Background: In a previous study of a Q fever outbreak in Birmingham, our group identified a non-infective complex of Coxiella burnetii (C.b.) antigens able to survive in the host and provoked aberrant humoral and cell-mediated immunity responses.
View Article and Find Full Text PDFBackground: Previous studies of inciting factors for a prolonged post-infection fatigue syndrome after Q fever (variously termed QFS or Q fever associated CFS/ME in the literature) showed that after the acute infection a high proportion of asymptomatic and QFS patients had Q fever antibody and also low levels in PBMC and bone marrow of Coxiella burnetii (C.b.) DNA with PCR assays directed against three different target sequences in different parts of the coxiella genome.
View Article and Find Full Text PDFBackground: Our previous studies of persistence of Coxiella burnetii in humans after an initial acute Q fever infection revealed raised, maintained antibody levels and low levels of coxiella genomic DNA at the age of 5 years from onset in Australian patients and at 12 years in patients in the 1989 Birmingham UK Q fever outbreak. Attempts to isolate the coxiella in standard cell culture and susceptible mice by serial passage of PCR positive PBMC and bone marrow were negative.
Aim: To retest PCR positive patient samples by more sensitive methods for viable coxiellas and for the coxiella cell components of antigen and specific lipopolysaccharide (LPS).
Background: The influence of immune response gene variations on the development of chronic complications of Q fever is presently unclear.
Aim: To compare the frequencies of allelic polymorphisms in immune response genes in different Q fever patient groups.
Design: Genetic association study.
Background: Long-term persistence of C. burnetii in infected animals was established in the 1950s and 60s, but the implications for human Q fever are not fully explored.
Aim: To compare the prevalence of markers of infection in a cohort of Q fever patients in Australia (up to 5 years after infection) with those in the 1989 Birmingham cohort (12 years after infection).
Introduction: Q fever is a serious but vaccine-preventable infectious disease that predominantly affects those working in the meat and agricultural industries. In October 2000, the Commonwealth Government introduced the National Q Fever Management Program. This economic evaluation assesses the cost-effectiveness and cost-utility of improved vaccine uptake among meat and agricultural industry workers.
View Article and Find Full Text PDFAcute primary Q fever is followed by various chronic sequelae. These include subacute Q fever endocarditis, granulomatous reactions in various organs or a prolonged debilitating post-infection fatigue syndrome (QFS). The causative organism, Coxiella burnetii, persists after an initial infection.
View Article and Find Full Text PDFObjectives: To investigate an abattoir outbreak of Q fever in southem New South Wales with reference to the protective effect and safety of the formalin-inactivated Q fever vaccine (Q Vax) administered before and during the outbreak.
Methods: In September 1998, after notification of four Q fever cases in the abattoir, a cohort investigation of 103 workers was undertaken. Data on age, sex, immune status, vaccination status and main work area were obtained from the medical officer administering the vaccination program and abattoir records.
We report the sexual transmission of Coxiella burnetii from a man with occupationally acquired Q fever to his wife. Fifteen days after coitus, his wife also developed serologically proven acute Q fever. C.
View Article and Find Full Text PDFEpidemiol Infect
June 2000
After a primary infection Coxiella burnetii may persist covertly in animals and recrudesce at parturition to be shed in the products of conception and the milk. Similar latent persistence and recrudescence occurs in man: namely, infection of placenta, heart valve or mural endocardium, bone or liver. The numbers of organisms, their viability and cellular form, and the underlying organ sites of latent infection for the coxiella are obscure.
View Article and Find Full Text PDFThe post-Q-fever fatigue syndrome (QFS) (inappropriate fatigue, myalgia and arthralgia, night sweats, changes in mood and sleep patterns) follows about 20% of laboratory-proven, acute primary Q-fever cases. Cytokine dysregulation resulting from chronic immune stimulation and modulation by persistence of Coxiella burnetii cells or their antigens is hypothesized. We studied cytokine release patterns of peripheral blood mononuclear cells (PBMC) stimulated with various ligands in short-term culture, from 18 patients with active QFS, and 27 controls: six with resolving QFS, five who had had acute primary Q-fever without subsequent QFS, eight healthy Q-fever vaccinees and eight healthy subjects without Q-fever antibody.
View Article and Find Full Text PDFAm J Respir Crit Care Med
September 1998
Infection with Mycoplasma pneumoniae has been shown to exacerbate asthma in humans. However, the role of M. pneumoniae in the pathogenesis of chronic asthma has not been defined.
View Article and Find Full Text PDFIn 1989, 147 individuals in the West Midlands, UK, were infected with Q fever. Five years later, following anecdotal reports of fatigue, we used a questionnaire-based case-control study to determine the prevalence of chronic fatigue syndrome symptoms in this group. Replies from 71 patients were compared with those from 142 age- and sex-matched controls.
View Article and Find Full Text PDFA reverse transcription-PCR assay which successfully amplified hepatitis C virus RNA from poorly stored archival sera was optimized. Maximum sensitivity was achieved with Moloney murine leukemia virus RNase H- reverse transcriptase and by a single round of PCR amplification of a short (112-bp) fragment of the 5' untranslated region of the viral genome.
View Article and Find Full Text PDFObjectives: To examine the efficacy of various batches of a formalin-inactivated whole cell Coxiella burnetti vaccine (Henzerling strain, Phase 1 [Q-Vax, CSL]) in the prevention of Q fever among abattoir workers.
Design And Setting: The study was a retrospective cohort survey of all employees at three South Australian abattoirs to determine the incidence of Q fever among vaccinated and unvaccinated employees during the period 1985 to 1990.
Results: There were two cases of Q fever among 2555 vaccinated employees of the three abattoirs, compared with 55 cases among 1365 unvaccinated employees.
Previous work in our laboratory has shown that lymphocytes from persons vaccinated with a formalin-inactivated Phase I Q fever vaccine (Q-Vax CSL Ltd) show a mitogenic response to Coxiella burnetii antigens. The mitogenic response is the sum of that from various subsets of CD4+, T helper cells, CD8+ T cells and probably B cells. It does not distinguish between T helper cell responses leading to formation of interferon-gamma (IFN-gamma)--a cytokine responsible for clearing intracellular infection with C.
View Article and Find Full Text PDFEfforts to improve laboratory diagnostic methods for infection due to Mycoplasma pneumoniae have involved the use of a cell-sheet culture method and a modified indirect hemagglutination method for IgM antibody, while direct detection of mycoplasma has employed antigen capture-enzyme immunoassay (Ag-EIA) and polymerase chain reaction (PCR) amplification of sequences within the P1 and 16S ribosomal RNA genes and quantification of the amplified DNA by dot blot hybridization (DBH). Cell-sheet culture was slightly more sensitive and more rapid than culture with cell-free diphasic medium. Indirect hemagglutination detection of IgM antibody to M.
View Article and Find Full Text PDFDirect detection assays for Mycoplasma pneumoniae were established by PCR amplification of short sequences within the foot protein/adhesin (P1) gene and the 16S ribosomal RNA gene. Specificity and sensitivity was excellent, no hybridization was observed with M. genitalium and other human Mycoplasma species.
View Article and Find Full Text PDFVaccination with an inactivated, whole cell, Q fever vaccine (Q-vax) induces lasting antibody conversion and a positive delayed-type hypersensitivity (DTH) skin reaction in about 60% of recipients but a long-lasting positive lymphoproliferative or mitogenic response to C. burnetii antigens with peripheral blood mononuclear cells (PBMC) in 85-95% of subjects. Analysis of the lymphoproliferative response to C.
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