When I get a virus infected file, I just PM GEH4EVR or SpiderX22 and send them the file.
JK - I don't think a kmz or kml file could contain a virus. They are essentially text files. Try opening any kml file in Notepad and you will see it's just clear text. Here's what the Avalanche file (http://www.gearthhacks.com/dlfile29151/Avalanche.htm) looks like:
<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://earth.google.com/kml/2.2">
<Document>
<name>Avalanche.kmz</name>
<Style id="sn_shaded_dot_copy1">
<IconStyle>
<scale>0.6</scale>
<Icon>
<href>http://maps.google.com/mapfiles/kml/shapes/shaded_dot.png</href>
</Icon>
</IconStyle>
<ListStyle>
</ListStyle>
</Style>
<StyleMap id="msn_shaded_dot_copy1">
<Pair>
<key>normal</key>
<styleUrl>#sn_shaded_dot_copy1</styleUrl>
</Pair>
<Pair>
<key>highlight</key>
<styleUrl>#sh_shaded_dot_copy1</styleUrl>
</Pair>
</StyleMap>
<Style id="sh_shaded_dot_copy1">
<IconStyle>
<scale>0.709091</scale>
<Icon>
<href>http://maps.google.com/mapfiles/kml/shapes/shaded_dot.png</href>
</Icon>
</IconStyle>
<ListStyle>
</ListStyle>
</Style>
<Placemark>
<name>Avalanche</name>
<description>Avalanche tumblng down a mountainside in Antarctica</description>
<LookAt>
<longitude>-59.63964646954713</longitude>
<latitude>-62.52075859446469</latitude>
<altitude>0</altitude>
<range>453.8018505672967</range>
<tilt>22.75405031690995</tilt>
<heading>18.4679487287435</heading>
</LookAt>
<styleUrl>#msn_shaded_dot_copy1</styleUrl>
<Point>
<coordinates>-59.63964646954713,-62.5207585944647,0</coordinates>
</Point>
</Placemark>
</Document>
</kml>