Effects ofKudoa septempunctatagenotype ST3 isolate from Korea on ddY suckling mice

Abstract

-This study investigated the effects of Kudoa septempunctata genotype ST3 spores on ddY suckling mice. Purified Kudoa septempunctata spores were administered into the stomachs of the mice at 5 · 10 6 or 5 · 10 7 spores/ mouse, with inactivated Kudoa (5 · 10 6 spores/mouse) or vehicle as controls. No abnormal clinical symptoms were observed and there were no variations in fluid accumulation ratio and cytokine gene expression in all groups. In addition, intact Kudoa spores and the 18S rDNA gene were only detected (by microscopy and quantitative PCR, respectively) in the groups administered such spores. This study thus confirms that spores from the ST3 strain of Kudoa septempunctata were excreted in the faeces without infecting the gastrointestinal tract in ddY suckling mice.Key words: Kudoa septempunctata, ST3 genotype, Food-borne disease, Myxozoa, Paralichthys olivaceus, suckling mice.Résumé -Effets de Kudoa septempunctata, génotype ST3 isolé de Corée, sur des souriceaux ddY à la mamelle. Cette étude a examiné les effets des spores de Kudoa septempunctata, de génotype ST3, sur des souriceaux à la mamelle de race ddY. Les spores purifiées de Kudoa septempunctata ont été administrées dans les estomacs des souris à 5 · 10 6 ou 5 · 10 7 spores/souris, avec comme témoins des Kudoa inactivés (5 · 10 6 spores/souris) ou un véhicule. Dans tous les groupes, aucun symptôme clinique anormal n'a été observé et il n'y avait pas de variation dans les taux d'accumulation de fluide ni dans l'expression des gènes de cytokines. De plus, des spores de Kudoa intactes et le gène d'ADNr 18S de Kudoa ont été détectés uniquement (par microscopie et PCR quantitative, respectivement) dans les groupes auxquels ont été administrées ces spores. Cette étude confirme donc que les spores de la souche ST3 de Kudoa septempunctata ont été excrétées dans les fèces sans infecter le tractus gastrointestinal chez les souriceaux ddY à la mamelle.

In vitroeffect of two commercial anti-coccidial drugs against myxospores ofKudoa septempunctatagenotype ST3 (Myxozoa, Multivalvulida)

“…1A), which was consistent with previous reports [1, 7]. Control spores with nuclei exhibiting only blue fluorescence (Hoechst 33342 positive and PI negative) were considered viable (Figs.…”

“…The spore genotypes were assessed by conventional PCR to amplify the cytochrome c oxidase subunit I ( cox 1 ; 751 bp) and large subunit rRNA ( rnl ; 817 bp) of the K. septempunctata mitochondrial gene [17]. The primer sets used were cox 1 -F1 (5′-TTTGTTCATCGGCACAATTC-3′), cox 1 -R1 (5′-ATAGCCTGGAACAAGGAATC-3′), rnl -F1 (5′-TGCCGTCATTCTGTTGTATT-3′), and rnl -R1 (5′-AATACCCATGCTGTGTTCAT-3′), as described in previous reports [1, 7, 17]. Negative controls (without template DNA) were included to check for contamination.…”

“…K. septempunctata spores have been isolated from raw olive flounder within 20 h after the fish was consumed by patients who developed diarrhoea, and the patients recovered completely within 24 h, suggesting that K. septempunctata spores are associated with transient clinical symptoms [10]. Several studies have reported clinical symptoms in animal models including the mouse [1, 7, 10], and permeability increase in the human intestinal epithelial monolayer [14]. Few reports on detection methods for K. septempunctata are available [10, 15, 16].…”

Is there evidence that Kudoa septempunctata can cause an outbreak of acute food poisoning?

“…Kawai et al [2] reported that diarrhea was induced in 4-5-day-old mice infected with K. septempunctata ; however, the remaining studies used the same methodology and showed conflicting results [7,8]. Overall, our findings suggest that the evidence for the pathogenicity of K. septempunctata is still weak, in light of the currently available literature.…”

“…Although the subjects and experimental methods in the study by Jang et al [7] were the same as those in the study by Kawai et al [2], the results differed. Kawai et al [2] were Japanese and claimed that the pathogenicity of K. septempunctata caused the outbreak of acute food poisoning; the authors of the other studies were Chinese and Korean.…”