Hepatozoon cf. terzii (Sambon & Seligman, 1907) infection in the snake boa constrictor constrictor from north Brazil: transmission to the mosquito Culex quinquefasciatus and the lizard Tropidurus torquatus

Specimens of Hepatozoon-infected Boa constrictor constrictor were obtained from localities in Pará State, north Brazil. Gametocytes in erythrocytes of the peripheral blood measured 10 x 2.5-16.2 x 3.7 microns. They were similar to those described as Haemogregarina terzii by Sambon & Seligmann (1907) in B. c. constrictor, in that they did not distort the infected erythrocyte, and their dimensions approximated those given by Carini (1947). Lungs and liver of infected snakes contained actively dividing meronts of a single type, and cysts containing two to six cystozoites were also present in the liver. Our initial feeding of Culex quinquefasciatus on infected snakes consistently resulted in a heavy death-rate of the engorged mosquitoes, with only a few surviving till the 9th day post feeding. These contained numerous oocysts which were undivided or in early stages of division. A fifth and final experiment, however, provided a few mosquitoes surviving up to 21 days post infection (dpi), and these contained fully sporulated oocysts measuring 190-200 microns in diameter and containing over 60 sporocysts of 19-30 microns in diameter. The number of sporozoites in each sporocyst was estimated as approximately 50. The nature of the parasite's sporogonic cycle in the mosquito thus justifies inclusion of this haemogregarine in the genus Hepatozoon. Two wild-caught specimens of the lizard Tropidurus torquatus were fed with mosquitoes containing fully developed oocysts (21 dpi). When sacrificed, three months later, large numbers of dizoic, tetrazoic and hexazoic cysts were demonstrated in their livers. Cystozoites released from these cysts were shown to possess a conspicuous refractile body.     

A comparative study on the biology of Cryptosporidium sp. from guinea pigs and Cryptosporidium parvum (Apicomplexa).

Cryptosporidium sp. from guinea pigs and C. parvum were compared morphologically, electrophoretically, and for the ability to infect suckling mice. Oocysts from guinea pigs measured 5.4 x 4.6 (4.8-5.6 x 4.0-5.0) microns and had a shape index (length/width) of 1.17 (1.04-1.33). Oocysts of C. parvum were similar and measured 5.2 x 4.6 (4.8-5.6 x 4.2-4.8) microns with a shape index of 1.16 (1.04-1.33). All suckling mice inoculated with oocysts of C. parvum became infected, whereas most, but not all, mice fed oocysts of the guinea pig isolate also became infected. However, mice inoculated with oocysts from guinea pigs produced on average 100-fold fewer oocysts by day 7 postinoculation than did mice infected with C. parvum, and the resulting infections were sparse and patchy along the ileum. Electrophoretic profiles were similar, but 125I surface labeling of outer oocyst wall proteins revealed striking differences between the two isolates. Cryptosporidium parvum had a wide molecular size range of 125I-labeled bands, whereas C. sp. from guinea pigs had a banding pattern clustered between 39 and 66 kDa, with a smaller number of bands greater than 100 kDa.     

Coccidian parasites (Apicomplexa: Eimeriidae) from two species of caimans, Caiman yacare daudin and Caiman latirostris daudin (Alligatoridae), from Paraguay

From October 1986 to January 1987, feces from 119 Caiman yacare and 12 Caiman latirostris were collected in Paraguay and later examined for coccidian oocysts; 69 of 119 (58%) samples from C. yacare and 3 of 12 (25%) samples from C. latirostris contained coccidian oocysts. Two eimerians infected C. yacare and both are described as new species. Sporulated oocysts of Eimeria paraguayensis n. sp. are ellipsoid, 34.0 x 23.6 (26-38 x 20-29) microns with sporocysts ovoid, 14.0 x 7.1 (10-19 x 6-10) microns. Sporulated oocysts of Eimeria caimani n. sp. are spheroid, 22.4 (19-29) microns with sporocysts ovoidal, 12.9 x 6.5 (8-17 x 5-8) microns. Isospora jacarei infected C. latirostris and is redescribed. Sporulated oocysts of I. jacarei are sub-spheroid, 13.2 x 12.1 (10-18 x 10-15) microns with sporocysts ellipsoid, 10.4 x 5.8 (7-13 x 4-11) microns. To date, members of the Eimeriidae found in Crocodylia include 5 species of Eimeria and 2 of Isospora including the new species described here.     

