脑粘体虫（英语：Myxobolus cerebralis）是一种寄生于鲑科（包括鲑鱼、鳟鱼及其同类）的粘孢子虫，可以导致养殖及野生的鲑鱼和鳟鱼发生旋转病。大约一个世纪前，在德国的虹鳟上首次发现了脑粘体虫，但范围很快就扩大了并出现在欧洲的大多数国家（包括俄罗斯）、美国、南非及其它国家。1980年代，研究发现脑粘体虫需要感染一种颤蚓科环节动物来完成生命周期。这一寄生虫利用刺丝囊胞的极丝刺入宿主细胞进行感染。

旋转病主要在幼鱼发病，并导致骨骼变形及损伤神经。发病的鱼以别扭的螺旋状向前“旋转”而不是正常地游动，同时也不容易找到饲料并容易被捕食。此病在幼鱼发病的致死率很高，感染的群体死亡率可高达90%，而存活的鱼也会因为残留在软骨及骨骼里的寄生虫而发生变形。它们作为寄生虫的储藏室存在，并不断向水中释放寄生虫而导致其它鱼死亡。脑粘体虫是对鱼类养殖业最具有负面影响的，也是致病性最高的粘体动物之一。它是首个致病机理和症状都得到科学描述的粘孢子虫。这一寄生虫不会传播给人。

Myxobolus cerebralis is a myxosporean parasite of salmonids (salmon, trout, and their allies) that causes whirling disease in farmed salmon and trout and also in wild fish populations. It was first described in rainbow trout in Germany a century ago, but its range has spread and it has appeared in most of Europe (including Russia), the United States, South Africa and other countries. In the 1980s, M. cerebralis was found to require a tubificid oligochaete (a kind of segmented worm) to complete its life cycle. The parasite infects its hosts with its cells after piercing them with polar filaments ejected from nematocyst-like capsules.