Comparative Analysis of Cross-Protective Immunity Among Three Geographically Distinct Isolates of <i>Eimeria kongi</i>
Coccidiosis is one of the most significant diseases affecting the rabbit industry and is caused by <i>Eimeria</i>. In a previous study, we identified a new species of <i>Eimeria kongi</i> (<i>E. kongi</i>-ZJK) from the northern region of China (Zhangjiakou, Hebei...
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| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-12-01
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| Series: | Animals |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2076-2615/14/23/3524 |
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| Summary: | Coccidiosis is one of the most significant diseases affecting the rabbit industry and is caused by <i>Eimeria</i>. In a previous study, we identified a new species of <i>Eimeria kongi</i> (<i>E. kongi</i>-ZJK) from the northern region of China (Zhangjiakou, Hebei Province) and studied its pathogenicity and immunogenicity. The aim of this study was to evaluate the pathogenicity, immunogenicity, and cross-immunogenicity from different geographical isolates of <i>E. kongi</i> for vaccine development. Two geographical isolates of <i>E. kongi</i>-QD from Qingdao, Shandong Province (eastern China), and <i>E. kongi-</i>CD from Chengdu, Sichuan Province (southwestern China), were isolated and identified. The pathogenicity, immunogenicity, and cross-immunogenicity among the three geographical isolates were evaluated. The pathogenicity results showed that after infecting rabbits with doses of 1 × 10<sup>3</sup> or fewer sporulated oocysts of <i>E. kongi</i>-QD and <i>E. kongi</i>-CD, the rabbits exhibited clinical symptoms but recovered quickly, indicating lower pathogenicity. Immunogenicity studies revealed that after immunizing rabbits with 1 × 10<sup>3</sup> sporulated oocysts of <i>E. kongi</i>-QD and <i>E. kongi</i>-CD for 14 days, followed by challenge with 1 × 10<sup>4</sup> homologous sporulated oocysts, the oocyst reduction rates in the immunized groups were 99.39% and 99.12%, respectively, compared with the non-immunized groups, demonstrating good immunogenicity. In cross-immunogenicity studies, rabbits were immunized with 1 × 10<sup>3</sup> sporulated oocysts of <i>E. kongi</i>-ZJK, <i>E. kongi</i>-QD, or <i>E. kongi</i>-CD and then challenged with 1 × 10<sup>4</sup> sporulated oocysts of heterologous isolate. The immunized groups showed no significant clinical symptoms, and the oocyst reduction rates ranged from 55.9% to 98.4%. <i>E. kongi</i>-CD exhibited cross-protection against <i>E. kongi</i>-ZJK and <i>E. kongi</i>-QD, making it an ideal candidate formulation for vaccine development. |
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| ISSN: | 2076-2615 |