It gets in your brain... AND IT WON'T LET YOU DIE!!!

Carl Zimmer dishes out more on our favorite parasite by revealing how it manages to stealthily sneak into your brain: via the immune system.

Antonio Barragan and his colleagues at the Karolinska Institute in Stockholm were puzzled at first about how Toxoplasma managed this swift journey. "When we looked for parasites in the blood, we found very few that were just swimming around," said Dr. Barragan, an associate professor. But the scientists observed many of the parasites inside immune cells known as dendritic cells.

Dr. Barragan was intrigued. Dendritic cells, common in the gut, often come into contact with pathogens. They respond by crawling to the lymph nodes or the spleen, where they communicate with other immune cells.

"That led us to think, what if this parasite is directing these cells to move and to disseminate through the body?" Dr. Barragan said. He and his colleagues put dendritic cells in a dish and injected them with Toxoplasma. They noticed that the parasites triggered a peculiar change: the dendritic cells became hyperactive, crawling for an entire day.

Not as interesting as their potential effects on the human psyche, but still pretty interesting nonetheless.

By the way... extra points for getting the reference behind this post's title.