Three Cases of Q Fever Osteomyelitis in Children and a Review of the Literature

A retrospective analysis of Q fever osteomyelitis in children, with recommendations

Osteomyelitis in children due to Q fever is a rare occurrence. In this study, we review 25 pediatric cases of this disease entity. The mean age of these 25 patients was 3.7years (range, 2-7 years). The risk factor for infection was history of contact with animals, such as cattle and sheep (23/25, 92.0%). The most common sites of infection were foot and ankle (12/25, 48.0%). The diagnosis of Q fever was confirmed by serologic testing in 25 children. On PCR, Coxiella burnetii was detected in 17 cases and it was not detected in the remaining five cases. A total of 22 children were treated with antibiotics, of which 15 received surgical treatment. The composition and duration of treatment varied greatly. Only 18 patients achieved significant recovery of joint mobility after drug and/or surgical treatment. Our current literature review show that the clinical manifestations of Q fever osteomyelitis in children are atypical. In the absence of serological test results, mNGS identification may be a good option. Compared with the guidelines that recommend doxycycline combined with hydroxychloroquine, we recommend that ciprofloxacin-based treatment combined with rifampicin or sulfamethoxazole/trimethoprim should be preferred in children under the age of 8 years, and the need for performing combined surgical debridement and determining the treatment duration should be evaluated according to their actual clinical situation.

Emerging technologies for enhanced removal of residual antibiotics from source-separated urine and wastewaters: A review

Antibiotic residues are of significant concern in the ecosystem because of their capacity to mediate antibiotic resistance development among environmental microbes. This paper reviews recent technologies for the abatement of antibiotics from human urine and wastewaters. Antibiotics are widely distributed in the aquatic environment as a result of the discharge of municipal sewage. Their existence is a cause for worry due to the potential ecological impact (for instance, antibiotic resistance) on bacteria in the background. Numerous contaminants that enter wastewater treatment facilities and the aquatic environment, as a result, go undetected. Sludge can act as a medium for some chemicals to concentrate while being treated as wastewater. The most sewage sludge that has undergone treatment is spread on agricultural land without being properly checked for pollutants. The fate of antibiotic residues in soils is hence poorly understood. The idea of the Separation of urine at the source has recently been propagated as a measure to control the flow of pharmaceutical residues into centralized wastewater treatment plants (WWTPs). With the ever increasing acceptance of urine source separation practices, visibility and awareness on dedicated treatement technologies is needed. Human urine, as well as conventional WWTPs, are point sources of pharmaceutical micropollutants contributing to the ubiquitous detection of pharmaceutical residues in the receiving water bodies. Focused post-treatment of source-separated urine includes distillation and nitrification, ammonia stripping, and adsorption processes. Other reviewed methods include physical and biological treatment methods, advanced oxidation processes, and a host of combination treatment methods. All these are aimed at ensuring minimized risk products are returned to the environment.

The First Confirmed Pediatric Chronic Osteomyelitis due to Coxiella Burnetii in Oman

We describe here the first confirmed case in Oman of chronic osteomyelitis due to Coxiella burnetii, in a previously healthy four-year-old Omani girl. After laboratory confirmation of C. burnetii infection using molecular and qualitative and quantitative serological assays, the case was successfully managed with a combination of oral ciprofloxacin and cotrimoxazole and thereafter followed up for a long period without remission.

Coxiella burnetti prosthetic joint infection in an immunocompromised woman: iterative surgeries, prolonged ofloxacin-rifampin treatment and complex reconstruction were needed for the cure

Background

Q fever is a zoonotic disease caused by the bacterium Coxiella burnetii, a strictly intracellular pathogen that can cause acute and chronic infection. Chronic Q fever can occur in immunocompetent as well as in immuno-compromised hosts, as a persistent localized infection. The main localizations are endocardial, vascular and, less frequently, osteoarticular. The most frequent osteoarticular form is spondyliscitis. Recommended treatment is combined doxycycline and hydroxychloroquine for 18 months, with cotrimoxazole as another option. Coxiella burnetti infection has been implicated in rare cases of prosthetic joint infection (PJI), and the medical and surgical management and outcome in such cases have been little reported.

