New guidelines are out regarding catchment rainwater tanks in Hawaii. You can find the full publication here.
The authors of this publication have addressed the importance of reducing the risk of Rat Lungworm Disease through proper management of the catchment tank.
“Hopefully studies will be done soon that will give us more definitive answers on effective treatment and barriers. In the meantime, do whatever you can to keep mollusks and the rats that are a necessary part of the life cycle of the parasite out of your system and off your roof. While no filters have been tested yet, using as small a one as possible (5 micron) might help.”