Effects of Kudoa septempunctata genotype ST3 isolate from Korea on ddY suckling mice

Area of Science:

• Parasitology
• Microbiology
• Animal Health

Background:

• Kudoa septempunctata is a myxosporean parasite found in marine fish.
• Understanding the pathogenicity of different Kudoa genotypes is crucial for food safety and aquaculture.

Purpose of the Study:

• To investigate the effects of Kudoa septempunctata genotype ST3 spores on ddY suckling mice.
• To determine if Kudoa ST3 spores can infect the gastrointestinal tract of young mice.

Main Methods:

• ddY suckling mice were orally administered purified Kudoa septempunctata ST3 spores at two different doses (5 × 10(6) or 5 × 10(7) spores/mouse).
• Control groups received inactivated Kudoa spores or vehicle.
• Mice were monitored for clinical symptoms, fluid accumulation, and cytokine gene expression.
• Microscopy and quantitative PCR were used to detect intact spores and 18S rDNA.

Main Results:

• No abnormal clinical symptoms were observed in any group.
• No significant variations in fluid accumulation ratio or cytokine gene expression were detected.
• Intact Kudoa spores and their 18S rDNA gene were only found in mice that received live spores.
• Spores were detected in the feces, indicating excretion rather than infection.

Conclusions:

• Kudoa septempunctata genotype ST3 spores are not infectious to the gastrointestinal tract of ddY suckling mice.
• The administered spores are excreted in the feces without causing pathological effects.
• This finding has implications for the safety assessment of Kudoa-infected seafood.