Coccidia (Apicomplexa) from heteromyid rodents in the southwestern United States, Baja California, and northern Mexico with three new species from Chaetodipus hispidus

Fecal samples from 223 heteromyid rodents of 4 genera and 13 species were collected from California, New Mexico, and Texas and from Baja California Norte and Sonora, Mexico. Of these, 84 (38%) were infected with coccidian oocysts; 72 of 84 (86%) infected animals had only 1 species of coccidian. Eleven species of coccidia were identified including 1 cyclosporan and 10 eimerians; the cyclosporan and 2 of the eimerians are described as new species. Sporulated oocysts of Cyclospora angimurinensis n. sp. were subspheroidal, 21.9 x 19.3 (19-24 x 16-22) microns, with sporocysts lemon-shaped, 11.9 x 9.5 (9-15 x 8-11) microns; it was found in 1 of 20 (4%) Chaetodipus hispidus. Sporulated oocysts of Eimeria chaetodipi n. sp. were subspheroidal, 16.7 x 14.6 (13-19.5 x 12-17) microns, with sporocysts ovoidal, 8.7 x 6.6 (7.5-10.5 x 5-7.5) microns; it was found in 3 of 20 (15%) C. hispidus. Sporulated oocysts of Eimeria hispidensis n. sp. were subspheroidal, 20.5 x 17.4 (17-23 x 14-21) microns, with sporocysts lemon-shaped, 9.3 x 7.2 (7.5-10.5 x 5-9) microns; it was found in 4 of 20 (20%) C. hispidus.(ABSTRACT TRUNCATED AT 250 WORDS)     

Coccidian parasites (Apicomplexa: Eimeriidae) from insectivores. IV. Four new species in Talpa europaea from England

Moles from England were examined for coccidian oocysts and all 64 Talpa europaea were infected; of 64 infected hosts, 56 (88%) had multiple infections representing two to six coccidian species when examined. Oocysts in 31 of the 64 samples remainedunsporulated. Three eimerians and one isosporan were studied from the 33 fecal samples that had sporulated oocysts and these are described as new species; Cyclospora talpae Pellérdy & Tanyi, 1968, and Isospora sofiae (Golemansky, 1978) Levine & Ivens, 1979, are redescribed; and Cyclospora sp., similar to C. talpae, is discussed. Sporulated oocysts of C. talpae are ellipsoidal, 14.3 X 9.6 (12-19 X 6-13) microns with sporocysts ovoid, 9.4 X 5.7 (6-13 X 4-8) microns; it was found in 21 of the 33 (63.6%) sporulated samples. Sporulated oocysts of Cyclospora sp. are subspheroidal to ellipsoidal, 12.5 X 8.9 (10-14 X 6-12) microns with sporocysts ovoid, 8.6 X 5.3 (6-10 X 4-6) microns; it was found in 21 of the 33 (63.6%) sporulated samples. Sporulated oocysts of Eimeria avonensis n. sp. are elongate-ellipsoidal, 15.0 X 9.6 (13-20 X 7-12) microns with sporocysts ovoid, 6.6 X 3.6 (5-9 X 3-7) microns; it was found in 15 of the 33 (45.5%) sporulated samples. Sporulated oocysts of Eimeria berea n. sp. are subspheroidal, 12.1 X 10.5 (10-15 X 8-14) microns with sporocysts ovoid, 6.3 X 3.9 (5-10 X 2-5) microns; it was found in 8 of the 33 (24.2%) sporulated samples.(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

