Dorisiella arizonensis n.sp., a Coccidium from the Desert Woodrat, Neotoma lepida

SUMMARY. Dorisiella arizonensis n. sp. (Sporozoa: Eimeriidae) is described from oocysts in the feces of a desert woodrat, Neotoma lepida , from Grand Canyon National Park, Arizona. The oocysts are spherical to subspherical, measure 20.8–21.8 × 20.8–22.9 μ, with a mean of 21.0 × 21.8 μ, and have a two-layered wall. They contain 1 to 3 refractile granules but no residual body. The two lemon-shaped sporocysts have a Stieda body, 8 sporozoites, and a few to many scattered, round, clear residual granules or bodies.     

Description of Pythonella scleruri n. sp. (Apicomplexa: Eimeriidae) from a brazilian bird rufous-breasted-leaftosser Sclerurus scansor, 1835 (Passeriformes: Furnariidae)

Coccidian oocysts containing 16 sporocysts with 4 sporozoites in each were observed in a faecal sample from Sclerurus scansor collected in the Itatiaia National Park, southeastern region of Brazil. The oocysts are characterized by ellipsoidal shape measuring 42.5 x 32.8 mm, with smooth, thick double-layered wall of a greenish-orange colour. An oocyst residuum of numerous scattered granules among the sporocysts in sporulated ones; 16 round sporocysts, averaging 10.5 x 10 mm each containing four elongated sporozoites; presence of residuum; absence of Stieda body. The presently described coccidian, recorded for the first time in birds, is a new species named P. scleruri.     

Two new Eimeria species (Apicomplexa: Eimeriidae) from the yellow-crowned Amazon Amazona ochrocephala (Aves: Psittacidae) in Brazil

In this study, we describe 2 new species of Eimeria associated with the yellow-crowned Amazon Amazona ochrocephala. Eimeria amazonae n. sp. has bilayered, ellipsoidal, and smooth oocysts that measure 48.9 × 36.2 μm; the length/width ratio is 1.35. The micropyle and oocyst residuum are both absent, but the polar granule is present. Ovoidal sporocysts are 22.2 × 11.9 μm. Stieda and sub-Stieda bodies and sporocyst residuum are present. The 2 elongate sporozoites are curved and measure 18.1 × 3.4 μm; both have 2 refractile bodies. Eimeria ochrocephalae n. sp. has bilayered, ellipsoidal, and smooth oocysts that measure 43.8 × 27.7 μm; the length/width ratio is 1.58. The micropyle and oocyst residuum are absent, but the polar granule is present; ovoidal sporocysts are 20.6 × 10.1 μm. Stieda and sub-Stieda bodies and sporocyst residuum are present; 2 elongate and curved sporozoites are 15.8 × 3.4 μm, each of which has 2 refractile bodies.     

Fine Structure of Oocyst Transformation and the Sporozoites of Leucocytozoon dubreuili*

SYNOPSIS. The sporogonic stages of Leucocytozoon dubreuili in the midgut and salivary glands of the simuliid vectors was studied by electron microscopy. Young uninucleate oocysts have a pellicle that initially resembles that of the ookinetc. Numerous electron-dense bodies and microtubules in the peripheral cytoplasm may be involved in the formation of the cyst wall. The dense bodies appear to give rise to the amorphous material of the wall. The tubules which run circumferentially beneath the oocyst's boundary probably serve as a skeletal support for the cell surface during deposition of the wall material. A subcapsular “space” which provides area for expansion of the developing sporozoites is formed in early multinucleate oocysts. The subcapsular “space” appears to be formed through a condensation of the peripheral cytoplasm, resulting in an osmotic gradient across the oocyst's limiting membrane. Consequently water diffuses out, creating a fluid-filled space. Sporozoite formation begins with localized thickenings on the oocyst's limiting membrane. Subsequent extension of the thickened regions into the subcapsular “space” marks the onset of sporozoite budding. The process is highly synchronized, and culminates with the production of up to 150 sporozoites about the sporoblastoid body. The structure of sporozoites from mature oocysts and of the salivary glands of the vector is basically similar, although salivary gland sporozoites are more elongate and have numerous electron-dense micronemes. The paired rhoptries in the latter sporozoites are more elongate and uniformly electron-dense than in oocyst sporozoites.     

Two new species of coccidia (apicomplexa: Eimeriidae) from the bearded false chameleon Chamaeleolis barbatus (Sauria: polychridae) from cinco pesos, Pinar Del Río, Cuba.

