Coprological examinations of three snowy owls, Nyctea scandiaca (L.) revealed the presence of a coecidium of the genus Eimeria that apparently represents a previously undescribcd species. Oocysts of Eimeria nycteae sp. n. were spherical to subspherical, 23.6 (23-25) x 22.2 (22-23) pm with a shape index 1.1 (1.0-1.1). The oocyst wall was bilayered, smooth - 0.75 pin thick. A polar granule was absent. Sporocysts were ellipsoidal, 18.5 (18-19) x 9.8 (9-10) pm with a shape index 1.9 (1.8-2.1) with Stieda and substieda bodies. A sporocyst residuum was present as small granules scattered among sporozoitcs. The sequence of the sporulation process of this new species is given and illustrated with photomicrographs. Owls examined did not exhibit any signs of alteration of their health status.
Four laboratory-hatched European kestrels Falco tinnunculus L. were fed on laboratory mice and common voles Microtus arvalis Pallas previously inoculated with different doses of sporulated oocysts of Caryospora kutzeri Böer, 1982. Two kestrels that were fed infected mice shed C. kutzeri oocysts 6 days after ingesting murine tissues. To compare direct and indirect transmissions, two of the kestrels were subsequently directly inoculated with 105 sporulated C. kutzeri oocysts and became patent on days 8 and 9 and shed caryosporan oocysts up to day 25 post inoculation. Additionally, four mice were inoculated with 106 oocysts in order to examine mouse tissues for the presence of developmental stages of C. kutzeri. No coccidian stages were found in the tissues of inoculated mice. The experiment showed that developmental stages of C. kutzeri are able to survive in mouse tissues and cause infection of suitable host after their ingestion.
An extrainlestinal coccidian parasite was identified in Schneider’s skinks Eumeces schneideri Daudin, 1802. Numerous tissue cysts were found in melanomacrophage aggregations in the liver of six of ten examined skinks. No tissue cysts were found in other tissues. Tissue cysts were 22-26 x 9-13 pm and contained a single sporozoite. Sporozoitcs were 10-13 x 2-4 pm, and contained a single nucleus, homogeneous inclusion and PAS positive granules, and were surrounded by PAS negative, 1.5-3.0 pm thick cyst wall. Transmission electron microscopy revealed that the tissue cyst wall was composed of granular material and the sporozoites contained crystalloid body with regular arrangements of units. Appearance of tissue cyst and structure of crystalloid body indicate that Schneider's skinks represent a paratenic host for non-determined Isospora species.
Intestinal microsporidiosis was documented by detecting abundant slightly curved spores (2.9 x 1.2 pm) in the faeces of five of twelve skinks Mabuya perrotetii Duméril et Bibron, 1839 that originated from Ghana. Clinically, the microsporidiosis was characterized by decreased appetite, diarrhea, and weight loss. Histopathological changes consisted of villous atrophy, blunting of mucosa and flattening of individual epithelial cells in the large intestine. The ultrastructure of microsporidian spores was consistent with an Encephalitozoon species. The PCR-RFLP assay and the heleroduplex mobility shift analyses were used to verify that the skink microsporidian is a species of the genus Encephalitozoon Levaditi, Nicolau et Schoen, 1923 and indicate that this microsporidian is not E. hellem, E. intestinalis or a strain of E. cuniculi. The microsporidia in African skink represent an Encephalitozoon species morphologically identical to Encephalitozoon lacerine Canning, 1981.
Seven of 12 lacertid lizards Acanthodactylus boskianus (Daiidin, 1802), passed oocysts of an Isospora species. Comparison with other species of the genus Isospora Schneider, 1881 indicated that found coccidium represented a new species, for which the name /. abdallahi is proposed. Sporulated oocysts of /. abdallahi are spherical or subspherical, 25.8 (24.5-29.0) x 23.9 (23.0-25.5) pm, shape index (length/width) being 1.07 (1.00-1.16), with a smooth, bilayered oocyst wall that is slightly yellowish, about 2 pm thick. Micropyle, oocyst residuum and polar granule are absent. Sporocysts are ovoidal, 15.4 (14.0-16.0 x 9.4 (9.0-10.0) pm, with smooth and colorless sporocyst wall, shape index 1.6 (1.5-1.8). Stieda body is dome-like, substieda body spherical to subspherical. Sporocyst residuum is composed of numerous granules of different size, scattered among sporozoites. Most oocysts are passed unsporulated; sporulation was completed within 12 h at 25'C. Endogenous development occurs inside nuclei of enterocytes in the small intestine.
Caryospora duszynskii Upton, Current et Barnard, 1984 was successfully transmitted to snakes of the genus Elaphe by feeding them previously infected mice. Fifty thousand oocysts were orally administered to two mouse strains, BALB/c and Crl:CD-1(ICR)BR, which were subsequently fed to captive-born coccidia-free Elaphe guttata (L.) in two respective independent experiments. Both E. guttata expelled C. duszynskii oocysts in their faeces, beginning on day 18 and 26 post infection (p.i.) and shed oocysts continuously through the end of the experiment, day 230 and 135 p.i., respectively. There were no parasitic stages or lesions in mice, as revealed by histological examination. Experiments proved that rodents serve as paratenic hosts for C. duszynskii. In summary we discuss the life-cycle strategies of Caryospora spp. in reptiles and present three general modes of their development.
A new Cryptosporidium species, C. saurophilum, is described from Schneider’s skinks Eumeces schneidert Daudin, 1802. Oocysts were fully sporulated in fresh faeces and measured 5.0 x 4.7 pm (4.4-5.6 x 4.2-5.2 pm). The new species differs from C. serpentis Levine, 1980 by having smaller oocysts, developing in a different location of intestine, and by the inability to infect snakes.
Cryptosporidium fragile sp. n. (Apicomplexa) is described from black-spined toads, Duttaphrynus melanostictus (Schneider) (Amphibia, Anura, Bufonidae) from the Malay Peninsula. The parasitized animals were directly imported from Malaysia and harboured C. fragile at the time of arrival. Oocysts were subspherical to elliptical with irregular contour in optical section, measuring 6.2 (5.5-7.0) × 5.5 (5.0-6.5) µm. Oocyst wall was smooth and colourless in light microscopy. The endogenous development of C. fragile in the stomach of black-spined toad was analysed in detail using light and electron microscopy. Cryptosporidian developmental stages were confined to the surface of gastric epithelial cells. In transmission experiments, C. fragile has not been infective for one fish species, four amphibian species, one species of reptile and SCID mice. Full length small subunit rRNA gene sequence was obtained. Phylogenetic reconstruction revealed distinct status of C. fragile within the clade of species with gastric localisation including Cryptosporidium muris Tyzzer, 1907, Cryptosporidium serpentis Levine, 1980 and Cryptosporidium andersoni Lindsay, Upton, Owens, Morgan, Mead et Blagburn, 2000. Described characteristics differentiate C. fragile from the currently recognized Cryptosporidium species. Our experience with the description of C. fragile has led us to revise the recommended criteria for an introduction of a new Cryptosporidium species name. C. fragile is the first species described and named from an amphibian host. Its prevalence of 83% (15/18) in black-spined toads within the 3 months after importation calls for strict quarantine measures and import regulation for lower vertebrates.