Cross-transmission studies with Eimeria arizonensis, E. arizonensis-like oocysts and Eimeria langebarteli: host specificity at the genus and species level within the Muridae

Cross-transmission experiments were done using sporulated oocysts of Eimeria arizonensis from Peromyscus truei and Peromyscus maniculatus, and oocysts of 2 putative species that resemble E. arizonensis, i.e., Eimeria albigulae from Neotoma albigula, and Eimeria onychomysis from Onychomys leucogaster. Oocysts of each species were inoculated into representatives of P. maniculatus and the latter 2 rodent species. Other experiments were conducted wherein oocysts of Eimeria langebarteli from Peromyscus leucopus were given to P. truei and P. maniculatus. Oocysts of E. arizonensis from P. truei and P. maniculatus could be transmitted only to P. maniculatus; likewise, oocysts of E. albigulae and E. onychomysis produced patent infections only in N. albigula and O. leucogaster, respectively. Oocysts of E. langebarteli from P. leucopus could be transmitted to P. truei, but not P. maniculatus. These results indicate that E. arizonensis, and the morphologically similar E. albigulae and E. onychomysis, are distinct species that are not transmissible between the genera of their respective hosts (Peromyscus, Neotoma, Onychomys), and that some isolates of E. langebarteli, reported from 6 species of Peromyscus and Reithrodontomys megalotis, may not always be infective to P. maniculatus.     

New host and locality records of coccidia (Apicomplexa: Eimeriidae) from rodents in the southwestern and western United States.

One hundred forty-seven murid and heteromyid rodents were collected from various sites in the southwestern and western United States (Arizona, Colorado, New Mexico, Texas, and Utah) and Baja California Norte, Mexico, and their feces were examined for coccidial parasites. Of these, 53 (36%) were infected with at least 1 coccidian; 45 of 53 (85%) of the infected rodents harbored only 1 species of coccidian. Infected rodents included: 10 of 22 (45%) Neotoma albigula, 3 of 11 (27%) Neotoma floridana, 2 of 14 (14%) Neotoma lepida, 15 of 29 (52%) Neotoma micropus, 5 of 8 (63%) Peromyscus crinitis, 6 of 6 (100%) Peromyscus difficilis, 1 of 2 (50%) Peromyscus eremicus, 9 of 34 (26%) Sigmodon hispidis, and 2 of 3 (67%) Sigmodon ochrognathus; 4 Neotoma cinerea, 3 Neotoma devia, 3 Neotoma mexicana, 1 Peromyscus maniculatus, 1 Onychomys leucogaster, 1 Onychomys torridus, 3 Chaetodipus fallax, and 2 Chaetodipus penicillatus were negative. Although no new species was found, the following coccidians were identified from infected rodents: Eimeria albigulae from N. albigula, N. floridana, and N. micropus, Eimeria antonellii from N. albigula and N. micropus, Eimeria ladronensis from N. albigula, N. floridana, N. lepida, and N. micropus, Eimeria arizonensis and Eimeria lachrymalis from P. crinitis and P. difficilis, Eimeria lachrymalis from P. eremicus, Eimeria tuskeegensis from S. ochrognathus, and Eimeria roperi, Eimeria sigmodontis, Eimeria tuskeegensis, Eimeria webbae, and an unidentified species of Eimeria from S. hispidis. This report documents 12 new host and several distributional records for Eimeria species from murid rodents in Arizona, Texas, and Utah.     

New Species of Eimeria from Arizona Rodents

SUMMARY. In a survey of 52 rodents of 25 species from Grand Canyon National Park, Arizona and its vicinity, the following species of Eimeria are described: E. tamiasciuri n. sp. from the red or spruce squirrel, Tamiasciurus hudsonicus; E. lateralis n. sp. and Eimeria sp. from the mantled ground squirrel, Citellus lateralis; E. eutamiae n. sp. from the cliff chipmunk, Eutamias dorsalis; E. thomomysis n. sp. from the pocket gopher, Thomomys bottae; E. perognathi n. sp. from the rock pocket mouse, Perognathus intermedius; E. albigulae n. sp. from the white-throated woodrat, Neotoma albigula; E. operculata n. sp. from Stephens' woodrat, Neotoma stephensi; E. peromysci n. sp. and E. arizonensis n. sp. from the piñon mouse, Peromyscus truei; E. eremici n. sp. from the cactus mouse, Peromyscus eremicus ; and E. onychomysis n. sp. from the northern grasshopper mouse, Onychomys leucogaster.     

