(CNN) — For the first time, a patient in an American hospital has been diagnosed with Ebola.

Should Americans worry after 1st Ebola diagnosis ? Read More

The unidentified man, who is being treated at a Dallas hospital, didn’t show symptoms until after four or five days of arriving in the United States from Liberia.

Citing privacy concerns, official are being tight-lipped about how he contracted the virus or how he’s being treated.

Shortly after the news broke Tuesday evening, more than 50,000 tweets about Ebola flew through Twitter in a one-hour period, many of them panicked responses.

Should we be concerned?

The short answer: no.