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PubMed1996

Population dynamics of two species of Eimeria (Apicomplexa: Eimeriidae) in deer mice (Peromyscus maniculatus): biotic and abiotic factors.

I investigated whether biotic factors (competitive exclusion between parasites and host immunity), abiotic factors (high temperature, low temperature, and rainfall), or a combination of the 2 affected the population dynamics of Eimeria arizonensis and Eimeria delicata in naturally infected deer mice (Peromyscus maniculatus). There was no evidence of competitive exclusion between E. arizonensis and E. delicata, nor were E. arizonensis population dynamics affected by host immunity (young deer mice were not infected significantly more frequently than adults). However, high temperatures were negatively associated with the prevalence of observed infections (r = -0.725, P < 0.001), suggesting sporulation of oocysts might be affected. In contrast, juvenile deer mice were infected with E. delicata more frequently than adults (z = 2.05, P < 0.02), suggesting that host immunity plays a role in the population dynamics of E. delicata. Temperature and rainfall during oocyst sporulation were not significantly associated with the prevalence of observed E. delicata infections. Finally, there was no evidence that a combination of biotic and abiotic factors was important in the population dynamics of either eimerian. Thus, the population dynamics of E. arizonensis seem to be controlled by abiotic factors, whereas those of E. delicata seem to be affected by biotic factors.

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PubMedDate not supplied

[Life cycle and nucleic acid distribution in the endogenous development stages of coccidia (Coccidiida, Eimeriidae) of the Vinogradov gerbil].

Studies were undertaken of the life cycles of three intestinal coccidia: Eimeria arabiana, E. bistratum and E. poljanski, parasites of meriones vinogradovi. The number of the asexual generations, the period of appearance of the endogenous stages and the first oocysts, localization were determined. The successive phases of the growth and development of schizonts of different generations, macrogametes and microgametocytes were described. The distribution of DNA and RNA in different endogenous stages of three kinds of coccidia were studied by methods of cytochemistry.

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PubMed1996

Coccidia of the collared peccary (Tayassu tajacu) in southern Texas with descriptions of three new species of Eimeria (Apicomplexa: Eimeriidae).

In February 1993, fresh fecal samples were collected from 47 collared peccaries (Tayassu tajacu) killed by hunters at the Chaparral Wildlife Management Area, southern Texas, USA. Five species of coccidia (Eimeria chaparralensis n. sp. [9/47, 19%], Eimeria dicotylensis n. sp. [21/47, 21%], Eimeria pecari n. sp. [2/47, 4%], Eimeria sp. [1/47, 2%], and Klossia sp. [1/47, 2%]) were observed. Measurements are in micron. Sporulated oocysts of E. chaparralensis are rough-walled, elongate ovoidal, 43.3 x 28.5 (37-52 x 26-35); sporocysts are elongate ellipsoidal 21.8 x 9.0 (16-27 x 7-12); micropyle (approximately 4.9), Stieda, and substieda body are present; sporocyst residuum is present in newly sporulated oocysts; polar granule and oocyst residuum are absent. Sporulated oocysts of E. dicotylensis are smooth-walled, ovoidal, 25.7 x 20.1 (23-29 x 17-23); sporocysts are ellipsoidal 13.0 x 6.9 (11-17 x 6-9); micropyle and oocyst residuum are absent; polar body sometimes present; Stieda body and sporocyst residuum always present. Sporulated oocysts of E. pecari are smooth-walled, elongate ellipsoidal, 26.8 x 18.1 (22-31 x 15-21); sporocysts are elongate ellipsoidal 16.4 x 5.9 (13-22 x 4-7); micropyle (approximately 5.8) with collar, Stieda body, substieda body, and sporocyst residuum are present; polar granule and small oocyst residuum sometimes present. There were no sex or age differences in prevalences of infection, and there were no positive or negative associations between any species of eimerian. The majority of hosts were infected with a single species of Eimeria. Overall prevalence of infection with eimerians was 23/47 (49%).