Parasitological examination of bearded false chameleons Chamaeleolis barbatus freshly imported from Cuba revealed the presence of 2 species of coccidia that are described as new. Oocysts of Isospora chamaeleolidis n. sp. are spherical to slightly subspherical, 16.1 (13-21) x 15.6 (13-19) microm, with a brownish and bilayered wall approximately 1.0-1.5 microm thick; outer layer markedly pitted. 0.75-1.0 microm thick. One, rarely 2, globular polar granules, 1.5 in diameter are present in the sporulated oocysts. Sporocysts are ellipsoidal, 10.8 (10-13) x 7.8 (7-9) microm, with a smooth, colorless, and unilayered sporocyst wall. Stieda body and substieda bodies are present. A sporocyst residuum is present, consisting of small granules of irregular size scattered among the sporozoites. Oocysts of Eimeria chamaeleolidisbarbati n. sp. are broadly oval, 19.0 (17-21) x 15.7 (15-17) microm, with a bilayered, colorless oocyst wall approximately 0.75 thick; outer layer of oocyst wall is smooth, 0.5 microm thick. One or 2, rarely 4, globular, irregular polar granules, approximately 1.5 microm in diameter, are present in sporulated oocysts. Sporocysts are broadly oval, 7.4 (7-8.5) x 6.1 (5.5-7) microm, with a smooth, colorless, and unilayered sporocyst wall, composed of 2 valves joined by suture; Stieda body and substieda bodies are absent.     

Extraintestinal stages fo Isospora ohioensis from dogs in mice

The development of Isospora ohioensis was studied in mice by feeding tissues of mice inoculated with oocysts to coccidia-free dogs and by the examination of mesenteric lymph nodes using light and electron microscopes. Extraintestinal organs of mice became infectious to dogs within 1 day after ingesting oocysts and remained infectious for at least 211 days after inoculation (DAI). Isospora ohioensis sporozoites were found in lymphoreticular cells of mesenteric lymph nodes of mice from 1-374 DAI. Intracellular sporozoites were located in parasitophorous vacuoles. Sporozoites grew from 5--6 to 11--16 micron in length on the 39th DAI but never lost the 2 crytalloid bodies typical for coccidian sporozoites. PAS-positive granules accumulated gradually in intracellular sporozoites with duration of infection in mice. The appearance of parasitophorous vacuoles varied with duration of infection. Beginning with 7 DAI, the vacuole contained a marginal zone of electron-dense material (up to 0.8 micron wide), giving the appearance of a cyst wall or sheath under the light microscope; a true cyst wall was was not found.     

Isospora thibetana N. Sp. (Apicomplexa, Eimeriidae), a Parasite of the Tibetan Siskin (Serinus thibetanus=Carduelis thibetanus) (Passeriformes, Fringillidae)

Tibetan siskins are birds native to the Himalayan region often imported into Italy for commercial purposes. Fecal examination of 45 imported subjects with clinical signs of diarrhoea revealed the presence of a large number of coccidian oocysls. After sporulation, accomplished by mixing feces with 2.5 % (w/v) acqueous K₂Cr₂O₇ at room temperature (22° C ± 1° C), exogenous stages of an Isospora species were revealed. The oocysts of this Isospora are spherical, have a bilayered colorless wall, and average 23.24 μm × 23.05 μm; oocyst residuum and micropyle are absent, while an oval polar granule is rarely present. The elliptical sporocysts average 18.44 μm × 10.97 μm and the Stieda body protrudes slightly from the end of the sporocyst. A spherical sporocyst residuum is present though it sometimes consists of scattered granules. The spindle-shaped sporozoites average 11.53 μm × 2.86 μm, and have two refractile bodies. The taxonomic position of the tibetan siskin is controversial. Some authors include this species in the genus Serinus , while others include it in the genus Carduelis. The coccidian species isolated from these tibetan siskins was, for this reason. compared with the Isospora species previously described both in the genus Carduelis and in the genus Serinus. As a result of this comparison a new species. Isospora thibetana , was named. In the intestine of dead subjects, oocysts were found only in the ileum where the mucosa was greatly thickened and presented a heavy leucocytic infiltration consisting mainly of lympho-monocytic cells. A similar infiltration was observed in liver and lungs as well.     

