Ceratonova shasta

Better known by its old name, Ceratomyxa shasta, this microscopic parasite causes hemorhaging and necrosis of the intestine of salmon and trout. Light infections can be cleared by some fish species, whereas larger doses result in mortality, especially in combination with high water temperatures. Mature myxospores released from fish are about 12µm long (1/10th the width of a human hair) and kidney-bean shaped. They have two centrally located polar capsules (stinging cells). The myxospores have to infect a freshwater polychaete worm and develop into actinospores for the parasite to be able to infect another fish and continue its lifecycle. C. shasta is not transmissable to humans.