ATLANTA -- A dead zebra on a card labeled “anthrax”.

A close-up of an oozing ulcer.

They might not replace baseball trading cards as a hobby, but the Centers for Disease Control says sick trading cards are amazingly popular. It’s CDC’s way of getting middle school kids interested in science and health.

The CDC gives the cards away for free at its visitor center, when the agency can keep them in stock. The sick cards disappear faster than a case of the 24 hour flu.

The CDC said as it developed the idea, it was careful not to be too graphic. “We changed images to make sure they weren’t scary for kids”, said Judy Gantt, the director of the CDC’s Global Health Oddysey.

What was scarier than the dead zebra on the anthrax card?

“The picture before the zebra was a woman who had anthrax on her eye," said Gantt.

"She basically lost her eye from anthrax. It was pretty gory.”

Right now the cards are out of stock, but you can download the pictures for free by clicking here.

What’s next for this truly sick idea? Foodborne illness trading cards are set to come out later this summer.