Ultrastructure of in vivo-produced caryocysts containing the coccidian Caryospora bigenetica (Apicomplexa: Eimeriidae)

A cotton rat was inoculated orally with oocysts of Caryospora bigenetica from the feces of a rattlesnake. Sixteen days later the rat was euthanized, and portions of the scrotum, foot pad and muzzle were processed for histological sections and transmission electron microscopy. Sporozoites within caryocysts had typical coccidian features such as an anterior and posterior refractile body, centrally located nucleus, micronemes, rhoptries, a conoid, a micropore near the anterior refractile body, a posterior pore, amylopectin granules, lipid bodies, a Golgi-like body, a mitochondrion and subpellicular microtubules. The infected host cell was spherical and surrounded by a fibrous wall-like covering, 0.35-1.00 microns thick. This outer covering, when viewed in stained histological sections, was periodic acid-Schiff (PAS)-positive.     

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)     

Four new species of Isospora from the small tree finch (Camarhynchus parvulus) from the Galapagos Islands

Four isosporan species are described from the small tree finch, Camarhynchus parvulus from Isabela Island on the Galapagos Archipelago. Isospora exigua n. sp. oocysts subspheroidal, one-layered, smooth, yellow-brown color, 20.4 X 20.1 (20-23 X 18-23) microns, with no micropyle, residuum, or polar body. Sporocysts ovoidal, 14 X 9.5 (13-15 X 8-10) microns, with small Stieda and substieda bodies and irregular-shaped residuum. Isospora rotunda n. sp. oocysts subspheroidal, single-layered, smooth, yellow-brown wall with large polar body and no micropyle or residuum, 20.9 X 20.8 (20-24 X 19-23) microns. Sporocysts ovoidal, 15 X 9.7 (13-16 X 9-10) microns with knob-like Stieda bodies, prominent substieda bodies and round residuum. Isospora fragmenta n. sp. oocysts subspheroidal with no micropyle or residuum but with many splinter-like polar granules and a smooth, colorless, single-layered wall, 25.3 X 24.2 (24-27 X 23-25) microns. Sporocysts piriform 15.4 X 11.5 (14-17 X 11-12) microns with knob-like Stieda bodies, prominent substieda bodies, and irregular-shaped residuum. Isospora temeraria n. sp. oocysts ellipsoidal with one polar body, no micropyle or residuum, and wall of a single layer, smooth, yellow-brown color, 25.4 X 21.1 (21-30 X 17-23) microns. Sporocysts piriform, 15 X 10 (14-15 X 9-11) microns with knob-like Stieda bodies, prominent substieda bodies, and a round residuum. One woodpecker finch, Cactospiza pallida, was found to be infected with I. exigua, and a warbler finch, Certhidea olivacea was infected with I. fragmenta.     

Coccidian parasites (Apicomplexa: Eimeriidae) from insectivores. VI. Six new species from the eastern mole, Scalopus aquaticus

