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PubMed1987

Pathogenesis of infection with Sarcocystis rauschorum (Apicomplexa) in experimentally infected varying lemmings (Dicrostonyx richardsoni).

This study describes the sequential formation of lesions associated with the endogenous development of Sarcocystis rauschorum (Apicomplexa: Sarcocystidae) in varying lemmings, Dicrostonyx richardsoni. Lethal doses of sporocysts (greater than 500) were orally administered to lemmings examined 1-6 days postinoculation (DPI) whereas sublethal doses were administered to lemmings examined subsequently. Transient necrosis and purulent inflammation, in association with precystic merogony, occurred in the liver by 4.5 DPI, peaked at 6 DPI and subsided beginning at 11 DPI with the liver returning to normal by 15 DPI. Cyst formation in skeletal and cardiac muscle was associated with purulent inflammation and sarcolemmal proliferation beginning at 9 DPI. These lesions persisted to 42 DPI. In addition, multifocal nonsuppurative meningoencephalitis was present in six of 11 infected lemmings examined between 11 and 15 DPI.

Animals↗
PubMed2003

Phylogenetic relationships of Hepatozoon (Haemogregarina) boigae, Hepatozoon sp., Haemogregarina clelandi and Haemoproteus chelodina from Australian reptiles to other Apicomplexa based on cladistic analyses of ultrastructural and life-cycle characters.

The phylogeny of representative haemozoan species of the phylum Apicomplexa was reconstructed by cladistic analyses of ultrastructural and life-cycle characteristics. The analysis incorporated 4 apicomplexans previously not included in phylogenetic reconstructions: Haemogregarina clelandi from the Brisbane River tortoise (Emydura signata), Hepatozoon sp. from the slaty grey snake (Stegonotus cucullatus), Hepatozoon (Haemogregarina) boigae from the brown tree snake (Boiga irregularis), and Haemoproteus chelodina from the saw-shelled tortoise (Elseya latisternum). There was no apparent correlation between parasite phylogeny and that of their vertebrate hosts, but there appeared to be some relationship between parasites and their intermediate hosts, suggestive of parasite/vector co-evolution.

Animals↗
PubMed2003

Characterization of an alpha tubulin gene sequence from Neospora caninum and Hammondia heydorni, and their comparison to homologous genes from Apicomplexa.

The gene coding for a tubulin has been isolated by the polymerase chain reaction and sequenced from 2 isolates of Neospora caninum (Nc-Liverpool and Nc-SweB1). The data show that the gene, as in Toxoplasma gondii, is single copy and contains 3 exons and 2 introns and is identical in sequence in the 2 isolates studied. Comparison of the predicted protein sequence shows it to be identical to the a tubulin protein encoded by the T. gondii gene. The majority of the nucleotide substitutions that have occurred during the evolution of the T. gondii and N. caninum genes from their common ancestor have occurred in the third codon position. A partial coding sequence for a tubulin was also obtained from Hammondia heydorni and compared to other a tubulin sequences from Apicomplexa. The results show the sequences of the T. gondii, N. caninum and H. heydorni a tubulin genes to be similar but not identical in sequence, thereby providing new evidence that N. caninum and H. heydorni are genetically distinct species.

Amino Acid Sequence↗
PubMed1990

Sarcocystis kirkpatricki n. sp. (Apicomplexa: Sarcocystidae) in muscles of raccoons (Procyon lotor) from Illinois.

