibicen (Latham, 1801) in Western Australia, is described and characterized morphologically and molecularly. Microscopic analysis of a faecal sample identified subspheroidal oocysts (n = 20), 20-22 × 18-20 (20.7 × 18.7); length/width (L/W) ratio 1.05-1.14 (1.10). Wall bi-layered, 1.0-1.3 (1.2) thick, outer layer smooth, c. 2/3 of total thickness. Micropyle and oocyst residuum absent, but usually two polar granules are present. Sporocysts (n = 28) ovoidal, 12-13 × 9-11 (12.6 × 9.7); L/W ratio 1.22-1.35 (1.30). Stieda body present, flattened to half-moon-shaped, c. 0.5 deep × 2.0 wide; sub-Stieda indistinct or barely discernible, c. 1.0 deep × 2.5 wide; para-Stieda body absent; sporocyst residuum present, composed of granules dispersed among the sporozoites. Sporozoites vermiform, with anterior and posterior refractile bodies and nucleus. Segments of three gene loci (18S rRNA, 28S rRNA and COI) were sequenced and I. elliotae n. sp. exhibited 99.8% genetic similarity to Isospora sp. MAH-2013a (KF648870) followed by 99.7% genetic similarity to Isospora neochmiae (Yang, Brice & Ryan, 2016) (KT224380) at the 18S rRNA gene locus. It shared 97.0% genetic similarity with an unnamed Isospora sp. (AY283852) at the 28S rRNA gene locus and it also shared the highest genetic similarity of 99.8% with the unnamed Isospora sp. from an American crow (OL999120) at the COI gene locus. Based on morphological and molecular data, this isolate is a new species named as I. elliotae n. sp.

Gastrointestinal parasites in wild rodents in Chiloé Island-Chile

Gastrointestinal parasites are well-documented in small mammals from north-central Chile, but little is known about endoparasites of rodents in southern Chile. A survey was conducted between January and February 2018 to evaluate gastrointestinal parasites and risk factors of wild rodents that live in rural areas in Northern Chiloé Island, Chile. A total of 174 fecal samples from rodents of six native and one introduced species were collected and examined using the Mini-FLOTAC method. Also, 41 individuals of four native wild rodent species were examined furtherly to determinate adult parasites from gastrointestinal tracts. The overall prevalence of endoparasites was 89.65% (156). Helminth egg types included: Rodentolepis spp., Capillariidae, Trichuris sp., Syphacia sp., oxyurid-type eggs, Strongyloides sp., Spirurid-type eggs, Strongilid-type eggs, Moniliformis sp., and an unidentified nematode egg and larvae. Protozoa comprised coccidia, amoeba, and unidentified cysts. From necropsies, adult parasites involved Syphacia sp. Trichuris sp., Protospirura sp. and Physaloptera sp. In Abrothrix olivacea, individuals with low-body-mass index exhibited reduced infection probability for Spirurid-type and Strongilid-type eggs. Some parasites in this study may affect human health. In rural settings where environmental conditions are changing, more research should be undertaken to understand parasitic infections in wildlife and implications for public health and conservation.

Eimeria melogale n. sp. (Apicomplexa: Eimeriidae) in the Javan ferret-badger (Melogale orientalis)

The Javan ferret-badger Melogale orientalis (Carnivora: Mustelidae: Helictidinae) is a small carnivore endemic to Indonesia. In the family Mustelidae, 10 Eimeria, 12 Cystoisopora, one Isospora, and one Hammondia species are known, but no eimeriid coccidia has been yet described in the subfamily Helictinidae (ferret badgers). Coproscopic examination of Javan ferret-badgers imported into the Czech Republic revealed the presence of coccidian oocysts. Sporulated oocysts differ from other Eimeria known in the family Mustelidae by their small size (12.4-16.1 × 10.4-13.4 μm) and ovoidal shape. Morphological data and phylogenetic analyses of 18S rRNA and COI genes indicated a new species of Eimeria found in faecal samples of Javan ferret badgers. The species is described as E. melogale n. sp.

Coccidia of Columbiformes: a taxonomic review of its Eimeriidae species and Eimeria columbinae n. sp. from Columbina talpacoti (Temminck, 1809) from Brazil

Coccidia (Chromista: Miozoa: Eimeriidae) of columbiform birds (Aves: Columbiformes) have been described since the end of the nineteenth century; however, some of these descriptions were poorly detailed or inconclusive. In this sense, the current work makes a detailed taxonomic revision reconsidering and organizing 18 Eimeria spp. and two Isospora spp. previously described or reported of Columbiformes. Along with this, a new species of Eimeria is morphologically and molecularly identified by the mitochondrial cytochrome c oxidase subunit 1 (COI) gene and by the 18S small subunit ribosomal RNA (18S) gene from the ruddy ground-dove Columbina talpacoti (Temminck, 1809) in the Médio Paraíba region of the State of Rio de Janeiro, southeastern Brazil. Eimeria columbinae n. sp. has subspheroidal oocysts, 14.7 × 13.2 μm, with smooth, bi-layered wall, ~ 1.1 μm and length/width ratio of 1.1. Micropyle and oocyst residuum are present, but polar granule is absent. Sporocysts are ellipsoidal to slightly asymmetrical, 9.0 × 5.1 μm, with both Stieda and sub-Stieda bodies. Sporocyst residuum present and sporozoites with refractile body and nucleus. This is the 19th description of an eimerian from Columbiformes in the World, and the second to have a molecular identification of the COI and 18S genes.

Isospora svecica sp. n. (Apicomplexa: Eimeriidae), a new species of coccidium from the white-spotted bluethroat Luscinia svecica cyanecula (Aves: Passeriformes: Muscicapidae)

Using a combination of morphological and molecular data, we describe a new apicomplexan parasite, Isospora svecica sp. n., from the white-spotted bluethroat, Luscinia svecica cyanecula, from the Czech Republic. Oocysts were found in its intestinal tract. Sporulation was exogenous and took 1-3 days. The oocysts were slightly ellipsoidal, of average size 26.17 × 20.33 μm, with a smooth bilayered wall. Micropyle, oocyst residuum, and polar granules were absent. Sporocysts were bottle-shaped, of an average size of 18.82 × 8.82 μm, with a thin, colourless wall. A conspicuous knob-like Stieda body was present. Substieda body was barely visible. Sporocyst residuum was present in the form of granules of various sizes. Sporozoites were banana-shaped and contained large anterior and small posterior refractile bodies. Partial DNA sequences of three genes were obtained from oocysts of Isospora svecica sp. n., being most closely related to other isosporans described from passerines. Little is known about the parasites of the avian family Muscicapidae, including coccidia, a highly prevalent parasitic protist group in all vertebrate classes. Only six species of the genus Isospora have so far been described in Muscicapidae, together with several "Isospora sp." that in fact most likely represent Isospora lacazei. The newly described Isospora svecica sp. n. differs morphologically from other coccidia reported from muscicapid birds, and represents the first coccidian species described from Luscinia svecica.