Excretion of living Borrelia recurrentis in feces of
infected human body lice.
Unite des Rickettsies, Institut Federatif de Recherche 48, Centre National de
Recherche Scientifique, Unite Mixte de Recherche 6020, Universite de la
Mediterranee, Faculte de Medecine, Marseille, France.
Louse-borne relapsing fever (LBRF), caused by Borrelia recurrentis, is 1 of the
most dangerous arthropod-borne diseases. Infection is thought to occur through
louse crushing. Lice feces have not been shown to contain living borreliae. We
infected 800 body lice by feeding them on a rabbit made spirochetemic by the
injection of 2 x 106 borreliae. The life span of infected lice was not
shortened. Once infected, lice remained infected for life but did not transmit
borreliae to their progeny or to nurse rabbits. B. recurrentis infection was
observed throughout lice and spread into hemolymph on day 5 after infection. We
describe 2 unprecedented phenomena. In hemolymph, B. recurrentis formed clumps
of aggregated borreliae. Using immunofluorescence assay, transmission electron
microscopy, and culture, we detected borreliae excreted in lice feces beginning
on day 14 after infection. We conclude that, similar to epidemic typhus and
trench fever, transmission of LBRF may be caused by lice feces.
PMID: 15871124 [PubMed - indexed for MEDLINE]