Sarcocysts of Sarcocystis kirkpatricki n. sp. (Apicomplexa: Sarcocystidae) are described from the skeletal and heart musculature of 66 (66%) of 100 raccoons (Procyon lotor) from Illinois. Histologic examination of muscle tissues from tongue, diaphragm, esophagus, and heart revealed that 61%, 47%, 32%, and 2%, respectively, contained sarcocysts of this species. Juvenile raccoons (less than 1 yr old) were more likely (P less than 0.01) to have sarcocysts in the tissues examined (52/60 or 87%) than were adults (14/40 or 35%). Histologically, sarcocysts in the 4 tissues were similar: the cyst wall was 2-3 microns thick, PAS negative, and had fine hairlike surface projections; interior septa were indistinct. Ultrastructurally, sarcocyst walls had short (mean = 2.8 microns), straight to sloping, villuslike projections. Longitudinal tubular filaments inside these projections extended from the tips to the base, where they terminated in a granular electron-dense layer of the primary cyst wall. Thin septa were within the sarcocysts. Feeding experiments utilizing dogs and cats as potential definitive hosts were negative.

Animals↗
PubMed1986

Immunoelectron microscopic demonstration of the exocytosis of dense granule contents into the secondary parasitophorous vacuole of Sarcocystis muris (Protozoa, Apicomplexa).

Merozoites of the parasitic protozoon Sarcocystis muris (Apicomplexa) possess three types of characteristic organelles with electron dense contents named rhoptries, micronemes, and dense granules, which are supposed to be involved in the parasite-host cell interactions during and after invasion. Dense granules were purified from a merozoite homogenate by centrifugation on a sucrose density gradient. It was shown by SDS polyacrylamide gel electrophoresis that they contain a major protein of 21 kDa. Polyclonal antibodies raised against this protein were applied to ultrathin frozen and Lowicryl-K4M-embedded sections of the parasite before and after host cell invasion. Dense granules were distinctly labeled by immunogold before and after invasion. After host cell invasion the parasite is enclosed in a secondary parasitophorous vacuole which contains an electron-dense material. This deposition was heavily labeled by anti 21 kDa antibodies which clearly demonstrated that the dense granule contents is released into the secondary parasitophorous vacuole.

Animals↗
PubMed1988

Efficacy of a pentaiodide resin disinfectant on Cryptosporidium parvum (Apicomplexa: Cryptosporidiidae) oocysts in vitro.

The resin-I5 column developed at Kansas State University was tested for efficacy against oocysts of Cryptosporidium parvum (Apicomplexa: Cryptosporidiidae). Cesium chloride gradient-purified oocysts were passed through 1.0-cm-diameter columns with lengths of 2.5, 5.0, and 10.0 cm at 23 C. Following column passage, oocyst viability was determined both in vitro by excystation and in vivo by the ability to establish infections in suckling mice. Oocysts were found to be retained by the pentaiodide resin in a linear fashion, probably by electrostatic interactions. Linear regression analysis revealed 100% of the oocysts should be removed in such a manner using a column length of greater than or equal to 25.7 cm. When compared to untreated control oocysts, less than 12% of the oocysts that passed through the columns appeared to be affected by the resin, as assessed by excystation. Inoculation of suckling mice with these column-treated oocysts supported the excystation data and revealed the coccidian to be viable. These results indicate that oocysts of C. parvum are retained on the pentaiodide column in a 1-hit manner and that, although killing of parasites may occur within the column, the greatest effect that the column may have on the parasite is as an electrostatic retention device.

Animals↗
PubMed1985

The species of Cryptosporidium (Apicomplexa: Cryptosporidiidae) infecting mammals.

Oocysts of Cryptosporidium muris (Apicomplexa: Cryptosporidiidae) were obtained from the feces of naturally infected calves. Oocysts were fully sporulated in fresh feces, measured 7.4 X 5.6 (6.6 - 7.9 X 5.3 - 6.5) micron, and possessed a longitudinal suture along one pole of the oocyst wall. Morphologic and biologic evidence obtained from this study demonstrated that C. muris is a species distinct from Cryptosporidium parvum, which has smaller oocysts.

Animals↗
PubMed2000

Cytology of Leidyana canadensis (apicomplexa: eugregarinida) in Lambdina fiscellaria fiscellaria larvae (lepidoptera: geometridae).