Description of a new Eimeria sp. and associated lesions in the kidneys of double-crested cormorants (Phalocrocorax auritus)

A new Eimeria sp. is described as the cause of an outbreak of renal coccidiosis in double-crested cormorants (Phalacrocorax auritus) in Georgia. Sporulated oocysts were spherical to subspherical and measured 16.1 x 16.5 (13.8-18 x 14-19) microm, with an average length-width ratio of 1:1. Oocyst wall was thin (1 microm), greenish, and pitted on the outer surface. Micropyle, micropylar cap, Stieda body, and polar bodies were absent. Small oocyst residuum (4-8 granules) was usually absent but occasionally present. Sporocysts were oval and measured 6.6 x 9.3 (6-7 x 8-10.5) microm, with an average length-width ratio of 1:1.4. A sporocyst residuum was present, located in between sporozoites, and was composed of numerous granules of unequal size. A small refractile body was present in each sporozoite. Collecting duct and distal renal tubular epithelial cells were distended by large oocysts in their cytoplasm, and many oocysts were present in the lumen of dilated tubules. Various stages of meronts, gamonts, and developing oocysts were present in other renal tubular epithelial cells. Multiple infections of parasitized cells were frequently observed, with cells containing up to 12 gamonts or developing oocysts. The importance of this Eimeria sp. on double-crested cormorant populations is not known. But in this case, significant lesions and mortality were associated with infection.     

Eimeria ornata N. Sp. (Apicomplexa: Eimeriidae) from the Ornate Box Turtle, Terrapene ornata ornata (Reptilia: Testudines), in Texas

Eimeria ornata n. sp. is described from the feces of 6/16 (37.5%) ornate box turtles, Terrapene ornata ornata , in northcentral Texas. Endogenously sporulated oocysts are ellipsoid 17.9 × 15.7(16-21 × 14-18) μm, with a thin, single-layered wall; shape index 1.14 (1.0-1.3). A micropyle is absent but a polar granule was present in one third of the oocysts. An oocyst residuum was present, consisting of numerous small globules situated either in a distinct mass or scattered within the oocyst. The sporocysts are elongate, 11.1 × 5.4 (9-13 × 5-6) μm, with an indistinct Stieda body at 1 pole. A sporocyst residuum is present, consisting either as a compact mass or as scattered granules. The sporozoites are elongate, 9.5 × 2.0 (8-12 × 2) μm, in situ, with spherical anterior and posterior refractile bodies. The new species is distinguished from the similar Eimeria carri Ernst & Forrester, 1973, from eastern box turtles, T. Carolina , by slight differences in oocyst morphology and endogenous sporulation.     

Comparative susceptibility of introduced forest-dwelling mosquitoes in Hawai'i to avian malaria, Plasmodium relictum

To identify potential vectors of avian malaria in Hawaiian native forests, the innate susceptibility of Aedes albopictus, Wyeomyia mitchellii, and Culex quinquefasciatus from 3 geographical sites along an altitudinal gradient was evaluated using local isolates of Plasmodium relictum. Mosquitoes were dissected 5-8 and 9-13 days postinfective blood meal and microscopically examined for oocysts and salivary-gland sporozoites. Sporogony was completed in all 3 species, but prevalence between species varied significantly. Oocysts were detected in 1-2% and sporozoites in 1-7% of Aedes albopictus that fed on infected ducklings. Wyeomyia mitchellii was slightly more susceptible, with 7-19% and 7% infected with oocysts and sporozoites, respectively. In both species, the median oocyst number was 5 or below. This is only the second Wyeomyia species reported to support development of a malarial parasite. Conversely, Culex quinquefasciatus from all 3 sites proved very susceptible. Prevalence of oocysts and sporozoites consistently exceeded 70%, regardless of gametocytemia or origin of the P. relictum isolate. In trials for which a maximum 200 oocysts were recorded, the median number of oocysts ranged from 144 to 200. It was concluded that Culex quinquefasciatus is the primary vector of avian malaria in Hawai'i.     

Susceptibility of species A, B, and C of Anopheles culicifacies complex to Plasmodium yoelii yoelii and Plasmodium vinckei petteri infections

The comparative susceptibilities of colonized species A, B, and C of Anopheles culicifacies complex and Anopheles stephensi were determined for 2 rodent malaria parasites Plasmodium vinckei petteri and Plasmodium yoelii yoelii. All the 3 members of the complex were found to support complete sporogony with varying success. Controls, A. stephensi, become readily infected, with >70% developing oocysts. Of the test groups, species A had the highest percentage of mosquitoes with oocysts (>25%) and sporozoites (>15%). Anopheles culicifacies species B were least susceptible; less than 10% had oocysts and sporozoites in the salivary glands. The results demonstrate that A. culicifacies species A is most susceptible and species B is least susceptible to infections with both the parasites.     

