Prevalence and distribution of Sarcocystis spp. among white-tailed deer of the southeastern United States

Sarcocysts were found by light microscopic examination of muscle in 199 (51%) of 390 white-tailed deer (Odocoileus virginianus) from the southeastern United States. Sarcocystis infections were detected more frequently in histologic sections of tongue (45%) than of heart (9%). Sarcocysts were significantly more prevalent in adult deer (54%) than fawns (26%) (P less than .01). Statistically significant differences in prevalence were not found in deer from different physiographic provinces or between sexes. Artificial digestion was more sensitive in detecting Sarcocystis infections than examination of histologic sections when both techniques were used to examine tongues of 35 deer. Three different size sporocysts, possibly representing at least two species of Sarcocystis, were recovered during feeding trials. Seven dogs (Canis familiaris) shed sporocysts 9 to 12 days after eating infected venison. Sporocysts measured 13.4-16.8 x 9.0-12.3 micrometers with an average measurement of 15.2 x 10.9 micrometers (N = 195). One of three cats (Felis catus) and one of two red foxes (Vulpes vulpes) first shed sporocysts of Sarcocystis 10 days after eating infected venison. Sporocysts from the cat measured 11.2-13.4 x 6.72-8.96 micrometers (avg 12.0 x 8.7 micrometers, N = 18), and those from the fox measured 11.2-15.7 x 9.0-11.2 micrometers (avg 13.6 x 10.2 micrometers, N = 7).     

Prevalence of Sarcocystis in wolves and white-tailed deer in Northeastern Minnesota

The prevalence of Sarcocystis (Protozoa: Sarcocystidae) in white-tailed deer (Odocoileus virginianus) from northeastern Minnesota was determined by histologic examination of tongue samples. Seventy-nine of 100 deer were infected; infection was higher in yearlings and adults than in fawns. Sporocysts of Sarcocystis were found in 3% of 72 wolf (Canis lupus) scats. Three of four captive wolves fed muscle from a white-tailed deer naturally infected with Sarcocystis shed sporocysts 12-14 days later.     

Sarcocystis of deer in South Dakota

The prevalence of Sarcocystis in white-tailed deer (Odocoileus virginianus) and mule deer (O. hemionus) in South Dakota was determined through microscopic examination of tongue samples. The percentage of Sarcocystis infection for both species of deer was determined for prairies east of the Missouri River, west of the Missouri River, and Black Hills of western South Dakota. Sixteen percent (N = 62) of the white-tailed deer tongues from East River, 69% (N = 42) from West River, and 74% (N = 23) from the Black Hills were infected. Prevalence for mule deer was 88% (N = 24), 78% (N = 63), and 75% (N = 12) from East River, West River, and the Black Hills, respectively. Of 50 tongue samples obtained from both species of deer during a special antlerless deer hunt in the Black Hills in 1978, 66% were infected. Coyotes (Canis latrans), dogs (Canis familiaris), red foxes (Vulpes vulpes), a gray fox (Urocyon cinereoargenteus), bobcat (Felis rufus), and raccoon (Procyon lotor) were fed muscle from white-tailed deer and mule deer naturally infected with Sarcocystis to determine their role as definitive hosts. All coyotes, dogs, and the gray fox shed sporocysts, while none were recovered from the other animals. Sporocysts shed by coyotes were counted and concentrated into an inoculum and administered to a white-tailed deer fawn, which was necropsied 85 days after inoculation. Sections of heart, tongue, esophagus, diaphragm, and skeletal muscle were found to be heavily infected with sarcocysts, while sarcocysts were not detected in a control fawn.     

Nomenclature of Sarcocystis in the ox and sheep and of fecal Coccidia of the dog and cat.

The nomenclature of Sarcocystis and related protozoan genera is reviewed, and modern diagnoses of the genera Isospora, Toxoplasma, Besnoitia, Sarcocystis, and Frenkelia in the coccidian family Eimeriidae are given. S cruzi (Hasselmann 1926) comb. n., S. hirsuta Moulé 1888, and S. hominis (Railliet and Lucet 1891) comb. n. are recognized in the muscles of the ox Bos taurus; S. ovicanis Heydorn, Gestrich, Melhorn, and Rommel 1975, and S. tenella Railliet 1886 are recognized in the muscles of the sheep Ovis aries; S. bigemina (Stiles 1891) comb. n., S. cruzi, S. ovicanis, S. bertrami Doflein 1901, S. miescheriana (Kühn 1865) Lankester 1882, I. ohioensis Dubey 1975, I. canis Nemeséri 1959, Isospora sp. n. Dubey, and Isospora sp. n. Trayser and Todd are recognized in dog (Canis familiaris) feces; and S. hirsuta, S. tenella, S. muris (Blanchard 1885) Labbé 1899, B. besnoiti (Marotel 1912) Henry 1913, Besnoitia sp. n. Frenkel, T. gondii (Nicolle and Manceaus 1908) Nicolle and Manceaux 1909, T. hammondi (Frenkel 1974) Levine and Nye 1976, I. rivolta (Grassi 1879) Wenyon 1923, and I. felis Wenyon 1923 are recognized in cat (Felis catus) feces. Hoareosporidium Pande, Bhatia, and Chauhan 1972 is considered a synonym of Sarcocystis.     

