The CDC has identified seven cases of a new strain of swine flu in the US. Five of the seven appeared in San Diego, California, and two near San Antonio, Texas. It is the same flu strain currently sweeping Mexico City, where schools and universities have been closed. The World Health Organization has reported 800 cases there so far, with 56 deaths.
The first two US cases were identified by monitoring stations near the border in San Diego and El Paso. You can accuse me of jumping to conclusions if you want, but I see a clear message here.
Stopping the spread of disease has always been an important, legitimate reason for having tightly secured and monitored borders. This is just a reminder.