Moore James D, Robbins Thea T, Friedman Carolyn S
a Bodega Marine Laboratory , Post Office Box 247 , Bodega Bay , California , 94923 , USA.
b California Department of Fish and Game, and Department of Medicine and Epidemiology , School of Veterinary Medicine, University of California-Davis, Bodega Marine Laboratory , Post Office Box 247 , Bodega Bay , California , 94923 , USA.
J Aquat Anim Health. 2000 Mar;12(1):26-34. doi: 10.1577/1548-8667(2000)012<0026:WSIFRA>2.0.CO;2.
Withering syndrome (WS) is a chronic wasting disease responsible for mass mortality in wild populations of black abalone Haliotis cracherodii. The etiology of WS is uncertain with limited evidence for the role of a gastrointestinal Rickettsiales-like prokaryote (RLP). We documented for the first time the occurrence of animals with clinical signs of WS and associated morphological changes in another haliotid species, the red abalone H. rufescens. In this study, 60 juvenile red abalone (8 cm) were randomly selected from a farmed population raised at 14°C that was known to have low-intensity RLP infections but lacked clinical signs of WS. The abalone were held in triplicate containers receiving water of approximately 14.7°C (Control, Co) or 18.5°C (elevated temperature, ET) and were fed equally for 220 d. Survival was 100% (30/30) for the Co group and 67% (20/30) for the ET group. The ET group animals had higher RLP infection intensities and showed more clinical signs (mantle retraction, lower weight gain, lower condition index) and morphological changes (digestive gland degeneration) associated with WS. In trials conducted immediately before termination of the experiment, ET group animals fed at half the rate of Co group animals. Among ET group animals, the intensity of RLP infections in the posterior portion of the esophagus was positively correlated with WS clinical signs and morphological changes, whereas no correlations were present among Co group animals. During 1997-1998 and in conjunction with elevated seawater temperatures associated with El Niño, several abalone farms in California experienced a dramatic increase in the proportion of red abalone showing signs of WS. Examination of 66 red abalone from five commercial farms revealed that animals with more advanced RLP infections had more severe WS clinical signs and associated morphological changes. Collectively, these data demonstrate that RLP infection plays a key role in the etiology of WS in red abalone and that warm water enhances the severity of the pathogenic effects of RLP infection.
消瘦综合征（WS）是一种慢性消耗性疾病，可导致黑鲍（Haliotis cracherodii）野生种群大量死亡。WS的病因尚不确定，关于胃肠道类立克次氏体原核生物（RLP）的作用证据有限。我们首次记录了另一种鲍科物种红鲍（H. rufescens）出现具有WS临床症状及相关形态变化的动物。在本研究中，从一个养殖群体中随机选取60只幼体红鲍（8厘米），该群体在14°C水温下养殖，已知RLP感染强度较低且无WS临床症状。将这些鲍鱼分别置于三个重复的容器中，分别接受约14.7°C的水（对照组，Co）或18.5°C的水（高温组，ET），并等量投喂220天。Co组的存活率为100%（30/30），ET组为67%（20/30）。ET组动物的RLP感染强度更高，表现出更多与WS相关的临床症状（外套膜收缩、体重增加较低、状况指数较低）和形态变化（消化腺退化）。在实验即将结束前进行的试验中，ET组动物的投喂量为Co组动物的一半。在ET组动物中，食管后部的RLP感染强度与WS临床症状和形态变化呈正相关，而Co组动物之间不存在相关性。在1997 - 1998年期间，随着与厄尔尼诺现象相关的海水温度升高，加利福尼亚州的几个鲍鱼养殖场中，出现WS症状的红鲍比例急剧增加。对来自五个商业养殖场的66只红鲍进行检查发现，RLP感染程度越严重的动物，其WS临床症状和相关形态变化越严重。总体而言，这些数据表明RLP感染在红鲍WS的病因中起关键作用，温水会加剧RLP感染的致病作用的严重程度。