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.     

Eimeria species (Apicomplexa: Eimeriidae) infecting Peromyscus rodents in the southwestern United States and northern Mexico with description of a new species

Of 198 deermice (Peromyscus spp) collected from various localities in the southwestern United States and northern Mexico, 106 (54%) had eimerian oocysts in their feces when examined. These included 50 of 106 (47%) Peromyscus truei, 34 of 54 (63%) Peromyscus maniculatus, 4 of 17 (24%) Peromyscus leucopus, and 18 of 21 (86%) Peromyscus eremicus. The following Eimeria were identified from infected mice: Eimeria arizonensis and Eimeria langebarteli from P. truei; E. arizonensis, Eimeria peromysci, and Eimeria delicata from P. maniculatus; E. arizonensis and Eimeria lachrymalis n. sp. from P. eremicus; and E. langebarteli from P. leucopus. Of the 106 Peromyscus found positive for Eimeria, 97 (91.5%) harbored only a single eimerian species at the time of examination. Sporulated oocysts of E. lachrymalis n. sp. were ellipsoid, 27-35 X 17-21 (30.8 +/- 1.7 X 19.1-0.9) micron, possessed a smooth wall and one polar granule, but lacked a micropyle and an oocyst residuum. Sporocysts were teardrop-shaped, 9-13 X 6-10 (10.9 +/- 0.9 X 7.9 +/- 0.5) micron, and had a Stieda body and sporocyst residuum, but no substieda body. Prepatent periods in experimental infections were 3-6 days after inoculation (DAI) for E. arizonensis (hosts: P. eremicus, P. maniculatus, P. truei); 4-5 DAI for E. peromysci (host: P. maniculatus); 6-9 DAI for E. langebarteli (hosts: P. truei, P. leucopus); and 8-10 DAI for E. lachrymalis (host: P. eremicus). Patency in these infections lasted 6-11 days for E. arizonensis, 5-10 days for E. peromysci, 14-40+ days for E. langebarteli, and 19-50+ days for E. lachrymalis. Eimeria lachrymalis appears to produce occult infections in P. eremicus that can be reactivated upon inoculation of the host with E. arizonensis.     

Eimerians in Harvest Mice, Reithrodontomys spp., from Mexico, California and New Mexico, and Phenotypic Plasticity in Oocysts of Eimeria arizonensis

ABSTRACT Between May 1979 and August 1991, 48.7% (57/117) of the harvest mice ( Reithrodontomys spp.) examined from 10 localities in Mexico, California and New Mexico had coccidian oocysts in their feces. A total of 46.7% (49/105) of the Reithrodontomys megalotis examined were positive for coccidian oocysts; this included samples from five states in Mexico (47.1%, 8/17), three counties in California (66.7%, 4/6) and two counties in New Mexico (45.1%, 37/82); 66.7% (8/12) of the Reithrodontomys montanus from one county in New Mexico also were infected. Only two coccidian species, Eimeria arizonensis and Eimeria langebarteli , were found in these hosts. Oocysts of E. langebarteli were found only in R. megalotis : in all three infected mice from Madera County, California, in the only mouse from San Bernardino County, California, and in 63% (5/8) of the infected mice from four states in Mexico. Oocysts of E. arizonensis were found in R. megalotis in Mexico, California, and New Mexico and in R. montanus from New Mexico. Sporulated oocysts of E. langebarteli differed slightly from those in previously published reports by having wider oocysts and larger sporocysts. Sporulated oocysts of E. arizonensis were variable in size, with those recovered from R. montanus significantly larger in length and width and sporocyst width than those from R. megalotis . The structure of the oocyst residuum was polymorphic, both within and between host species, and within the same mouse; it could appear as one large globule, two globules, several to many smaller globules, or as a compact mass of many small granules. Oocysts with a variable residuum were larger than those with one globule in all oocyst/sporocyst dimensions. Only 9% (5/57) of the infected mice were discharging oocysts of both eimerians when examined.     

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.     