Eimeria pavoaegyptica sp. nov. (Apicomplexa: Eimeriidae) in faeces of Indian peacocks, Pavo cristatus Linnaeus, 1758 (Galliformes: Phasianidae) from Egypt

Coprological examination of 15 Indian peacocks, Pavo cristatus, revealed the presence of a coccidium species of the genus Eimeria, which apparently represents a previously undescribed species. Sporulation is exogenous and fully developed oocysts of Eimeria pavoaegyptica sp. nov. are ellipsoidal, with a dimension of 15 (13-16) × 12 (10-12.9) microm and with a shape index of 1.25 (1-1.3). The sporulated oocysts have no micropyle but enclose one large rectangular-shaped polar granule and an oocyst residuum. The oocysts have a distinct two-layered wall, which is ~approximately1.7 microm thick. The outer layer has a smooth texture; it fills ~? of the total thickness and appears bicolored. The sporocysts are boat-shaped, of about 10 (9-11) × 4 (4-4.7) microm; their average shape-index is 2.5 microm with a small pointed Stieda body and a smooth, thin single-layered wall. No substieda body is detected. The sporocysts contain numerous, nearly uniform granular residua. The sporozoites are banana-shaped, 6 × 3 microm and each has two different-sized refractile bodies.     

Exit of Plasmodium sporozoites from oocysts is an active process that involves the circumsporozoite protein

Plasmodium sporozoites develop within oocysts residing in the mosquito midgut. Mature sporozoites exit the oocysts, enter the hemolymph, and invade the salivary glands. The circumsporozoite (CS) protein is the major surface protein of salivary gland and oocyst sporozoites. It is also found on the oocyst plasma membrane and on the inner surface of the oocyst capsule. CS protein contains a conserved motif of positively charged amino acids: region II-plus, which has been implicated in the initial stages of sporozoite invasion of hepatocytes. We investigated the function of region II-plus by generating mutant parasites in which the region had been substituted with alanines. Mutant parasites produced normal numbers of sporozoites in the oocysts, but the sporozoites were unable to exit the oocysts. In in vitro as well, there was a profound delay, upon trypsin treatment, in the release of mutant sporozoites from oocysts. We conclude that the exit of sporozoites from oocysts is an active process that involves the region II-plus of CS protein. In addition, the mutant sporozoites were not infective to young rats. These findings provide a new target for developing reagents that interfere with the transmission of malaria.     

Eimeria saudiensis n. sp. (Apicomplexa: Eimeriidae) from the Arabian oryx (Oryx leucoryx) in Saudi Arabia

Oocysts of Eimeria saudiensis n. sp. (Apicomplexa: Eimeriidae) are described from the feces of the Arabian oryx, Oryx leucoryx, from the Riyadh Zoo, Saudi Arabia. The oocysts were ellipsoidal or slightly ovoid, 31.2 x 24.5 (24.3-36.5 x 20.0-27.6) micron with a bilayered wall about 1.7 micron thick. The micropyle was covered by a dome-shaped cap. The oocyst residuum was absent, but tiny polar granules were present. The sporocysts were elongate ovoid, 14.3 x 7.2 (11.5-18.5 x 6.0-9.0) micron, had a Stieda body, but lacked a substiedal body. The sporocyst residuum was present, composed of numerous small granules. The sporozoites were elongate club-shaped, and contained two prominent refractile bodies.     

Optimized excystation protocol for ruminant Eimeria bovis- and Eimeria arloingi-sporulated oocysts and first 3D holotomographic microscopy analysis of differing sporozoite egress

