Q fever in children

Q fever is a zoonosis caused by Coxiella burnetii. Farm animals and pets are the main reservoirs of infection, and transmission to human beings is mainly accomplished through inhalation of contaminated aerosols. This illness is associated with a wide clinical spectrum, from asymptomatic or mildly symptomatic seroconversion to fatal disease. Q fever in children has been rarely reported. We reviewed published work on this topic. Seroepidemiological studies show that children are frequently exposed to C burnetii. However, children are less frequently symptomatic than adults following infection, and may have milder diseases. Using the standard diagnostic criteria, we identified 46 published paediatric cases only. Self-limited febrile illness and pneumonia were the most common manifestations of acute Q fever. Chronic disease manifested as endocarditis and osteomyelitis. A history of exposure to possible sources of infection with C burnetii in a child with a compatible infectious syndrome should prompt testing for Q fever. Studies are required to determine the spectrum of morbidity associated with Q fever during childhood.     

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.     

Q fever

Q fever is a worldwide zoonosis caused by the pathogen Coxiella burnetii causing acute and chronic clinical manifestations. The name "Q fever" derives from "Query fever" and was given in 1935 following an outbreak of febrile illness in an abattoir in Queensland, Australia. C burnetii is considered a potential agent of bioterrorism (class B by the Centers for Disease Control).     

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.     

Q fever

An outbreak of Q fever occurred in Scotland during this summer and was reported in news headlines. Despite these newsworthy headlines, Q fever remains poorly understood. The causative organism, Coxiella burnetii, has a worldwide distribution, with the notable exception of New Zealand. Even with its ubiquitous nature, Q fever is rarely reported. We explore some of the underlying reasons for this apparent under diagnosis together with some of the diagnostic challenges posed by this obligate intracellular pathogen. The host range for this microbe spans arthropods, through to birds and a diverse range of mammals including livestock, companion animals and man. In most, infection remains sub-clinical, however, in some, infection can cause severe and life-threatening complications. Furthermore, possible long-term persistence within those infected, may result in long-term sequelae disassociated from initial risk factors or acute clinical presentation. We review current thinking on C. burnetii, and identify some of our current knowledge gaps.     

Q fever in Europe

In order to give a European overview, members of the editorial board of Eurosurveillancewere asked a few questions about the surveillance of Q fever in the countries they represent and the possible occurrence of similar outbreaks in recent years. We rece     

Q fever endocarditis

Q fever endocarditis, which is seen most often in Great Britain and Australia, has been rarely observed in the United States. A patient with an eight month febrile illness who had signs and symptoms of endocarditis and serologic studies diagnostic of Q fever endocarditis is reported. A history of extensive travel makes it unclear where he originally contracted the disease. Q fever endocarditis is probably underdiagnosed and should be looked for in any case of culture negative endocarditis or chronic fever of unknown origin.     

Q fever encephalitis

Encephalitis is a rare but documented complication of acute Q fever. We report here the case of a 48-year-old lady who presented with an acute illness characterised by influenza-like symptoms, pneumonia and neurological disturbance but in whom the serology was suggestive of chronic rather than acute Q fever.     

Q fever pneumonia

Pneumonia is one of several clinical syndromes that results from inhalation of Coxiella burnetii. This microorganism, the etiologic agent of "Q" (query) fever, infects a wide range of animals and insects. Cattle, sheep, goats, and cats are the reservoirs whereby this agent is spread to humans. High concentrations of C burnetii are present in the placenta and at parturition, the organism is shed into the environment to be inhaled by humans. Following an incubation period that ranges from four to 30 days (mean 14 days), fever, headache, malaise, and cough ensue. The clinical presentation of pneumonia may range from a mild to a severe illness--the latter with the clinical picture of rapidly progressive pneumonia. There are no characteristic features of Q fever pneumonia but the severe headache and the epidemiological history should serve as clues. Treatment with tetracycline or rifampin for two weeks usually results in cure. Many cases of Q fever pneumonia remit without antibiotic therapy. The diagnosis is usually confirmed serologically using a complement fixation or microimmunofluorescence test.     

