All the members of the Furon Race are all named after diseases and viruses on earth - Cryptosporidium (for Crypto), Orthopox (for Pox), and Menengitis, for example.
The quote "I heard that the dolphins are doing a good job contacting the extraterrestrials. I heard that from the mice!" from Orthopox is a reference to "The Hitchhiker's Guide to the Galaxy" (radio series, books, TV series, album, movie, towel, etc).
The gas-mask worn by Silhouette is the mask from the Pandemic Studies logo
The character of General Armquist is satirizing real-life General Douglas MacArthur, who also has a signature corn-cob pipe.