Claire Howell (OSU Bartholomew Lab, Microbiology) developed a water-sampling method that can quickly detect harmful levels of Ich in wild river systems. White spot disease is caused by the globally distributed freshwater fish parasite Ichthioptherius multifilis (Ich). Outbreaks of this disease are difficult to control, and can result in catastrophic mortality events of both wild and cultured fishes. The parasite has a direct, temperature-dependent life cycle that enables rapid multiplication when hosts are plentiful and environmental conditions are favorable. Accurate detection is central to the control of Ich infections and prevention of host mortality particularly in wild systems where chemical treatments are not feasible. A sampling method based on molecular analysis of water samples for parasite DNA was developed and tested. The small subunit ribosomal DNA (ssrDNA) of Ich isolates was collected from the Klamath River and used to develop and validate a novel qPCR assay. This method will protect vulnerable fish populations, includinng migrating adult salmon.
Howell, C.K., Atkinson, S.D, Bartholomew, J.L. and Hallett, S.L. 2019. Development and application of a qPCR assay targeting Ichthyophthirius multifiliis in environmental water samples. Dis. Aquat. Organ. 134(1):43-55.