What diseases are transmitted by lice? - briefly
Body lice transmit epidemic typhus (Rickettsia prowazekii), trench fever (Bartonella quintana), louse‑borne relapsing fever (Borrelia recurrentis), and, rarely, plague (Yersinia pestis).
What diseases are transmitted by lice? - in detail
Lice serve as vectors for several bacterial infections that have caused significant morbidity throughout history. The body louse (Pediculus humanus corporis) is the primary agent of transmission; the head louse (Pediculus humanus capitis) rarely carries pathogens.
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Epidemic typhus – caused by Rickettsia prowazekii. Infection follows ingestion of louse feces that enter the skin through scratching or mucous membranes. Symptoms begin with abrupt fever, severe headache, and a macular rash that spreads from trunk to extremities, sparing the face and palms. Untreated cases may progress to pneumonitis, encephalitis, or death. Doxycycline is the drug of choice; chloramphenicol is an alternative for pregnant patients.
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Trench fever – caused by Bartonella quintana. The organism is excreted in louse feces and transmitted similarly to typhus. Clinical presentation includes recurrent fever spikes, severe leg pain, and a transient, non‑purpuric rash. Illness is usually self‑limiting, but antibiotics such as doxycycline or azithromycin accelerate recovery and reduce carriage.
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Louse‑borne relapsing fever – caused by Borrelia recurrentis. Transmission occurs when contaminated louse feces are rubbed into abraded skin. The disease is characterized by repeated episodes of high fever, chills, headache, and myalgia, each lasting several days and separated by afebrile intervals. Diagnosis relies on microscopy of peripheral blood during febrile periods. Intravenous penicillin G or ceftriaxone effectively clears the infection.
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Potential secondary infections – heavy infestation may facilitate secondary bacterial skin infections (e.g., cellulitis, impetigo) due to scratching and breach of the epidermal barrier. These are managed according to standard antimicrobial guidelines.
Control of louse‑borne diseases hinges on eradication of the vector through regular laundering of clothing at temperatures above 60 °C, use of insecticidal powders, and improvement of personal hygiene in crowded or unsanitary environments. Surveillance in refugee camps, prisons, and homeless populations remains essential because outbreaks can reappear when conditions favor louse proliferation.