Q fever endocarditis

Despite a worldwide distribution of Coxiella burnetii, only single cases of Q fever endocarditis have been reported outside Great Britain and Australia. We present 10 patients; five were female, only four had a history of environmental exposure, and the mitral valve was involved as commonly as the aortic valve. One patient had congenital aortic stenosis, and three patients had a prosthetic valve. We confirm the importance of hepatic involvement, thrombocytopenia and hypergammaglobulinemia as diagnostic features. Diagnosis was established by finding an elevated complement-fixing antibody to Phase I C. burnetii antigen. Tetracycline, with or without lincomycin or cotrimoxazole, was used in nine patients, and one patient received cotrimoxazole as the sole antibiotic agent. Optimal duration of therapy is unknown. In one patient, relapse followed when treatment was stopped after 18 months. Valve replacement was necessary in five patients, because of hemodynamic problems. Five patients died, and the mean survival is 36 months with a range of five to 66 months. We suggest that Q fever endocarditis is frequently missed, and we recommend clinicians to consider the diagnosis in all cases of culture-negative endocarditis.     

Q fever pneumonia

PURPOSE OF REVIEW: In this era of emerging infectious diseases and bioterrorism it is important to be up to date with the diagnosis and management of Q fever pneumonia. RECENT FINDINGS: A considerable amount of new information has emerged regarding the pathogenesis of Coxiella burnetii infection. The complete genome of this microorganism has now been sequenced and there are several unique features. The spectrum of manifestations of infection due to C. burnetii continues to expand. Some of the more recently described findings are acalculous cholecystitis, rhabdomyolysis, long-term persistence of Coxiella, post Q fever fatigue syndrome, and hemolytic uremic syndrome. Pneumonia as a manifestation of acute Q fever shows tremendous geographic variation, being common in one area of a country such as Spain but not in another area. SUMMARY: Pneumonia continues to be an important manifestation of infection with C. burnetii. It responds to treatment with doxycycline, quinolones or macrolides.     

Q热疫苗研究

Q热(Q fever)为一种世界性分布的重要人兽共患病,疫苗接种是预防Q热的最有效手段。专性细胞内寄生的贝氏柯克斯体是Q热的病原体,灭活I相贝氏柯克斯体Q热疫苗(WCV)免疫保护效能几乎为100%,但是其免疫副反应强。氯仿-甲醇提取贝氏柯克斯体(CMR)和三氯醋酸提取贝氏柯克斯体可溶性抗原(TCA)Q热疫苗保留灭活Q热疫苗的免疫保护效能,且免疫副反应显著减轻。但CMR和TCA Q热疫苗均需要用鸡胚大量培养贝氏柯克斯体,需要在高等级生物防护实验室采用复杂步骤提取、纯化贝氏柯克斯体,这些使Q热疫苗的生产成本高、批量生产难。近十年来,国内外Q热疫苗研究着力于分子疫苗,并已经由研究贝氏柯克斯体保护性抗原转移到筛选能诱导特异性细胞免疫应答的CD4⁺和CD8⁺T细胞表位上,以期望T细胞表位在机体内高效表达,诱导机体产生良好的抗Q热保护性免疫应答。     

Cellular immunity in Q fever: specific lymphocyte unresponsiveness in Q fever endocarditis

Human infection with the rickettsia Coxiella burnetii presents as acute influenza-like primary Q fever, subacute granulomatous hepatitis, or chronic endocarditis with hepatitis. To investigate whether persistent infection is associated with a possible immunologic defect, we tested lymphocyte proliferation specific for Coxiella in vitro in peripheral blood mononuclear cells from patients and controls. All four patients with endocarditis had profound lymphocyte unresponsiveness to Coxiella antigens with normal proliferation to control antigens. Hepatitis and primary Q fever were associated with vigorous responses in vitro to Coxiella antigens. Suppression of lymphocyte unresponsiveness was in part mediated by an antigen-nonspecific, glass-adherent cell. We hypothesize that specific T cell unresponsiveness is an important factor in persistent infection with C. burnetii and offer in vitro lymphocyte stimulation as a more specific diagnostic test to distinguish cases of endocarditis among those with chronic hepatitis due to Q fever.