Leptospirosis & Water Purifiers

So I continued reading up on water filters.  Apparently there's a nasty bacteria, Leptospirosis, that is 0.1 micron in size, which is smaller than the absolute pore size of most water filters.  Doulton's ceramic filters are 0.9 micron, and Katadyn Pocket is 0.2 micron.  Only one filter I found is purifier-grade, which is the Sawyer Point Zero Two, claiming a 0.02 micron pore width.  I'm currently searching for more information on purifiers.

Apparently Leptospirosis can be killed by several methods, including boiling, UV sterilization, or the addition of iodine or chlorine (in concentrations as for a swimming pool).  Of course a bacteriologically uncertain water source should be treated.

Also, on REI's website is an interesting article on water treatment for international travel. They don't mention the Sawyer, but they do refer to several limited-life filters that I had looked at previously.  My take on it is that suspect water should be pre-treated chemically then run through a filter.  Water from a reasonable source (no virii or bacteria < 1 micron) ought to be ok with a filter and not a purifier.  Still, the Sawyer Point Zero Two would be nice to have.