A paradox of parasite prolonging the life of its host. Pearl mussel can disable the accelerated senescence program in salmon

A unique case is analyzed when the accelerated senescence program (progeria) in salmon (Salmonidae) can be canceled by larval parasite of the gills-freshwater pearl mussel Margaritifera margaritifera. As a result, the maximum age of Salmo fishes hosting the mussel can be as high as 13 years. The mollusk-fish system made it possible to demonstrate that the parasite can inhibit senescence of the host and stimulate nonspecific resistance to stress, i.e., can control longevity. The mussel proved to increase the resistance to epitheliomata and cutaneous mycoses. The parasite is perceived to neutralize the senile changes in the salmon regulatory cascade hypothalamus-pituitary-peripheral endocrine glands-hypothalamus.