Walker Anna N, Lee Richard F, Frischer Marc E
Department of Pathology, Mercer University School of Medicine, Macon, Georgia 31207, USA.
Dis Aquat Organ. 2009 Jul 23;85(3):193-7. doi: 10.3354/dao02072.
Infection with the parasitic dinoflagellate Hematodinium sp. can be devastating to blue crab Callinectes sapidus populations. Morbidity and mortality appear to depend on the burden of parasitic organisms. Heavily infected crabs become lethargic and, if not preyed upon, succumb to overwhelming infection. We report on the transmission of Hematodinium sp. into blue crabs that were fed pieces of infected tissues and examined for evidence of infection at time periods from 1 to 48 h and for the general state of their health after 4 d. During the first 16 h after feeding, Hematodinium sp. was found in the gut, followed by large increases in hemolymph hemocytes and the appearance of hemocytic nodules in tissues. By 16 h, the hemocytic nodules appeared poorly circumscribed and disorganized. No nodules were seen in a heavily infected crab after 24 h. By the end of the 48 h after feeding, 73% (11 of 15) of the crabs had shown evidence of infection with Hematodinium sp. Those crabs with infection intensities (Hematodinium sp. as percent of cells in hemolymph) higher than 20% were dead within 4 d.
感染寄生性双鞭毛虫哈氏藻（Hematodinium sp.）会对蓝蟹（Callinectes sapidus）种群造成毁灭性打击。发病率和死亡率似乎取决于寄生生物的数量。严重感染的螃蟹会变得行动迟缓，如果不被捕食，就会死于严重感染。我们报告了将哈氏藻喂给蓝蟹后其传播情况，在喂食后的1至48小时内检查感染证据，并在4天后检查它们的总体健康状况。喂食后的前16小时内，在肠道中发现了哈氏藻，随后血淋巴血细胞大幅增加，组织中出现血细胞结节。到16小时时，血细胞结节边界不清且结构紊乱。24小时后，在一只严重感染的螃蟹中未发现结节。喂食后48小时结束时，73%（15只中的11只）的螃蟹显示出感染哈氏藻的证据。那些感染强度（哈氏藻占血淋巴中细胞的百分比）高于20%的螃蟹在4天内死亡。
