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Rectal contents of 56 adult bobcats (Lynx rufus) in 2014 and 2017 from remote areas of Mississippi were examined microscopically for parasite stages after the sugar flotation method. Among the helminths, eggs/larvae found were: Paragonimus sp. in 12, Toxocara cati-like in 16, trichurid-capillarid-like in 3, hookworms in 27, and lungworms in 28. Among the protozoa, oocysts/cysts found were: Cystoisospora felis-like in 2, Cystoisospora rivolta-like in 4, Cryptosporidium sp. in 1, and Giardia sp. in 1. Additionally, numerous Sarcocystis sporocysts were detected in the feces of 12 bobcats; sporocysts were described morphologically. The status of C. felis derived from the bobcat and other wild felids is reviewed and compared with C. felis from the domestic cat. It is the first record of C. rivolta from the bobcat. The presence of eggs of Paragonimus sp. and T. cati in feces of 21.4% and 28.5%, respectively, suggests a role for the bobcat in the dissemination of these zoonotic helminths in the environment in the wild. Taxonomy of coccidia of wild Felidae is discussed and Isospora lyncisLevine and Ivens, 1981 from the Lynx is now regarded as a species inquirenda., (© American Society of Parasitologists 2023.)

The summer tanager, Piranga rubra (L., 1758) is a medium-sized songbird formerly belonging to the tanager family Thraupidae but now has been placed within the family Cardinalidae. Nothing is known about the coccidian parasites of this stunningly colorful bird. Feces from 2 P. rubra found dead in McCurtain County, Oklahoma were collected and examined for coccidia; 1 was found to be passing a new species of Isospora. Oocysts of Isospora mccurtainensis n. sp. are subspheroidal to ovoidal with a smooth bilayered wall, measure (length × width [L × W]) 21.7 × 19.5 μm, and have a L/W ratio of 1.1; a micropyle and oocyst residuum were absent but a bilobed and refractile polar granule is present. Sporocysts are ellipsoidal and measure 13.9 × 8.6 μm, L/W 1.6; a knoblike Stieda body is present as well as a distinct sub-Stieda body. The sporocyst residuum is composed of a granular compact cluster with a dense, irregular mass of granules lying between and dispersed among the sporozoites. This is the first coccidian reported from P. rubra and, most important, only the first known from the Cardinalidae in the mainland of the United States., (© American Society of Parasitologists 2021.)

The wood thrush, Hylocichla mustelina, is a North American passerine bird closely related to other thrushes and is widely distributed across North America. Nothing is known of the coccidian parasites of this bird. Feces from a single H. mustelina found dead in McCurtain County, Oklahoma were collected and examined for coccidia; it was found to be passing a new species of Isospora. Oocysts of Isospora gmelini n. sp. are subspheroidal to ellipsoidal with a smooth bilayered wall, measure (length [L] × width [W]) 19.5 × 16.5 μm, and have a L/W ratio of 1.2; a micropyle and oocyst residuum were absent but polar granule(s) are present. Sporocysts are ellipsoidal to elongate and measure 13.4 × 8.9 μm, L/W 1.5; a buttonlike Stieda body is present, but sub-Stieda and para-Stieda bodies are absent. The sporocyst residuum is composed of a compact spheroid with a dense, irregular mass of finer granules lying between and dispersed among the sporozoites. Although several isosporans have been reported from other turdid birds, mainly from Brazil and Costa Rica, this is the initial coccidian reported from H. mustelina and only the second known from the Turdidae in the mainland of the United States., (© American Society of Parasitologists 2020.)

Carnivorous mammals are a trophic guild with an important role in the dissemination of parasite infective stages (larvae, eggs, cysts, and oocysts). In the present study, new samples of coprolites attributed to carnivorous mammals, obtained from 2 archaeological caves, were analyzed for the presence of parasites with the aim to increase the knowledge about parasites in rockshelters that could have spread to humans and other mammals. To this purpose, fragments of 3 coprolites from Cerro Casa de Piedra, cave 5 and cave 7, were examined. Coprolites were rehydrated in aqueous trisodium phosphate and processed by spontaneous sedimentation. High parasite richness was observed and new parasite species for archaeological contexts were found. The parasitological findings in Puma concolor coprolites associated with caves suggest the importance of these carnivores in the dissemination of parasites in areas with high re-use of space and steady conditions of temperature, humidity, and radiation.