Case presentation

We report an unusual case of chronic Q fever involving a hip arthroplasty in an immunocompromised woman treated with tumor necrosis factor (TNF)-α blockers for rheumatoid arthritis. Numerous surgical procedures (explantation, “second look”, femoral resection and revision by megaprosthesis), modification of the immunosuppressant therapy and switch from doxycycline-hydroxychloroquine to prolonged ofloxacin-rifampin combination therapy were needed to achieve reconstruction and treat the PJI, with a follow-up of 7 years.

Conclusions

Coxiella burnetti PJI is a complex infection that requires dedicated management in an experienced reference center. Combined use of ofloxacin-rifampin can be effective.

Q Fever Osteoarticular Infection in Children

Studies of this condition, which is underestimated in children, will aid in its diagnosis and treatment.

Q fever osteoarticular infection in children is an underestimated disease. We report 3 cases of Q fever osteomyelitis in children and review all cases reported in the literature through March 2018. A high index of suspicion is encouraged in cases of an unusual manifestation, prolonged course, relapsing symptoms, nonresolving or slowly resolving osteomyelitis, culture-negative osteomyelitis, or bone histopathology demonstrating granulomatous changes. Urban residence or lack of direct exposure to animals does not rule out infection. Diagnosis usually requires use of newer diagnostic modalities. Optimal antimicrobial therapy has not been well established; some case-patients may improve spontaneously or during treatment with a β-lactam. The etiology of treatment failure and relapse is not well understood, and tools for follow-up are lacking. Clinicians should be aware of these infections in children to guide optimal treatment, including choice of antimicrobial drugs, duration of therapy, and methods of monitoring response to treatment..

A systematic review on the health outcomes associated with non-endocarditis manifestations of chronic Q fever

The aim of this study was to systematically review the non-endocarditis manifestations of chronic Q fever and understand the significance of non-specific symptoms like pain and fatigue in chronic endovascular, osteomyelitis and abscess due to chronic Q fever. We performed a systematic review using Pub Med (the National Library of Medicine (NLM)) and Scopus databases. All studies in English on chronic Q fever that listed clinical manifestations other than infective endocarditis (IE) and chronic fatigue syndrome (CFS). Meta-analysis was carried out to investigate the effects of patient's health outcomes (pain, fatigue, the need for surgery and mortality) on vascular infections, osteomyelitis and abscess. Among cases not presenting as IE or CFS, vascular infections and osteomyelitis were the most common chronic Q fever disease manifestations. There were distinct regional patterns of disease. Compared with infective endocarditis, these are significantly associated with increased risk of pain: osteomyelitis (relative risk (RR) = 4.13, 95% confidence interval (CI) 3.36-5.07), abscess (RR = 3.59, 95% CI 3.28-3.93) and vascular infection (RR = 2.46, 95% CI 1.99-3.03). The strongest significant association was observed between osteomyelitis and pain. There was no significant association between fatigue and these manifestations. Clinicians have to be aware of uncommon manifestations of chronic Q fever as they present with non-specific symptoms and are significantly associated with increased risk of morbidity and mortality. The findings emphasise the need to investigate patients with positive chronic Q fever serology presenting with acute or chronic pain for possible underlying complications.

Pathologic changes and immune responses against Coxiella burnetii in mice following infection via non-invasive intratracheal inoculation

Q fever is a worldwide zoonosis caused by Coxiella burnetii. Human Q fever is typically acquired through inhalation of contaminated aerosols, resulting in an initial pulmonary infection. In this study, BALB/c mice were infected with C. burnetii via an intratracheal (IT) route using a non-invasive aerosol pulmonary delivery device to directly place the living C. burnetii organisms into the lungs of the mice. The bacterial loads, pathological lesions, and antibody and cellular responses were analyzed and compared with those of mice infected via an intraperitoneal (IP) route. Compared with mice infected via an IP route, mice infected via an IT route exhibited a higher bacterial load and more severe pathological lesions in the heart and lungs at days 3 and 7 post-infection (pi). The levels of interferon-γ and IL-12p70 in the serum of mice infected via the IT route were significantly higher than those of mice infected via the IP route at day 3 pi. In conclusion, this murine model of acute C. burnetii infection via IT inoculation closely resembles the natural route of C. burnetii infection than that of IP injection. Thus, this newly developed model will be useful for investigating the pathogenesis and immunity of C. burnetii aerosol infection, as well as for the evaluation of therapeutic drugs and preventive vaccines of Q fever.

