Proliferative kidney disease is caused by:

Correct option is A

Correct Answer: (a) Tetracapsuloides bryosalmonae
Explanation:
→ PKD is a major parasitic disease affecting salmonids, caused by T. bryosalmonae.
→ Leads to kidney swelling, anemia, and high mortality.
Information Booster:
→ Temperature-dependent disease; outbreaks occur in warm months.
→ Parasite life cycle involves bryozoan hosts.
→ Important in trout aquaculture across Europe and North America.
Additional Information:
(b) Myxobolus cerebralis causes whirling disease.