Showing papers on "Coccidia published in 1993"

Differentiation of Toxoplasma gondii from closely related coccidia by riboprint analysis and a surface antigen gene polymerase chain reaction.

Abstract: The tachyzoite of the human pathogen Toxoplasma gondii is morphologically indistinguishable from the proliferative stages of some other zoonotic coccidia, including Sarcocystis. To determine the identity of such coccidia obtained from human tissues and other sources, we compared riboprints (through restriction enzyme analysis of the polymerase chain reaction [PCR]-amplified small subunit rRNA gene) of the following protozoa: the RH and ts-4 strains of T. gondii, lines OH3 and S11, which are two recently isolated T. gondii-like parasites from Brazil, Neospora caninum, Sarcocystis species, and the malarial parasite Plasmodium berghei. In addition, the protozoan genomes were examined by PCR for homologs of surface antigen genes of T. gondii, and by Southern hybridization to the heterologous rRNA gene probe pSM 389. Strains OH3, S11, ts-4, and RH shared identical riboprints, and OH3, S11, and ts-4 have p22 and p30 surface antigen gene structures similar to RH. In contrast, riboprints for N. caninum and T. gondii differ with respect to Dde 1 sites, and moreover, their genomes vary significantly from one another at both the p22 and p30 gene loci. The riboprints of Sarcocystis and P. berghei differ markedly from T. gondii and N. caninum and from each other. Bam HI pSM 389 restriction fragment length polymorphisms differentiate ts-4 from RH, OH3, and S11. Our results confirm that OH3 and S11 are indeed T. gondii, but that N. caninum and T. gondii are likely to be separate species, thereby resolving previous uncertainties concerning the identity of these parasites. Together, the variation in riboprints and surface antigen gene structure reflects the phylogenetic diversity among these coccidia, and in addition, confirms the value of riboprinting in the identification of apicomplexan parasites such as T. gondii.

The Biology of Fish Coccidia

Abstract: Publisher Summary This chapter discusses the biology of fish coccidia. The oocyst and, particularly, the structure of its contained sporocysts, are important features in differentiating the genera and species of coccidia in fishes. Except for three genera, Cryptosporidium, Octosporella, and Isospora, the fish coccidia have oocysts containing four sporocysts, each with two sporozoites (tetrasporocystic and dizoic). As with coccidia from other groups of vertebrates, the gut is often the favoured site for development, but fish coccidia are remarkable for their extra intestinal development. Regarding the life cycles of fish coccidia, their sequential development is similar to that observed in coccidia from other vertebrates. In the life cycles of fish coccidia, transmission is of two main types. The simpler method is by direct transmission involving faecal contamination. The second mode of transmission is indirect and involves an invertebrate host. However, some fish coccidia employ both methods. Both the direct and indirect mode of transmission are described in detail.

Prevalence of Cryptosporidium sp. and Isospora belli among AIDS patients attending Santos Reference Center for AIDS Sao Paulo Brazil.

Abstract: From March 1991 to February 1992, 276 stool samples from 131 patients with the acquired immunodeficiency syndrome (AIDS) (average, 2.1 samples per patient) and stool samples from 81 presumed immunocompetent individuals were studied for the prevalence of Cryptosporidium sp. and Isospora belli. The techniques employed were a modified formol-ether concentration, carbol (phenol) auramine staining, and a modified Kinyoun acid-fast method. The prevalence of both coccidia among AIDS patients was 25.9% (34 of 131). Cryptosporidium sp. oocysts were demonstrated in 25 (19.1%) AIDS patients and I. belli in 13 (9.9%). Coinfection for coccidia of both species was found in 4 (3%) AIDS subjects. Among the presumed immunocompetent individuals, coccidia were not demonstrated in their 81 stool specimens. This study, like others, confirms the worldwide importance of these coccidia among AIDS patients and the necessity of suitable techniques for demonstration of oocysts in stool samples.