Eimeria ladronensis n. sp. and E. albigulae (Apicomplexa: Eimeriidae) from the woodrat, Neotoma albigula (Rodentia: Cricetidae)

Of 50 white-throated woodrats (Neotoma albigula) collected from Socorro Co., New Mexico, 21 (42%) had eimerian oocysts in their feces when examined. Of the 21 Neotoma found positive for Eimeria, 19 (90%) harbored a single eimerian species at time of examination. Eimeria albigulae Levine, Ivens & Kruidenier, 1957, was found in 18 (86%), and E. ladronensis n. sp. was found in five (24%) infected woodrats. Sporulated oocysts of E. ladronensis are ellipsoidal, 19-25 X 13-15 (21.4 +/- 1.3 X 14.1 +/- 1.1) micron, have a smooth wall and one or two polar granules, but lack a micropyle and an oocyst residuum. Sporocysts are tapered at one end, 7-10 X 6-7 (8.5 +/- 0.7 X 6.5 +/- 0.3) micron, and have a Stieda body and sporocyst residuum, but no substieda body. Prepatent periods for E. albigulae and E. ladronensis n. sp. are 5-6 and 8-9 days, respectively; patent periods are 7-18 and approximately 11 days, respectively.     

Enzyme variation of Eimeria arizonensis from Peromyscus truei and P. boylii

Cricetid rodents, Peromyscus truei and P. boylii, were inoculated with sporulated oocysts of Eimeria arizonensis collected from wild P. truei maintained in the lab. In P. truei the prepatent period was 4-5 days, the patent period was 9-11 days, and sporulated oocysts were 21.5 x 25.0 (20-23 x 24-26) microns with sporocysts 7.7 x 12.0 (6-8 x 10-13) microns. In P. boylii the prepatent period was 6-7 days, the patent period was 8-9 days, and sporulated oocysts were 20.1 x 23.2 (18-22 x 21-24) microns with sporocysts 6.8 x 10.0 (5-8 x 9-12) microns. Sporulated oocysts from both host species were used in direct side-by-side comparison of isozyme banding patterns using protein electrophoresis. The parasite has polytypic loci for leucine aminopeptidase (LAP), lactate dehydrogenase (LDH), and 6-phosphogluconate dehydrogenase (6-PGD). In oocysts from P. truei, LAP showed one band with fast migration and LDH and 6-PGD each showed two bands, one with fast and one with slow migration. In oocysts from P. boylii, LAP and LDH each had one band with slow migration and 6-PGD had one band with moderate migration. Oocysts of E. arizonensis collected from P. boylii were used to inoculate P. truei. The prepatent and patent periods, structural measurements, and isozyme banding patterns of the resultant oocysts were the same as those from P. truei when inoculated with oocysts from P. truei.     

Enzyme Variation of Eimeria arizonensis from Peromyscus truei and P. boylii

ABSTRACT. Cricetid rodents, Peromyscus truei and P. boylii , were inoculated with sporulated oocysts of Eimeria arizonensis collected from wild P. truei maintained in the lab. In P. truei the prepatent period was 4–5 days, the patent period was 9–11 days, and sporulated oocysts were 21.5 × 25.0 (20–23 × 24–26) μm with sporocysts 7.7 × 12.0 (6–8 × 10–13) pm. In P. boylii the prepatent period was 6–7 days, the patent period was 8–9 days, and sporulated oocysts were 20.1 × 23.2 (18–22 × 21–24) pm with sporocysts 6.8 × 10.0 (5–8 × 9–12) pm. Sporulated oocysts from both host species were used in direct side-by-side comparison of isozyme banding patterns using protein electrophoresis. The parasite has polytypic loci for leucine aminopeptidase (LAP), lactate dehydrogenase (LDH), and 6-phosphogluconate dehydrogenase (6-PGD). In oocysts from P. truei , LAP showed one band with fast migration and LDH and 6-PGD each showed two bands, one with fast and one with slow migration. In oocysts from P. boylii , LAP and LDH each had one band with slow migration and 6-PGD had one band with moderate migration. Oocysts of E. arizonensis collected from P. boylii were used to inoculate P. truei. The prepatent and patent periods, structural measurements, and isozyrne banding patterns of the resultant oocysts were the same as those from P. truei when inoculated with oocysts from P. truei.     

