The First Detection of Kudoa hexapunctata in Farmed Pacific Bluefin Tuna in South Korea, Thunnus orientalis (Temminck and Schlegel, 1844)

Abstract

The consumption of fish and shellfish worldwide is steadily increasing, and tuna is a particularly valuable fish species. However, infection caused by Kudoa spp. is causing problems in many fish including the Pacific bluefin tuna (Thunnus orientalis), and there is much controversy about the association of these infections with foodborne disease. In this study, using haematological and histological analyses of the blood and internal organs (liver, spleen, kidney, heart, stomach, intestine, gill, and muscle) of Pacific bluefin tuna cultured in South Korea, infection with Myxosporea was first identified, and molecular biological analysis was conducted. In this study, Kudoa hexapunctata was finally identified. The Pacific bluefin tunas analysed in this study did not show any gross pathology lesions, such as visible cysts and/or myoliquefaction, of infection with this species. The histological analytical results can provide guidelines for the identification of K. hexapunctata. In the case of K. hexapunctata-induced infection, unlike other countries, such as Japan, there have been no reports in South Korea, and this study is the first to detect K. hexapunctata infection in Pacific bluefin tuna cultured in South Korea. The correlation between K. hexapunctata and food poisoning is not yet clear, however, it is thought that continuous observation of its infection is necessary.

Clinical Assessment of Thermotherapy Applications during Hepatectomy and Laparotomy in Sturgeon (Acipenser ruthenus): Impact on Bioparameter Variations Based on Liver Condition

“…To assess the health status of the experimental fish, the condition factors (CF) were calculated using the following formula [ 22 , 23 ]: Condition factor (CF) = Body mass (g)/{Total body length (cm)} 3 × 100 …”

“…The water temperature was maintained at 18 • C until the induction of the initial anesthesia. To assess the health status of the experimental fish, the condition factors (CF) were calculated using the following formula [22,23]:…”

Relationship Between Liver Histology and High Temperature on the Recovery Following Hepatectomy and Laparotomy in Sturgeon, <em>Acipenser ruthenus</em>

“…To assess the health status of the experimental fish, the condition factors (CF) were calculated using the following formula [22,23]:…”

Re‐evaluation of certain aspects of the EFSA Scientific Opinion of April 2010 on risk assessment of parasites in fishery products, based on new scientific data. Part 1: ToRs1–3

“…Two Kudoa species, K. septempunctata and K. hexapunctata, have been identified as the causative agents of food poisoning following consumption of raw farmed or wild fish in Japan and Korea (Kang et al., 2020 ; Kawai et al., 2012 ; Sung et al., 2023 ; Suzuki et al., 2015 ). Other species may be involved in hitherto unclarified episodes of adverse reactions after raw fish consumption.…”