LMBV and Chemicals
Could there be a connection between the largemouth bass virus and chemical use? The chemicals used in lakes to eradicate hydrilla and other water weeds cause some strange side effects in fish for a day or two as noted by anglers who have caught fish in reservoirs that have been sprayed. It's certainly possible that chemical applications can cause side effects in any water body particularly with the potential "mixed bags" used by different groups from agencies to private citizens.
When a body of water has been sprayed for weed eradication, signs are posted that indicate you shouldn't eat the fish or swim in the area. That means the chemicals aren't totally safe. Add to this minor concern that landowners using lawn fertilizers, farm run-off etc. all eventually drift down into the water and there's a chemical hodgepodge occurring in every lake in the nation.
The potential certainly exists that the immune systems of fish are weakened under such conditions. But the truth is, even the biologists studying the LMBV still don't really understand it nor know where it comes from or what actually causes it to begin with.