What diseases do fleas cause? - briefly
Fleas transmit bacterial illnesses such as plague (Yersinia pestis), murine typhus, flea‑borne spotted fever (Rickettsia spp.) and Bartonella infections that can cause cat‑scratch disease. They also serve as vectors for the tapeworm Dipylidium caninum in dogs and cats.
What diseases do fleas cause? - in detail
Fleas act as vectors for several pathogenic agents that affect humans and animals. Their bites can also cause direct health problems such as severe itching, allergic dermatitis, and anemia when infestations are heavy.
Bacterial infections transmitted by fleas
- Plague (Yersinia pestis) – classic rodent‑associated disease; transmitted when an infected flea feeds on a host. Forms include bubonic (painful lymph node swelling), septicemic (bloodstream infection), and pneumonic (lung involvement). Rapid progression requires prompt antibiotic therapy, typically streptomycin or tetracycline.
- Murine (endemic) typhus (Rickettsia typhi) – acquired through flea feces that contaminate bite sites or mucous membranes. Symptoms: fever, headache, rash, and malaise. Doxycycline is the treatment of choice.
- Spotted fever group rickettsioses (Rickettsia felis) – associated mainly with the cat flea (Ctenocephalides felis). Presents with fever, rash, and sometimes neurologic signs. Doxycycline is effective.
- Bartonellosis (Bartonella henselae) – cat‑scratch disease variant transmitted by cat fleas. Manifests as regional lymphadenopathy, fever, and, rarely, hepatic or ocular complications. Azithromycin or doxycycline may be used.
Other flea‑borne pathogens
- Flea‑borne relapsing fever (Borrelia recurrentis‑like species) – rare, produces recurring fever spikes, headache, and myalgia. Treatment mirrors that of other relapsing fevers, generally with tetracycline or erythromycin.
- Leptospira spp. – occasional reports of transmission via contaminated flea saliva, leading to leptospirosis with renal and hepatic involvement. Doxycycline or penicillin regimens are standard.
Direct effects of flea feeding
- Allergic dermatitis – hypersensitivity to flea saliva causes erythema, papules, and intense pruritus. Management includes antihistamines, topical corticosteroids, and rigorous flea control.
- Anemia – severe infestations, especially in young or debilitated animals, can result in significant blood loss, leading to weakness, pallor, and, in extreme cases, fatality. Treatment involves supportive care and rapid eradication of the parasites.
Effective prevention relies on integrated pest management: regular use of topical or oral insecticides on pets, environmental treatment of bedding and carpets, and control of rodent reservoirs. Early recognition of flea‑associated illnesses and appropriate antimicrobial therapy reduce morbidity and prevent outbreaks.