What does a flea that parasitises humans feed on, and what disease can it transmit? - briefly
The human flea (Pulex irritans) consumes the blood of its host. It can transmit Yersinia pestis, the bacterium that causes plague.
What does a flea that parasitises humans feed on, and what disease can it transmit? - in detail
The human‑infesting flea obtains nutrition exclusively from the blood of its host. Adult females require a blood meal to develop eggs, while males also feed intermittently to sustain metabolic activity. Blood is drawn from the capillary network in the skin using specialized mouthparts that pierce the epidermis and secrete anticoagulant saliva to facilitate ingestion.
The species most commonly associated with human parasitism, Pulex irritans, is capable of transmitting Yersinia pestis, the bacterium responsible for plague. Transmission occurs when an infected flea regurgitates bacteria into the bite wound during feeding. The pathogen can then enter the bloodstream, leading to the classic forms of plague: bubonic, septicemic, and pneumonic. Early signs include sudden fever, swollen lymph nodes, and chills; without prompt antimicrobial therapy, mortality rates rise sharply.
Key points:
- Primary diet: vertebrate blood, predominantly human when available.
- Female reproductive cycle depends on blood intake for egg production.
- Vector competence: capable of carrying and inoculating Y. pestis.
- Disease mechanism: bacterial regurgitation during blood extraction.
- Clinical outcomes: rapid onset of plague symptoms, high fatality without treatment.