Successful excystation of sporulated Eimeria spp. oocysts is an important step to acquire large numbers of viable sporozoites for molecular, biochemical, immunological and in vitro experiments for detailed studies on complex host cell-parasite interactions. An improved method for excystation of sporulated oocysts and collection of infective E. bovis- and E. arloingi-sporozoites is here described. Eimeria spp. oocysts were treated for at least 20 h with sterile 0.02 M _L-cysteine HCl/0.2 M NaHCO₃ solution at 37 °C in 100% CO₂ atmosphere. The last oocyst treatment was performed with a 0.4% trypsin 8% sterile bovine bile excystation solution, which disrupted oocyst walls with consequent activation of sporozoites within oocyst circumplasm, thereby releasing up to 90% of sporozoites in approximately 2 h of incubation (37 °C) with a 1:3 (oocysts:sporozoites) ratio. Free-released sporozoites were filtered in order to remove rests of oocysts, sporocysts and non-sporulated oocysts. Furthermore, live cell imaging 3D holotomographic microscopy (Nanolive®) analysis allowed visualization of differing sporozoite egress strategies. Sporozoites of both species were up to 99% viable, highly motile, capable of active host cell invasion and further development into trophozoite- as well as macroment-development in primary bovine umbilical vein endothelial cells (BUVEC). Sporozoites obtained by this new excystation protocol were cleaner at the time point of exposure of BUVEC monolayers and thus benefiting from the non-activation status of these highly immunocompetent cells through debris. Alongside, this protocol improved former described methods by being is less expensive, faster, accessible for all labs with minimum equipment, and without requirement of neither expensive buffer solutions nor sophisticated instruments such as ultracentrifuges.     

Two new eimerians (Apicomplexa) from insectivorous mammals in Madagascar

Fecal samples from 126 insectivorous mammals in Madagascar were collected between spring 1999 and fall 2001. In the Afrosoricida, 21 species in 5 genera were sampled, including 17 species of Microgale (31/96, 32% infected), Hemicentetes semispinosus (1/2, 50%), Oryzorictes hova (1/5, 20%), Setifer setosus (8/13, 61.5%), and Tenrec ecaudatus (5/8, 62.5%); in the Soricomorpha, only Suncus murinus was examined and 1/2 (50%) were infected. Two morphotypes of eimeriid oocysts, representing 2 presumptive new species, were found in 47 (37%) infected animals; only 2 afrosoricid hosts (2% of all hosts, 4% of infected hosts) had both oocyst morphotypes. Sporulated oocysts of the first morphotype, Eimeria tenrececaudata n. sp., are subspheroidal, 18.8 × 17.4 (17-22 × 15-20), with a length∶width ratio (L/W) of 1.1 (1.0-1.2); they lack a micropyle but may contain 0-2 polar granules and a single, small round oocyst residuum, 3 × 2.3. Sporocysts are lemon-shaped, 9.9 × 6.6 (9-11 × 5-8), with a L/W of 1.5 (1.2-2.0); they have a prominent, slightly flattened Stieda body and a substieda body but lack a parastieda body. The sporocyst residuum consists of only a few granules between the sporozoites, which are sausage-shaped and have a large posterior refractile body. Oocysts of the second morphotype, Eimeria setifersetosa n. sp. are spheroidal to subspheroidal, 30.1 × 28.6 (27-34 × 25-34), with a L/W of 1.1 (1.0-1.2); they lack both micropyle and oocyst residuum, but 1-2 polar granules are usually present. Sporocysts are subspheroidal to broadly ellipsoidal, 9.6 × 7.3 (9-11 × 6-8), with a L/W of 1.3 (1.1-1.7); they have a broad Stieda body, lack sub- and parastieda bodies, and have a residuum of a few granules scattered throughout the sporocyst. Sporozoites were not clearly defined, but what seemed to be a single large refractile body is seen, presumably in each sporozoite.     

Three new species of Isospora Schneider, 1881 (Apicomplexa: Eimeriidae) from the lesser seed-finch, Oryzoborus angolensis (Passeriformes: Emberizidae) from Brazil

Three new coccidian (Apicomplexa: Eimeriidae) species are reported from the lesser seed-finch, Oryzoborus angolensis from Brazil. Sporulated oocysts of Isospora curio n. sp. are spherical to subspherical; 24.6 x 23.6 (22-26 x 22-25) microm, shape-index (SI, length/width) of 1.04 (1.00-1.15). Oocyst wall is bilayerd, approximately 1.5 microm thick, smooth and colourless. Micropyle and oocyst residuum are absent. The sporocysts are ovoid, 13.2 x 10.9 (15-17 x 10-13) microm, SI = 1.56 (1.42-1.71), with a small Stieda body and residuum composed of numerous granules scattered among the sporozoites. Sporozoites are elongated and posses a smooth surface and two distinct refractile bodies. Oocysts of Isospora braziliensis n. sp. are spherical to subspherical, 17.8 x 16.9 (16-19 x 16-18) microm, with a shape-index of 1.06 (1.00-1.12) and a smooth, single-layered wall approximately 1 microm thick. A micropyle, oocyst residuum and polar granules are absent. Sporocysts are ellipsoid and slightly asymmetric, 13.2 x 10.8 (12-14 x 9-12) microm, SI = 1.48 (1.34-1.61). Each sporocyst contains a barely visible Stieda body and a residuum composed numerous of granules. Sporozoites are elongated and each of them contains two distinct refractile bodies. Oocysts of Isospora paranaensis n. sp. are subspherical to broadly ellipsoid 24.3 x 19.8 (22-26 x 18-22) microm, SI = 1.22 (1.15-1.38) with smooth single-layered wall approximately 1.5 microm thick. A micropyle and oocyst residuum are absent, but one distinct ellipsoid polar granule (2.5-3.5 x 1.5-2.5 microm) is present. Sporocyst are ovoid, 15.7 x 10.1 (14-18 x 8-12) microm, SI = 1.46 (1.31-1.72), with distinct Stieda and sub-Stieda bodies. Each sporocyst contains a spherical sporocyst residuum, 4 microm in diameter All described isosporan species represent a possible cause of acute coccidiosis for O. angolensis in captivity.     

