본 내용은 최근 국내 양식 넙치에서 발생하는 연쇄구균병에 관하여 정리한 내용으로, 주요 균 종은 Streptococcus iniae, S. parauberis 그리고 Lactococcus garvieae이다. 최근 발생경향은 지금 까지 보고된 내용과 2002년에서 2017년 사이에 국립수산과학원 균주은행의 기탁균주에 대한 정보를 기초자료로 검토하였다. S. iniae와 L. garvieae는 계속 검출빈도가 줄어들었고, 균주은행 기탁균주의 경우에도 두 균주 각각 2012년과 2002년 이후로 기탁 건수가 없었다. 최근 양식 넙치에서 우점적으로 분리되는 연쇄구균병의 원인세균은 S. parauberis이다. 또한 육안적 증상 과 병리조직학적 변화를 함께 비교 · 검토하였는데, S. iniae 감염에서는 안구백탁, 출혈, 장염 그 리고 복수저류가, S. parauberis 감염에서는 체색흑화, 심외막염이 주요증상이다. L. garvieae 감 염은 연쇄구균병에서 나타나는 증상이 공통적으로 나타나지만, 독성은 다른 두 종의 증상과 비교하여 약한 것으로 판단되었다. 병리조직학적 증상은 급성인지 만성인지에 따라 내부 장기 별로 변성진행에 차이를 나타내지만 육안적으로 관찰되는 주요증상이 조직학적 소견에 반영 된다.

Recently, mass mortality of the young abalone Haliotis discus hannai has occurred in commercial seed production farms in Korea. The mortality rate was above 50% of the total cultured organisms in the farm, and the shell length of the moribund organisms was about 3cm. The mortal phenomenon was that the young abalones were weakly scattered on the bottom of the pond from the attachment matrix, or that they could not be moved back to their normal positions. The diseased farmed Pacific abalone had abdominal edema. From the edema in the moribund individuals, three bacterial strains were isolated and all the strains were identified as Vibrio harveyi. These strains were compared with thirty six strains isolated from the fish. The results was that the Vibrio harveyi from the fish were sorted into genogroup A or B; however, the three strains of the diseased farmed Pacific abalone were sorted into genogroup A and the new genogroup C. The identical mortality and pathological symptoms of the naturally infected organisms were reproduced by artificial infection with WA AG-1 and WA CS-5 strains. The LD50 of WA AG-1 and WA CS-5 were each 1.0×103 cfu animal-1 and 1.7×104 cfu animal-1.

This study is for the consideration of the existence tendency of Kudoa septempunctata in olive flounder. In general, muscle has shown a strong PCR positive reaction in spores containing tissues rather than non-containing tissues. However, blood PCR results showed opposed tendency. In various organs of the tested fish containing spores in muscle tissue, heart had shown positive reaction along with muscle at PCR analysis. Muscle fiber necrosis was observed at the histological observation, and this degeneration was common in both samples. The one sample was the PCR positive muscle containing spore and the other was the PCR positive muscle non-containing spore. Both of muscle tissues indicated a positive reaction at ISH (in-situ hybridization) against K. septempunctata.

Abstract - We are aim to evaluate lysozyme and antibacterial activity of cultured catfish, Silurus asotus, that fed supplementally with Galla rhois extracts for eight weeks. Lysozyme activity in the spleen and serum of administrated group was higher than not administrated group, but in mucus of the lysozyme activity was no regular than other organ. The lysozyme activity of the spleen, kidney, serum of administrated fishes were increased after 2 weeks and that was highest after 8 weeks. Ht and GLU in serum of administrated fishes were gradually increased but GOT was decreased after 8 weeks. There is no significant differences in HB (Hemoglobin) and TP (Total Protein) each groups. Furthermore, there is no pathohistological changes of kidney and liver of tested fishes. The cumulative survival rates of administrated group after intraperitoneal injection of Aeromonas veronii with 6.5×106 cfu mL-1 was presented 33% in 9 days. As the Results, Galla rhois extracts has any beneficial effects for immunity elevation and antibacterial activity in catfish, Silurus asotus.

Shortfin eel (Anguilla bicolor pacifica) is a species of commercial importance and its production is greatly affected due to the infection by Heterosporis anguillarum. In this study, we evaluated the effect of H. anguillarum infection on the growth of Shortfin eel. A disease that trunk muscle of cultured shortfin eel, Anguilla bicolor pacifica, were irregular and resulted in death, breakout of the commercial eel culture farm. We observed that the trunk muscle of infected eels were irregular and represented white or yellowish externally. Histopathologically, a great numbers of large or small spores and sporophorocysts were also observed in degenerated muscle layer. The cloning of specific gene of H. anguillarum, encoding small subunit ribosomal RNA (SSU-rRNA) was amplified by the polymerase chain reaction(PCR) from the muscle lesion of diseased eel. The size of clone gene is well matched with the size of small subunit ribosomal RNA of H. anguillarum and thus confirming the infection by H. anguillarum.

최근 국내의 양식 메기에 표피 박리와 근육 괴사를 특징으로 하는 새로운 질병이 발생하였다. 그 폐사율은 낮으나 질병으로 인한 상품가치의 저하로 경제적 손실이 크다. 병어로부터 원인균을 분리하고 자연감염어와 인위감염어의 병리학적 변화를 관찰하였다. 원인균은 Aeromonas veronii로 동정되었으며, 원인균을 건강어에 인위감염시켜 폐사 및 증상의 발현을 매일 관찰하였다. 인위감염된 어류의 증상은 자연감염어와 유사하였으며 원인균을 감염시킨 후 7일 이내에 모두 폐사하였다. 병어의 조직표본을 제작하여 관찰한 결과, 자연감염어의 간, 비장, 신장의 울혈 및 간세포 변성과 비장 협조직의 초자적변성이 관찰되었으며, 특히 심장에서 염증성 변성과 세균응집체가 관찰되었다. 소화관에서의 울혈과 점막고유층의 섬유화 현상도 특징적이었다. 자연감염어에 비해 약한 경향이지만 인위감염어의 조직학적 변화도 관찰되었으며, 소화관에서의 조직학적 변성은 관찰되지 않았다.