Selection and characterization of a precocious line of Eimeria media

Abstract

Coccidiosis, caused by the infection of Eimeria parasites, is one of the most common diseases in domestic rabbits. Live anticoccidial vaccine formulated with attenuated precocious lines of pathogenic eimerian parasites is expected to be valuable for the control of rabbit coccidiosis as a similar strategy to produce anticoccidial vaccines against chicken coccidiosis has being used for several decades. Eimeria media, moderate pathogenic, is widespread in China. Therefore, attenuated anticoccidial vaccines against rabbit coccidiosis should contain vaccine strain(s) of E. media. In this study, a precocious line of E. media (Empre) was selected by collecting and propagating the early excreted oocysts with 16 successive generations. The prepatent period of Empre reduced from 108 h of its parental strain (Emwt) to 70 h. The fecundity of Empre was about 1/10 to 1/3 lower than that of Emwt. Each sporocyst of Empre sporulated oocyst contained only one large refractile body instead of two smaller ones seen in the parental strain. When vaccinated with 1 × 10 3 or 1 × 10 4 precocious line oocysts, the rabbits were completely protected against homologous challenge with the parental strain 14 days post challenge by terms of body weight gain and oocyst output counting, indicating the efficacy of Empre. Meanwhile, all immunized rabbits showed no clinical sign post immunization, indicating the safety of Empre. For coimmunization, 1 × 10 3 Empre oocysts and 5 × 10 2 oocysts of a precocious line of E. intestinalis (EIP8) were inoculated to each rabbit in a trial. No diarrhea or mortality was found after vaccination, and the weight gains of the vaccinated group were similar to that of unvaccinated-unchallenged control (UUC) group, while the weight gains of the vaccinated group were similar to that of unvaccinated-unchallenged control (UUC) group (P > 0.05), but significantly higher than that of UCC group (P < 0.01) after challenge, indicating it is safe and effective when using co-immunization. These results together show that Empre, as a precocious line, is a good candidate of precocious line of E. media for anticoccidial vaccine development.

Investigation of gastrintestinal parasites in rabbits of the species Oryctolagus cuniculus in the Northwest region of São Paulo, Brazil

“…In other countries, in New Zealand rabbits, with different age groups, both on farms and in homes, Eimeria spp. was frequently observed, which corroborates the data of our work (Okumu et al, 2014;Jing, et al, 2016;Mäkitaipale et al, 2017;Maziz-Bettahar et al, 2018;Ola-Fadunsin et al, 2019;Gu et al, 2019).…”

Efficacy of Ficus sycomorus (Sycamore Fig) Extract on Intestinal Coccidiosis in Experimentally Infected Rabbits

“…4 Diclazuril-treated group: challenged with 3 × 10 4 E. intestinalis oocysts and treated with diclazuril 0.05 mg/Kg BW orally for three consecutive days beginning from the 4th day post challenge. 5 It was found that the positive control group had a higher score for mucosal hyperplasia (3.33 ± 0.33) than the negative control group (0.00 ± 0.00), which was not significantly differed from either diclazuril (2.83 ± 0.17) or extract (3.00 ± 0.00) treated groups (p < 0.03). The same trend appeared in the results of the intensity of the coccidia parasite in the intestinal mucosa (p < 0.01).…”

“…4 Extract-treated group: challenged with 3 × 10 4 E. intestinalis oocysts and treated with F. sycomorus extract 100 mg/kg body weight orally for four consecutive days beginning from the 4th day post coccidiosis challenge. 5 Fisher's exact test, significant at p < 0.05.…”

“…Thirteen of them infect the gastrointestinal tract causing intestinal coccidiosis, while E. stiedae infects the endothelial cells of the bile ducts and causes hepatic coccidiosis [4]. E. intestinalis is one of the highly pathogenic and immunogenic species [5]. This disease is known to cause severe clinical symptoms, such as depression, low weight gain, diarrhea, and mortality [6].…”

Assessment of the Immunoprotective Efficacy of Recombinant 14-3-3 Protein and Dense Granule Protein 10 (GRA10) as Candidate Antigens for Rabbit Vaccines against Eimeria intestinalis

“…Therefore, it is more promising to prevent and control rabbit coccidiosis via vaccination. Recent research on rabbit coccidia vaccines has focused on a precocious line of live vaccines, such as E. media [11], E. intestinalis [12], and E. magna [13], which have shown good anticoccidial effects. However, live vaccines carry the risk of virulence reversion and are expensive to produce [14].…”