Roblack is correct about UV being able to help control outbreaks of Ick; however one would need to research the correct amount of flow through the UV sterilizer to do the job. This would not be a universal GPH either; it would depend on design of the sterilizer and the wattage of the UV bulb.
For instance the Turbo-Twist UV Sterilizer recommends the following:
Model 9W, Flow Rate for Parasites - 55 gph, Flow Rate for Algae - 121 gph, Flow Rate for Bacteria - 253 gph
Model 18W, Flow Rate for Parasites - 110 gph, Flow Rate for Algae - 240 gph, Flow Rate for Bacteria - 500 gph
Model 36W, Flow Rate for Parasites - 290 gph, Flow Rate for Algae - 680 gph, Flow Rate for Bacteria - 1550 gph
I would consider a UV sterilizer more of a maintenance tool, not a curing tool.