Sarcocystis fayeri sp. n. from the horse.

Hearts, diaphragms, esophagi, and spinal cords from 266 horses were obtained at slaughter in Creston, Ohio. Tissues were examined microscopically for Sarcocystis in sections, digested in trypsin to obtain bradyzoites, and fed to 10 dogs and 10 cats. Intramuscular cysts were found in selections of two hearts from 57 horses and four esophagi from 107 horses. The cysts were up to 900 micron long and up to 70 micron wide. The cyst wall was 1 to 2 micron thick and cross-striated. The enclosed bradyzoites were banana-shaped, 15 to 20 by 20 to 3 micron, and contained several PAS-positive granules. Bradyzoites were found in trypsin digests of seven of 57 (13%) equine tissues (heart, diaphragm, esophagus but not spinal cord) in one experiment and 10 of 47 (21%) esophagi, eight of 47 (17%) diaphragms but none of 47 hearts and spinal cords in another experiment. All of 10 dogs shed sporulated sporocysts or oocysts in feces 12 to 15 days (12 in one, 13 in eight, and 15 days in one) after digesting tissues from 169 horses. The sporocysts were 11 to 13 (12.0 +/- 0.5) by 7 to 8.5 (7.9 +/- 0.5) micron. In histologic sections of canine small intestine the sporocysts were located in the lamina propria near the tips of the villi. The 10 cats fed tissues from 266 horses did not shed Sarcocystis. A new name, S. fayeri, is proposed for this organism. Sarcocystis fayeri sporocysts (12 by 8 micron) are shorter than those of S. betrami (15 by 10 micron), the other species of Sarcocystis from the horse. The prepatent period is 12 to 15 days for S. fayeri and 8 days for S. bertrami (synonym S. equicanis Rommel and Geisel 1975).     

Sarcocystis in free-ranging herbivores on the National Bison Range.

Heart, esophagus, diaphragm and skeletal muscle obtained from various herbivores on the National Bison Range were examined grossly for Sarcocystis. Sarcocystis was found in 81, 50, 50, and 13% of the mule deer, (Odocoileus hemionus), white-tailed deer (O. virginianus), elk (Cervus elaphus), and bison (Bison bison), respectively.     

Sarcocystis hemionilatrantis (Sp. N.) life cycle in mule deer and coyotes.

Fifteen coyotes (Canis latrans) shed sporulated sporocysts in their feces after eating freshly ground skeletal muscles from a mule deer (Odocoileus hemionus hemionus) infected with microscopic-sized cysts of Sarcocystis. Sporocysts were shed intermittently from 12 to 36 days after ingestion of the infected meat. Sporocyst size averaged 14.4 X 9.3 mum. Eleven mule deer fawns orally inoculated with these sporocysts became infected and 9 of 11 died between post-inoculation days (PID) 27 and 63. Clinical signs of anorexia, weight loss, pyrexia and weakness were evident prior to death. A calf (Bos taurus) and two lambs (Ovis aries) orally inoculated with these sporocysts did not become infected and remained healthy throughout the experiments. Similarly, uninoculated control animals consisting of three mule deer fawns, two lambs and one calf remained healthy during the experiment. Preliminary histologic examinations conducted on selected tissues from all animals revealed microscopic-sized schizogonous stages in macrophages, between muscle fibers and near blood vessels in the esophagus, heart, biceps femoris, semi-membranosus, diaphragm and tongue from seven of eight fawns which died between PID 27 and 39. Developing or mature muscle cysts were not found in fawn tissue until PID 60. Sarcocysts were found in the three infected fawns examined after this time. Muscle cysts or earlier schizont stages were not found in tissues from the inoculated or uninoculated calves and lambs. A single muscle cyst was found in one control fawn; the other two control fawns were negative for both muscle cysts and other schizogonous stages. These results established that the life cycle of this species of Sarcocystis can be completed with coyotes as the definitive host and mule deer as the intermediate host. Based on the demonstrated host specificity and earlier findings, the name Sarcocystis hemionilatrantis is proposed for this parasite of mule deer and coyotes.     

