Phylogenetic position of Eimeria antrozoi, a bat coccidium (Apicomplexa: Eimeriidae) and its relationship to morphologically similar Eimeria spp. from bats and rodents based on nuclear 18S and plastid 23S rDNA sequences.

Partial plastid 23S and nuclear 18S rDNA genes were amplified and sequenced from 2 morphologically similar Eimeria species. E. antrozoi from a bat (Antrozous pallidus) and E. arizonensis from deer mice (Peromyscus spp.), as well as some other Eimeria species from bats and rodents. The phylogenetic trees clearly separated E. antrozoi from E. arizonensis. The phylogenies based on plastid 23S rDNA data and combined data of both plastid and nuclear genes grouped 2 bat Eimeria and 3 morphologically similar Eimeria species from rodents into 2 separate clades with high bootstrap support (100%, 3 rodent Eimeria species; 72-97%, 2 bat Eimeria species), which supports E. antrozoi as a valid species. The rodent Eimeria species did not form a monophyletic group. The 2 bat Eimeria species formed a clade with the 3 morphologically similar rodent Eimeria species (E. arizonensis, E. albigulae, E. onychomysis, all from cricetid rodents) with 100% bootstrap support, whereas 2 other rodent Eimeria species (E. nieschulzi, E. falciformis, from murid rodents) formed a separate clade with 100% bootstrap support. This suggests that the 2 Eimeria species from bats might be derived from rodent Eimeria species and may have arisen as a result of lateral host transfer between rodent and bat hosts.     

Molecular characterization and phylogenetic analysis of Eimeria from turkeys and gamebirds: implications for evolutionary relationships in Galliform birds

In order to determine the evolutionary relationships among Eimeria species that parasitize birds of the Galliformes, the 18s rDNA gene and a portion of the cytochrome oxidase subunit 1 (cox-1) were amplified from Eimeria species isolated from turkeys, chukars, and pheasants. The phylogenetic analysis of these sequences suggests that species infecting chickens are polyphyletic and, therefore, do not all share a direct common ancestor. Both the 18s rDNA and the cox-1 sequences indicate that Eimeria tenella and Eimeria necatrix are more closely related to Eimeria of turkeys and pheasants than to other species that infect the chicken. It is, therefore, likely that the chicken Eimeria spp. represent 2 separate ancestral colonizations of the gut, one of which comprises E. tenella and E. necatrix that infect the ceca, while the other includes Eimeria acervulina, Eimeria brunetti, Eimeria maxima, and Eimeria mitis, which infect the upper regions of the intestine.     

Eimeria chihuahuaensis sp.n. and Other Coccidia from Dipodomys spp. in El Paso County, Texas

SYNOPSIS. Dipodomys merriami Mearns and Dipodomys ordi Woodhouse were surveyed for coccidia in El Paso County, Texas. Infections with Eimeria chobotari. Eimeria dipodomysis and Eimeria balphae were 24.8%. 4.4%, and 11%, respectively, for D. ordi. Dipodomys merriami had an infection level of 23.8% with E. chobotari . Four animals concurrently harbored E. chobotari and E. balphae or E. dipodomysis or a new species Eimeria chihuahuaensis. Male and female host infection levels were not significantly different. The new species is described and photographs of 3 previously described Eimeria from Dipodomys are presented.     

Coccidia in camels (Camelus dromedarius) in Saudi Arabia

Saudi Arabian camels (Camelus dromedarius) are infected with three species of Eimeria: E. dromedarii (28.4%), E. rajasthani (22.2%), and E. cameli (19.2%); 41.6% of the animals examined were positive. The highest prevalence of infection was reported in the western region of the country. Mixed infection with two Eimeria species is most common; E. dromedarii was most frequently and generally the most predominant species. Eimeria dromedarii and E. rajasthani are described for the first time from Saudi Arabian camels.     

Eimeria species (Apicomplexa: Eimeriidae) from arctic ground squirrels (Spermophilus parryii) and red squirrels (Tamiasciurus hudsonicus) in Alaska and in Siberia, Russia

Fecal samples from arctic ground squirrels (Spermophilus parryii) collected in Alaska (n = 90) and Russia (n = 46) and from red squirrels (Tamiasciurus hudsonicus) in Alaska (n = 35) were examined for the presence of Eimeria spp. (Apicomplexa: Eimeriidae). Four species were recovered from arctic ground squirrels, including Eimeria callospermophili (prevalence = 18%), Eimeria cynomysis (23.5%), Eimeria lateralis (19%), and Eimeria morainensis (77%). A single species, Eimeria tamiasciuri (91%), was recovered from red squirrels. Eimerians recovered from arctic ground squirrels represent new host records, and the single species from red squirrels is a new geographic record. Alaskan arctic ground squirrel prevalence was higher for E. callospermophili (Alaska = 22% vs. Russia = 9%), E. cynomysis (34% vs. 2%), and E. lateralis (27% vs. 4%), but not E. morainensis (78% vs. 76%).     

