Attempted Cross-Transmission of Coccidia Between Sheep and Goats and Description of Eimeria ovinoidalis sp. n.

SYNOPSIS.
Attempted infection of 2 young lambs with oocysts of Eimeria christenseni from a goat was unsuccessful. Negative results were obtained also when young kids were fed oocysts of Eimeria ninakohlyakimovae from sheep. There was no difficulty in infecting lambs with the sheep coccidium resembling E. ninakohlyakimovae nor goats with the goat coccidium E. christenseni. Oocysts from the goat measured 38.4 × 26.7 m, but were easily distinguished from Eimeria ahsata from the sheep by sporocyst size and shape, and from Eimeria ovina by oocyst size. Eimeria ninakohlyakimovae -like oocysts from sheep averaged 23.0 ×18.2 m and were morphologically indistinguishable from previously reported goat coccidia.
Since no cross infections of sheep and goats could be accomplished with oocysts of Eimeria sp. characteristic of one or the other host, I concluded that sheep coccidia previously known as E. ninakohlyakimovae are distinct from morphologically similar goat coccidia and therefore constitute a separate species. Since the name E. ninakohlyakimovae was first used for coccidia from the goat, the sheep coccidium is renamed Eimeria ovinoidalis with oocyst structure and endogenous stages similar to those previously described from the sheep.     

Coccidia of the domestic goat (Capra hircus) in Saudi Arabia.

Faeces of 228 domestic goats (Capra hircus) from the central region of Saudi Arabia were examined for the presence of coccidian oocysts. Ten species of coccidia were identified and described. A total of 90.3% of the specimens were positive, most of them contained 100-1000 oocysts per g of faecal sample. Kids less than 1 year old had higher oocyst counts than goatlings or adult goats. Mixed infections with three to five species were found in 69.7% of the specimens and six to eight species were found in 10.1%. Eimeria arloingi and E. hirci were most prevalent. E. alijevi, E. ninakohlyakimovae, E. caprina, E. christenseni and E. apsheronica were less common. E. jolchijevi, E. caprovina and E. punctata were relatively rare.     

Experiments with defined multispecific coccidial infections in lambs.

The behaviour of four species of Eimeria was studied in lambs which were given either monospecific or multispecific infections. In the presence of other species the patency of oocyst production of E. ovina and E. weybridgensis was extended and the total number of oocysts produced by all species except E. ninakohlyakimovae was increased. Clinical symptoms were observed only in lambs which received E. ninakohlyakimovae.     

Hepatic coccidiosis in the goat

Coccidial oocysts were seen in the bile from five goats infected with coccidia either naturally or artificially. The oocysts measured on average 21.3 by 18.3 microns and resembled those of Eimeria ninakohlyakimovae. Livers and gall bladders of infected animals showed various degrees of histopathological changes. In the worst case, bile had a thick consistency and contained blood and necrotic debris. Apart from those in the bile, oocysts were seen in liver smears and in the centrilobular vein in two histological sections. Forms resembling meronts and measuring on average 200 by 147 microns were seen in sections of bile duct.     

Coccidia of wombats: correction of host-parasite relationships. Eimeria wombati (Gilruth and Bull, 1912) Comb. Nov. and Eimeria ursini Supperer, 1957 from the hairy-nosed wombat and Eimeria arundeli sp. n. from the common wombat.

Coccidial oocysts morphologically consistent with Eimeria ursini Supperer 1957, and E. tasmaniae Supperer 1957 were recovered from the feces of wild and captive hairy-nosed wombats (Lasiorhinus latifrons) in Australia. Eimeria arundeli so. n. was recovered from the feces of wild and captive common wombats (Vombatus ursinus). Eimeria arundeli oocysts are ellipsoidal to slightly ovoid 60.2--67.2 (63.7) X 40.6--47.6 (43.4); micropyle 3 in diameter usually visible; with oocyst wall granular, dark brown and occasionally opaque, 4--7 thick; inner oocyst wall clear, about 1.5 thick; small oocyst residuum present, four sporocysts ovoid 22.4--29.4 (25.8) X 12.6--15.4 (14.1) with protuberant Stieda body; opposite end of sporocyst also often slighly pointed; large granular sporocyst residuum obscuring sporozoites. Gametocytes of E. arundeli sp. n. and of an organism which is consistent with E. tasmaniae, are described developing in the lamina propria of villi in the small intestine. The stages in the hairy-nosed wombat are those described as Ileocystis wombati Gilruth and Bull 1912. It is suggested that the identification of the host of Supperer's E. ursini and E. tasmaniae as V. ursinus was in error and that the allopatric L. latifrons is the natural host. Eimeria tasmaniae Supperer 1957 is suppressed and E. wombati (Gilruth and Bull, 1912) comb. nov. is proposed and redescribed. No schizonts were identified among the endogenous stages, consistent with observations in the literature on other coccidia with similar gametocyte and oocyst structure.     