Primary immune responses of selected small mammal species to heterologous erythrocytes.

1. We surveyed the primary humoral immune responsiveness of six small mammal species (Peromyscus leucopus, Microtus pinetorum, Perognathus hispidus, Neotoma floridana, Onychomys leucogaster, Mus musculus) collected from wild populations in central Oklahoma using sheep red blood cells (SRBC) as the immunogen and a splenic plaque-forming cell (PFC) assay. 2. Individuals within each wild species examined produced antibodies to a single intraperitoneal injection of SRBC, however, considerable interspecific and intraspecific variation in responsiveness was indicated. 3. Overall, primary immune responsiveness varied from 0 to 5013 PFC/10(6) cells. Spleen weights, total splenic nucleated cell yields, PFC/spleen, PFC/mg spleen, and PFC/10(6) cells were significantly different among species. 4. Mean cell yield in M. pinetorum was greater than in P. leucopus and CD-1 laboratory mice (included as positive controls). Number of PFC/10(6) cells was greater in CD-1 laboratory mice than P. hispidus and P. leucopus. The coefficient of variation for PFC/10(6) cells in CD-1 laboratory mice was 38% compared to 109, 129, and 56% for M. pinetorum, P. hispidus, and P. leucopus, respectively. 5. Interspecific and intraspecific differences among wild species may be a reflection of disparate life histories and other environmental selection pressures.     

Intragenomic movement,sequence amplification and concerted evolution in satellite DNA in harvest mice,Reithrodontomys: Evidence from in situ hybridization

Three DNA probes isolated from three species ofReithrodontomys (R. montanus, R. megalotis, R. fulvescens) were used to examine within and among species variation in the chromosomal location of satellite DNA and constitutive heterochromatin. These probes hybridized to the centromeric regions on all chromosomes in six species of the subgenusReithrodontomys. Additionally, nearly all extra-centromeric C-band positive regions (with the exception of some heterochromatic material on the X and Y) hybridized to these probes. Within the subgenusReithrodontomys both the chromosomal distribution and organization of satellite DNA has changed throughout evolution. The evolutionary transition has been from a totally centromeric position inR. fulvescens to centromeric and non-centromeric regions in other species that have undergone extensive chromosomal rearrangements from the primitive karyotype for peromyscine rodents. In addition, the monomer repeat of the satellite sequence differs betweenR. fulvescens (monomer defined by PstI) and the remaining species in the subgenusReithrodontomys (monomer defined by EcoRI). These results suggest at least two amplification events for this satellite DNA sequence. Models and mechanisms concerned with the homogenization and spread of satellite sequences in complex genomes are evaluated in light of theReithrodontomys data. From a phlyogenetic standpoint, the satellite sequences composing heterochromatic regions were restricted to the subgenusReithrodontomys, which supports morphological differences used to recognize two subgenera,Reithrodontomys andAporodon. Probes failed to hybridize to any part of the karyotype ofR. mexicanus (subgenusAporodon) or to seven species from other closely related genera (Baiomys, Neotoma, Nyctomys, Ochrotomys, Onychomys, Peromyscus, Xenomys), some of which are considered as potential sister taxa forReithrodontomys.     

Coccidian parasites (Apicomplexa: Eimeriidae) of Graptemys caglei and Graptemys versa (Testudines: Emydidae) from Texas

Nineteen map turtles, Graptemys caglei and Graptemys versa were collected from the Guadalupe and Colorado River watersheds of south-central Texas and examined for coccidial parasites. Thirteen of the 19 turtles (68%), including 11 of 16 (69%) G. caglei and 2 of 3 (67%) G. versa, were infected with at least 1 coccidian. Five Eimeria spp. (E. chrysemydis, E. graptemydos, E. lutotestudinis, E. pseudogeographica, and E. trachemydis) were harbored by G. caglei, and 2 eimerians (E. graptemydos and E. mitraria) infected G. versa. This represents new host records for these previously described coccidians and is the first time parasites have been documented in turtles of both species.     