Intestinal Protozoa Infections

Abstract: This article reviews important intestinal protozoal infections in cats. Among intestinal protozoa, Giardia and coccidia are the most important infections. Giardiasis is a common problem in catteries, especially where young kittens run free on the floor. Overcrowding and high humidity favour the survival and transmission of Giardia. Diagnosis is made by fecal examination by direct or concentration methods. Metronidazole is the drug of choice for treating giardiasis. Among the coccidial parasites, Isospora felis and Cryptosporidium sp. are the common infections. Virtually all cats become infected with Isospora felis. The pathogenicity of I. felis is controversial. Cryptosporidium parvum infection is a zoonosis. Cryptosporidium is transmitted by direct fecal-oral cycle. Cryptosporidial infections appear to be clinical in immunosuppressed cats. No drug has been found satisfactory for treatment of cryptosporidiosis.

The enteritis complex in domestic rabbits: A field study.

Abstract: A study of the causative agents of enteritis in domestic rabbits from 44 different accessions is described. In descending order of frequency, the organisms most commonly demonstrated were intestinal and hepatic coccidia (Eimeria species), Escherichia coli, Clostridium spp., Salmonella, Bacillus piliformis, and rotavirus. The species of Eimeria identified included those moderately pathogenic and coccidia of low pathogenicity. Using seven antisera against known enterpathogenic strains of E. coli, only one strain, O15, was identified in three cases. Clostridium perfringens or C. spiroforme was demonstrated in the intestinal contents in 11 cases, and lesions compatible with clostridial enteropathy were identified on gross and histopathology. In a serological survey, over 50% of 200 fryer rabbits submitted to Ontario abattoirs and of animals from commercial rabbitries had detectable antibody to rotavirus, indicating the widespread distribution of rotaviral infections in this species. In the cases of enteritis studied, two or more potentially pathogenic organisms were frequently identified, emphasizing that several different organisms may be acting in concert to produce clinical disease.

Coccidia (Apicomplexa), Genetic Diversity, and Environmental Unpredictability of Four Chromosomal Species of the Subterranean Superspecies Spalax ehrenbergi (Mole-Rat) in Israel

Abstract: Forty-five mole-rats, representing 4 chromosomal species (2n = 52, 54, 58, 60) of the superspecies Spalax ehrenbergi, were collected from 12 localities in Israel in 4 distinct climatic regions. Feces were examined for coccidian oocysts and 41 (91%) were infected; 26 (63%) had multiple infections of up to 5 coccidian species, 4 of which are described here as new species. Sporulated oocysts of Eimeria anzanensis n. sp. were ellipsoidal 18.3 x 12.5 Am (14-22 x 10-16) and had elongate-ovoidal sporocysts 7.3 x 4.9 Am (5-10 x 3-7); it occurred in 39 of 45 (87%) mole-rats, including all chromosomal species. Sporulated oocysts of Eimeria spalacensis n. sp. were ovoidal 23.4 x 18.3 Am (17-29 x 12-21) with ovoidal sporocysts 9.4 x 6.8 Am (6-12 x 4-10); it occurred in 7 of 45 (16%) mole-rats (2n = 54, 58, 60). Sporulated oocysts of Eimeria carmelensis n. sp. were subspheroidal to ellipsoidal 19.1 x 16.5 Am (14-25 x 11-20) and had sporocysts that were spheroidal to ellipsoidal 8.6 x 6.2 Am (6-13 x 4-8); it occurred in 5 of 45 (11%) mole-rats (2n = 58, 60). Sporulated oocysts of Isospora spalacensis n. sp. were ellipsoidal 14.6 x 11.0 Am (12-17 x 9-14) with ellipsoidal to ovoidal sporocysts 8.5 x 4.5 Am (7.5-11 x 4-7); it occurred in 5 of 45 (11%) mole-rats (2n = 58, 60). Twenty-five of 45 (56%) mole-rats (all 4 species) were infected with a previously described form, Eimeria elliptica Sayin, Dincer, and Meric, 1977. The genetic diversity of mole-rats in Israel is known to increase chromosomally (2n = 52 - 60) and genically (heterozygosity (H) = 0.035 - 0.069) as the environment becomes more demanding (i.e., increasingly warm, dry, and climatically unpredictable). At the same time, there is an increased diversity of coccidian parasites. This suggests correlation among host chromosomal variability, habitat, and increased prev- alence of multiple infections, a pattern also seen in other fossorial rodents infected with coccidia.