Construction of PCR primers to detect and distinguish Eimeria spp. in northern bobwhites and a survey of Eimeria on gamebird farms in the United States

Coccidiosis is an important disease in captive gamebirds, including northern bobwhites (Colinusvirginianus). Three Eimeria species, Eimeria lettyae, Eimeria dispersa, and Eimeria colini, have been described in bobwhites. Distinguishing the various Eimeria spp. is often problematic because of similarity in oocyst morphology and site of infection and thus requires live bird infections to distinguish between the coccidian species. To aid in identification and diagnosis, PCR specific primers were generated against the internal transcribed spacer region 1 (ITS-1) of the ribosomal RNA gene using sequences obtained from coccidian-positive samples collected from diagnostic cases or litter from captive bobwhites. Three distinct Eimeria spp. were detected. Species-specific primers were constructed and used to survey the prevalence of the species in 31 samples collected from 13 states. The primers survey results identified E. lettyae, E. dispersa, and Eimeria sp. in 20 (64.5%), 22 (71%), and 29 (93.5%) of the samples, respectively. Mixed infections were common: 13 (41.9%) samples had 3 Eimeria spp., 14 (45.2%) had 2 spp., and 4 (12.9%) samples had only 1 species. The species were widely distributed over the area sampled and were not associated with the age of the flock.     

Eimeria spp. (Apicomplexa: Eimeriidae) from the eastern chipmunk (Tamias striatus) in Pennsylvania with a description of one new species

Intestinal contents of 41 eastern chipmunks (Tamias striatus) from Armstrong County, Pennsylvania, were examined for the presence of Eimeria spp. Three previously named species were identified: E. lateralis (prevalence = 9%), E. ovata (3%), and E. vilasi (74%); 1 new species, Eimeria tamiensis n. sp. (74%), is described here. This report extends the geographic ranges of the named species into Pennsylvania. Sporulated oocysts of E. tamiensis n. sp. are ovoid and 18.6 x 14.5 (16-23 x 12-17) microm, with no micropyle or residuum. Sporocysts are ellipsoid and 8.6 x 5.4 (7-10 x 4-8) microm. with a Stieda body and granular residuum. Prevalences of E. lateralis and E. vilasi were similar to those reported previously. The differences in prevalences may be due to different life-history strategies of high- and low-prevalence Eimeria species.     

Conservation of proteins involved in oocyst wall formation in Eimeria maxima, Eimeria tenella and Eimeria acervulina

Vaccination with proteins from gametocytes of Eimeria maxima protects chickens, via transfer of maternal antibodies, against infection with several species of Eimeria. Antibodies to E. maxima gametocyte proteins recognise proteins in the wall forming bodies of macrogametocytes and oocyst walls of E. maxima, Eimeria tenella and Eimeria acervulina. Homologous genes for two major gametocyte proteins - GAM56 and GAM82 - were found in E. maxima, E. tenella and E. acervulina. Alignment of the predicted protein sequences of these genes reveals that, as well as sharing regions of tyrosine richness, strong homology exists in their amino-terminal regions, where protective antibodies bind. This study confirms the conservation of the roles of GAM56 and GAM82 in oocyst wall formation and shows that antibodies to gametocyte antigens of E. maxima cross-react with homologous proteins in other species, helping to explain cross-species maternal immunity.     

Characterization of the complete mitochondrial genomes of five Eimeria species from domestic chickens