Jaw muscle functional anatomy in northern grasshopper mouse, Onychomys leucogaster, a carnivorous murid

The jaw muscle anatomy of the northern grasshopper mouse, Onychomys leucogaster, was observed and the mechanical basis of the insectivorous/carnivorous adaptations were examined. Compared with Peromyscus maniculatus, a granivorous relative of Onychomys, there is a reduction of some aponeuroses within the masseter deep layer. This characteristic indicates that shearing meat or crushing arthropod exoskeletons requires less occlusal pressure than does grinding plant material. In Onychomys both the anterior and posterior portions of the masseter deep layer are more anterodorsally inclined, so that the line of action of the masseter lies further from the jaw joint than in Peromyscus. A strong incisal bite for killing vertebrates such as other rodents can be produced by a jaw mechanism with the high lever advantage of this muscle, which compensates for the decline in muscle mass. Our quantitative analysis suggests that the disappearance of an aponeurosis along the zygomatic plate in Onychomys decreases the stretch of the corresponding muscle, i.e., the anterior fibers of the masseter deep layer, accompanying jaw opening, and increases the maximum gape necessary for hunting large prey.     

Geographic variation in rodent-flea relationships in the presence of black-tailed prairie dog colonies

We characterized the relationship between fleas and their rodent hosts in the presence of prairie dog colonies and compared them to adjacent assemblages away from colonies. We evaluated the rodent-flea relationship by quantifying prevalence, probability of infestation, flea load, and intensity of fleas on rodents. As prairie dog burrows provide refugia for fleas, we hypothesized that prevalence, flea load, and intensity would be higher for rodents that are associated with black-tailed prairie dog colonies. Rodents were trapped at off- and on-colony grids, resulting in the collection of 4,509 fleas from 1,430 rodents in six study areas. The rodent community composition varied between these study areas. Flea species richness was not different between prairie dog colonies and the surrounding grasslands (p = 0.883) but was positively correlated with rodent species richness (p = 0.055). Prairie dog colonies did not increase the prevalence of fleas (p > 0.10). Flea loads on rodents did not vary between off- and on-colony grids at three of the study areas (p > 0.10). Based on the prevalence, infestation rates, and flea loads, we identified Peromyscus maniculatus, Onychomys leucogaster, and two Neotoma species as important rodent hosts for fleas and Aetheca wagneri, Orchopeus leucopus, Peromyscopsylla hesperomys, Pleochaetis exilis, and Thrassisfotus as the most important fleas associated with these rodents. Prairie dog colonies did not seem to facilitate transmission of fleas between rodent hosts, and the few rodent-flea associations exhibited significant differences between off- and on-colony grids.     

Coccidian parasites (Apicomplexa: Eimeriidae) of Microtus spp. (Rodentia: Arvicolidae) from the United States, Mexico, and Japan, with descriptions of five new species

Beginning in July 1980, 149 voles (Microtus spp.) representing 9 species and 14 subspecies collected in Japan, Mexico and the United States were examined for coccidia; 67 (45%) had oocysts in their feces. These included 1 of 3 (33%) M. californicus sactidiegi; 0 of 1 M. longicaudus longicaudus; 0 of 1 M. l. macrurus; 48 of 111 (43%) M. mexicanus including 11 of 26 (42%) M. m. fulviventer, 1 of 2 (50%) M. m. fundatus, 13 of 31 (42%) M. m. mexicanus, 1 of 4 (25%) M. m. mogollonensis and 22 of 48 (46%) M. m. subsimus; 5 of 8 (63%) M. montanus arizonensis; 6 of 6 M. montebelli montebelli; 2 of 4 (50%) M. oregoni oregoni; 5 of 13 (38%) M. pennsylvanicus pennsylvanicus; 0 of 1 M. quasiater and 0 of 1 M. townsendii townsendii. The following coccidians were identified from infected voles: Eimeria saxei n. sp. (syn. E. wenrichi "B") from M. c. sactidiegi; E. ochrogasteri, E. saxei, E. wenrichi (syn. E. wenrichi "A"), and Eimeria sp. from M. m. fulviventer, Eimeria sp. from M. m. fundatus; E. ochrogasteri, E. saxei, Eimeria tolucadensis n. sp., E. wenrichi, and Eimeria sp. from M. m. mexicanus; E. wenrichi from M. m. mogollonensis; Eimeria coahuiliensis n. sp., E. saxei, Eimeria subsimi n. sp., E. wenrichi, Eimeria sp., and Isospora mexicanasubsimi n. sp. from M. m. subsimus; E. tamiasciuri and E. wenrichi from M. m. arizonensis; Eimeria spp. from M. m. montebelli; E. saxei and E. wenrichi from M. o. oregoni; and E. ochrogasteri and E. wenrichi from M. p. pennsylvanicus. Sporulated oocytsts of Eimeria coahuiliensis n. sp. were ellipsoid, 29.6 X 19.6 (27-34 X 18-22) micron with ovoid sporocysts 14.4 X 8.9 (13-18 X 8-10) microns. Sporulated oocysts of Eimeria saxei n. sp. were subspheroid, 13.0 X 11.0 (11-14 X 10-12) micron with ovoid sporocysts 7.5 X 4.0 (6-9 X 4-5) micron. Sporulated oocysts of Eimeria subsimi n. sp. were ovoid/subspheroid, 25.1 X 18.7 (22-28 X 17-21) micron with ellipsoid sporocysts 13.9 X 7.4 (13-15 X 6-8) micron. Sporulated oocysts of Eimeria tolucadensis n. sp. were subspheroid, 25.4 X 20.3 (23-26 X 19-23) micron with ellipsoid sporocysts 11.3 X 7.8 (10-13 X 7-9) micron. Sporulated oocysts of Isospora mexicanasubsimi n. sp. were subspheroid, 23.7 X 23.1 (21-26 X 21-26) micron with ovoid sporocysts 14.9 X 10.8 (12-16 X 10-12) micron.(ABSTRACT TRUNCATED AT 400 WORDS)     

