Naive and immune specific-pathogen-free rabbits were inoculated in the duodenum with sporocysts of Eimeria coecicola or Eimeria intestinalis. Samples were taken from the following tissues: duodenum (site of penetration of sporozoites), ileum (specific target site of the endogenous development of E. intestinalis), vermiform appendix (target site of E. coecicola) and two extraintestinal sites, mesenteric lymph nodes (MLNs), and spleen. The presence of sporozoites was checked by immunohistochemistry. In rabbits primary-infected with E. coecicola, large numbers of sporozoites were detected in the duodenum, extraintestinal sites, and vermiform appendix. The abundance of sporozoites in the spleen, MLN, and appendix was significantly reduced in the immune rabbits, and the migration seemed impeded. In the rabbits infected with E. intestinalis, sporozoites were absent in the spleen and MLN, indicating that the route of migration is different from that of E. coecicola. The number of sporozoites in the crypts of the ileum was markedly reduced in the immune animals.

• MeSH
• Antigens, Protozoan metabolism   MeSH
• Eimeria growth & development   immunology   pathogenicity   MeSH
• Host-Parasite Interactions MeSH
• Coccidiosis immunology   parasitology   MeSH
• Rabbits MeSH
• Lymph Nodes parasitology   MeSH
• Specific Pathogen-Free Organisms MeSH
• Intestinal Diseases, Parasitic * MeSH
• Peyer's Patches metabolism   parasitology   MeSH
• Antibodies, Protozoan immunology   MeSH
• Spleen parasitology   MeSH
• Sporozoites growth & development   immunology   pathology   MeSH
• Intestine, Small metabolism   parasitology   pathology   MeSH
• Animals MeSH
• Check Tag
• Rabbits MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Antigens, Protozoan MeSH
• Antibodies, Protozoan MeSH

The SPF rabbits were inoculated with oocysts of Eimeria flavescens and the first newly developed oocysts were recovered. They were used for inoculation of other rabbits which consequently excreted oocysts sooner than in the previous passage. By repeated use of this method, the prepatent period was shortened after 18 passages by more than 60 h. The endogenous development of this precocious line (PL) differed from that of the original strain (OS). Compared to OS, two asexual generations, second (or third) and fourth, were absent in PL. The first merogony took place in the jejunum and ileum in OS and, in contrast, in the large intestine in PL. Like in other rabbit coccidia, two types of meronts (A and B) were seen in each generation. However, the ratio of B: A meronts in the last (fifth) asexual generation as well as ratio of microgamonts:macrogamonts differs in OS and PL.

• MeSH
• Eimeria growth & development   pathogenicity   ultrastructure   MeSH
• Coccidiosis parasitology   transmission   veterinary   MeSH
• Rabbits MeSH
• Oocysts growth & development   MeSH
• Specific Pathogen-Free Organisms MeSH
• Intestinal Diseases, Parasitic pathology   transmission   veterinary   MeSH
• Sporozoites growth & development   MeSH
• Life Cycle Stages * MeSH
• Intestinal Mucosa parasitology   pathology   MeSH
• Intestine, Small parasitology   pathology   MeSH
• Intestine, Large parasitology   pathology   MeSH
• Microscopy, Electron, Transmission veterinary   MeSH
• Animals MeSH
• Check Tag
• Rabbits MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

The endogenous cycle of Eimeria flavescens was studied in specific pathogen-free rabbits by means of histology and transmission electron microscopy. In total, five asexual generations were observed and two types of meronts and merozoites were found in each generation. Type A gave rise to a smaller number of thick polynucleate merozoites in which daughter merozoites were formed by endomerogony, while in the type B meronts slender uninucleate merozoites arose from ectomerogony. The first generation meronts were found in the crypts and proximal part of the villi of the duodenum and jejunum, whereas the three following generations developed in the superficial epithelium of the large intestine (cecum, vermiform appendix and colon). The last merogony as well as gamogony took place in crypts of the large intestine.

• MeSH
• Eimeria growth & development   pathogenicity   ultrastructure   MeSH
• Microscopy, Electron MeSH
• Coccidiosis parasitology   pathology   MeSH
• Rabbits parasitology   MeSH
• Specific Pathogen-Free Organisms MeSH
• Intestinal Diseases, Parasitic parasitology   pathology   MeSH
• Parasitic Diseases, Animal parasitology   pathology   MeSH
• Life Cycle Stages MeSH
• Intestinal Mucosa parasitology   pathology   MeSH
• Animals MeSH
• Check Tag
• Rabbits parasitology   MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH