Two new Eimeria species (Protozoa: Eimeriidae) from wild rock ptarmigans, Lagopus muta islandorum, in Iceland

Comparative molecular analyses of Eimeria Schneider (Apicomplexa: Eimeriidae) species from rock ptarmigan in Iceland, Svalbard-Norway, and Japan

The rock ptarmigan (Lagopus muta) has a Holarctic breeding distribution and is found in arctic and sub-arctic regions. Isolated populations and glacial relicts occur in alpine areas south of the main range, like the Pyrenees in Europe, the Pamir mountains in Central Asia, and the Japanese Alps. In recent decades considerable effort has been made to clarify parasite infections in the rock ptarmigan. Seven Eimeria spp. have been reported parasitizing rock ptarmigan. Two of those species, E. uekii and E. raichoi parasitizing rock ptarmigan (L. m. japonica) in Japan, have been identified genetically. Here we compare partial sequences of nuclear (18S rRNA) and mitochondrial (COI) genes and we detail the morphology of sporulated oocysts of E. uekii and E. raichoi from Japan, E. muta and E. rjupa, from the rock ptarmigan (L. m. islandorum) in Iceland, and two undescribed eimerian morphotypes, Eimeria sp. A, and Eimeria sp. B, from rock ptarmigan (L. m. hyperborea) in Norway (Svalbard in the Norwegian Archipelago). Two morphotypes, ellipsoidal and spheroidal, are recognized for each of the three host subspecies. Our phylogenetic analysis suggests that the ellipsoidal oocyst types, E. uekii, E. muta, and Eimeria sp. A (Svalbard-Norway) are identical and infects rock ptarmigan in Japan, Iceland, and Svalbard-Norway, respectively. Eimeria uekii was first described in Japan in 1981 so that E. muta, described in Iceland in 2007, and Eimeria sp. A in Svalbard-Norway are junior synonyms of E. uekii. Also, phylogenetic analysis shows that the spheroidal oocyst types, E. rjupa and Eimeria sp. B (Svalbard-Norway), are identical, indicating that rock ptarmigan in Iceland and Svalbard-Norway are infected by the same Eimeria species and differ from E. raichoi in Japan.

Molecular identification of two Eimeria species, E. uekii and E. raichoi as type B, in wild Japanese rock ptarmigans, Lagopus muta japonica

Thus far, two types of Eimeria parasites (E. uekii and type B) have been morphologically identified in wild Japanese rock ptarmigans, Lagopus muta japonica. Although high prevalences were reported for these parasites, genetic analyses have not been conducted. We first clarified the phylogenetic positions of two eimerian isolates using genetic analyses of 18S rRNA and mitochondrial cytochrome c oxidase subunit I gene regions. Consequently, of 61 samples examined, 21 and 11 samples were positive for E. uekii and type B, respectively. Additionally, the infection rate increased in the summer. Molecular analyses revealed both Eimeria isolates formed their own clusters; E. uekii was included in clades of chicken Eimeria and type B was include in clades of turkey Eimeria. Based on our findings in this study and previous data, we herein propose type B as E. raichoi. These genetic data will be helpful to conduct detailed classification and understand the impact of these parasites for conservation of endangered Japanese rock ptarmigans.

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Molecular analyses revealed Eimeria isolates from Japanese rock ptarmigans formed own clades.

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The species was phylogenetically closely related to virulent chicken Eimeria spp.

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Based on morphological data and sequences, Eimeria type B was proposed as a new species E. raichoi.

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These parasites could be the key factor for conservation of the endangered birds.

Surveillance of Eimeria species in wild Japanese rock ptarmigans, Lagopus muta japonica, and insight into parasitic seasonal life cycle at timberline regions of the Japanese Alps

