Bartonella quintana is transmitted by the infected faeces of body lice. Recently, this bacterium was detected in cat fleas ( Ctenocephalides felis ) and in two humans with chronic adenopathy whose only risk factor was contact with cat fleas. In this study, a total of 960 C. felis were divided into 12 groups (2 control groups and 10 infected groups) each containing 80 fleas. The fleas were fed B. quintana ‐inoculated human bloo...