Any zapper is good. You can try the simple pulser which is the very basic form of the zapper. Here it is:
Take a new nine volt dc battery and wet your fingers. Put one finger of one hand on the negative terminal and tap with one finger of your other hand on the positive terminal. Do this as fast as you can for 7 minutes. Then rest for 20 minutes. Do this three rounds and your done.
This effectively removes viral infections. Try it and see it for yourself.