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PubMed1997

Eimeria spp. (Apicomplexa: Eimeriidae) from black- and white-tailed prairie dogs (Cynomys ludovicianus and Cynomys leucurus) in central and southeast Wyoming.

Feces collected from live-trapped black- (Cynomys ludovicianus) and white-tailed prairie dogs (Cynomys leucurus) from central and southeastern Wyoming were examined to determine the presence and prevalence of eimerian species. Six species (Eimeria adaensis [black-tailed prairie dog prevalence = 33%, white-tailed prairie dog prevalence = 51%], Eimeria beecheyi [8%, 28%], Eimeria callosper-mophili [64%, 71%], Eimeria lateralis [3%, 7%], Eimeria morainensis [19%, 8%], and Eimeria spermophili [2%, 1%]) were identified from both host species. Eimeria pseudospermophili was found infecting only black-tailed (prevalence = 1%) and Eimeria bilamellata only in white-tailed prairie dogs (2%). Reinfections in individual hosts were observed with E. callospermophili and E. adaensis. Comparison of these results with the published literature suggests that the host genera Cynomys and Spermophilus share a common guild of eimerians and that members of this guild have a long evolutionary association with these hosts, or host switching, or both, is common between these groups.

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PubMedDate not supplied

[Effect of ultrasound on Eimeria tenella (Coccidiida, Eimeriidae)].

Ultrasonics (frequency--20 kHz intensity--11.9 w/cm2 and external lateral surface--1.88 cm2) can annihilate for 8 minutes from 90 to 100% of non-sporulated and for 16 minutes 99.5 to 100% of sporulated oocysts of E. tenella maintained in 10ml suspension plunged into a bath with ice. The destruction rate of oocysts depends on the duration of the ultrasonics effect and the increase of its intensity. It should be noted that the increase in intensity is more effective in this respect than the extension of ultrasonics effect.

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PubMed1997

Isospora tiaris n.sp. (Apicomplexa: Eimeriidae) from the sooty grassquit (Tiaris fuliginosa), a passeriform bird of South America.

Isospora tiaris n. sp. is described from the feces of an adult bird, a sooty grassquit (Tiaris fuliginosa) from Venezuela. The oocysts are subspherical, 27.1 x 23.8 (24.7-30.0 x 21.2-26.5) microns with a bilayered, smooth, colorless wall. A micropyle and oocyst residuum are absent; an ellipsoidal polar granule is usually present. Sporocysts are ovoidal, 14.7 x 10.8 (12.4-16.8 x 8.8-12.4) microns with prominent Stieda and substieda bodies and a residuum composed of small uniform granules.

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PubMed1997

Eimeria (Protozoa: Eimeriidae) from North American sciurids, Glaucomys sabrinus and Tamias townsendii: with a description of a new species.

From 1990 to 1991, 11 northern flying squirrels, Glaucomys sabrinus, and 30 Townsend's chipmunks, Tamias townsendii, were live-trapped, marked, and released in MacDonald Forest, Benton Co., Oregon and their feces at each capture examined for the presence of coccidian parasites. Two eimerians were found in G. sabrinus: Eimeria dorneyi and a second species we describe here as new. One species, Eimeria vilasi, was identified from T. townsendii. Sporulated oocysts of the new eimerian are strongly ellipsoidal, pointed at 1 end, and are 47.2 x 25.0 (41-52 x 22-31) microns with ovoidal sporocysts, 19.0 x 10.5 (17-21 x 9-11) microns. A micropyle and oocyst residuum are absent, but, occasionally, a polar granule is present in the oocyst. In the sporocysts, Stieda and substieda bodies are present, as is a membrane-bound residuum. Sporulated oocysts of E. dorneyi are uniformly ellipsoidal, 23.0 x 14.7 (17-26 x 13-16) microns with elongate ellipsoidal sporocysts, 11.6 x 5.7 (9-13 x 5-7) microns. A micropyle and oocyst residuum are absent, but 1 polar granule is present. A Stieda body is present, but sub- and parastieda bodies are absent. The sporocyst residuum is composed of granules in a compact mass. Here we provide phototype (hapantotype) specimens archived in a nationally accredited museum and a line drawing (cartoon) to supplement the one provided by Soon and Dorney because their drawing did not show the sporocyst residuum given in the written description.