Thirteen eastern moles, Scalopus aquaticus, collected in West Texas were examined for coccidian oocysts; 11 (85%) were infected and eight (73%) of these had multiple infections representing two or more species. One cyclosporan, three eimerians, and two isosporans were studied and all are described as new species. Sporulated oocysts of Cyclospora megacephali n. sp. were subspheroidal, 18.5 X 15.7 (14-21 X 12-18) microns; they had sporocysts pointed at one end with Stieda bodies nearly as wide as the sporocysts themselves, and were 15.0 X 7.2 (11-17 X 6-9) microns; C. megacephali was found in four (31%) hosts. Sporulated oocysts of Eimeria scalopi n. sp. were spheroidal to subspheroidal, 13.6 X 12.6 (11-17 X 11-15) microns with sporocysts lemon-shaped, 8.7 X 5.5 (7-10 X 4-7) microns; it was found in six (46%) hosts. Sporulated oocysts of Eimeria aquatici n. sp. were asymmetrically ellipsoidal, 17.0 X 10.6 (14-20 X 9-14) microns with sporocysts elongately ovoidal, 9.0 X 5.2 (8-11 X 4-6) microns; it was found in two (15%) hosts. Sporulated oocysts of Eimeria motleiensis n. sp. were subspheroidal, 17.0 X 15.3 (15-20 X 13-18) microns with sporocysts ovoidal, 10.7 X 6.8 (10-13 X 6-8) microns; it was found in seven (54%) hosts. Sporulated oocysts of Isospora motleiensis n. sp. were spheroidal to subspheroidal, 13.6 X 12.0 (10-17 X 8-15) microns with sporocysts broadly ovoidal, 9.5 X 6.7 (7-11 X 4-8) microns; it was found in nine (69%) hosts. Sporulated oocysts of Isospora aquatici n. sp. were subspheroidal, 20.9 X 18.4 (15-24 X 13-21) microns with sporocysts ellipsoidal, 11.8 X 9.0 (9-14 X 7-11) microns; it was found in two (15%) hosts.     

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

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

In vitro excystation of Cryptosporidium baileyi from chickens

Release of sporozoites from the oocysts of Cryptosporidium baileyi is described from Nomarski interference-contrast microscopy. Just prior to excystation, the four sporozoites became motile and rearranged themselves within the oocyst. The sporozoites were then rapidly expelled through an opening that formed in the oocyst wall, and the residuum was either released or retained within the oocyst. Excysted sporozoites were crescent shaped and measured 5.0-9.0 microns X 1.0-1.6 micron (mean = 6.8 X 1.1 microns). Excystation occurred when sodium taurocholate or a mixture of trypsin and sodium taurocholate was present in the incubation medium. High levels of excystation occurred at 37 degrees or 40 degrees C, but excystation did not occur at 4 degrees C. The ability of biles from two avian and two mammalian hosts to produce excystation of C. baileyi was also studied. After a 2-h incubation at 40 degrees C, the percentages of excystation were 69.5% in goat bile, 45.0% in pig bile, 33.0% in chicken bile, and 34.5% in turkey bile.     

A new species of coccidian (Apicomplexa: Eimeriidae) from the prairie racerunner, Cnemidophorus sexlineatus viridis (Sauria: Teiidae), in Arkansas.

Feces from 26 prairie racerunners, Cnemidophorus sexlineatus viridis Lowe, 1966, from Arkansas, were examined for coccidian parasites. One of these was found to be infected with oocysts of an undescribed eimerian, which is described herein as new. Sporulated oocysts of Eimeria sexlineatus n. sp. were cylindrical, 30.4 x 17.1 (28-32 x 16-19) microns, with a shape index (length/width) of 1.8 (1.6-2.0). A micropyle and oocyst residuum were absent but 1 (to several) polar granule(s) was present. Sporocysts were ellipsoidal, 10.7 x 8.5 (9.6-11.2 x 8.0-8.8) microns, with a shape index of 1.3 (1.2-1.4). A sporocyst residuum was present but Stieda, substieda, and parastieda bodies were absent. Sporozoites were elongate, 13.2 x 2.7 microns (12.0-14.4 x 2.4-3.2) in situ, containing a single, spherical posterior refractile body. Oocysts and endogenous developmental stages were found within the gall bladder epithelium of the infected lizard. This represents the first time a coccidian has been reported from a North American whiptail lizard.     

Biology and pathogenicity of Eimeria spinosa Henry, 1931 in experimentally infected pigs.

