Bartonella henselae

Bartonella henselae, formerly Rochalimæa henselae, is a bacterium that is the causative agent of cat-scratch disease (bartonellosis). It primarily infects red blood cells and endothelial cells and is transmitted to humans through scratches, bites, or flea vectors associated with domestic and feral cats.

Bartonella henselae is a member of the genus Bartonella, one of the most common types of bacteria in the world. It is a facultative intracellular microbe that targets red blood cells. In the United States, about 20,000 cases are diagnosed each year, most under 15 years old. Most often, it is transmitted by scratches or bites from kittens. Higher prevalence is reported in warm, humid climates where flea infestations are more common.