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PubMed1997

Eimeria schmidti n. sp. (Apicomplexa: Eimeriidae) from the sandy fringe-toed lizard (Acanthodactylus schmidti) in Saudi Arabia.

Eimeria schmidti n.sp. is described from the gall bladder of Acanthodactylus schmidti from Al-Thomama area in the central region of Saudi Arabia. Sporulated oocysts are ellipsoid 31.2 x 23.3 (26.9-36.4 x 21.2-26.0). Oocyst wall is smooth, greenish yellow, 1.31 (1.16-1.41) um thick and two-layered. Micropyle, polar granule and oocyst residuum are absent. Sporocysts are ellipsoid 12.6 x 9.3 (10.9-14.1 x 7.6-10.0) um. Sporocyst residuum is present. The sporocysts lack a stieda body. Sporozoites are banana shaped blunt at one end and tapered at the second end. Eimeria species from Lacertidae are compared.

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PubMed1997

Two new species of Eimeria (Apicomplexa, Eimeriidae), from local chickens (Gallus domesticus) in Saudi Arabia.

In this study, two new species of Eimeria parasitizing domestic fowl (Gallus domesticus) are described. Species data were recorded as follow: Eimeria jeddahensis sp. n. with ovoidal occysts 23.5-29.2 x 17.5-22.4 (25.78 +/- 0.357 x 20.32 +/- 0.33) microns, with smooth single layered wall; bilobed polar granule and micropyle present. Sporocysts elongated ovoidal 10-13.5 x 6.3-8.0 (12.03 +/- 0.135 x 7.10 +/- 0.070) microns with a thick, knob like Stieda body and residuum. Eimeria waeli sp. n. with ellipsoidal oocysts 26.5-31.0 x 23.5-27.0 (28.30 +/- 0.327 x 25.30 +/- 0.278) microns with a double-layered wall; polar granule and micropyle present. Sporocysts ovoidal 13.5-16.0 x 7.0-9.5 (14.67 +/- 0.135 x 8.32 +/- 0.162) microns with distinct Stieda body and residuum. The host bird belongs to order Galliformes.

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PubMed1998

A new coccidian parasite (Apicomplexa: Eimeriidae) from the legless lizard Diplometopon zarudnyi (Amphisbaenia: Trogonophidae) in Saudi Arabia.

Large numbers of coccidian oocysts belonging to the genus Isospora were obtained from the intestinal contents of ten legless lizards Diplometopon zarudnyi collected from eastern region, Saudi Arabia. The oocysts are spherical to subspherical, 33.3 x 30.9 (28.6-35.2 x 26.8-32.7) microns with a bilayered wall 1.4 (1.3-1.6) microns thick. Micropyle, polar granule and oocyst residuum are absent. The sporocysts are ellipsoid, 20.1 x 13.8 (17.5-22.3 x 12.2-15.4) microns. A sporocyst residuum, stieda and substieda bodies are present. Sporozoites are banana shaped, blunt at one end and tapered at the other and containing spherical anterior and posterior refractile bodies of the same size. Since this Isospora sp. does not resemble, any other species of Isospora previously described from lizards of the genus Diplometopon, it has been named Isospora diplometoponi n.sp. after the host generic name.

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PubMed1998

Exogenous stages of Eimeria bemricki n. sp. (Apicomplexa: Eimeriidae) from the great gray owl, Strix nebulosa (Foster).

Exogenous stages of a new species of Eimeria are described from feces of a captive great gray owl, Strix nebulosa, held at the Gabbert Raptor Center, University of Minnesota, St. Paul, Minnesota. Oocysts (n = 100) of Eimeria bemricki are spherical to subspherical, 19.2 x 19.0 (21.5-16.0 x 21.0-16.0) microm, with ovoidal sporocysts (n = 100), 10.0 x 6.5 (12.0-7.0 x 7.0-5.5) microm and sporozoites (n = 20), 8.2 x 3.2 (6.8-10.1 x 2.5-3.9) microm. Stieda bodies, substieda bodies, polar bodies, and sporocyst residua are present, but micropyle, oocyst residuum, and parastieda bodies are absent. Three refractile bodies are contained in each sporozoite.