A rare case of Prosthetic Joint Infection associated with Coxiella burnetii

We report here the case of a Prosthetic Joint Infection (PJI) associated with Coxiella burnetii in a 62-year-old man with a revised total hip arthroplasty. The diagnosis was performed first by 16S rDNA sequencing on hip fluid aspirate, and confirmed by specific qPCR. Q fever has been reported in few cases of Prosthetic Joint Infections, often associated with chronic evolution and iterative surgeries. This case report alerts about such an unexpected diagnosis in a patient with no known risk factors.

Chronic Q Fever Infections in Israeli Children: A 25-year Nationwide Study

BACKGROUND

Q fever is a zoonosis caused by the bacterium Coxiella burnetii (C. burnetii) with a worldwide distribution. Our aim was to assess the epidemiology, clinical manifestations and treatment regimens of chronic Q fever infections in Israeli children during the past 25 years.

METHODS

Cases were collected from the national Q fever reference laboratory database. Demographic, epidemiologic and clinical data were reviewed using a structured questionnaire sent to the referring physician. Cases were defined according to the new Dutch Consensus Guidelines.

RESULTS

A total of 16 children originating from all regions of the country were found positive for chronic Q fever infections. The most common infection site was bone or joint (8/16, 50%), all in previously healthy children. Endovascular infections were found in 5 children (31%), all with an antecedent cardiac graft insertion. According to the new Consensus Guidelines, 9 children (56%) had a proven infection, 3 (19%) a probable infection and 4 (25%) a possible chronic Q fever infection. Almost all cases were treated with a long-term antibiotic regimen, often necessitating a change in medication because of persistent or rising titers.

CONCLUSIONS

Although pediatric chronic Q fever infections are rare, incidence has been rising. The most common infection site was bone or joint. A high index of suspicion is necessary, even in cases of previously healthy children without a possible exposure history. Use of the relatively new diagnostic tools in combination with serologic methods is helpful in diagnosing proven cases. There is no consensus as to the selection or duration of antibiotic treatment.

Coxiella burnetii Multilevel Disk Space Infection, Epidural Abscess, and Vertebral Osteomyelitis Secondary to Contiguous Spread From Infected Abdominal Aortic Aneurysm or Graft: Report of 4 Cases Acquired in the US and Review of the Literature

Background

Chronic Coxiella burnetii infections such as vertebral osteomyelitis caused by contiguous spread from an infected abdominal aortic graft or aneurysm have been rarely reported and are associated with significant morbidity and mortality.

Methods

We present the first four reported US acquired cases of Coxiella burnetii vertebral osteomyelitis caused by contiguous spread from an infected abdominal aortic graft or aneurysm.

Results

Presenting symptoms included progressive back pain, malaise, and weight loss with recent or remote animal exposure. Typical imaging findings demonstrated a peri-aortic collection with extension to the paraspinal muscles and vertebrae. Antibiotic regimens included doxycycline with either hydroxychloroquine or a quinolone for at least 2 years or as chronic suppression.

Conclusions

C. burnetii vertebral osteomyelitis is rare and can occur by contiguous spread from an abdominal aneurysm or vascular graft infection. It should be suspected in patients where pre-antibiotic cultures are negative with animal/farming exposure.

From Q Fever to Coxiella burnetii Infection: a Paradigm Change

Coxiella burnetii is the agent of Q fever, or "query fever," a zoonosis first described in Australia in 1937. Since this first description, knowledge about this pathogen and its associated infections has increased dramatically. We review here all the progress made over the last 20 years on this topic. C. burnetii is classically a strict intracellular, Gram-negative bacterium. However, a major step in the characterization of this pathogen was achieved by the establishment of its axenic culture. C. burnetii infects a wide range of animals, from arthropods to humans. The genetic determinants of virulence are now better known, thanks to the achievement of determining the genome sequences of several strains of this species and comparative genomic analyses. Q fever can be found worldwide, but the epidemiological features of this disease vary according to the geographic area considered, including situations where it is endemic or hyperendemic, and the occurrence of large epidemic outbreaks. In recent years, a major breakthrough in the understanding of the natural history of human infection with C. burnetii was the breaking of the old dichotomy between "acute" and "chronic" Q fever. The clinical presentation of C. burnetii infection depends on both the virulence of the infecting C. burnetii strain and specific risks factors in the infected patient. Moreover, no persistent infection can exist without a focus of infection. This paradigm change should allow better diagnosis and management of primary infection and long-term complications in patients with C. burnetii infection.