Ultrastructure of Sarcocystis sp. from the muscle of a white-tailed deer (Odocoileus virginianus)

Sarcocystis sp. from the muscle of naturally infected white-tailed deer (Odocoileus virginianus) was examined by transmission electron microscopy. The primary cyst wall forms regularly spaced protrusions filled with electron-lucent ground substance; no fibrils are present in the protrusions. The cysts are divided by septa into compartments containing typical coccidian metrocytes and merozoites. Taxonomy of the protozoon from the white-tailed deer-dog is discussed.     

Parasitism among white-tailed deer and domestic sheep on common range

Parasitism was studied in white-tailed deer (Odocoileus virginianus) and domestic sheep (Ovis aries) which shared a common range in eastern West Virginia. Of 30 species of internal parasites, 11 were found in deer and 22 in sheep. Five parasites, Sarcocystis sp., Cysticercus tenuicollis, Oesophagostomum venulosum, Cooperia punctata, and Gongylonema pulchrum, occurred in both deer and sheep. An index of similarity of 17.2 suggests that the parasite faunas of these hosts are distinct, and that it is unlikely that white-tailed deer are reservoirs of common parasites of domestic sheep in the southern Appalachian region.     

Sarcocystis infections among snakes in Israel

Natural infection with Sarcocystis has been recovered from 11 species of snakes from Israel and the adjacent territories (Cisjordan), infection was most abundant in subadults. Sporocyst dimensions obtained from the different snakes overlapped in size, but even in a same host species formed distinct size cohorts clustering either around 8.5 x 6.5 microns and 11.0 x 8.5 microns or around 11.0 x 8.5 microns and 12 x 10 microns. Sporocyst-size distribution was, however, altered following cross infections or in consecutively emitted feces. The largest cohort size conformed with the sporocyst dimensions of S. murivipera Matuscka, Heydorn, Mehlhorn, Abd-Al-Az, Diesing, Bichler 1987, described from Vipera palaestinae, one of the snake species included in the present study. Among infected snakes were rodent predators but also species feeding on smaller prey (reptiles). Sporocysts from eight of these species including some small-prey feeders, were available for infecting rodents, all, like S. murivipera, developed into sarcocysts in laboratory white mice (Mus musculus), but in none of the inoculated rodents from other genera, or reptiles. Sarcocysts found in free-ranging house mice infected V. palaestinae. Despite of an apparent conspecificity, Sarcocystis from the different snake species demonstrated a pronounced variation in their virulence to mice. Primary wall was identical in all ultrastructurally studied sarcocysts found in both house mice and laboratory mice fed on sporocysts from the diverse snake species.     

Experimental infections of Sarcocystis cruzi, Sarcocystis tenella, Sarcocystis capracanis and Toxoplasma gondii in red foxes (Vulpes vulpes)

Four littermate 6-wk-old red foxes (Nos. 1-4) were fed Toxoplasma gondii, Sarcocystis cruzi, S. tenella and S. capracanis. One littermate fox (No. 5) served as the control. Two foxes (Nos. 1, 2) were fed tissue cysts of T. gondii and two foxes (Nos. 3, 4) were fed oocysts of T. gondii. Twenty-one to 42 days later, the same five foxes were used to test the infectivity of meat of goat, sheep, and ox experimentally inoculated with Sarcocystis. Fox 2 was fed goat meat and shed S. capracanis-like sporocysts 10 days later. Foxes 3 and 4 were fed beef, and they shed S. cruzi-like sporocysts 9 days later. Fox 5 was fed sheep meat and shed S. tenella-like sporocysts 8 days later. Foxes were killed between 36 and 55 days of the experiment and their tissues were inoculated into mice to recover T. gondii. All foxes remained clinically normal and T. gondii was recovered from all inoculated foxes and not from the control. Sarcocystis sporocysts from foxes induced lethal infections in goats, sheep, and ox. The sporocysts, meronts, merozoites, and sarcocysts of fox-derived parasites were similar to those derived from coyotes or dogs. It was concluded that the red fox can act as a final host for the three pathogenic species of Sarcocystis in cattle, sheep, and goats.     

Sarcocystis leporum in cottontail rabbits and its transmission to carnivores.