Chicken coccidiosis caused by members of the genus Eimeria causes significant economic losses worldwide. In the present study we sequenced the complete mitochondrial DNA (mtDNA) sequences of six Eimeria species and analyzed features of their gene contents and genome organizations. The complete mt genomes of E. acervulina, E. brunetti, E. maxima, E. necatrix, E. tenella and E. praecox were 6179bp, 6148bp, 6169bp, 6214bp, 6213bp and 6174bp in size, respectively. All of the mt genomes consist of 3 genes for proteins (cox1, cox3, and cytb), 12 gene fragments for the large subunit (LSU) rRNA, and 7 gene fragments for the small subunit (SSU) rRNA, but no transfer RNA genes. The organization of the mt genomes is similar to that of Plasmodium, but distinct from Babesia and Theileria. The putative direction of translation for 3 genes (cox1, cox3, and cytb) was the same in all six Eimeria species. The contents of A+T of the mt genomes were 65.35% for E. acervulina, 65.43% for E. brunetti, 64.53% for E. maxima, 65.04% for E. necatrix, 64.98% for E. tenella and 65.59% for E. praecox. The AT bias has a significant effect on both the codon usage pattern and amino acid composition of proteins. Phylogenetic analyses using concatenated nucleotide sequences of the 2 protein-coding genes (cytb and cox1), with three different computational algorithms (Bayesian analysis, maximum parsimony and maximum likelihood), all revealed distinct groups with high statistical support, indicating that the six Eimeria spp. represent six distinct but closely-related species. These data provide novel mtDNA markers for studying the molecular epidemiology and population genetics of the six Eimeria spp., and should have implications for the molecular diagnosis, prevention and control of coccidiosis in domestic chickens.     

Phylogenetic relationships among rodent Eimeria species determined by plastid ORF470 and nuclear 18S rDNA sequences

Phylogenetic analyses for 10 rodent Eimeria species from different host genera based on plastid ORF470 and nuclear 18S rDNA sequences were done to infer the evolutionary relationships of these rodent Eimeria species and their correlation to morphology and host specificity. The phylogenies based on both data sets clearly grouped the 10 rodent Eimeria species into two major lineages, which reflect more their morphological differences than host specificity. Species in lineage A have spheroidal to subspheroidal sporulated oocysts, are similar in size (18-29 x 17-23; xbar = 22 x 20 microm), have an oocyst residuum and one-two polar granules; these include Eimeria albigulae (Neotoma), Eimeria arizonensis (Peromyscus, Reithrodontomys), Eimeria onychomysis (Onychomys) and Eimeria reedi (Perognathus). Species in lineage B, including Eimeria falciformis (Mus), Eimeria langebarteli (Reithrodontomys), Eimeria nieschulzi (Rattus), Eimeria papillata (Mus), Eimeria separata (Rattus) and Eimeria sevilletensis (Onychomys) have different shapes (ovoid, ellipsoid, elongated ellipsoid, etc.), differ greatly in size (10-27 x 9-24; xbar = 19 x 16 microm) and all lack an oocyst residuum. Thus, The oocyst residuum was the most determinant feature that differentiated the two lineages. The accession numbers of ORF470 of E. albigulae, E. arizonensis, E. falciformis, E. nieschulzi, E. onychomysis, E. papillata, E. reedi, E. separata, E. sevilletensis, E. langebarteli are AF311630-AF311639 and 18S rDNA of E. langebarteli, E. papillata, E. reedi, E. separata, E. sevilletensis are AF311640-AF311644.     

Comparison of the ITS1 and ITS2 rDNA in Eimeria callospermophili (Apicomplexa:Eimeriidae) from sciurid rodents

The taxonomy of the coccidia has historically been morphologically based. The purpose of this study was to establish if conspecificity of isolates of Eimeria callospermophili from 4 ground-dwelling squirrel hosts (Rodentia: Sciuridae) is supported by comparison of rDNA sequence data and to examine how this species relates to eimerian species from other sciurid hosts. Eimeria callospermophili was isolated from 4 wild-caught hosts, i.e., Urocitellus elegans, Cynomys leucurus, Marmota flaviventris , and Cynomys ludovicianus . The ITS1 and ITS2 genomic rDNA sequences were PCR generated, sequenced, and analyzed. The highest intraspecific pairwise distance values of 6.0% in ITS1 and 7.1% in ITS2 were observed in C. leucurus. Interspecific pairwise distance values > 5% do not support E. callospermophili conspecificity. Generated E. callospermophili sequences were compared to Eimeria lancasterensis from Sciurus niger and Sciurus niger cinereus and to Eimeria ontarioensis from S. niger. A single, well-supported clade was formed by E. callospermophili amplicons in neighbor joining and maximum parsimony analyses. However, within the clade, there was little evidence of host or geographic structuring of the species.     

Coccidian assemblages in the Wyoming ground squirrel, Spermophilus elegans elegans.