Chronic Recurrent Multifocal Q Fever Osteomyelitis in Children: An Emerging Clinical Challenge

BACKGROUND

Clinical disease caused by Coxiella burnetii occurs infrequently in children. Chronic Q fever is particularly uncommon and endocarditis is rarely seen. A small number of cases of Q fever osteomyelitis have been described but the pathophysiology is not well understood and optimal treatment is unknown.

METHODS

We describe a series of cases of chronic recurrent multifocal Q fever osteomyelitis cases diagnosed in children from a single region in Australia.

RESULTS

Between 2011 and 2014, 9 cases of chronic recurrent multifocal Q fever osteomyelitis were diagnosed based on clinical findings, suggestive serology and detection of C. burnetii DNA by polymerase chain reaction testing of biopsy samples (8/9). All required surgical management; antibiotic and adjuvant therapies did not appear to be consistently effective and 2 cases had clinical resolution in the absence of directed antimicrobial therapy.

CONCLUSIONS

Chronic recurrent multifocal osteomyelitis is a rare manifestation of chronic Q fever infection in children. The pathophysiology of this condition is poorly understood, and effective treatment options have not been established.

18F-FDG PET/CT as a central tool in the shift from chronic Q fever to Coxiella burnetii persistent focalized infection: A consecutive case series

Because Q fever is mostly diagnosed serologically, localizing a persistent focus of Coxiella burnetii infection can be challenging. F-fluorodeoxyglucose positron emission tomography/computed tomography (F-FDG PET/CT) could be an interesting tool in this context.We performed a retrospective study on patients diagnosed with C burnetii infection, who had undergone F-FDG PET/CT between 2009 and 2015. When positive F-FDG PET/CT results were obtained, we tried to determine if it changed the previous diagnosis by discovering or confirming a suspected focus of C burnetii infection.One hundred sixty-seven patients benefited from F-FDG PET/CT. The most frequent clinical subgroup before F-FDG PET/CT was patients with no identified focus of infection, despite high IgG1 serological titers (34%). For 59% (n = 99) of patients, a hypermetabolic focus was identified. For 62 patients (62.6%), the positive F-FDG PET/CT allowed the diagnosis to be changed. For 24 of them, (38.7%), a previously unsuspected focus of infection was discovered. Forty-two (42%) positive patients had more than 1 hypermetabolic focus. We observed 21 valvular foci, 34 vascular foci, and a high proportion of osteoarticular localizations (n = 21). We also observed lymphadenitis (n = 27), bone marrow hypermetabolism (n = 11), and 9 pulmonary localizations.We confirmed thatF-FDG PET/CT is a central tool in the diagnosis of C burnetii focalized persistent infection. We proposed new diagnostic scores for 2 main clinical entities identified using F-FDG PET/CT: osteoarticular persistent infections and lymphadenitis.

Endemic Q Fever in New South Wales, Australia: A Case Series (2005-2013)

Q fever is endemic in Australia, and during the period 2005-2013 our laboratory diagnosed 379 cases in New South Wales. To evaluate clinical symptoms, epidemiology, mode of diagnosis, antibody profiles, and treatment, a subset of 160 (42%) Q fever cases were analyzed in detail following the return of a questionnaire by the patient's doctor and from their laboratory reports. Overall, 82% patients were male and predominantly middle aged. The majority of patients (89%) had animal contact among which 63% were with cattle, 11% with sheep, and 7% with kangaroos. Clinical symptoms were nonspecific: myalgia (94%), fever (91%), headache (80%), acute fatigue (64%), and arthralgia (55%). Most cases (93%) were acute, and serology (immunofluorescence) was the main diagnostic modality. Positive real-time polymerase chain reaction results were useful in the diagnosis of both acute and chronic Q fever, as was the isolation of Coxiella burnetii in cell culture. Doxycycline was the antibiotic most commonly used.