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PubMed1998

A new Eimeria species (Apicomplexa: Eimeriidae) infecting Onychomys species (Rodentia: Muridae) in New Mexico and Arizona.

Fecal samples from 3 species of Onychomys (Rodentia: Muridae) captured in New Mexico and Arizona were examined for coccidia. Six of the 59 (10%) were infected with a new species of Eimeria. Sporulated oocysts (n = 105) of this new species are subspheroidal, 17.4 x 16.1 (14-21 x 13-19) microm, with ellipsoidal sporocysts 10.4 x 5.7 (9-12 x 5-8) microm. This species occurred in 3 of 24 (13%) Onychomys arenicola, 2 of 31 (6%) Onychomys leucogaster from New Mexico, and 1 of 4 (25%) Onychomys torridus from Arizona. Isolates recovered from O. leucogaster and O. torridus were inoculated into O. leucogaster (n = 5) and produced infections with a prepatent period of 7 days and a patent period of 7-23 days.

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PubMed2000

Taxonomic position of the human intestinal protozoan parasite Isospora belli as based on ribosomal RNA sequences.

The taxonomic positions of Isospora belli and other members of the genus Isospora are controversial. We determined the small-subunit ribosomal RNA of I. belli and used this sequence in combination with other coccidian RNA sequences for analysis of the taxonomic position of I. belli. The phylogenetic trees we obtained provide molecular evidence for three clades within a monophyletic group that represents the suborder Eimeriina. The clade containing I. belli consists of tissue-cyst-forming coccidia (Toxoplasma and Neospora) and members of the genus Isospora (I. ohioensis, I. suis, I. belli). The second clade, representing a sister clade of that containing the Isospora species, contains members of the genus Sarcocystis. The third one consists of members of the family Eimeriidae, including Eimeria and Cyclospora species. This shows that although I. belli as well as other members of the genus Isospora belong to the suborder Eimeriina, the family to which they belong is not Eimeriidae but rather Sarcocystidae. We suggest that the genus Isospora should be removed from the family Eimeriidae and placed into the family Sarcocystidae within the suborder Eimeriina.

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PubMed2004

The current status of the small subunit rRNA phylogeny of the coccidia (Sporozoa).

There is no current comprehensive assessment of the molecular phylogeny of the coccidia, as all recently published papers either deal with subsets of the taxa or sequence data, or provide non-robust analyses. Here, we present a comprehensive and consistent phylogenetic analysis of the available data for the small-subunit ribosomal RNA gene sequence, including a number of taxa not previously studied, based on a Bayesian tree-building analysis and the covariotide model of evolution. The assumptions of the analysis have been rigorously tested, and the benefits and limitations highlighted. Our results provide support for a number of prior conclusions, including the monophyly of the families Sarcocystidae (cyst-forming coccidia) and Eimeriidae (oocyst-forming coccidia), but with bird-host Isospora species in the Eimeriidae and mammal-host species in the Sarcocystidae. However, it is clear that a number of previously reported relationships are dependent on the evolutionary model chosen, such as the placements of Goussia janae, Lankesterella minimia and Caryospora bigenetica. Our results also confirm the monophyly of the subfamilies Toxoplasmatinae and Sarcocystinae, but only some of the previously reported groups within these subfamilies are supported by our analysis. Similarly, only some of the previously reported groups within the Eimeriidae are supported by our analysis, and the genus Eimeria is clearly paraphyletic. There are unambiguous patterns of host-parasite relationship within the coccidia, as most of the well-supported groups have a consistent and restricted range of hosts, with the exception of the Toxoplasmatinae. Furthermore, the previously reported groups for which we found no support all have a diverse range of unrelated hosts, confirming that these are unlikely to be natural groups. The most interesting unaddressed questions may relate to Isospora, which has the fewest available sequences and host-parasite relationships apparently not as straightforward as elsewhere within the suborder.