Five of 16 (31%) rufous-capped warblers (Basileuterus rufifrons) and 2 of 5 (40%) ovenbirds ( Seiurus aurocapilla ) sampled from Costa Rica were positive for a novel species of Isospora. Oocysts have a thin, smooth, double-layered, colorless wall and measure 22.3 μm ± 1.6 μm × 24.3 μm ± 1.5 μm (19-25 μm × 21-28 μm) with an average length-width (L/W) ratio of 1.0 (1-1.3). Oocyst residuum and micropyle are absent, but 0-4 spherical to cigar-shaped polar granules (1-2.5 μm) are present. Sporocysts are ovoid and measure 11.8 μm ± 0.9 μm × 16 μm ± 1.7 μm (10-14 μm × 12-19 μm) with an average L/W ratio of 1.6 (1.0-1.9). A knob-like Stieda body continuous with the sporocyst wall and a trapezoidal compartmentalized substieda body are present. Each sporocyst contained 4 sporozoites and a diffuse sporocyst residuum consisting of many variable-sized granules, some as large as 2 μm. This is the second description of an Isospora species in New World warblers (Passeriformes: Parulidae) and the first report of Isospora from both the rufous-capped warbler and ovenbird.

Despite the availability of many parasitological methods for detection of Cryptosporidium and Isospora (Cystoisospora) belli in fecal samples, there are uncertainties about the accuracy of these techniques in laboratory practice. In this study, 27 formalin-fixed positive stool samples for Cryptosporidium and 15 for I. belli were analyzed by 2 concentration methods, sedimentation by centrifugation (SC) and formalin-ethyl acetate (FE), and by 3 tintorial techniques, modified Ziehl-Neelsen (ZN), safranin (SF), and auramine (AR). No significant differences were observed on Cryptosporidium identification between concentration methods, while a significantly higher number of I. belli oocysts (P < 0.0001) was detected in fecal smears concentrated by the SC than by the FE method. Fecal samples processed by FE produced a median oocyst loss to the fatty ring of 34.8% for Cryptosporidium and 45.4% for I. belli. However, FE concentration provided 63% of Cryptosporidium and 100% of I. belli slides classified as superior for microscopic examination. Regarding the efficiency of staining methods, a more significant detection of Cryptosporidium oocysts was observed in fecal smears stained by ZN (P < 0.01) or AR (P < 0.05) than by the SF method. Regular to high-quality slides for microscopic examination were mostly observed in fecal smears stained with AR or ZN for Cryptosporidium and with SF or ZN for I. belli. This study suggests a great variability in oocyst power detection by routine parasitological methods, and that the most frequent intestinal coccidians in humans have specific requirements for concentration and staining.

Isospora bors n. sp. (Apicomplexa: Eimeriidae) is described from 6 of 30 (20%) Baiuch rock gecko Bunopus tuberculatus Blanford in Saudi Arabia. Sporulated oocysts are subspheroidal to spheroidal, 18 × 16 (17-20 × 15-17) μm, with a bilayered, smooth, yellow-orange wall, without striae or micropyle. Polar body and oocyst residuum, both absent. Sporocysts are ovoidal, 10 × 7 (9-11 × 6-9) μm, with a Stieda body and sporocyst residuum. Endogenous stages developed in the cytoplasm of epithelial cells of the small intestine and above the host cell nucleus.