The eugregarine Leidyana canadensis infects the larval gut of the eastern hemlock looper, Lambdina fiscellaria fiscellaria. Guts of infected larvae were chemically fixed, embedded in epoxy resin, and sectioned for light and electron microscopy to describe the cytology of L. canadensis and its pathology in the larval host. Oocysts of L. canadensis are ingested by larval hemlock looper. Trophozoites emerge from the oocysts, pass through the peritrophic membrane into the ectoperitrophic space, and attach to the epithelium of the midgut by means of an apical epimerite. The epimerite does not actually penetrate the affected epithelial cell; instead, it causes an invagination of the plasma membrane of the cell. The center of the epimerite contains membrane cisternae, and mitochondria line its periphery. Microtubules and mitochondria in the host cell cytoplasm surround the epimerite. At the light microscopic level, there appeared to be septa between the epimerite and the protomerite and between the protomerite and the deutomerite; however, in the electron microscope, no septa were evident. Only differences in the concentrations and nature of the inclusions in the cytoplasms of these three regions were apparent. The deutomerite contains a single nucleus in the central-posterior area. After an undetermined period, the epimerite detaches from the host gut epithelium and is withdrawn into the protomerite, and the trophozoites float freely in the ectoperitrophic space before differentiating into gamonts. Division of the single, large nucleus into numerous small nuclei appears to occur prior to syzygy. Gamonts pair and a cyst wall is laid down around them, forming a gametocyst. Oocysts are extruded from mature gametocysts, in chains, through sporoducts.

Animals↗
PubMed2003

Description of the gamonts of a small species of Hepatozoon sp. (Apicomplexa, Hepatozoidae) found in Crotalus durissus terrificus (Serpentes, Viperidae).

A small species of the genus Hepatozoon found in a specimen of Crotalus durissus terrificus from the Botucatu region, São Paulo State, Brazil is described. The morphologic alterations induced in the snake's erythrocytes by the presence of this parasite are described. Morphology and morphometric analyses were performed using the Qwin Lite 2.5 computerized image analysis system (Leica). The Hepatozoon possessed a small and short body (8.1+/-0.5 microm long and 3.8+/-0.4 microm wide), with round extremities. The cytoplasm varied from pale blue to basophilic and had no granulations. Its nucleus was large, occupied a large area of the cytoplasm, and was irregular in shape and not condensed. Despite its small size, this parasite induced important changes in the host cell. Total parasitemia observed was 56.6%.

Animals↗
PubMed2005

Seasonal variation of Hepatozoon spp. (Apicomplexa, Hepatozoidae) parasitemia from Boa constrictor amarali (Serpentes, Boidae) and Hydrodynastes gigas (Serpentes, Colubridae).

The aim of this study was to evaluate the parasitemia variation of three Hepatozoon species in Brazilian snakes. This study was conducted between 2001 and 2003 and included Hepatozoon terzii from Boa constrictor amarali, and Hepatozoon migonei and Hepatozoon cyclagrasi from Hydrodynastes gigas. It was observed that the parasitemia tended to decrease in all three Hepatozoon species but the parasites were not eliminated. This data suggest that Hepatozoon infection may be similar to Toxoplasma gondii infection, in that it persists throughout host life.

Animals↗
PubMed2006

Morphological and morphometrical characterization of gametocytes of Hepatozoon procyonis Richards, 1961 (Protista, Apicomplexa) from a Brazilian wild procionid Nasua nasua and Procyon cancrivorus (Carnivora, Procyonidae).

The species Hepatozoon procyonis Richards, 1961 was described in Procyon lotor in the USA and then in other reports in the USA, while in Panama H. procyonis has been described in Procyon cancrivorus. The objective of this paper is to report the occurrence of this species in the Brazilian procionids P. cancrivorus and Nasua nausa and to describe the morphology and morphometrics of the gametocytes. The analysis was based on blood smears, stained with Giemsa, which were examined under a photonic microscope. The morphometry was done with an ocular micrometer. It was based on the morphological characteristics and morphometric data on the gametocyte. It can be concluded that the species of the genus Hepatozoon that occurs in Brazilian procionids is the same as that occurring in procionids in Central and North America.

