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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.

A man with newly diagnosed AIDS presented with months of back pain and fever. Computed tomography (CT) results demonstrated aortitis with periaortic tissue thickening. DNA amplification of biopsy tissue revealed Bartonella quintana, and Bartonella serologies were subsequently noted to be positive. The patient improved with prolonged doxycycline and rifabutin treatment. This case illustrates how molecular techniques are increasingly important in diagnosing Bartonella infections.

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.

This chapter is devoted to a discussion of three topics: The discovery of the major etiologic agents of rickettsial disease, their vectors, and mechanisms of transmission; The major technological developments that have facilitated the study, control, and treatment of rickettsiae and rickettsial diseases; and the evolution of the concept of rickettsia from a microbial entity which is neither a typical bacterium nor a typical virus to a well-characterized set of bacteria. Contents of Volume I include: Etiology; Rocky Mountain Spotted Fever (RMSF); Epidemic and Endemic Typhus Fevers; Trench Fever; Scrub Typhus; Q Fevers; Rickettsialpox; Staining Rickettsiae; Preantibiotic Chemotherapy; Early Vaccines; The Yolk Sac Revolution; Rickettsiae as Organisms and Rickettsial Physiology. Reprints., Pub. in Biology of Rickettsial Diseases, v1 ch2 p15-32 1988.

This study was directed towards the isolation of rickettsial antigens and detection of antibodies. Stock supplies of Gilliam, Kato and Karp strains of Rickettsia tsutsugamushi were propagated in embryonated chick eggs and used for infecting cultured cells. Infected McCoy cell extracts containing soluble anti-gen as well as infected yolk sacs were inoculated into guinea pigs to produce antisera. However, the yield of antibody was low and only detectable by fluorescent antibody techniques. More recently, progress was made in growing R. tsutsugamushi in BHK sub 21 cells as a monolayer or in suspension cultures. Irradiated cells seem to enhance rapid rickettsial proliferation Solubilization after freezing and thawing and by sonication and Triton X-11 treatment was used to isolate soluble antigen for characterization and further purification. In these studies, infected cells as well as isolated samples used in the studies were fixed and examined by electron microscopy to monitor the structure of the organism and the host cell as well as some of the isolated and purified samples.

This study is directed towards the isolation of rickettsial antigens and detection of antibodies. Stock supplies of Gilliam, Kato and Karp strains of Rickettsia tsutsugamushi were propagated in embryonated chick eggs and used for infecting cultured cells. Infected McCoy cell extracts containing soluble antigen as well as infected yolk sacs were inoculated into guinea pigs to produce antisera. However the yield of antibody was low and only detectable by fluorescent antibody techniques. More recently progress was made in growing R. tsutsugamushi in BHK (21) cells as a monolayer or in suspension cultures. An enzyme immunoassay test to detect antibodies to Rochalimeae quintana in sera from patients with trench fever was evaluated with soluble antigens. This test detected antibodies in sera from known cases that were negative to other serological tests. However, there is an antigen that cross reacts with other rickettsia which appears to be a lipopolysaccharide antigen. This lipopolysaccharide seems to be related serologically to scrub typhus antigen. Infected cells as well as isolated samples used in the studies were fixed and examined by electron microscopy to monitor the structure of the organism and the host cell as well as some of the isolated and purified samples.