Life cycle and biology of Eimeria lettyae sp. n. (Protozoa: Eimeriidae) from the northern bobwhite, Colinus virginianus (L.)

A new species of coccidium, Eimeria lettyae sp. n. (Protozoa: Eimeriidae) was recovered from feces of the northern bobwhite, Colinus virginianus (L.), from Pennsylvania and Florida. Oocysts measured 21.1 microns (16.4 to 25.8) by 17.2 microns (14.1 to 21.2); index (L/W ratio) = 1.22. Oocysts lacked a micropyle, residuum, and polar granules. Sporozoites penetrated the upper 1/2 of the villi, then moved to the lamina propria at the base of the villi. There were five asexual generations, all of which developed above the nucleus of the host cell. Meronts measured 9.4 X 7.0 microns, 18.6 X 11.2 microns, 11.8 X 10.1 microns, 7.1 X 6.2 microns, and 20.2 X 12.8 microns, respectively. These matured at 32, 40, 48, 56, and 72 hr postinoculation (PI) and contained 12, 50+, 24 to 36, 12 to 24, and 50+ merozoites, respectively. Infection was most intense in the duodenum although some gamonts were found in the ileum and ceca. The prepatent period was 88 to 91 hr PI. Sporulation time was 18 hr at 25 C. The peak of oocyst production was broad and extended from 4 days PI through 14 days PI. Oocysts were passed for at least 67 to 76 days PI. Eimeria lettyae sp. n. did not infect chickens (Gallus domesticus), domestic turkeys (Meleagris gallopavo), ring-necked pheasants (Phasianus cochicus), chukar partridge (Alectoris graeca), or Japanese quail (Coturnix coturnix). Immunizing bobwhite with E. lettyae sp. n. did not protect against challenge with E. dispersa. Immunizing bobwhites 25 times with 10(2) or 10(3) sporulated oocysts of E. lettyae did not entirely eliminate oocyst production following challenge with the same species.     

Analysis of Coccidian Oocyst Populations by Means of Flow Cytometry

Flow cytometry was employed as a tool to analyze and characterize batches of oocysts from laboratory and field isolates of Eimeria spp. from chickens and to propagate sub-populations of batches of oocysts. Oocyst batches were cleaned of debris by a combination of salt flotation, washing and treatment with dilute sodium hypochlorite (1.5% aqueous). Oocyst size and shape were registered by forward-angle light scatter with the argon laser excitation set at 488 nm at 300 mW. Sub-populations of oocysts were collected by map gating and used for microscopy or for propagation. The profile of particle size was characteristic for each species. Propagation of sub-populations of oocysts of specified sizes resulted in cultures of coccidia that were pure species or nearly pure species. The small size of E. mills caused difficulty in separation from the remaining fine debris. This technique was useful for studying the variation in oocyst size within populations and characterization of field isolates of mixed species. Propagation of pure species from mixed isolates by bit-map gating had the same limitations as micromanipulation because of the overlapping size of Eimeria spp. Chancaerization is further limited by the lack of suitable size/shape standards for flow cytometry-Key words. Cell sorter. Eimeria spp., oocyst shape, oocyst size.     

Coccidian parasites (Apicomplexa: Eimeriidae) from insectivores. VII. Six new species from the hairy-tailed mole, Parascalops breweri

Sixteen hairy-tailed moles, Parascalops breweri, collected from the northeastern U.S.A. were examined for coccidian oocysts; all were infected with multiple species of coccidia and 3 genera were represented. Two cyclosporans, 2 eimerians, and 2 isosporans are described as new species. Sporulated oocysts of Cyclospora ashtabulensis n. sp. are subspheroid to ellipsoid, 18 X 14 (14-23 X 11-19) microns, and sporocysts are ovoid, 12 X 7 (8-14 X 5-9) microns; C. ashtabulensis was found in 7 of 16 (44%) moles. Sporulated oocysts of Cyclospora parascalopi n. sp. are spheroid, 17 X 14 (13-20 X 11-20) microns, and sporocysts are ovoid, 11 X 7 (8-14 X 5-8) microns; C. parascalopi was found in 8 of 16 (50%) moles. Sporulated oocysts of Eimeria aethiospora n. sp. are subspheroid to ellipsoid, 19 X 13 (15-24 X 10-16) microns, and sporocysts are ovoid, 11 X 6 (8-13 X 4-7) microns; E. aethiospora was found in 4 of 16 (25%) moles. Sporulated oocysts of Eimeria titthus n. sp. are subspheroid, 16 X 14 (13-19 X 11-17) microns, and sporocysts are ellipsoid, 11 X 6 (9-13 X 4-7) microns; E. titthus was found in 4 of 16 (25%) moles. Sporulated oocysts of Isospora ashtabulensis n. sp. are ellipsoid, 20 X 14 (16-24 X 10-18) microns, and sporocysts are ovoid, 10 X 7 (7-14 X 5-10) microns; I. ashtabulensis was found in 5 of 16 (31%) moles.(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