A single-species isolate of E. spinosa from a diarrheic weaned pig was used to determine the endogenous development and pathogenicity of this swine coccidium. Seven out of 14 inoculated pigs developed endogenous stages or passed oocysts of E. spinosa in their feces. Immunosuppressive treatment with cyclophosphamide had no effect on the susceptibility to infection with E. spinosa in young pigs. The endogenous stages developed within the apical cytoplasm of the enterocytes lining the distal part of the villi in the posterior jejunum. The asexual development comprised three generations of meronts, which were seen at 5, 7 and 9 days post-infection (DPI). Meronts of the first generation measured 6-8 microns and produced 10-14 merozoites 4-6 microns in length. The second generation of meronts measured 6-8 microns and contained 10-20 merozoites 4-6 microns in length. Third generation mature meronts (8-10 microns) on DPI 9 contained 12-20 merozoites measuring 5-7 microns, which were more crescent-shaped and less blunt than the merozoites at 5 and 7 DPI. Merogony continued after formation of the gametes and the first fully developed macrogametes (10-14 microns), microgametes (9-12 microns), and oocysts were also seen at 9 DPI. The prepatent period was 8 or 9 days, but the patent period was not determined. In the present study E. spinosa infection did not produce overt clinical signs. Pathological changes consisted of an inflammatory infiltration in the lamina propria of the posterior jejunum, Peyer's patches activation and sporadic erosions scattered at the villous tips. No villous atrophy in association with a large number of endogenous stages was observed.     

Isospora daphnensis n. sp. (Apicomplexa: Eimeriidae) from the medium ground finch (Geospiza fortis) from the Galapagos Islands

In March and April 1987 fecal samples from 237 nestling birds, including 199 from 85 nest sites of Geospiza fortis, 23 from 12 nest sites of Geospiza scandens, 6 from 2 nest sites of Geospiza magnirostris, and 9 from 2 nest sites of hybrids involving Geospiza fuliginosa and G. fortis, were collected from Daphne Major in the Galapagos archipelago and examined for coccidia. Only 3 of 4 nestlings from 1 nest site of G. fortis (1.5%) had oocysts in their feces. Two of the 3 infected nestlings had concurrent infections of Isospora temeraria, and all 3 nestlings were infected with a new species. Isospora daphnensis n. sp. Sporulated oocysts of I. daphnensis n. sp. are ellipsoidal, 27.3 x 23.6 (22-30 x 20-27) microns; a polar body is present, but no oocyst residuum or micropyle occurs. The oocyst wall, approximately 1.5 microns thick, is composed of a mammillated outer layer and thinner inner layer. Sporocysts are ovoid, 15.2 x 10.2 (15-16 x 9-11) microns and have a nipplelike Stieda body and a small substieda body. The sporocysts contain an irregularly shaped, smoothly contoured residuum with uniform granules and 4 sporozoites with a large refractile body at one end and lying randomly in the sporocysts.     

Attempted cross-transmission of coccidia between sheep and goats and description of Eimeria ovinoidalis sp. n.

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 X 26.7 microns, 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 X 18.2 microns 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. ninakohlykimovae 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.     

Changes in nurse cell nuclei during synchronous infection with Trichinella spiralis

The rate of enlargement of nuclei was determined on 4-microns-thick sections of synchronously infected mouse thigh muscle. Normal muscle nuclei had a geometric mean volume of 84 microns and a range of 42-170 microns 3. At days 5, 6, 7, 8, and 10 and 6 mo after infection, mean nuclear volume was 177 (100-315) microns 3, 254 (140-462) microns 3, 278 (172-447) microns 3, 681 (407-1,138) microns 3, 512 (326-804) microns 3, and 509 (298-870) microns 3, respectively. Size of nuclei for any given day followed a log normal distribution. On days 7 and 8 after infection, 31% of enlarged nuclei had 2 nucleoli, whereas only 15% had 2 nucleoli on day 10. One percent of enlarged nuclei in 6-mo-old nurse cells had double nucleoli. The number of enlarged nuclei in 6-mo-old nurse cells was determined from serial sections of infected tongue muscle. Each nurse cell contained an average of 40 enlarged nuclei. Sixty-four percent of nurse cells examined (n = 55) had between 30 and 60 enlarged nuclei. However, there was great variation in the range (7-142). These results are discussed in relation to the development of the nurse cell.     

