what everyday shape is the virus particle of marburg compared to in the book?

From the text:

"Marburg was the first filovirus to be discovered. The word filovirus is Latin and means "thread virus". The filoviruses look alike, as if they are sisters, and they resemble no other virus on earth. While most viruses are ball-shaped particles that look like peppercorns, the thread viruses have been compared to strands of tangled rope, to hair, to worms, to snakes. When they appear in a great flooding mess, as they so often do when they have destroyed a victim, they look like a tub of spaghetti that has been dumped on the floor. Marburg particles sometimes roll up into loops. The loops resemble Cheerios.

Marburg is the only ring-shaped virus known."

The shape of the virus is compared to a ring.... or Cheerios.