One thousand nineteen Wyoming ground squirrels (Spermophilus elegans elegans) from 4 populations in southern Wyoming were examined for intestinal parasites. The most prevalent parasites were 6 species of coccidia: Eimeria beecheyi, Eimeria bilamellata, Eimeria callospermophili, Eimeria larimerensis, Eimeria morainensis, and Eimeria spermophili. Most ground squirrels harbored 2 or more species. This eimerian assemblage was present across populations and over years. Differences in the prevalence of infection were not found among host age classes or between sexes. The presence or absence of helminths was independent of the presence and absence of Eimeria. A log-linear model to test the independence of the distribution of Eimeria spp. among hosts revealed 3 significant positive associations, for E. bilamellata and E. beecheyi, E. morainesis and E. callospermophili, and E. larimerensis and E. bilamellata.     

Coccidia (Apicomplexa: Eimeriidae) from sciurid rodents (Eutamias, Sciurus, Tamiasciurus spp.) from the western United States and northern Mexico with description of two new species

Since May 1979, 190 rodents in the family Sciuridae, representing three genera and nine species, have been collected in the western United States and northern Mexico and examined for coccidia; 71 (37%) had coccidian oocysts in their feces. These included 2 of 12 (17%) Eutamias canipes; 7 of 12 (58%) E. dorsalis; 18 of 50 (36%) E. merriami; 33 of 96 (34%) E. obscurus; 3 of 4 (75%) E. townsendii; 3 of 9 (33%) Sciurus aberti; 1 of 1 S. griseus; 1 of 1 Tamiasciurus hudsonicus mogollonensis; and 3 of 5 (60%) T. mearnsi. The following coccidians were identified from infected rodents: Eimeria cochisensis n. sp. and Eimeria dorsalis n. sp. from E. canipes, E. cochisensis, E. dorsalis, and E. tamiasciuri from E. dorsalis, E. dorsalis and E. tamiasciuri from E. merriami; E. cochisensis, E. dorsalis, E. tamiasciuri, and E. wisconsinensis from E. obscurus; E. cochisensis and E. dorsalis from E. townsendii; E. ontarioensis and E. tamiasciuri from S. aberti; E. tamiasciuri from S. griseus; E. tamiasciuri and E. toddi from T. h. mogollonensis; and E. tamiasciuri from T. mearnsi. Sporulated oocysts of Eimeria dorsalis n. sp. were ovoid, 21.9 x 16.8 (17-24 x 14-20) micrometer with sporocysts ovoid, 11.5 x 6.9 (10-14 x 6-8) micrometer. Sporulated oocysts of Eimeria cochisensis n. sp. were spheroid to subspheroid, 16.7 x 15.3 (15-18 x 14-17) micrometer, with sporocysts ovoid, 8.4 x 5.6 (6-11 x 4-7) micrometer. Fifty-five of 71 (77%) infected hosts had oocysts of only one eimerian species in their feces at the time they were examined. One eimerian, E. tamiasciuri, was found in seven of nine host species in three genera. A list is provided of all eimerians (22, including the species described here) that have been described in the literature from Eutamias, Sciurus, and Tamiasciurus spp.     

Coccidia in Camels (Camelus dromedarius) in Saudi Arabia1

Saudi Arabian camels {Camelus dromedarius) are infected with three species of Eimeria: E. dromedarii (28.4%), E. rajasthani < 22.2%), and E. cameli (19.2%); 41.6% of the animals examined were positive. The highest prevalence of infection was reported in the western region of the country. Mixed infection with two Eimeria species is most common; E. dromedarii was most frequently and generally the most predominant species. Eimeria dromedarii and E. rajasthani are described for the first time from Saudi Arabian camels.     

Cross-transmission of Eimeria spp. (Protozoa, Apicomplexa) of rodents--a review

A total of 169 cross-transmission attempts has been made with 44 (11.8%) of the 372 named species of Eimeria of rodents. Of these, 161 were rodent-to-rodent, 6 rodent-to-lagomorph, and 1 each rodent-to-carnivore and rodent-to-bird. None of the last three categories was successful. In the rodent-to-rodent combinations, 39 (80%) of the 49 attempts to transmit a coccidian species from one rodent species to another of the same genus were successful, and only 14 (12.5%) of the 112 attempts to transmit a coccidium to a rodent of a different genus were successful. Eight of the successful attempts were with E. chinchillae, which was the only truly euryxenous species of Eimeria in the group. Two successful attempts were between between the closely related rodent genera Spermophilus and Cynomys, and two were both of E. separata from Rattus norvegicus to some genetic strains but not to others of Mus musculus. One attempt with E. vermiformis from Mus musculus to Rattus norvegicus required treatment of the rat with the immunosuppressant dexamethasone to succeed. More cross-transmission studies are needed to determine the host spectra of the species of Eimeria and other coccidian genera, and to determine the roles of genetics and immunosuppression in their transmission.     

