Definition of whirling disease in English:

whirling disease

noun

mass noun
  • A disease of trout caused by a parasitic protozoan, affecting the balance of the fish and causing it to swim with a whirling motion.

    The protozoan is Myxosoma cerebralis, phylum Sporozoa

    ‘In yet another controversy, the new EPA chief's family fish farm stands accused of introducing trout infected with the deadly whirling disease - which causes fish to swim in circles - into Utah rivers.’
    ‘In some rivers whirling disease causes little harm to fish, but it can also suddenly erupt, causing a so-called ‘hot zone’ in which thousands of young fish die.’