Isospora peromysci Davis, 1967 (Apicomplexa: Eimeriidae) in Peromyscus leucopus and P. maniculatus (Rodentia: Cricetidae) from Texas

Oocysts of Isospora peromysci (Davis, 1967) (Apicomplexa: Eimeriidae) were recovered from the feces of 1/30 (3.3%) white-footed mice, Peromyscus leucopus , in Johnson County, Texas. This report represents a new host and geographic record for the parasite. The coccidium was also found in 1/20 (5.0%) deer mice, P. maniculatus , from the same locale. Morphological data are provided on the sporulated oocyst of I. peromysci and comparisons are made with previously published information on the species from other geographic localities.     

Isospora peromysci Davis, 1967 (Apicomplexa: Eimeriidae) in Peromyscus leucopus and P. maniculatus (Rodentia: Cricetidae) from Texas

Oocysts of Isospora peromysci (Davis, 1967) (Apicomplexa: Eimeriidae) were recovered from the feces of 1/30 (3.3%) white-footed mice, Peromyscus leucopus, in Johnson County, Texas. This report represents a new host and geographic record for the parasite. The coccidium was also found in 1/20 (5.0%) deer mice, P. maniculatus, from the same locale. Morphological data are provided on the sporulated oocyst of I. peromysci and comparisons are made with previously published information on the species from other geographic localities.     

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.     

Five new species of Coccidia (Apicomplexa: Eimeriidae) from colubrid snakes of Ecuador.

Fecal samples from 11 colubrid snakes, representing 10 species, collected in Ecuador during October 1994 were examined for coccidian parasites. Feces of 4 individuals, representing 4 host species, contained coccidian oocysts. Three species of Eimeria and 2 species of Isospora were observed and are described here as new. Oocysts of both Eimeria and Isospora were found in the feces of a slug-eating snake, Dipsas vermiculata. Sporulated oocysts of the Eimeria sp. are spheroid to subspheroid, 16.7 by 16.6 microm (14-18 by 14-18 microm) and those of the Isospora sp. are spheroid and 15.0 microm (13-18 microm) in diameter. Imantodes cenchoa, the common bluntheaded treesnake, was infected with a species of Eimeria. These sporulated oocysts are ellipsoid, 23.3 by 16.2 microm (25-21 by 15-17 microm). Sporulated eimerian oocysts from Leptodeira annulata, the southern cat-eyed snake, are subspheroid, 22.5 by 18.8 microm (19-26 by 17-21 microm). Feces of a juvenile Imantodes lentiferus, the bluntheaded vine snake, contained ovoid to ellipsoid isosporan oocysts, which measured 21.6 by 15.0 microm (20-23 by 14-16 microm) when sporulated.