Experimental infection of human body lice with Acinetobacter baumannii
Linda Houhamdi1, Didier Raoult
1Unité des Rickettsies, Institut Fédératif de Recherche 48, Centre National de Recherche Scientifique, Marseille, France.
Abstract:
The human body louse is currently recognized as a vector of Rickettsia prowazekii, Borrelia recurrentis, and Bartonella quintana. Previous studies have reported the isolation of Acinetobacter baumannii from the body lice of homeless patients. To study how the body louse acquires A. baumannii, we infected a rabbit by infusing 2 x 10(6) colony-forming units of the louse strain of A. baumannii. Two hundred body lice were infected by feeding on the bacteremic rabbit and compared with 200 uninfected lice and two groups of 200 lice feeding on rabbits infected either with another strain of A. baumannii or A. lwoffii. Each louse group received maintenance feedings once a day on another seronegative rabbit. Body lice that fed on rabbits infused with each Acinetobacter species demonstrated a generalized infection. The body lice did not transmit their infection to the nurse rabbit by bite while feeding or to their progeny (eggs and larvae). The lice excreted living Acinetobacter species within their feces. Only the louse strain of A. baumannii was pathogenic for the body louse. An increased mortality rate was observed between the second and third days post-infection; however, they remained infected for their lifespan.
Insights
Human body lice can acquire Acinetobacter baumannii from infected rabbits. While lice excrete the bacteria, they do not transmit it to new hosts or offspring, though the louse strain is pathogenic to the lice themselves.
Area of Science:
- Medical Entomology
- Bacteriology
- Vector-Borne Diseases
Background:
- Human body lice (Pediculus humanus humanus) are known vectors for Rickettsia prowazekii, Borrelia recurrentis, and Bartonella quintana.
- Acinetobacter baumannii has been previously isolated from body lice found on homeless individuals.
- The transmission dynamics and host-pathogen interactions of A. baumannii in body lice require further investigation.
Purpose of the Study:
- To investigate the acquisition and transmission of Acinetobacter baumannii by the human body louse.
- To determine if body lice can acquire A. baumannii from a bacteremic host.
- To assess the pathogenicity of A. baumannii to body lice and its potential for transmission.
Main Methods:
- A rabbit model was used to induce bacteremia with a louse-associated strain of A. baumannii.
- Body lice were infected by feeding on bacteremic rabbits and compared to control groups.
- Infected lice were monitored for generalized infection, transmission to naive rabbits, transmission to progeny, and mortality.
Main Results:
- Body lice successfully acquired a generalized infection when feeding on rabbits infused with Acinetobacter species.
- Infected lice did not transmit Acinetobacter species to a naive rabbit host via feeding or to their eggs and larvae.
- The louse strain of A. baumannii was pathogenic to the body louse, causing increased mortality, but lice remained infected throughout their lifespan.
- Living Acinetobacter species were excreted in the feces of infected lice.
Conclusions:
- Human body lice can serve as a reservoir for Acinetobacter baumannii, acquiring it from an infected host.
- Body lice do not appear to be significant vectors for transmitting A. baumannii to new hosts or through vertical transmission.
- A. baumannii, particularly the louse-associated strain, can be pathogenic to the body louse, impacting its survival.
