Defense contractor Lockheed Martin had less than 1 percent of its systems infected, but still had disruptions.
The Massachusetts Institute of Technology found its e-mail servers congested from the amount of messages created.
Railway and freight hauler CSX had to stop trains because of the Nachi worm, the Associated Press reported.
Airline Air Canada canceled flights on Tuesday because its network couldn't deal with the amount of traffic generated by the Nachi worm.
The Pentagon and military had myriad infections of the Sobig.F virus and the Nachi worm, various news agencies reported.
When your OS and mail products can make trains and planes stop running, that's pretty serious. Exactly how long can people pretend that the risks of MS products are not higher than those of other competitors?