The difference between the three most common pathogenic (capable of causing disease) microorganisms are:
Bacteria: single celled organisms which lack well defined nuclear membranes and other specialized functional cell parts and reproduce by cell division or spores. Bacteria may be free living organisms or parasites.
Cyst: a capsule or protective sac produced about themselves by many protozoan, as well as some bacteria and algae as preparation for entering a resting or a specialized reproductive stage. Generally, 2 - 50 micron in diameter.
Virus: a parasitic infectious microbe, composed almost entirely of nucleic acid, which can cause disease(s) in humans. Viruses can only reproduce within living cells. They are 0.004 – 0.1 microns in size about 100 times smaller than bacteria.
Still unsure that the Outback is the answer for you? Below is a comparison chart of emergency use products which will help you make a decision. Many of these products are clearly NOT practical for emergency preparedness, food/water storage, or for other disaster relief and survival applications, as many of these devices are only designed for recreational use.
The Outback's a Purifying Filter, which can remove viruses, at a greater than 4 log (99.99%) virus reduction rate.