The Japanese rock ptarmigan, Lagopus muta japonica, inhabits the alpine zone of mountainous areas at 3000 m above sea level. Since L. m. japonica is endangered due to a decline in the overall population, controlling infectious diseases such as those caused by protozoan parasites is a critical factor in the conservation of this species. Although Eimeria spp. are considered to have a negative impact on Japanese rock ptarmigan populations, the ecological interactions between the parasites and their hosts have not yet been fully clarified. We therefore conducted seasonal surveys of the prevalence of Eimeria spp. in Japanese rock ptarmigan populations. In addition, we recorded the ambient temperature in ptarmigan habitat and characterized the ability of eimerian isolates to acquire infectivity. Eimeria spp. were detected in 217 of 520 (41.7%) Japanese rock ptarmigan fecal samples in 2006 and in 177 of 308 (57.5%) fecal samples in 2007. Specifically, we observed two types of oocysts characteristic of E. uekii and type B. In adult birds and chicks, infection rates increased towards August (summer) and then decreased as the temperature decreased toward November (winter). Oocyst counts per gram (OPG) of feces peaked in August in adults and chicks, and OPG values were markedly higher in chicks than in adults. Isolated Eimeria spp. oocysts sporulated at temperatures as low as 8 °C and remained viable after being stored at 4 °C for 6 months. Our findings suggest that Eimeria spp. can complete their annual lifecycle in the cold timberline regions inhabited by the host, the Japanese rock ptarmigan, and that Eimeria spp. infection is widespread in the bird populations examined.

Host-Parasite Interactions and Population Dynamics of Rock Ptarmigan

Populations of rock ptarmigan (Lagopus muta) in Iceland fluctuate in multiannual cycles with peak numbers c. every 10 years. We studied the ptarmigan-parasite community and how parasites relate to ptarmigan age, body condition, and population density. We collected 632 ptarmigan in northeast Iceland in early October from 2006 to 2012; 630 (99.7%) were infected with at least one parasite species, 616 (98%) with ectoparasites, and 536 (85%) with endoparasites. We analysed indices for the combined parasite community (16 species) and known pathogenic parasites, two coccidian protozoans Eimeria muta and Eimeria rjupa, two nematodes Capillaria caudinflata and Trichostrongylus tenuis, one chewing louse Amyrsidea lagopi, and one skin mite Metamicrolichus islandicus. Juveniles overall had more ectoparasites than adults, but endoparasite levels were similar in both groups. Ptarmigan population density was associated with endoparasites, and in particular prevalence of the coccidian parasite Eimeria muta. Annual aggregation level of this eimerid fluctuated inversely with prevalence, with lows at prevalence peak and vice versa. Both prevalence and aggregation of E. muta tracked ptarmigan population density with a 1.5 year time lag. The time lag could be explained by the host specificity of this eimerid, host density dependent shedding of oocysts, and their persistence in the environment from one year to the next. Ptarmigan body condition was negatively associated with E. muta prevalence, an indication of their pathogenicity, and this eimerid was also positively associated with ptarmigan mortality and marginally inversely with fecundity. There were also significant associations between fecundity and chewing louse Amyrsidea lagopi prevalence (negative), excess juvenile mortality and nematode Capillaria caudinflata prevalence (positive), and adult mortality and skin mite Metamicrolichus islandicus prevalence (negative). Though this study is correlational, it provides strong evidence that E. muta through time-lag in prevalence with respect to host population size and by showing significant relations with host body condition, mortality, and fecundity could destabilize ptarmigan population dynamics in Iceland.

A new eimeriid (Apicomplexa) species from endangered Attwater's prairie chickens (Tympanuchus cupido attwateri) in Texas

The Attwater's prairie chicken (APC; Tympanuchus cupido attwateri Bendire, 1894) has been a federally listed endangered species since 1967. Several captive propagation programs consisting of small populations are being used to keep this species from extinction. Fecal samples were collected from APCs in April 2007 and again in August 2008 from 2 separate captive propagation facilities in Texas after clinical signs of coccidiosis were observed. One Eimeria species was observed (Eimeria attwateri), which we describe as a putative new species. Sporulated oocysts are ellipsoidal, 30.0 × 18.4 (27.4-31.3 × 16.0-22.4) µm. Oocysts have a smooth wall 0.7 µm thick and lack both a micropyle and oocyst residuum, but 1 ellipsoidal polar granule is present, 2.3 × 1.9 (2.1-2.4 × 1.7-2.0) µm. Sporocysts have a nipple-like Stieda body with a rounded opposite end and are 14.0 × 7.1 (10.2-16.8 × 6.0-9.2) µm. The sporocysts contain a sporocyst residuum usually consisting of 2-4 dispersed globules, and each sporozoite contains 2 large posterior spheroid refractile bodies 3.4 µm wide. Nucleotide sequence amplified from the 18S rDNA does not match any DNA sequence information for publicly available Eimeria species, and phylogenetic reconstructions place this species with other eimerians from Galliformes. The discovery of a potentially pathogenic species of Eimeria in captive APCs is of great importance, and managers should be aware of the potential devastating effect(s) this parasite could have on the APC conservation programs.