Between September and October 1991 and again during September 1992, skinks (Emoia spp.) were collected from various localities on Fiji and Papua New Guinea (PNG) and examined for coccidians. One of 4 (25%) De Vis' emo skinks (Emoia pallidiceps) from PNG harbored an undescribed species of Isospora in its feces. Oocysts of Isospora grinbikpelapalai n. sp. were ellipsoidal to subspheroidal, 18.1 × 14.9 (17-20 × 14-16) μm, with a bilayered wall and a length/width index (L/W) of 1.2. Both micropyle and oocyst residuum were absent, but a prominent polar granule was present. Sporocysts were ovoidal, 10.7 × 7.6 (10-11 × 7-8) μm, with a L/W index of 1.4. Stieda and sub-Stieda bodies were present, but para-Stieda bodies were absent. The sporocyst residuum consisted of large scattered globules dispersed between sporozoites. Sporozoites were elongate with spheroidal anterior and posterior refractile bodies. Isospora grinbikpelapalai was also found in 1 of 2 (50%) Pope's emo skinks (Emoia popei) from PNG. One of 13 (8%) white-bellied copper-striped skinks (Emoia cyanura), from Fiji, was passing another undescribed species of Isospora in its feces. Oocysts of Isospora casei n. sp. were elongate, 31.8 × 21.3 (28-35 × 18-24) μm, with a bilayered wall and a L/W index of 1.5. Micropyle, oocyst residuum, and polar granule were all absent. Sporocysts were ovoidal, 15.3 × 10.6 (14-16 × 10-12) μm, with a L/W index of 1.4. Stieda and sub-Stieda bodies were present, but para-Stieda bodies were absent. The sporocyst residuum consisted of scattered globules among sporozoites or as a cluster surrounding sporozoites. Sporozoites were elongate with spheroidal anterior and posterior refractile bodies. Isospora casei was also found in 1 of 2 (50%) Fiji slender treeskinks (Emoia concolor) from Fiji. This represents the first report of coccidia from Emoia spp. and, to our knowledge, the initial documentation of reptilian coccidia from herpetofauna from Papua New Guinea.

Seven thrush species (Turdidae) from Costa Rica were examined for intestinal parasites; 21 of the 84 (25%) birds sampled were positive for a new species of Isospora. Oocysts of Isospora zorzali n. sp. have thin, smooth, double, and colorless walls; they measure 19.7 ± 1.5 µm × 18.6 ± 1.4 µm (16-24 µm × 15-21 µm), with an average length-width ratio of 1.1 µm. Sporocysts are ovoid, measure 8.5 ± 1.1 µm × 14.5 ± 1.7 µm (7-11 µm × 11-18 µm) with an average length-width ratio of 1.7 µm. A nipple-like stieda body continuous with the sporocyst wall is present, but no substieda body was observed. A sporocyst residuum consisting of large equal sized granules was observed either clumped together or diffusely. The sporocysts fill the entire oocysts with little to no open space observed. This is the first report of Isospora species from any of the sampled host species and also the first report from any species of thrush in Costa Rica.

Numerous microscopic studies of coccidian oocysts from avian feces have become the basis for species identification. In contrast, molecular studies of wild birds' Coccidia are still in their infancy and are mostly based on DNA extracted from the blood stages of these parasites. Linking microscopic and molecular data requires a method that reliably extracts DNA from single oocysts with parallel detailed morphological examination of the same cell. We offer a thorough manual of isolating, photographing, and trapping single oocysts from avian feces, followed by extraction of parasite DNA and amplification of mitochondrial DNA from the same cells. In 39 single oocysts from 6 wild blackcaps, we combined microscopic studies of individual cells with studies on their mitochondrial haplotype. In 72% of the single oocysts sampled, we detected unambiguous sequences. From feces and blood of investigated birds, we obtained 6 different haplotypes of Isospora sp. (iSAT1-iSAT 6), finding both the same haplotype in different host individuals and various haplotypes in the same host individual. Our described methodology enables linking the huge amount of morphological data with innovative gene analysis. This method expands the scope of genetic studies conducted on Isospora species, including routine molecular analysis of single oocysts isolated from fecal samples.

During a parasite survey, we collected data on the presence and distribution of feather mites, intestinal parasites, and blood parasites of small ground finches (Geospiza fuliginosa) from 4 islands in the Galapagos. We recorded 4 species of feather mites, with the most common species, Trouessartia geospiza, present on the majority (77% [308/400]) of individuals. Birds with high loads of T. geospiza came from larger islands and had higher body masses. We identified 3 species of intestinal Isospora (Isospora fragmenta, Isospora temeraria, and Isospora exigua) in fecal samples that showed a diurnal pattern of oocyst release. Among samples collected in the afternoon, infection prevalence was 61% (11/18), while only 0.5% (1/192) contained oocysts in the morning. We screened 40 individuals from one island (Isabela) for blood parasites using molecular markers. Although no parasites of Haemoproteus, Leucocytozoon, or Plasmodium were detected, a high proportion of birds (80% [32/40]) had systemic Isospora spp. infections. A high infection prevalence (74% [20/27]), but low infection intensity, was confirmed using optical microscopy. This result could either be due to the detection of a previously unidentified systemic Isospora sp. parasite, or a result of the previously described Isospora spp. parasites causing systemic infections.