Muscle from Sarcocystis-infected cottontail rabbits (Sylvilagus floridanus) was fed to coccidia-free cats (Felis domestica) and dogs (Canis familiaris). Only cats became infected and shed sporocysts in their feces. The prepatent period ranged from 10 to 25 days and the patent period from 3 to 46 days. Sporocysts were fully sporulated when shed. They contained 4 sporozoites and a coarse granular residuum and averaged 9.4 by 13.6 micron (N=55). Doses of 200-75,000 sporocysts were orally administered to 5 domestic rabbits (Oryctolagus cuniculus). Domestic rabbits did not become infected, suggesting a strict host specificity for the intermediate host S. floridanus.     

The nine-banded armadillo (Dasypus novemcinctus) is an intermediate host for Sarcocystis neurona

The nine-banded armadillo (Dasypus novemcinctus) is an intermediate host of at least three species of Sarcocystis, Sarcocystis dasypi, Sarcocystis diminuta, and an unidentified species; however, life cycles of these species have not been determined. Following feeding of armadillo muscles containing sarcocysts to the Virginia opossum (Didelphis virginiana), the opossums shed sporulated Sarcocystis sporocysts in their faeces. Mean dimensions for sporocysts were 11.0x7.5 microm and each contained four sporozoites and a residual body. Sporocysts were identified as Sarcocystis neurona using PCR and DNA sequencing. A 2-month-old foal that was negative for S. neurona antibodies in the CSF was orally inoculated with 5x10(5) sporocysts. At 4 weeks post-infection, the foal had a 'low positive' result by immunoblot for CSF antibodies to S. neurona and by week 6 had a 'strong positive' CSF result and developed an abnormal gait with proprioceptive deficits and ataxia in all four limbs. Based on the results of this study, the nine-banded armadillo is an intermediate host of S. neurona.     

Failure to detect infection in fallow deer (Cervus dama) exposed to Theileria cervi from white-tailed deer

A frozen stabilate was produced from Theileria cervi sporozoites in salivary glands of adult Amblyomma americanum. The stabilate was inoculated into three fallow deer (Cervus dama) and two white-tailed deer (Odocoileus virginianus). Following inoculation, the white-tailed deer developed parasitemias as determined by blood smear examination at 11 and 13 days postexposure. Repeat examination of blood from the three fallow deer for 30 days postexposure failed to reveal observable piro-plasms. These findings indicate that fallow deer are not as susceptible to the Theileria cervi found in white-tailed deer from North America. Thus, there are some questions regarding the taxonomic position of this organism.     

Transmission studies with Sarcocystis idahoensis of deer mice (Peromyscus maniculatus) and gopher snakes (Pituophis melanoleucus)

Transmission studies with Sarcocystis idahoensis of deer mice (Peromyscus maniculatus) and gopher snakes (pituophis melanoleucus) were conducted to determine host specificity of various stages of the parasite. Sporocysts were not passed by four dogs or four cats fed infected skeletal muscle from deer mice. Seven white mice (Mus musculus) and 34 white-footed mice (Peromyscus leucopus) were negative for sarcocysts and liver meronts following oral inoculation with S. idahoensis sporocysts; however, excystation of sporocysts occurred in two white-footed mice killed four hours post inoculation (PI). A gopher snake orally inoculated with sporocysts remained negative for coccidia for two months PI. Three deer mice orally inoculated and three intraperitoneally (IP) inoculated with tachyzoites from liver meronts developed sarcocysts in their skeletal muscles similar to those seen in deer mice orally inoculated with sporocysts. Liver meronts were not found. Ten deer mice orally inoculated and 10 deer mice inoculated IP with bradyzoites from S. idahoensis sarcocysts remained negative for sarcocysts and liver meronts at necropsy 17 days PI.     

Experimental infection of dogs with Sarcocystis from wapiti.

Ten domestic dogs became infected with Sarcocystis when fed simple portions of heart, esophagus and diaphragm from a two-year-old female wapiti (Cervus canadensis). The prepatent period was 14 days in all exposed dogs; the patent period ranged from 8 to 20 days. Neither the 10 control dogs, nor two dogs fed sporocysts collected from the infected dogs passed sporocysts within the study period. Sporocysts averaged 16.5 by 11.1 micron in size.     

