Because the plant is unaffected as the worms benefit
The DNA virus uses nucleus of the host to replicate it genetic material since it lack reverse transcriptase enzyme.The similarities between the DNA virus with human protein it make difficult to treat this virus without damaging the host cell.
while
RNA virus has reverse transcriptase enzyme which is used to replicate its genetic material, but it lack ability to check errors, which led to higher mutation rate.The transcriptase enzyme is used to make vaccine which is used to treat RNA virus
An exposure to sarin or sarin like chemical will caused the sarcoplasmic reticulum to be continuously stimulated by the continual electrical signal. This will open the calcium channels and allows the calcium ions to bind continuously with troponin. Sarin is an organophosphorus chemical which is highly poisonous. It is used as a chemical weapon of destruction.