COCCIDIOSIS

Morphological and molecular biology identification of Cystoisospora sp. in the blue fox, Alopex lagopus (Linnaeus, 1758)

To investigate the prevalence and molecular characteristics of Cystoisospora sp. in blue fox (Alopex lagopus), Sheather's sugar floatation method was conducted to detect coccidia in 423 fresh fecal samples randomly collected from blue fox farms from three cities in China. The overall prevalence of coccidia was 1.4% (6/423), and three Cystoisospora sp. (Cystoisospora fennechi, Cystoisospora sp. I and Cystoisospora vulpina) were identified by their morphological characteristics. The 18S ribosomal RNA (rRNA) and cytochrome c oxidase subunit I (COI) locus sequences were sequenced for molecular biological identification, homology comparison, and phylogenetic analysis of Cystoisospora sp. by single-oocyst selection technology and multi-locus-nested PCR amplification. At the 18S rRNA and COI loci, C. vulpina had 99.48% and 99.59% homology, respectively, with Cystoisospora canis and Cystoisospora ohioensis from canines. Phylogenetic analysis indicated that C. vulpina was clustered in a clade with Cystoisospora sp. from Canidae, which the relatives are consistent with the hosts. To our knowledge, this is the first report on molecular identification and evolutionary analysis of C. vulpina at two different loci.

Nucleolar hypertrophy as an indicator of transcription in cells infected with second generation meronts of Eimeria tenella

Changes in nuclei and nucleoli of cells of chicken cecum infected with Eimeria tenella were studied in living cells by interference microscopy and in fixed and stained tissues using light level microscopy. As soon as merozoites began to transform into second generation meronts, there was an increase in the size of both the nucleus and the nucleolus of the host cell. The dry weight of the nucleus increased somewhat, but there was a greater increase and a correlation of the dry mass of the nucleolus with the size of the parasite as measured by interference microscopy. In fixed and stained tissues, there was a correlation between the area of the nucleolus and the area of the parasite. Removal of nucleic acids with DNase and/or RNase showed high concentrations of both in the nucleoli and a residue of protein. The increased nucleolar size indicates a high level of transcription in infected cells and allows the conclusion that the parasite somehow induces transcription to occur. Since transcription is a highly specific process, the high degree of host and site specificity shown by nearly all coccidia is consistent with a hypothesis that the coccidia share a portion of the host genome.

Fecal transmission of calf cryptosporidia between calves and pigs

All of 17 calves 1 to 21 days old and 23 of 24 1-day-old pigs inoculated orally with calf feces containing cryptosporidia oocysts became infected with cryptosporidia. Infectivity was maintained by discontinuous passage in calves, with storage in potassium dichromate solution for up to eight weeks between passages. Cryptosporidia shed in calf feces also were infectious for calves directly after collection, without storage in potassium dichromate (two calves). Infected calves and pigs shed cryptosporidia oocysts in their feces for several days (mean of 10 days). Those necropsied at this stage of infection had many cryptosporidia and partial atrophy of villi in their ilea. All of the pigs and 60% of the calves also had cryptosporidia infections in their large intestines at this stage. It was concluded that calf cryptosporidia can be transmitted via feces to calves and to pigs.

Cryptosporidial enteritis in a patient with congenital hypogammaglobulinemia

Cryptosporidium is a potentially pathogenic coccidial protoxoan known to inhabit the striated border of interestinal epithelium in several animal species. Recently two cases of human intestinal cryptosporidiosis have been described. The purpose of this report is to document a third case of chronic debilitating cryptosporidial enteritis in a young boy with congenital hypogammaglobulinemia. The endogenous protozoan life cycle and morphologic features are examined as studied by light and electron microscopy.

The appearance of bisporocytic oocysts of Eimeria maxima in drug-treated chicks

A line of Eimeria maxima acquired resistance to Lerbek (a mixture of clopidol and methyl benzoquate) after serial passage against rising drug levels. Abnormal bisporocystic oocysts which appeared throughout this series were picked out individually and these produced infections in further groups of chicks. Serial passages of selected bisporocystic forms raised their proportion in oocyst yields to about 80% after 10-14 passages, but a few normal oocysts were still present.

Bovine cryptosporidiosis: a transmission and scanning electron microscopic study of some stages in the life cycle and of the host-parasite relationship

Transmission and scanning electron microscopy of the ileal mucosae from 12 calves infected with Cryptosporidium sp. showed cryptosporidia free in the lumen and attached to epithelium. The attached parasites were interpreted to be extracellular and adherent to the microvillous border of epithelial cells. Stages of the organism included crescentic-free merozoites, trophozoites, schizonts, gametes and oocysts. Attached parasites were detected chiefly at villous tips and all stages were present on a single villus. Attachment sites were characterized by absence or disintegration of microvilli, disorganization of the terminal web and development of a specialized attachment zone. There were increased numbers of lysosomes and irregularities in the nuclear membrane of parasitized epithelial cells. It was concluded that cryptosporidia exist in bovine intestine as extracellular parasites and cause epithelial changes that in turn probably cause or contribute to diarrheal disease.

Effect of 6-amino-9-(substituted benzyl)purines on oocyst sporulation

A series of experiments have been conducted utilizing 11 strains of Eimeria representing 4 of the major species to measure the effect of arprinocid [6-amino-9-(2-chloro-6-fluorobenzyl)purine] and the dichloro analog L-628,914 [6-amino-9-(2,6-dichlorobenzyl)purine] on oocyst sporulation. The results of these studies show that oocysts harvested from chickens fed graded levels of these compounds and infected with E. acervulina, E. maxima, E. necatrix, or E. tenella have a decreased capacity to sporulate. This effect was observed against each of the species of Eimeria tested at levels well below the proposed use level of 60 ppm to 70 ppm of arprinocid.

Cryptosporidiosis in Two Juvenile Rhesus Monkeys

A coccidium of the genus Cryptosporidium, previously unreported in simians, was observed in two juvenile Rhesus monkeys. The organisms were restricted in one to the epithelium of the common bile, intrahepatic and pancreatic ducts and gall bladder and in the other to the epithelium of the small and large intestines. Epithelial hyperplasia and mucosal inflammation were common histologic features. Small bulbous enlargements that might be misinterpreted as cryptosporidia projected from the epithelial cells of some gall bladders of noninfected monkeys.

Cryptosporidial Infection in a Calf

An 8-month-old female calf had a coccidian of the genus Cryptosporidium. This is the first report of cryptosporidial infection in cattle. The clinical syndrome was characterized by diarrhea, debilitation, and a chronic course. Gross lesions related to the infection were mild; however, histopathologic findings in the small intestine were generally characterized by villous atrophy and the presence of various developmental forms of Cryptosporidia in the microvillous border of the epithelium. The existence of signs and lesions very similar to those reported in the turkey and guinea pig suggests that disease in the calf might have been caused by cryptosporidial infection.

Eimeria tenella: cultivation of the asexual stages in cultured animal cells

Eimeria tenella, an intracellular protozoan parasite of the cecal epithelium of chickens, developed asexually in monolayer cultures of mammalian fibroblasts, mammalian epithelial cells, and avian fibroblasts mintained under various mediums at 41 degrees C. Sexual stages of the parasite were not seen. Established cell lines and secondary cell cultures were equally suitable for cultivation of the parasite.