Cross-Transmission of Eimeria spp. (Protozoa, Apicomplexa) of Rodents—A Review

A total of 169 cross-transmission attempts has been made with 44 (11.8%) of the 372 named species of Eimeria of rodents. Of these, 161 were rodent-to-rodent, 6 rodent-to-lagomorph, and 1 each rodent-to-carnivore and rodent-to-bird. None of the last three categories was successful. In the rodent-to-rodent combinations, 39 (80%) of the 49 attempts to transmit a coccidian species from one rodent species to another of the same genus were successful, and only 14 (12.5%) of the 112 attempts to transmit a coccidium to a rodent of a different genus were successful. Eight of the successful attempts were with E. chinchillae , which was the only truly euryxenous species of Eimeria in the group. Two successful attempts were between the closely related rodent genera Spermophilus and Cynomys , and two were both of E. separata from Rattus norvegicus to some genetic strains but not to others of Mus musculus. One attempt with E. vermiformis from Mus musculus to Rattus norvegicus required treatment of the rat with the immunosuppressant dexamethasone to succeed. More cross-transmission studies are needed to determine the host-spectra of the species of Eimeria and other coccidian genera, and to determine the roles of genetics and immunosuppression in their transmission.     

Electrophoretic and immunologic characterization of proteins of merozoites of Eimeria acervulina, E. maxima, E. necatrix, and E. tenella.

Merozoites of Eimeria acervulina, Eimeria maxima, Eimeria necatrix, and Eimeria tenella were compared by gel electrophoresis, western-blotting with chicken antiserum, indirect fluorescent antibody reactions, and antiserum neutralization. Merozoites from the 4 species had dissimilar patterns of proteins and antigens in soluble and membrane fractions. Coomassie blue staining of SDS-PAGE gels revealed 16-22 protein bands depending on the species of merozoite but only 3 bands per species in the membrane fractions. Homologous and heterologous antisera recognized 5-12 soluble fraction bands and 3-7 membrane fraction bands on immunoperoxidase-stained western blots, depending on the species. When antisera from infected chickens were used in an indirect fluorescent antibody reaction, the merozoites of E. tenella and E. necatrix had a strong reaction with homologous and heterologous antisera. Merozoites of E. acervulina and E. maxima reacted with homologous antisera but had a weak or no reaction with heterologous antisera. Chicken antiserum against E. tenella had no effect on the viability of E. tenella merozoites when they were inoculated into chicken embryos.     

Description and phylogeny of a new species of Eimeria from double-crested cormorants (Phalacrocorax auritus) near Fort Gaines, Georgia

The renal parasite Eimeria auritusi has caused several mortality events in double-crested cormorants (DCC; Phalacrocorax auritus) in the Midwest and southeastern United States. This parasite has only been detected during large-scale outbreaks, and its presence and prevalence in healthy populations of cormorants is unknown. In this study, 80 DCC were collected from the Chattahoochee River near Fort Gaines, Georgia, and examined for kidney and intestinal coccidia. Eighteen (22.5%) and 56 (70%) of the DCC were positive for E. auritusi and a new species of intestinal Eimeria, respectively. Oocysts of the new intestinal Eimeria species had a thin colorless wall, were ovoid with rare bumps on the outer surface, and measured 17.1 microm +/- 1.5 x 14.7 microm +/- 1.0 (16-18.5 x 13-17), with an average length:width ratio of 1.17 microm (1.03-1.29). A prominent micropyle (4-4.5 microm) was present, and a large oval-to-round polar body (2.5 microm) was located beneath the micropyle. Sporocysts were ovoid and measured 9.6 microm +/- 0.6 x 5.9 microm +/- 0.5 (8.5-10.5 x 5-6.5), with an average length:width ratio of 1.63 (1.3-1.82) with small stieda body present. Amplification and sequencing of a fragment of the 18S rRNA gene indicated that the 2 DCC Eimeria species and 2 Eimeria species from cranes were in a separate group from other Eimeriidae. These data indicate that E. auritusi and this new species of intestinal Eimeria are prevalent in this apparently healthy DCC population. The cause of renal coccidiosis outbreaks in other populations of cormorants is unknown but could be due to crowding or stress during the winter months or some other associated pathogen or immunosuppressor that might predispose individuals to clinical disease.