Eimeria pipistrellus n. sp. from Pipistrellus kuhlii (Chiroptera: Vespertilionidae) in Saudi Arabia

Fecal samples from 12 Pipistrellus kuhlii captured at Shagrah, Saudi Arabia, were examined for coccidia and three (25%) found to harbor a undescribed eimerian, herein described as Eimeria pipistrellus n. sp. Sporulated oocysts were subspherical, 24.8 x 23.2 (22-27 x 20-25) microns, with a bilayered and smooth wall. The micropyle was absent, but a large oocyst residuum and a single polar granule were present. Sporocysts were ovoid, 11.6 x 8.3 (10.5-13 x 7.5-9) microns, with a prominent Stieda body, but without a substiedal body; sporozoites lay head to tail in sporocysts and contained one large posterior refractile body. Eimeria pipistrellus n. sp. is the 3rd species of the genus Eimeria found from bats of the genus Pipistrellus.     

Eimeria gozaishoensis n. sp. from the Formosan serow (Capricornis crispus swinhoei)

Eimeria gozaishoensis n. sp. was found in the Formosan serow (Capricornis crispus swinhoei). The oocysts were ovoid, 29.41 +/- 0.58 x 20.77 +/- 0.41 microns with a bilayered wall. A micropyle and micropylar cap were observed, but a polar granule and oocyst residuum were absent. Sporocysts were ovoid, 11.78 +/- 0.30 x 7.60 +/- 0.31 microns, with sporocyst residuum and Stieda body. The new species differs from other known species of the genus by the morphology of oocysts and that domestic goats apparently could not be infected. The sporulation time was 6 to 7 days.     

Metazoan-protozoan parasite co-infections and host body weight in St Kilda Soay sheep

For hundreds of years, the unmanaged Soay sheep population on St Kilda has survived despite enduring presumably deleterious co-infections of helminth, protozoan and arthropod parasites and intermittent periods of starvation. Important parasite taxa in young Soay sheep are strongyles (Trichostrongylus axei, Trichostrongylus vitrinus and Teladorsagia circumcincta), coccidia (11 Eimeria species) and keds (Melophagus ovinus) and in older animals, Teladorsagia circumcincta. In this research, associations between the intensity of different parasite taxa were investigated. Secondly, the intensities of different parasite taxa were tested for associations with variation in host weight, which is itself a determinant of over-winter survival in the host population. In lambs, the intensity of strongyle eggs was positively correlated with that of Nematodirus spp. eggs, while in yearlings and adults strongyle eggs and coccidia oocysts were positively correlated. In lambs and yearlings, of the parasite taxa tested, only strongyle eggs were significantly and negatively associated with host weight. However, in adult hosts, strongyles and coccidia were independently and negatively associated with host weight. These results are consistent with the idea that strongyles and coccidia are exerting independent selection on Soay sheep.     

Quantification of the crowding effect during infections with the seven Eimeria species of the domesticated fowl: its importance for experimental designs and the production of oocyst stocks.

The 'crowding effect' in avian coccidia, following administration of graded numbers of sporulated oocysts to na?ve hosts, is recognisable by two characteristics. First, increasing doses of oocysts give rise to progressively higher oocyst yields, until a level of infection is reached (the 'maximally producing dose') above which further dose increases result in progressive decreases in oocyst yields. Second, the number of oocysts produced per oocyst administered (the 'reproductive potential') tends to decrease as the oocyst dose is increased. The dose that gives the maximal reproductive potential is the 'crowding threshold' and doses exceeding this are 'crowded doses'. Graded doses of Eimeria acervulina, Eimeria brunetti, Eimeria maxima, Eimeria mitis, Eimeria necatrix, Eimeria praecox or Eimeria tenella were given to chickens of the same breed, sex and age, reared on the same diet, under identical management. The two characteristics of the crowding effect were demonstrated graphically and, by interpolation, the estimated crowding thresholds were 903, < or =16, 39, < or =14, < or =16, < or =16 or 72 sporulated oocysts, respectively, for the seven Eimeria species enumerated above. This is apparently the first report of definitive experiments to quantify a crowding effect in E. brunetti, E. maxima, E. mitis, E. necatrix and E. praecox. Maximum experimental reproductive potentials were considerably lower than the theoretical reproductive potentials for all seven species. The interaction between availability of host intestinal cells and immunity contributing to the crowding effect is discussed. Standard curves obtained under specified conditions should be used to estimate appropriate infective doses for experimental designs or in vivo production of oocyst stocks. For experiments on effects of chemotherapy or immunisation on oocyst production, an infective dose lower than the crowding threshold should be used. For efficient production of laboratory or factory oocyst stocks, the maximally producing dose (which is greater than the crowding threshold), should be used.     