Subacute, tetracycline-responsive, granulomatous osteomyelitis in an adult man, consistent with Q fever infection

Osteomyelitis due to Coxiella burnetii infection is a rare condition in adults. We report the case of a healthy young man presenting with subacute osteomyelitis of the left cheek bone, evolving gradually after an episode of acute febrile illness. Histological evaluation confirmed subacute granulomatous inflammation. Despite antibody titres not reaching the standard cut-off for chronic Q fever (phase I IgG 1/160, phase II IgG 1/2560), osteomyelitis was radiologically and histologically confirmed. A 6-month course of doxycycline/hydroxychloroquine brought clinical and radiological cure while various conventional antibiotic treatments had failed to improve the clinical condition. Currently, at 6-month follow-up, no relapse has occurred and antibody titres have declined. A shorter course of doxycycline/hydroxychloroquine than that used for chronic Q fever osteomyelitis may be sufficient to treat subacute Q fever osteomyelitis in some cases.

A Case of Pediatric Q Fever Osteomyelitis Managed Without Antibiotics

Q fever osteomyelitis, caused by infection with Coxiella burnetti, is rare but should be included in the differential diagnosis of children with culture-negative osteomyelitis, particularly if there is a history of contact with farm animals, and/or granulomatous change on histologic examination of a bone biopsy specimen. We describe a case of Q fever osteomyelitis in a 6-year-old boy in which a decision was made not to treat the patient with combination antimicrobial agents, balancing possible risks of recurrence against potential side effects of prolonged antibiotic treatment. The patient had undergone surgical debridement of a single lesion and was completely asymptomatic after recovery from surgery. This case suggests that a conservative approach of watchful waiting in an asymptomatic patient with chronic Q fever osteomyelitis may be warranted in select cases when close follow-up is possible.

Q Fever Chronic Osteomyelitis in Two Children

We report 2 cases of chronic Q fever osteomyelitis in 10- and 5-year-old girls who presented with distal right femoral and left parasternal granulomatous osteomyelitis, respectively. Both were treated with ciprofloxacin and rifampin with good response. Q fever osteomyelitis is a challenging diagnosis in children, and the choice of antimicrobial treatment is difficult because of limited available data.

A Rare Case of Q Fever Osteomyelitis in a Child From Regional Australia

Q fever osteomyelitis is a rare disease. We report an eighth pediatric case from regional Australia. Serology is the first-line diagnostic test, with confirmation by PCR on tissue specimens. In endemic settings, Q fever should be considered in the differential diagnosis of chronic osteomyelitis; in particular, presumed chronic-recurrent multifocal osteomyelitis should be considered a possible presentation of Q fever osteo-articular disease in children.

Pediatric acute Q fever mimics other common childhood illnesses

Knowledge of Q fever has increased over the last decades, but research has mainly focused on adults. Data in children are scarce, and current knowledge is mostly based on case reports. The aim of this study was to determine predictors for acute Q fever in children in the general population. We retrospectively studied all children tested for Coxiella burnetii by serology and/or PCR upon request of their general practitioner in the regional laboratory for Medical Microbiology of the Jeroen Bosch during the Q fever outbreak in the Netherlands between 2007 and 2011. A total of 1061 patients was analyzed. Influenza-like illness and respiratory tract infection were the most common presentations of acute Q fever, mimicking other common childhood illnesses. None of the reported symptoms was significantly related to a positive test outcome and therefore presenting signs or symptoms have no predictive value in diagnosing Q-fever in children. Only diagnostic tests are reliable. As the infection generally follows a mild and uncomplicated course, we question if the difficulty of recognizing pediatric Q fever is a problem worth solving.

A case of Q fever prosthetic joint infection and description of an assay for detection of Coxiella burnetii

We present the first published case of Coxiella burnetii prosthetic joint infection. Diagnosis was established with PCR and culture of periprosthetic tissue and synovial fluid (and serology). A novel PCR assay is described herein. Q fever should be considered in patients with prosthetic joint infection without an identified pathogen.

