New case study: safeguarding rainbow trout from PKD

Proliferative kidney disease (PKD) is a seasonal health challenge affecting rainbow trout farms across the UK.

Caused by a naturally occurring parasite, the disease can lead to reduced fish welfare and economic losses. Without an effective vaccine, farmers have relied on carefully timed, low‑level exposure to help fish develop natural immunity. However, until recently, producers had limited data on when parasites were present in the environment or how much exposure fish actually received.

Valued at over £435k, MPERT - a project between Kames Fish Farming, University of Aberdeen, University of Nottingham, and the British Trout Association - applied new monitoring tools on Scottish trout farms to better understand when and where fish encounter PKD parasites, and how their immune systems respond.

Across multiple farm sites, the team combined environmental sampling, fish health screening, and immune‑response testing over a 16‑month period. They tracked parasite presence in water, measured infection levels in fish, and monitored the development of parasite‑specific antibodies. This provided the first detailed picture of PKD exposure patterns in Scottish production systems. Results showed that exposure levels vary by site and season, and that fish develop immunity gradually, with measurable responses appearing toward the end of the study period.

The project also explored a promising rapid on‑farm test using CRISPR‑based technology, capable of detecting parasite DNA in under an hour. With further refinement, this could give farmers a practical tool for early detection.

Overall, MPERT improved understanding of PKD dynamics in Scotland and provided farmers with evidence-based guidance to support better stock management and planning.

The full title of this project is 'Proliferative kidney disease (PKD): modelling parasite exposure and immune response to safeguard farmed rainbow trout in Scotland'.

Read the full case study