rickettsia

Etymology
From genus name, from, equivalent to.

Noun

 * 1) Any of a group of gram-negative bacteria, of the genus, carried as parasites by ticks, fleas and lice, that cause typhus and other diseases.
 * 2)  Any bacterium of the order.

Usage notes
Rickettsia has no connection with rickets, which is a disease caused by vitamin D deficiency.

Etymology
or.