Fecal samples (n = 636) from 10 species of shrews collected in Alaska (n = 540) and northeastern Siberia (n = 96) were examined for the presence of coccidia (Apicomplexa: Eimeriidae). Five distinct oocyst morphotypes were observed. Three types were consistent with oocysts of previously recognized coccidia species from other shrew hosts. These were Eimeria inyoni, E. vagrantis, and Isospora brevicauda, originally described from the inyo shrew (Sorex tenellus), dusky shrew (S. monticolus), and northern short-tailed shrew (Blarina brevicauda), respectively. We found 5 new host records for E. inyoni, 3 for E. vagrantis, and 3 for I. brevicauda. The 2 additional oocyst morphotypes, both from the tundra shrew (Sorex tundrensis), are putative new species. Sporulated oocysts of Eimeria beringiacea n. sp. are subspheroidal, 17.7 x 15.6 microm (14-24 x 13-20 microm) with a length (L)/width (W) ratio of 1.1 (1.0-1.4); these lack a micropyle (M), an oocyst residuum (OR), and a polar granule (PG). Sporocysts are ellipsoidal, 10.3 x 6.1 microm (7-14 x 4-8 microm), with a L/W ratio of 1.7 (1.3-2.3) and have a Stieda body (SB), Substieda body (SSB), and sporocyst residuum (SR). Oocysts of Eimeria tundraensis n. sp. are spheroidal to subspheroidal, 24.8 x 23.5 microm (23-26 x 22-25 microm), with a L/W ratio of 1.1 (1.0-1.2); these lack a M and OR, but a single PG is present. Sporocysts are elongate ellipsoidal, 15.4 x 8.3 microm (13-17 x 7-9 microm), with a L/W ratio of 1.9 (1.4-2.1) and have a SB, SSB, and SR.

Eighty-eight fecal samples from 2 species of pika, Ochotona collaris and Ochotona hyperborea, collected in Alaska (N = 53) and Russia (N = 35), respectively, were examined for the presence of coccidia (Apicomplexa: Eimeriidae). Five oocyst morphotypes were observed. In O. collaris, we found Eitmeria calentinei, Eimeria cryptobarretti, and Eimeria klondikensis, whereas in O. hyperborea, we found Eimeria banffensis, E. calentinei, E. cryptobarretti, E. klondikensis, and Isospora marquardti. This study represents new geographic records for all 5 coccidia and new host records for E. cryptobarretti and I. marquardti. Only minor quantitative differences were seen between the sporulated oocysts we studied and those reported in their original descriptions.

Canine intestinal coccidiosis is a cause of diarrhea in young dogs and dogs that are immunocompromised. Reports in the literature indicate that experimental reproduction of clinical coccidiosis with Cystoisospora canis (syn. Isospora canis) is difficult, and few studies have been done with C. canis. Experimental oral infections were attempted in 22, 6- to 8-wk-old female beagles with 5 x 10(4) (n = 2) or 1 x 10(5) (n = 20) sporulated C. canis oocysts. Diarrhea was observed in all inoculated dogs. Diarrhea began 2-3 days before oocyst excretion. Five of the 22 dogs were given an anticoccidial (sulfadimethoxine) because of their clinical signs. The mean prepatent period was 9.8 days (range, 9-11 days, n = 22 dogs), and the patent period was 8.9 days (range, 7-18 days, n = 20 dogs). Two dogs exhibiting clinical coccidiosis were examined at necropsy 10 days after infection. Developmental stages of C. canis were present in cells in the lamina propria throughout the entire small intestine in both dogs. Microscopic lesions observed in both of these dogs were villous atrophy, dilation of lacteals, and hyperplasia of lymph nodes in Peyer's patches. Results of bacterial and viral examinations of these 2 dogs were negative, indicating that intestinal coccidiosis was the cause of the diarrhea. Our study indicates that C. canis can be a primary cause of diarrhea in young dogs.

