What diseases does a louse transmit? - briefly
Body lice are vectors of epidemic typhus (Rickettsia prowazekii), trench fever (Bartonella quintana), and relapsing fever (Borrelia recurrentis); head lice have not been shown to transmit significant pathogens.
What diseases does a louse transmit? - in detail
Lice are vectors for several bacterial infections, each linked to a specific species of the parasite. The body louse (Pediculus humanus corporis) transmits the most clinically significant pathogens, while head and pubic lice are generally limited to causing irritation and secondary skin infection.
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Epidemic (louse‑borne) typhus – caused by Rickettsia prowazekii. Transmission occurs when infected louse feces contaminate skin abrasions or mucous membranes. Symptoms include high fever, severe headache, macular rash beginning on the trunk, and potential complications such as pneumonia or encephalitis. Untreated mortality can reach 10 % but declines sharply with doxycycline therapy.
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Trench fever – caused by Bartonella quintana. The organism is excreted in louse feces and enters the host through scratching or micro‑abrasions. Clinical picture features relapsing fever spikes, severe leg pain, headache, and occasional rash. The disease is self‑limiting over several weeks; doxycycline or azithromycin accelerate recovery.
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Louse‑borne relapsing fever – caused by Borrelia recurrentis. Infection follows the same route as other louse‑borne diseases. Patients experience recurrent episodes of high fever, chills, myalgia, and a characteristic “migratory” rash. Prompt treatment with a single dose of tetracycline or penicillin halts the relapse cycle.
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Pediculosis corporis – infestation itself may lead to pruritus, secondary bacterial cellulitis, and anemia in severe cases, especially among impoverished populations.
Head lice (Pediculus humanus capitis) and crab lice (Pthirus pubis) do not act as disease carriers under normal circumstances; their impact is confined to itching, skin inflammation, and potential secondary infection from scratching.
Control measures focus on personal hygiene, regular laundering of clothing and bedding at temperatures ≥ 60 °C, and the use of approved pediculicides. In outbreak settings, mass delousing, environmental decontamination, and prompt antibiotic treatment of confirmed cases are essential to prevent morbidity and mortality.