Repeated findings of unidentified small Isospora-like coccidia in faecal specimens from travellers returning to The Netherlands.

Abstract: Findings are described of small (8-10 microns) coccidian oocysts in the stools of 9 patients presenting with diarrhoea, all of whom with a history of travelling in South Asia and/or South America in the years 1986 and 1987. There was no indication of immunodeficiency. These oocysts, which were immature in freshly excreted stools, could be induced to sporulate into a two-sporocysts stage and are now recognized as Cyclospora spec.

Recombinant Coccidia and Its Use in a Vaccine

Abstract: The present invention provides for recombinant coccidia comprising a relatively non-pathogenic strain of coccidia to which has been introduced DNA from one or more other strains or species of coccidia. In an aspect of the invention, there is provided a recombinant coccidiosis vaccine comprising a relatively non-pathogenic strain of coccidia to which has been introduced sufficient DNA of one or more other strains or species of coccidia to produce immunity to the multiple species in a host through inoculation of the host by the recombinant species.

Enteric Coccidia (Apicomplexa) in the Small Intestine of the Northern Spotted Owl (Strix occidentalis caurina)

Abstract: Sporulated oocysts (mean dimensions = 13.0 × 10.8 μm) and sporocysts (11.3 × 5.5 μm) of a coccidian resembling Frenkelia sp. or Sarcocystis sp. were present in the lamina propria of the small intestine of a naturally infected northern spotted owl (Strix occidentalis caurina) collected near Medford, Oregon (USA). Dimensions of these oocysts and sporocysts appear to be considerably smaller than those from other sarcocystid species with avian definitive hosts. Additionally, numerous developmental stages and unsporulated oocysts (mean dimensions 22.8 × 17.8 μm) of a possible species of Isospora also were observed in the intestinal epithelium. This constitutes the first report of enteric coccidia from spotted owls. Neither parasite appeared to cause the death of the bird.

[One more biological characteristic of coccidia in the genus Cryptosporidium (Sporozoa: Apicocomplexa)].

Abstract: Suckling rats were used as a model host for our previous EM studies of the endogenous development of Cryptosporidium parvum isolated from spontaneously infected calves (Beĭer e. a., 1990; Beĭer, Sidorenko, 1990). In the course of repeated infections it was noticed that the oocysts discharged by the recipient host (rat) were obviously larger than those in the donor's (calf's) isolates. Keeping in mind the presumable taxonomic significance of coccidian oocysts as a constant and rather reliable tool for species discrimination we made a comparative quantitative and statistical analysis of the mean values of oocysts of C. parvum, originating from several sources (table 2): a random human isolate (N 1), several random isolates from spontaneously infected calves (N 2-5), isolates from calves (N 6-8) used as the infecting material for suckling rats, and fecal samples from the experimentally infected rats (N 9-15). The results obtained have shown that the oocysts discharged by rats (N 9-15) were larger that those of calf origin (N 6-8), with the differences being statistically significant with 95% confidence. Besides, within the same host (rat) at least two oocyst groups were distinguished (N 9-11 and 12-15, resp.) whose differences in mean values also appeared statistically significant. The larger oocysts displayed differences in morphology bearing distinct walls which were never observed either in the donor isolates or in the smaller population of the recipient oocysts. The established differences in oocyst dimensions lay presumably within the frames of the normal reaction of C. parvum and other Cryptosporidium species, due to biological peculiarities of unusual life cycles of these unique coccidia: their homoxenous (i.e. confined to one host body only) development is combined with polyxeny (i.e. a wide host specificity that involves the number of host species representing different environmental conditions). The parasite's ability to change its functional morphology and size may appear some kind of preadaption to the number of varying conditions met by these polyxenous coccidia. This and other relevant assumptions are discussed in the paper.