Species of coccidia (Apicomplexa: Eimeriidae) in shrews from Alaska, U.S.A., and northeastern Siberia, Russia, with description of two new species

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.     

Prevalence of coccidia and gastrointestinal nematode infections in cross bred goats in the dry areas of Sri Lanka

The prevalence and intensity of oocysts of coccidia, particularly Eimeria species, and eggs of gastrointestinal nematodes in kids (2–4 months), young goats (5–12 months) and adult goats (>1 year) were determined in five large herds managed extensively in five villages in the dry zone. Of the representative samples examined, oocysts were found in 88% of kids, 91% of young goats and 83% of adults. Seven species of Eimeria were identified in faecal samples by salt flotation. Eimeria ninakohlyakimovae (31%), E. alijevi (29%) and E. arloingi (21%) were the most common species in all age categories. Other species encountered were E. christenseni (7%), E. jolchijevi (6%), E. hirchi (3%) and E. aspheronica (1%). Gastrointestinal nematode eggs were found in 89% of the kids, 94% of the young goats and 84% of the adult goats. Identification of gastrointestinal nematodes revealed Haemonchus contortus (90%) followed by Oesophogostomum spp. (8.5%) and Trichostrongylus spp. (1%) in all three age categories examined. Both Eimeria and gastrointestinal nematodes were found in 77% of the kids, 86% of the young goats and 71% of adult goats. The mean oocyst counts per gram of faeces in kids, young goats and adult goats were 9728, 1946, and 2667, respectively. The oocyst counts were not different significantly between age groups (P>0.05). The mean egg counts per gram of faeces in kids, young goats and adult goats were 1217, 1641 and 1092, respectively. The egg counts in kids were significantly lower than that in young goats (P<0.05). The intensity of Eimeria and gastrointestinal nematode infections between herds were significantly different (P<0.01).     

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)     

Winter Resistant Oocysts in the Pasture as a Source of Coccidial Infection in Lambs

Lambs born in pens with slatted floor were brought out at 2–5 weeks of age on pastures heavily grazed by sheep the previous years. About 16 days later the oocyst output of the lambs rapidly increased to high levels. Lambs on pastures which never had been grazed by sheep earlier, had moderate oocyst counts. Between 11 and 25 days after the beginning of grazing there were significantly more lambs with diarrhoea on permanent pastures compared with pastures never grazed by sheep earlier. It was found that lambs were heavily infected during the first 2 days on permanent pastures. Thirteen housed lambs were given 10–50 g of soil from a permanent pasture as a water suspension by a stomach tube. Fifteen days later there was a steep rise in the oocyst output in most of them, and 11 of the 13 lambs developed diarrhoea and 2 died. None of 10 lambs given uninfected soil and none of 12 untreated controls showed diarrhoea and the oocyst output remained on a moderate level. It is concluded that oocysts which have survived the winter in the pasture are the main source of infection with Eimeria spp. in lambs with this kind of management. Soil-eating is the most likely source of infection during the first days on pasture.     

Eimeria (Protozoa: Eimeriidae) of the Cottontail Rabbit Sylvilagus audubonii in Northeastern Colorado, with Descriptions of Three New Species

SYNOPSIS. All of 100 cottontail rabbits Sylvilagus audubonii were found to be infected with 1-6 species of Eimeria. Three new species, E. audubonii, E. neoirresidua and E. poudrei are described from this host. Sub-spherical oocysts of E. audubonii average 21.2 by 17.1 μ; polar body, micropyle, oocyst residuum and sporocyst residuum are all absent; ellipsoidal sporocysts average 12.9 by 5.8 μ. Ovoid to ellipsoidal oocysts of E. neoirresidua average 25.7 by 17.9 μ; polar body and oocyst residuum are absent; micropyle and sporocyst residuum are present; ellipsoidal sporocysts average 14.5 by 6.4 μ. Ovoid to ellipsoidal oocysts of E. poudrei average 26.0 by 18.1 μ; polar body is lacking; micropyle, oocyst residuum and sporocyst residuum are present; ellipsoidal sporocysts average 14.4 by 6.4 μ. Three species of Eimeria previously described in the literature, E. maior Honess, 1939, E. media form honessi Carvalho, 1943 and E. environ Honess, 1939 are redescribed. A detailed structural and statistical analysis of each species is presented with at least 200 sporulated oocysts measured in each instance. A host list and a key to the Eimeria of cottontails is given. The use of detailed studies of oocyst size and structure as a tool for specific diagnosis of the Eimeria of cottontails is discussed.