Scholarlink

Purpose <p><i>Henneguya</i> sp. is a crucial myxosporean parasite known to cause milky flesh or tapioca disease in the freshwater fish population, leading to heavy mortality. Studies to investigate its host range and to monitor their prevalence in wild and aquacultured fish are necessary.</p> Methods <p>The infected orange-spotted snakehead (<i>Channa aurantimaculata</i>) fish samples showing clinical signs such as severe ulceration and open wounds on the mouth and operculum were collected from an ornamental fish-rearing unit in Chennai, Tamil Nadu. The sample was diagnosed with myxosporean infection by microscopic observation, morphological records and DNA sequencing followed by phylogenetic analysis.</p> Results <p>The <i>Henneguya</i> infection was identified in <i>C. aurantimaculata</i> for the first time. Necropsy of the infected fish revealed characteristic multifocal whitish-yellow, oval-shaped cysts measuring 3–5&#xa0;mm in length on the liver and spleen. The wet mount of cysts showed numerous mature <i>Henneguya</i> spores that were uninucleate, elongated, lenticular and ellipsoidal with the bluntly rounded anterior end gradually tapering off to the posterior with a caudal elongation. The spore body measured 12.1 ± 0.9&#xa0;μm (10.1–14.7&#xa0;μm) × 7.1 ± 0.6&#xa0;μm (5.3–8.5&#xa0;μm) with two slightly unequal pyriform polar capsules of 6.1 ± 0.5&#xa0;μm (5.1–7.4 )× 2.5 ± 0.4&#xa0;μm (1.6–3.9) (large); 6.0 ± 0.4&#xa0;μm (5.2–6.4) × 2.5 ± 0.3&#xa0;μm (1.7–3.1) (small) and a caudal elongation of 16.1 ± 1.2&#xa0;μm in length. The parasite was confirmed to be a <i>Henneguya</i> sp. by PCR amplification of SSrRNA followed by gene sequencing. The sequence generated was submitted in the GenBank under accession number PP852214.1 The maximum likelihood analysis revealed that the obtained sequence is a close relative of <i>H. exilis</i> with pairwise sequence variation of 3.3% and a homology of 99.04%.</p> Conclusion <p>The findings highlight the potential impact of <i>Henneguya</i> sp. on ornamental fish health, underscoring the need for vigilant monitoring and management in India.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Morphology and Phylogenetic Analysis of Henneguya sp. Infecting the Orange-Spotted Snakehead (Channa Aurantimaculata) from Tamil Nadu, India

  • 期刊论文

  • 发表日期：

    2025年1月7日

查看全文
  • Arumugam Uma,
  • Palaniappan Subash,
  • Jayasimhan Praveenraj

摘要

Purpose

Henneguya sp. is a crucial myxosporean parasite known to cause milky flesh or tapioca disease in the freshwater fish population, leading to heavy mortality. Studies to investigate its host range and to monitor their prevalence in wild and aquacultured fish are necessary.

Methods

The infected orange-spotted snakehead (Channa aurantimaculata) fish samples showing clinical signs such as severe ulceration and open wounds on the mouth and operculum were collected from an ornamental fish-rearing unit in Chennai, Tamil Nadu. The sample was diagnosed with myxosporean infection by microscopic observation, morphological records and DNA sequencing followed by phylogenetic analysis.

Results

The Henneguya infection was identified in C. aurantimaculata for the first time. Necropsy of the infected fish revealed characteristic multifocal whitish-yellow, oval-shaped cysts measuring 3–5 mm in length on the liver and spleen. The wet mount of cysts showed numerous mature Henneguya spores that were uninucleate, elongated, lenticular and ellipsoidal with the bluntly rounded anterior end gradually tapering off to the posterior with a caudal elongation. The spore body measured 12.1 ± 0.9 μm (10.1–14.7 μm) × 7.1 ± 0.6 μm (5.3–8.5 μm) with two slightly unequal pyriform polar capsules of 6.1 ± 0.5 μm (5.1–7.4 )× 2.5 ± 0.4 μm (1.6–3.9) (large); 6.0 ± 0.4 μm (5.2–6.4) × 2.5 ± 0.3 μm (1.7–3.1) (small) and a caudal elongation of 16.1 ± 1.2 μm in length. The parasite was confirmed to be a Henneguya sp. by PCR amplification of SSrRNA followed by gene sequencing. The sequence generated was submitted in the GenBank under accession number PP852214.1 The maximum likelihood analysis revealed that the obtained sequence is a close relative of H. exilis with pairwise sequence variation of 3.3% and a homology of 99.04%.

Conclusion

The findings highlight the potential impact of Henneguya sp. on ornamental fish health, underscoring the need for vigilant monitoring and management in India.