Project description:The prevalence of body lice among 2,288 sheltered homeless persons in the city of Marseille during 2000-2017 was 12.2% and significantly decreased over time. We report a positive association between body lice infestations and older age, duration of stays in France for migrants, frequent consumption of alcohol, and tobacco smoking.
Project description:In 2015, we investigated Bartonella quintana and typhus group rickettsiae in body lice from homeless persons in Bogotá, Colombia. We found B. quintana-infected body lice and seroprevalence of this microorganism in 19% of homeless persons and typhus group rickettsiae in 56%. Public health professionals should start preemptive measures and active vector control.
Project description:To determine the presence of Bartonella quintana in head and body lice from persons in different locations in Ethiopia, we used molecular methods. B. quintana was found in 19 (7%) genotype C head lice and in 76 (18%) genotype A body lice. B. quintana in head lice was positively linked to altitude (p = 0.014).
Project description:As part of a survey for trench fever among homeless people in Marseilles, France, we attempted isolation of Bartonella quintana from body lice. A decontamination protocol of immersion in 70% ethanol with 0.2% iodine was devised and was tested with a laboratory colony of body lice. Lice which had been experimentally contaminated with either Escherichia coli, Staphylococcus epidermidis, or Acinetobacter spp. were successfully decontaminated, and this process did not prevent the culture of B. quintana from these lice. One hundred sixty-one lice obtained from homeless patients were studied by the protocol. B. quintana was isolated on axenic medium from 15 of 161 body lice and was detected in 41 of 161 lice by PCR. Acinetobacter spp. and Serratia marcescens were also isolated from body lice. The sensitivities of PCR and culture of B. quintana were 98 and 36%, respectively. These procedures may be useful for epidemiologic studies of trench fever and for the recovery of strains for characterization and comparison.
Project description:Human body and head lice are highly related haematophagous ectoparasites but only the body louse has been shown to transmit Bartonella quintana, the causative agent of trench fever. The mechanisms by which body lice became a vector for B. quintana, however, are poorly understood. Following oral challenge, green fluorescent protein-expressing B. quintana proliferated over 9 days postchallenge with the number of bacteria being significantly higher in whole body vs. head lice. The numbers of B. quintana detected in faeces from infected lice, however, were approximately the same in both lice. Nevertheless, the viability of B. quintana was significantly higher in body louse faeces. Comparison of immune responses in alimentary tract tissues revealed that basal transcription levels of peptidoglycan recognition protein and defensins were lower in body lice and the transcription of defensin 1 was up-regulated by oral challenge with wild-type B. quintana in head but not in body lice. In addition, the level of cytotoxic reactive oxygen species generated by epithelial cells was significantly lower in body lice. Although speculative at this time, the reduced immune response is consistent with the higher vector competence seen in body vs. head lice in terms of B. quintana infection.
Project description:Human head lice and body lice are morphologically and biologically similar but have distinct ecologies. They were shown to have almost the same basic genetic content (one gene is absent in head lice), but differentially express certain genes, presumably responsible for the vector competence. They are now believed to be ecotypes of the same species (Pediculus humanus) and based on mitochondrial studies, body lice have been included with head lice in one of three clades of human head lice (Clade A). Here, we tested whether head and body lice collected from the same host belong to the same population by examining highly polymorphic intergenic spacers. This study was performed on lice collected from five homeless persons living in the same shelter in which Clade A lice are prevalent. Lice were individually genotyped at four spacer loci. The genetic identity and diversity of lice from head and body populations were compared for each homeless person. Population genetic structure was tested between lice from the two body regions and between the lice from different host individuals.We found two pairs of head and body lice on the same homeless person with identical multi locus genotypes. No difference in genetic diversity was found between head and body louse populations and no evidence of significant structure between the louse populations was found, even after controlling for a possible effect of the host individual. More surprisingly, no structure was obvious between lice of different homeless persons.We believe that the head and body lice collected from our five subjects belong to the same population and are shared between people living in the same shelter. These findings confirm that head and body lice are two ecotypes of the same species and show the importance of implementing measures to prevent lice transmission between homeless people in shelters.
Project description:Background The body and head lice of humans are conspecific, but only the body louse functions as a vector to transmit bacterial pathogens such as Bartonella quintana. Both louse subspecies have only two antimicrobial peptides, defensin 1 and defensin 2. Consequently, any differences in the molecular and functional properties of these two louse subspecies may be responsible for the differential vector competence between them. Methods To elucidate the molecular basis of vector competence, we compared differences in the structural properties and transcription factor/microRNA binding sites of the two defensins in body and head lice. Antimicrobial activity spectra were also investigated using recombinant louse defensins expressed via baculovirus. Results The full-length amino acid sequences of defensin 1 were identical in both subspecies, whereas the two amino acid residues in defensin 2 were different between the two subspecies. Recombinant louse defensins showed antimicrobial activities only against the representative Gram-positive Staphylococcus aureus but not against either Gram-negative Escherichia coli or the yeast Candida albicans. However, they did show considerable activity against B. quintana, with body louse defensin 2 being significantly less potent than head louse defensin 2. Regulatory sequence analysis revealed that the gene units of both defensin 1 and defensin 2 in body lice possess decreased numbers of transcription factor-binding sites but increased numbers of microRNA binding sites, suggesting relatively lower transcription activities of body louse defensins. Conclusions The significantly lower antibacterial activities of defensin 2 along with the reduced probability of defensin expression in body lice likely contribute to the relaxed immune response to B. quintana proliferation and viability, resulting in higher vector competence of body lice compared to head lice. Graphical Abstract Supplementary Information The online version contains supplementary material available at 10.1186/s13071-023-05802-4.
Project description:Human head and body lice are obligatory hematophagous ectoparasites that belong to a single species, Pediculus humanus. Only body lice, however, are vectors of the infectious Gram-negative bacterium Bartonella quintana. Because of their near identical genomes, yet differential vector competence, head and body lice provide a unique model system to study the gain or loss of vector competence. Using our in vitro louse-rearing system, we infected head and body lice with blood containing B. quintana in order to detect both differences in the proliferation of B. quintana and transcriptional differences of immune-related genes in the lice. B. quintana proliferated rapidly in body lice at 6 days post-infection, but plateaued in head lice at 4 days post-infection. RNAseq and quantitative real-time PCR validation analyses determined gene expression differences. Eight immunoresponse genes were observed to be significantly different with many associated with the Toll pathway: Fibrinogen-like protein, Spaetzle, Defensin 1, Serpin, Scavenger receptor A and Apolipoporhrin 2. Our findings support the hypothesis that body lice, unlike head lice, fight infection from B. quintana only at the later stages of its proliferation.
Project description:The human body louse is known as a vector for the transmission of three serious diseases-specifically, epidemic typhus, trench fever, and relapsing fever caused by Rickettsia prowazekii, Bartonella quintana, and Borrelia recurrentis, respectively-that have killed millions of people. It is also suspected in the transmission of a fourth pathogen, Yersinia pestis, which is the etiologic agent of plague. To date, human lice belonging to the genus Pediculus have been classified into three mitochondrial clades: A, B, and C. Here, we describe a fourth mitochondrial clade, Clade D, comprising head and body lice. Clade D may be a vector of B. quintana and Y. pestis, which is prevalent in a highly plague-endemic area near the Rethy Health District, Orientale Province, Democratic Republic of the Congo.