Q Fever endocarditis: does serology predict outcome?

Q fever is an ubiquitous zoonosis caused by Coxiella burneti, an intracellular bacterium that can produce acute or chronic infections in humans. These forms are characterized by different evolution, serological profile and treatment that must be very long to achieve a cure in chronic forms. However, the serological profile for diagnosis and the real value of serology for predicting outcome are controversial, and management dilemmas for many patients with Q fever infection are continuously emerging. In this article, we describe in a comprehensive manner the different clinical presentations of the disease, making a critical overview of the evidence for serological predictions. We also take a broad view of new available diagnostic techniques and finally, we give recommendations for treatment.

Q fever as a cause of recurrent soft-tissue nodules and abscesses in a child

A 3-year-old boy from a cattle property in Queensland, Australia developed chronic, multifocal, recurrent subcutaneous nodules and abscesses during a period of 2 years. Serologic and histologic findings and management options are discussed.

Q fever osteomyelitis: a case report and literature review

Q fever is a worldwide zoonosis caused by Coxiella burnetii. The clinical manifestations of Q fever include endocarditis, pneumonitis and hepatitis. Disease awareness and evolving diagnostic tests have enabled the recognition of unusual manifestations of Q fever. We report a case of Q fever osteomyelitis. A 51-year-old patient was admitted to hospital because of fever, leg weakness, and asthenia. His past medical history included surgery and a bone graft for the treatment of a giant cell tumor on the distal part of the femur. Blood and bone biopsy cultures were negative. Bone histological examination was consistent with a sub-acute or chronic inflammatory reaction that involved foci of epithelioid and gigantocellular infiltrates and necrosis. Serology testing revealed high antibody titers to C. burnetii antigens (phase I: IgG 3200; IgA 200; phase II: IgG 6400; IgA 400), which is indicative of chronic Q fever. The specific Polymerase Chain Reaction (PCR) of the abscess sample from the femoral region was positive for C. burnetii. The patient was treated for chronic Q fever with doxycycline and hydroxychloroquine for 18 months and recovered gradually without recurrence of pain or functional impairment. Q fever osteomyelitis is a rare and most likely underestimated disease. Epithelioid and gigantocellular granulomatous osteomyelitis in the context of culture-negative bone specimens should raise suspicion of Q fever. Serological tests, specific PCR and cell culture can provide evidence of a C. burnetii infection. Although bone diffusion may be a concern, the currently recommended treatment for Q fever was effective in this case.

Chronic multifocal osteomyelitis: is infectious causation a moot point?

Chronic multifocal osteomyelitis (CMO) is an uncommon disease entity with descriptions possibly emanating from the medical literature over one century ago, and there are numerous disease entities which have been historically detailed and which are probably synonymous. The illness is one of chronicity with exacerbating and remitting focal bony lesions. The differential diagnosis for a bony lesion which ultimately proves to be CMO is initially quite broad. There is no absolute pathognomonic clinical finding, and the diagnosis is highly dependent on clinical course, histopathology, and an absence of microbial infection. Recent studies have focused on immune dysfunction or dysregulation, and there are now many other diseases which are inflammatory in nature and which have been diagnosed among patients with CMO. Despite the aforementioned, the potential for direct infectious causation or indirect causation by infectious stimulation of immunity cannot be entirely excluded. Infection as a mechanism for pathogenesis must continue to be entertained. Multi-centre studies are key to future research.

Successful management of chronic multifocal Q fever Osteomyelitis with adjuvant interferon-gamma therapy

We present a 3-year-old girl who had chronic recurrent multifocal osteomyelitis caused by Coxiella burnetii despite long-term dual antibiotic therapy. Excellent clinical response was achieved and sustained when immunomodulatory therapy with interferon-γ was initiated. This is the case of a first child who was successfully treated with interferon-γ as adjuvant therapy for chronic multifocal Q fever osteomyelitis.