In vitro excystation of Sarcocystis capracanis, Sarcocystis cruzi and Sarcocystis tenella (Apicomplexa)

Improved rates of in vitro excystation of sporozoites from sporocysts of Sarcocystis capracanis, Sarcocystis cruzi, and Sarcocystis tenella were obtained by pretreating sporocysts with an aqueous sodium hypochlorite (NaOCl) solution followed by incubation in excysting fluid (EF). After pretreatment with NaOCl, sporocysts were washed 4 times in Hanks' balanced salt solution and then incubated in various EF (pH 7.4) at 38.5 C in 5% CO2-95% air. Maximum rates of excystation (free sporozoites/(sporozoites in sporocysts + free sporozoites) X 100) for all 3 species of Sarcocystis occurred at 4 hr after incubation in EF. These rates were 17% for S. capracanis after incubation in EF containing 2% trypsin + 10% caprine bile; 90% for S. cruzi in 2% trypsin + 10% bovine bile; and 20% for S. tenella in 2% trypsin + 10% caprine bile. Only a 40% excystation rate occurred in sporocysts of S. cruzi that had been stored previously for 14 days in aqueous potassium dichromate. Excysted sporozoites of S. capracanis, S. cruzi, and S. tenella penetrated and developed to mature meronts in bovine pulmonary artery endothelial cells or bovine monocytes.     

Ultrastructure of the cyst and life cycle of Sarcocystis sp. from wild sheep (Ovis musimon)

Sarcocystis sp. (Eimeriina: Sarcocystidae) is described as a heteroxenous coccidian with domestic dogs as an experimental definitive host and wild sheep (Ovis musimon) as natural intermediate hosts. Mature sarcocysts of this Sarcocystis sp. were examined by transmission electron microscopy. Sarcocysts in various muscle tissues were microscopic, had a thin primary cyst wall and septa and measured 81.0 x 30.5 microns. The cysts were located within muscle cells and were limited by a primary cyst wall (PCW). The cyst surface was highly folded forming densely packed projections. Between the PCW projections the surface of the cyst was marked with pit-like invaginations. The ground substance of the cyst formed a layer at the periphery of the cyst, filled the projections and formed septa which divided the cyst into compartments. Sarcocysts contained numerous bradyzoites that were 15.2 x 3 microns and few metrocytes 11.5 x 3.5 microns. Twelve days after ingesting Sarcocystis sp.-infected wild sheep meat, four dogs began passing sporocysts in their feces: two domestic cats did not pass oocysts or sporocysts after ingesting meat from the same animals. Sporocysts measured 14.8 x 9.9 microns.     

Sarcocystis Infection in Sheep from South-Western Norway

The occurrence of Sarcocystis infection and pathological changes were recorded in samples of the heart, diaphragm, and oesophagus from 198 healthy sheep representing 3 different age groups, obtained from an abattoir. The infection rate of S. gigantea (syn. S. tenella) was 18.2 %, and the distribution within groups was: ewes 30.0 %, yearlings 11.6 %, lambs nil. The infection rate of S. tenella (syn. S. ovicanis) was 65.1 %, and the corresponding distribution was: ewes 83.5 %, yearlings 74.4 %, and lambs 25.0 %. A third type of Sarcocystis sp. displaying thick wall was found in 3 samples. Focal interstitial infiltrates of mononuclear cells were demonstrated in 47.9 % of the hearts, in 19.6 % of the diaphragms and in 31.3 % of the oesophagi. The occurrence of Sarcocystis and the focal interstitial mononuclear cell infiltrates were positively correlated (P < 0.0001). Morphologically identical sporocysts typical of S. tenella were produced by dogs and foxes fed naturally infected sheep tissues. A cat fed S. gigantea macrocysts produced sporocysts characteristic for the species. Sarcocystis; pathology; life cycle; final hosts; sheep.     

Experimental transmission of Sarcocystis speeri Dubey and Lindsay, 1999 from the South American opossum (Didelphis albiventris) to the North American opossum (Didelphis virginiana)

Sarcocystis speeri Dubey and Lindsay, 1999 from the South American opossum Didelphis albiventris was successfully transmitted to the North American opossum Didelphis virginiana. Sporocysts from a naturally infected D. albiventris from Argentina were fed to 2 gamma-interferon knockout (KO) mice. The mice were killed 64 and 71 days after sporocyst feeding (DAF). Muscles containing sarcocysts from the KO mouse killed 71 DAF were fed to a captive D. virginiana; this opossum shed sporocysts 11 days after ingesting sarcocysts. Sporocysts from D. virginiana were fed to 9 KO mice and 4 budgerigars (Melopsittacus undulatus). Schizonts, sarcocysts, or both of S. speeri were found in tissues of all 7 KO mice killed 29-85 DAF; 2 mice died 39 and 48 DAF were not necropsied. Sarcocystis stages were not found in tissues of the 4 budgerigars fed S. speeri sporocysts and killed 35 DAE These results indicate that S. speeri is distinct from Sarcocystis falcatula and Sarcocystis neurona, and that S. speeri is present in both D. albiventris and D. virginiana.