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PubMed2002

The phylogeny of Goussia and Choleoeimeria (Apicomplexa; Eimeriorina) and the evolution of excystation structures in coccidia.

The phylogenetic relationships of Goussia janae and Choleoeimeria sp. were analyzed using the small subunit ribosomal RNA gene (SSU rDNA). This is a first attempt to study the molecular phylogeny of coccidian genera parasitizing strictly poikilotherm hosts. The biliary Eimeria-like coccidia of reptiles classified into the genus Choleoeimeria form a sister clade to the family Eimeriidae, which confirms the separate generic status of the genus Choleoeimeria. The position of Goussia is less robustly resolved, since it forms a trichotomy with the Eimeriidae and Sarcocystidae, or alternatively constitutes the earliest branch of the coccidian lineage. Morphological similarities, namely the extracytoplasmic location of the endogenous stages, and the presence of sutures in the sporocyst wall are discussed in the context of the traditional classification of eimeriids. In contrast to the morphology-based systematics, the monophyly of Goussia and Choleoeimeria is not supported by the SSU rDNA data.

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PubMedDate not supplied

[Toxoplasmids, their life cycle and systematic position].

Recent evidence on the life cycles of the toxoplasmids (Toxoplasma, Besnoitia, Sarcocystis, Hammondia, Frenkelia) has been analysed. The availability of the complex life cycles, including the alternation of sexual and asexual reproduction, in addition to gametogenesis involving the independent development of gametes that produce unequal numbers of gametes, makes it possible to include the toxoplasmids into the family Eimeriidae within the order Coccidiida. A detailed evidence recently provided for Isospora has suggested a kinship of this typical coccidian genus with toxoplasmids. At the same time much similarity is obvious between Isospora and Eimeria in the general pattern of their life cycles. Hence, the family Eimeriidae is suggested to be divided into two subfamilies: Eimeriinae Wenyon, 1926 with Eimeria as the type genus and Isosporinae Wenyon, 1926 with Isospora, Toxoplasma, Besnoitia, Sarcocystis, Frenkelia and Hammondia. The main features of the former subfamily are: various oocyst structures, the lack of the extra-intestinal development, obligatory monoxeny. The main characters of the latter subfamily: oocysts of the same pattern, the involvement of extra-intestinal development, shifts from facultative to obligatory heteroxeny.

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PubMedDate not supplied

Phylogenetic analysis of coccidia based on 18S rDNA sequence comparison indicates that Isospora is most closely related to Toxoplasma and Neospora.

The phylogenetic relationships and taxonomic affinities of coccidia with isosporan-type oocysts have been unclear as overlapping characters, recently discovered life cycle features, and even recently discovered taxa, continue to be incorporated into biological classifications of the group. We determined the full or partial 18S ribosomal RNA gene sequences of three mammalian Isospora spp., Isospora felis, Isospora ohioensis and Isospora suis, and a Sarcocystis sp. of a rattlesnake, and used these sequences for a phylogenetic analysis of the genus Isospora and the cyst-forming coccidia. Various alveolate 18S rDNA sequences were aligned and analyzed using maximum parsimony to obtain a phylogenetic hypothesis for the group. The three Isospora spp. were found to be most closely related to Toxoplasma gondii and Neospora caninum. This clade in turn formed the sister group to the Sarcocystis spp. included in the analysis. The results confirm that the genus Isospora does not belong to the family Eimeriidae, but should be classified together with the cyst-forming coccidia in the family Sarcocystidae. Furthermore, there appear to be two lineages within the Sarcocystidae. One lineage comprises Isospora and the Toxoplasma/Neospora clade which share the characters of having a proliferative phase of development preceding gamogony in the definitive host and an exogenous phase of sporogony. The other lineage comprises the Sarcocystis spp. which have no proliferative phase in the definitive host and an endogenous phase of sporogony.

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