Q fever osteoarticular infection: four new cases and a review of the literature

Q fever is a worldwide-occurring zoonosis caused by Coxiella burnetii. Better knowledge of the disease and of evolving diagnostics can enable recognition of unusual manifestations. Reported here are four cases of Q fever osteoarticular infections in adults: two cases of Q fever tenosynovitis, which represent the first two reports of this infection, and two cases of Q fever spondylodiscitis complicated by paravertebral abscess. In addition, the literature is reviewed on the 15 previously reported cases of Q fever osteoarticular infection, six of which were vertebral infections. Osteomyelitis is the usual manifestation Q fever osteoarticular infection. Because its onset is frequently insidious, diagnosis is usually delayed. The main differential diagnosis is mycobacterial infection, based on the histological granulomatous presentation of lesions. Whereas serology is the reference diagnostic method for Q fever, detection of C. burnetii in tissue specimens by PCR and cell culture provides useful additional evidence of infection. Culture-negative osteoarticular samples with granulomatous presentation upon histological examination should raise suspicion of Q fever.

Clinical manifestations of Q fever in adults and children

Q fever is a common zoonosis with almost a worldwide distribution caused by Coxiella burnetii. Farm animals and pets are the main reservoirs of infection and transmission to humans is usually via inhalation of contaminated aerosols, which may be carried by the wind far from the original source of infection. Occupational groups with close association with farm or wild animals are most at risk, however travellers occasionally become infected. The disease is associated with a wide spectrum of clinical manifestations and symptoms, ranging from asymptomatic infection to fatal disease. Awareness of the disease and newer diagnostic methods led to increase of recognition and detection in cases with various or multiple symptoms in adults and children. However, children seem to be less frequently symptomatic and may have milder disease. This review of Q fever cases examines clinical manifestations and symptoms of Q fever in both adults and children and shows that certain symptoms and their severity have altered presentation in children with acute and chronic Q fever when compared to adults.

Clinical and pathologic changes in a guinea pig aerosol challenge model of acute Q fever

Acute Q fever is a zoonotic disease caused by the obligate intracellular bacterium Coxiella burnetii and can manifest as a flu-like illness, pneumonia, or hepatitis. A need exists in Q fever research for animal models mimicking both the typical route of infection (inhalation) and the clinical illness seen in human cases of Q fever. A guinea pig aerosol challenge model was developed using C. burnetii Nine Mile phase I (RSA 493), administered using a specialized chamber designed to deliver droplet nuclei directly to the alveolar spaces. Guinea pigs were given 10(1) to 10(6) organisms and evaluated for 28 days postinfection. Clinical signs included fever, weight loss, respiratory difficulty, and death, with the degree and duration of response corresponding to the dose of organism delivered. Histopathologic evaluation of the lungs of animals infected with a high dose showed coalescing panleukocytic bronchointerstitial pneumonia at 7 days postinfection that resolved to multifocal lymphohistiocytic interstitial pneumonia by 28 days. Guinea pigs receiving a killed whole-cell vaccine prior to challenge with the highest dose of C. burnetii were protected against lethal infection and did not develop fever. Clinical signs and pathological changes noted for these guinea pigs were comparable to those seen in human acute Q fever, making this an accurate and valuable animal model of human disease.

Clinicopathologic aspects of animal and zoonotic diseases of bioterrorism

We live in an era of emerging infectious diseases and the threat of bioterrorism. Most of the infectious agents of modern concern, from plague to avian influenza H5N1, are zoonotic diseases: infectious agents that reside in quiet animal reservoir cycles that are transmitted occasionally to humans. The public health, health care, and veterinary communities have an enormous challenge in the early recognition, reporting, treatment, and prevention of zoonotic diseases. An intimate understanding of the natural ecology, geographic distribution, clinical signs, lesions, and diagnosis of these diseases is essential for the early recognition and control of these diseases.

Q fever

Q fever is a zoonosis with many manifestations. The most common clinical presentation is an influenza-like illness with varying degrees of pneumonia and hepatitis. Although acute disease is usually self-limiting, people do occasionally die from this condition. Endocarditis is the most frequent chronic presentation. Although Q fever is widespread, practitioner awareness and clinical manifestations vary from region to region. Geographically limited studies suggest that chronic fatigue syndrome and cardiovascular disease are long-term sequelae. An effective whole-cell vaccine is licensed in Australia. Live and acellular vaccines have also been studied, but are not currently licensed.