Relapse is common in immunocompetent and immunosuppressed humans infected with Isospora belli and is believed to be associated with the presence of extraintestinal stages. In the present study, we examined this important stage in an AIDS patient using histological, immunohistological, histochemical, and ultrastructural methods to better understand the development and structure of this stage and to develop better means of detecting infections. Antisera made in rabbits to Isospora suis, Toxoplasma gondii, Hammondia hammondi, Sarcocystis neurona, Neospora caninum, and Caryospora bigenetica were tested against I. belli tissue cysts in the avidin-biotin peroxidase complex (ABC) immunohistological test. Most antisera reacted positively in the ABC test at dilutions of 1:100 but not at dilutions of 1:250. Some antisera to N. caninum and H. hammondi reacted positively at dilutions of 1:1,000 in the ABC test. Most reactive antisera stained the tissue cyst wall and not the enclosed zoite. Eight histochemical tests were examined and most were nonreactive with I. belli zoites or tissue cysts. Transmission electron microscopy revealed that the tissue cyst wall was composed of granular material and was directly beneath the parasitophorous vacuole membrane. Zoites were in the center of the tissue cysts and were surrounded by fibrillar material that appeared to originate from the zoite surface. Tubulelike structures were present in the granular tissue cyst wall and in the fibrillar material that surrounded the zoite. Zoites contained a crystalloid body. New findings in the present study consisted of identifying what are probably early tissue cysts that lack a developed tissue cyst wall, demonstrating that more than 1 tissue cyst can occupy a host cell, describing the distribution of micronemes and the shedding of zoite membranes, and identifying tubular structures in the inner tissue cyst wall and inner compartment.

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.

From 1990 through 1994, fecal samples were collected and examined for coccidian parasites from 26 giant land tortoises Geochelone nigra, from 715 lava lizards Tropidurus spp., from 139 land iguanas Conolophus subcristatus, and from 128 marine iguanas Amblyrhynchus cristatus, all of which inhabit various islands in the Galápagos Archipelago. None of the samples from A. cristatus or from C. subcristatus was infected with coccidia. Only 1 of 26 (4%) G. nigra was infected with a single Eimeria species that we describe here as new. A total of 262 of 715 (37%) individuals representing 3 species of Tropidurus discharged oocysts of 1-3 different coccidian species; these included 2 previously described species Eimeria tropidura and Isospora insularius, and an eimerian that we describe here as new. Additionally, 104 fecal samples from Tropidurus spp. were from 51 animals recaptured in either 2 or 3 yr; 21 had no infections in any year, 15 were infected at least once, 14 were infected in 2 yr, and only 1 was infected during 3 yr. No animal was recaptured and sampled during each of the 4 yr of this study. Of the 262 infected individuals, 30 (12%) had multiple coccidial infections at the time of collection (eimerian and isosporan, or 2 eimerians). Where determination of the sexes was possible in the lava lizards, there was no difference in prevalence rates between males (39%) and females (41%). Sporulated oocysts of the new eimerian from Tropidurus are ellipsoidal, 27.1 x 15.6 (25-31 x 14-18) microns, with a polar body, but without a micropyle or oocyst residuum; they contain ellipsoidal sporocysts, 11.8 x 6.7 (10-14 x 6-8) microns, without Stieda, sub-, or parastieda bodies, but with a sporocyst residuum. Sporulated oocysts of the new eimerian from G. nigra are ellipsoidal to ovoidal, 21.6 x 18.1 (18-25 x 16-20) microns, with a large polar body, but without a micropyle or oocyst residuum; they contain ellipsoidal sporocysts 10.7 x 7.0 (8-12 x 5-8) microns, with Stieda body but no sub- or parastieda bodies. Also present is a sporocyst residuum of medium to large granules randomly distributed among the sporocysts.

Two-hundred-fifty-three turtles, representing 26 species within 5 families (Chelydridae, Emydidae, Kinosternidae, Testudinidae, Trionychidae) were examined for coccidia. Of these, 127 (50%) were found to harbor 1 or more of 28 species of eimerians, or isosporan, or both. One-hundred-thirteen (89%) of the infected turtles were aquatic species, whereas only 14 (11%) of the infected turtles were terrestrial species. Two-fold more aquatic turtles were infected with coccidia (113 of 200, 57%) compared to only 26% (14 of 53) of the terrestrial species. This report documents 14 new host and 8 new geographic records for eimerians from turtles in Arkansas and Texas.

