Bartonella is a bacteria spread by ____.

Bartonella is a genus of bacteria known to be transmitted primarily by fleas, which makes this answer the most accurate. One of the most notable species within this genus, Bartonella henselae, is associated with cat scratch fever and is commonly spread through flea-infested cats. The life cycle of fleas allows them to become carriers of this bacterium, which can then be transmitted to other animals or humans through their bites.

Ticks, mosquitoes, and sandflies are also vectors for various other pathogens, but they are not the primary vectors for Bartonella species. While ticks can transmit some species of Bartonella, the predominant vector recognized for the transmission of these bacteria, especially in domestic settings involving cats and dogs, is fleas. Thus, understanding the primary transmission route of Bartonella reinforces the importance of flea control in preventing infections associated with these bacteria.