Sporogonic development of Hepatozoon americanum (Apicomplexa) in its definitive host, Amblyomma maculatum (Acarina)

Light microscopic observations of the sporogonic development of Hepatozoon americanum are described in its acarine host, Amblyomma maculatum. Laboratory-reared nymphal ticks were fed on 2 dogs infected with H. americanum. Nymphal ticks were sampled daily, starting 3 days after being placed on a parasitemic dog, until 18 days after infestation (PI), and then every 3 or 4 days until replete nymphs molted. Ticks were examined as unstained wet mounts and hematoxylin-eosin-stained paraffin sections. Gametes were found within the gut cells of nymphs 4 and 6 days PI. Although differentiation of gamonts into gametes was not detected, syngamy and sporogony were observed. Sporogony appears to occur wholly within tick gut cells, followed by release of mature oocysts into the hemocoel. The earliest evidence of sporoblast formation was observed 23 days PI and of sporozoite formation, 10 days later. Mature oocysts were first found 42 days PI in newly molted adult ticks. Most adult ticks (>98%) that were dissected contained mature oocysts. Oocysts were multisporocystic, and sporocysts contained a variable number of sporozoites. Oocysts in various stages of development were often seen within the same tick, and the number of mature oocysts ranged from 4 to 573.     

Further studies on the development of gamonts and oocysts of Eimeria magna in cultured cells

Monolayer, cell-line cultures of embryonic bovine trachea, Madin-Darby bovine kidney (MDBK), and monolayers (RK-1) or aggregates of primary rabbit kidney cells were inoculated with merozoites obtained from rabbits that had been inoculated 3 to 5 1/2 days earlier with Eimeria magna. Merozoites obtained from from rabbits 3 days entered cells and underwent only merogony, whereas 3 1/2-5 1/2-day-old merozoites formed gamonts as well as meronts. Merozoites arising from the first or second meront generation in culture formed another meront generation or gamonts. Third-generation merozoites formed only gamonts. Most merozoites remained within the parasitophorous vacuole of the original host cell and transformed into macro- or microgamonts or meronts. Some such macro- and microgamonts then fused with each other to form larger multinucleated bodies. Such microgamonts formed microgametes, but multinucleate macrogamonts did not form oocysts. Mature microgamonts were 34 microns in diameter, and contained several hundred biflagellate microgametes. Mature macrogamonts measured 29.1 x 21.5 microns, unsporulated oocysts were 31.2 x 22 microns, and sporulated oocysts were 32 x 23.1 microns. Oocysts obtained from cell cultures were sporulated and then inoculated by gavage into rabbits, which passed E. magna oocysts 6--10 days later. Sporozoites, obtained from oocysts produced in culture or from rabbits that had been inoculated with the vitro-produced oocysts, developed to first- and second-generation meronts in MDBK or RK-1 cultures.     

Coccidia in the mammary glands of shrews (Order: Insectivora)

Three of 6 female long-clawed shrews, Sorex unguiculatus Dobson, 1890, collected on the island of Hokkaido, Japan, were found to have unsporulated oocysts and sexual stages (both macro- and microgamonts) in varying stages of development of an unidentified coccidium in both lactating and nonlactating mammary glands. Gamonts developed in the alveoli of the mammary glands, and oocysts were found in the lactiferous ducts and in pools of milk. Mature macrogamonts were 11.9 x 15.2 microm (10-14 x 14-20 microm), whereas completely developed microgamonts with many gametes were 14.8 x 16.8 microm (10-18 x 13-20 microm). Oocysts in tissue sections were 19.5 x 13.8 microm and had a smooth outer wall that was <1 microm thick. Little histopathology was associated with the infections. Infected cells were enlarged and appeared cloudy, and in some areas there was leucocytic infiltration by macrophages, small and large lymphocytes, neutrophils, and eosinophils. No basophil was seen. We also found sections of a nematode, probably a Mammanidula sp., in sections of an active mammary gland in 1 of the shrews not infected with the coccidium.