The Malacosporean Myxozoan Parasite Tetracapsuloides bryosalmonae : A Threat to Wild Salmonids

is a myxozoan parasite responsible for proliferative kidney disease (PKD) in a wide range of salmonids. PKD, characterized by high mortality and morbidity, is well known for affecting aquaculture operations and wild salmonid populations across Europe and North America. The life cycle of revolves around freshwater bryozoan and salmonid fish hosts. In recent years, has been reported among wild salmonids from the European countries where it has not been reported previously. is believed to be a possible reason for the diminishing wild salmonid populations in the natural water bodies of many European countries. Climate crisis driven rising water temperature can further accelerate the distribution of . Expansion of the geographical distribution of may further advocate the decline of wild salmonid populations, especially brown trout ( ) in their habitats. Mathematical models are used to understand the pattern and distribution of among the host in the natural water bodies. The present manuscript not only summarizes the incidences of among the wild salmonid populations, but also discusses the contemporary understanding about the development of in its hosts and the influences of various factors in the spread of the disease in the wild.