Effect of gamma-irradiation on oocysts of Eimeria necatrix.

Effect of gamma radiation on oocysts of Eimeria necatrix was investigated. It was observed that oocysts exposed to 200 kR or above did not sporulate. Irratiation at 10-150 kR caused a progressive decrease in sporulation. Irradiation affected normal development of unsporulated oocysts as the zygote protoplasm divided into unequal masses or was shattered into granules. Increase in the intensity of irradiation of sporulated oocysts resulted in the progressive decrease in severity of the resultant infections in chicks and their effects - mortality, type of lesions developed, total oocyst production and immunity produced - were comparable with infections induced by decreasing the number of unirradiated oocysts. Infection produced by 1000 unirradiated oocysts was comparable with that resulting from 50 000 oocysts irradiated at 25 kR. Infection obtained with 20 000 unexposed oocysts approximated to that produced by 50 000 oocysts irradiated at 2-5 kR. It was concluded that irradiation abolished infectivity of the oocysts/sporozoites rather than bringing about attenuation of the parasite.     

Comparative Excystation of Four Species of Poultry Coccidia

SYNOPSIS. Examination of the crop, gizzard, and intestinal contents of chickens fed suspensions of either Eimeria acervulina or E. tenella oocysts and turkeys fed either E. meleagrimitis or E. gallopavonis oocysts indicated that, in all 4 species, (1) oocysts apparently remained unchanged while in the crop, (2) sporocysts were liberated from oocysts while the latter were passing through the gizzard, (3) sporozoites were activated and escaped from liberated sporocysts after they had reached the small intestine, and (4) sporozoites within intact oocysts in the crop, gizzard, and intestines were not activated.
In vitro , trypsin 1–300 alone caused a small percentage of sporozoites to excyst from mechanically liberated sporocysts. The percentage of excystation increased greatly when trypsin was added to sodium taurocholate and increased even more when it was combined with chicken or turkey bile.
The two duodenal species ( E. acervulina and E. meleagrimitis ) differed both in vivo and in vitro from the two cecal species ( E. tenella and E. gallopavonis ). The duodenal species excysted in less time and farther anteriorly in the small intestine than did the cecal species. In addition, sporozoites of the two cecal species survived much longer in media containing trypsin plus bile or sodium taurccholate than did those of the two duodenal species.     

Eimeria cryptotis n. sp. (Apicomplexa: Eimeriidae) from the least shrew, Cryptotis parva (Insectivora: Soricidae), in north-central Texas

From March through November 1987, 14 least shrews, Cryptotis parva (Say), were collected in portions of north-central Texas and examined for coccidian parasites; only 1 (7.1%) was found to be passing oocysts. Eimeria cryptotis n. sp. is described herein as new and represents the only coccidian reported thus far from C. parva. Sporulated oocysts are subspherical, 16.4 x 15.3 (14-18 x 13-17) microns; shape index 1.1 (1.0-1.2) microns. A micropyle and oocyst residuum are absent, but a polar granule is present. The sporocysts are ovoid, 10.6 x 7.0 (9-11 x 6-8) microns; shape index 1.5 (1.4-1.8) microns. Stieda and substieda bodies and a sporocyst residuum are present. The sporozoites are elongate and only 2 could be observed well enough to measure (11.2 x 2.4 and 8.8 x 2.4 microns) because they are normally obscured by the sporocyst residuum. Sporozoites lack refractile bodies and contain a centrally located nucleus. The new species can be distinguished from the majority of insectivore coccidia on the basis of oocyst size.