Animals↗
PubMed1997

Ultrastructure and cytochemistry study of Goussia sparis (Protozoa: Apicomplexa) stages from the intestine of the gilthead sea bream Sparus aurata L. (Pisces: Teleostei).

The ultrastructure and cytochemistry of merogonial and gamogonial stages and early unsporulated oocysts of Goussia sparis in the intestine of Sparus aurata were studied. The typical pellicle was observed in some stages. The different stages might appear in intraepithelial or supraepithelial positions, but they were always intracellular. First steps of two apparently different endomerogonies were observed in intra- and supraepithelial positions, respectively. An apparent ectomerogony also occurred in supraepithelial stages. Developing macrogamonts showed surface invaginations and were densely packed with ribosomes, well-developed rough endoplasmic reticulum, mitochondria, amylopectin granules, lipidic droplets, and wall-forming-like bodies. The latter could participate in the formation of the oocyst wall. Abundant and large mitochondria, together with residual nuclei, appeared in advanced microgamonts. Microgametes showed two flagella with microtubul arranged according to the typical pattern. An increase in polysaccharide content was observed with coccidian development, reaching a maximum in zygotes and unsporulated oocysts.

Amylopectin↗
PubMed2001

Ultrastructure of developmental stages of Hemolivia stellata (Apicomplexa: Haemogregarinidae) in the cane toad Bufo marinus and in its vector tick Amblyomma rotondatum.

The fine structure of the hemogregarine Hemolivia stellata Petit, Landau, Baccam and Lainson, 1990 developmental stages in the cane toad Bufo marinus L. and the vector tick Amblyomma rotondatum Koch, 1844 are described. In the liver of the toad, merozoites bound by a pellicle were located free and in the cytoplasm, and young and encased mature polynucleated meronts were located in a parasitophorous vacuole (PV). Premature gametocytes in the erythrocytes were bound by a bilayered membranous wall and the mature gametocytes were encased in a bivalved capsule, suture sites occurring at both gametocyte extremities. In the tick gut cells, oocysts located within a PV formed oblong, pellicle-bound sporokinetes, with a small apical complex, a few short rhoptries, and a fragmented crystalloid body. Liberated sporokinetes re-entered gut cells to proceed with their differentiation into sporocysts within a PV with elaborate rims which suggested engagement in active metabolite cross-transport. With maturity, the sporocyst wall gradually transformed into a hard capsule. Differences in fine structural development between species of Hemolivia and the insect-transmitted Hepatozoon are conspicuous. The fine structure and course of development of H. stellata are very similar to those of the previously described Hemolivia mariae; their sporokinetes differ, however, in having conspicuous rhoptries rather than spherical-granular anlagen bodies, and fragmented rather than continuous crystalline bodies.

Animals↗
PubMed2005

Aggregata andresi n. sp. (Apicomplexa: Aggregatidae) from the ommastrephid squid Martialia hyadesi in the SW Atlantic Ocean and some general remarks on Aggregata spp. in cephalopod hosts.

A new species of coccidian, Aggregata andresi, is described from the digestive tract of the flying squid Martialia hyadesi, an ommastrephid squid that lives in cold subantarctic waters in the Southwest Atlantic. Gamogonic and sporogonic stages were observed in the digestive tract of 96.5% studied hosts. Oocysts were ovoid to subspheroid in shape, 170-590 microm in length and 200-530 microm in width. Each oocyst contained approximately 45,000 sporocysts. Sporocysts measured 9.5-10 microm in length and 8-8.5 microm in width. The surface of the sporocyst wall was smooth and the cyst wall thick. Each sporocyst contained three sporozoites measuring 16-20 microm in length and 2-2.5 microm width. A. andresi is the second species of Aggregata to be reported from a nerito-oceanic cephalopod host.

Animals↗