From March 1991 to February 1992, 276 stool samples from 131 patients with the acquired immunodeficiency syndrome (AIDS) (average, 2.1 samples per patient) and stool samples from 81 presumed immunocompetent individuals were studied for the prevalence of Cryptosporidium sp. and Isospora belli. The techniques employed were a modified formol-ether concentration, carbol (phenol) auramine staining, and a modified Kinyoun acid-fast method. The prevalence of both coccidia among AIDS patients was 25.9% (34 of 131). Cryptosporidium sp. oocysts were demonstrated in 25 (19.1%) AIDS patients and I. belli in 13 (9.9%). Coinfection for coccidia of both species was found in 4 (3%) AIDS subjects. Among the presumed immunocompetent individuals, coccidia were not demonstrated in their 81 stool specimens. This study, like others, confirms the worldwide importance of these coccidia among AIDS patients and the necessity of suitable techniques for demonstration of oocysts in stool samples.

Since May 1979, 458 shrews (Blarina sp. and Sorex spp.) representing 20 species collected in Canada, Japan, and the United States were examined for coccidia; 110 (24%) had oocysts in their feces, including 8 of 21 (38%) B. brevicauda from Massachusetts, Ohio, Pennsylvania, and Vermont; 2 of 7 (29%) S. caecutiens from Hokkaido and Honshu; 14 of 63 (22%) S. cinereus from Colorado, New Mexico, Pennsylvania, Vermont, Manitoba, and Ontario; 3 of 7 (43%) S. fontinalis from Pennsylvania; 11 of 16 (69%) S. fumeus from Massachusetts, Minnesota, Pennsylvania, Vermont, and Ontario; 1 of 4 (25%) S. haydeni from Minnesota; 6 of 8 (75%) S. longirostris from Florida and Virginia; 1 of 2 (50%) S. ornatus from California; 5 of 12 (42%) S. pacificus from California and Oregon; 13 of 41 (32%) S. palustris from California, Colorado, and New Mexico; 1 of 2 (50%) S. tenellus from California; 11 of 105 (10%) S. trowbridgii from California, Oregon, and Washington; 10 of 48 (21%) S. unguiculatus from Hokkaido; and 24 of 112 (21%) S. vagrans from Arizona, California, Colorado, New Mexico, Oregon, and Washington. The following coccidians were identified from infected shrews: Eimeria brevicauda n. sp. from B. brevicauda; Eimeria fumeus n. sp. from S. fumeus, S. pacificus, S. unguiculatus, and S. vagrans; Eimeria inyoni n. sp. from S. tenellus; Eimeria palustris n. sp. from S. cinereus, S. fontinalis, S. fumeus, S. haydeni, S. longirostris, S. ornatus, S. pacificus, S. palustris, S. tenellus, S. trowbridgii, and S. vagrans; Eimeria vagrantis n. sp. from S. fumeus, S. trowbridgii, and S. vagrans; Isospora brevicauda n. sp. from B. brevicauda; and Isospora palustris n. sp. from S. pacificus, S. palustris, S. trowbridgii, S. unguiculatus, and S. vagrans. The world literature on coccidian parasites of shrews (16 eimerians and 3 isosporans exclusive of the 7 new species described here) is reviewed.

Isospora manchacensis n. sp. is described from ground skinks, Scincella lateralis (Say, 1823) from Louisiana. Overall prevalence at 6 sites near Lake Ponchartrain was 43.1% (59/137) and ranged from 8% (1/13) to as high as 60% (6/10). Endogenous stages develop inside the nuclei of epithelial cells in the small intestine. Infected hypertrophic nuclei migrate from the basal lamina of the host cell to the luminal striated border. Oocysts in freshly passed fecal pellets usually contain a single contracted sporont that divides to form 2 sporoblasts. These undergo a brief pyramid stage followed by sporulation within 45-50 hr. Sporulated oocysts have a single-layered wall and measure 25.0 X 22.6 (20.0-28.9 X 18.6-26.0) micron. The lemon-shaped sporocysts measure 12.8 X 10.2 (11.1-15.2 X 9.0-11.0) micron and contain a Steida body, a spherical to oval substeida body, and a dispersed, granular sporocyst residuum. Prepatent periods in skinks fed 700 and 1,400 oocysts ranged from 24 to 32 days. Experimentally infected skinks produced large numbers of oocysts continuously during the 3-4 wk they were monitored after the onset of patency, but exhibited no signs of disease. Experimental doses of 200 oocysts failed to produce infections in skinks monitored for as long as 7 wk.

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)