A cluster of Coxiella burnetii infections associated with exposure to vaccinated goats and their unpasteurized dairy products.

An outbreak of Q fever occurred among patients and staff of a psychiatric institution in southern France. Some of the patients and staff left the institution daily to work on a farm where goats were raised for raw milk and cheese production. The goats had all been vaccinated annually with a commercial vaccine containing phase II Coxiella burnetii antigen. A serologic survey revealed that 40 (66%) of the 61 patients and staff had elevated titers to C. burnetii. Seropositive persons were more likely to report an acute illness (P = 0.001), fever (P = 0.04), weakness (P = 0.04), arthralgia (P = 0.04), and headaches (P = 0.06) in the preceding year than were seronegative persons. Seropositivity rates were significantly higher among persons who worked on the farm and consumed unpasteurized milk products (69% [22 of 32]; P = 0.007), those who only had worked on the farm (75% [9 of 12]; P = 0.009), and those who only had consumed unpasteurized milk products (75% [9 of 12]; P = 0.009), compared with those who had not worked with the goats or consumed unpasteurized milk products (0 of 5). Despite vaccination against Q fever, no antibodies to C. burnetii were detectable in 17 (59%) of 29 goats. All 12 seropositive goats had antibodies to both phase I and phase II antigens, indicating that they were naturally infected, and two of three goats examined were shedding C. burnetii in their milk. Vaccination of this herd did not prevent the outbreak and might have increased shedding of C. burnetii in the dairy products.     

Virulent Coxiella burnetii does not activate human dendritic cells: role of lipopolysaccharide as a shielding molecule

Coxiella burnetii is an obligate intracellular bacterium and the etiological agent of the zoonotic disease Q fever. Acute human Q fever is characterized by flu-like symptoms that, in some cases, can result in a persistent infection that may reactivate months or years after initial exposure. Mechanisms by which this obligate parasite evades clearance by the host immune response during persistent infection are unknown. Here, we characterized the interaction of C. burnetii with dendritic cells (DC), critical components of both innate and adaptive immunity. Human DC were infected with two isogenic C. burnetii strains that differ in LPS length. Infection by the Nine Mile phase I (NMI) strain, which is fully virulent and produces full-length LPS, did not result in DC maturation. In contrast, infection by the avirulent Nine Mile phase II strain, producing a severely truncated LPS, resulted in toll-like receptor 4-independent DC maturation and approximately 10-fold more IL-12 and TNF production. NMI did not actively inhibit DC maturation as NMI-infected DC subsequently matured if treated with Escherichia coli LPS or Nine Mile phase II. Furthermore, removal of LPS from NMI dramatically increased its ability to stimulate DC. We propose a model whereby LPS of virulent C. burnetii masks toll-like receptor ligands from innate immune recognition by DC, thereby allowing replication without significant maturation or inflammatory cytokine production. This immune evasion strategy may allow C. burnetii to persist in an immunocompetent host.     

Virulence of pathogenic Coxiella burnetii strains after growth in the absence of host cells

Coxiella burnetii is a gram-negative bacterium that causes the zoonotic disease Q fever. Traditionally considered an obligate intracellular agent, the requirement to be grown in tissue culture cells, embryonated eggs, or animal hosts has made it difficult to isolate strains and perform genetic studies on C. burnetii. However, it was recently demonstrated that the attenuated Nine Mile Phase 2 (NM2) C. burnetii strain will grow axenically in acidified citrate cysteine medium (ACCM) in a 2.5% oxygen environment. The current study was undertaken to determine whether more virulent C. burnetii strains could be grown in ACCM, and whether virulence would be maintained after passage. The ACCM medium supported an ?1000-fold expansion of Nine Mile Phase 1 (NM1), NM2, M44, and Henzerling strains of C. burnetii, whereas the Priscilla (Q177) strain expanded only 100-fold, and the K strain (Q154) grew poorly in ACCM. To determine if passage in ACCM would maintain the virulence of C. burnetii, the NM1 strain was grown for up to 26 weekly passages in ACCM. C. burnetii maintained in ACCM for 5 or 8 passages maintained full virulence in a mouse model, but NM1 passaged for 23 or 26 times was somewhat attenuated. These data demonstrate that virulent strains of C. burnetii can be successfully passaged in ACCM; however, some strains can lose virulence after extended passage, and other strains grow poorly in this medium. The loss of virulence in axenic culture was associated with some truncation of lipopolysaccharide chains, suggesting a possible mechanism for attenuation.     

Natural history of Q fever in goats

During the spring of 1999, an outbreak of Q fever resulted in 30 abortions among 174 (17%) goats in a caprine cooperative in Newfoundland. The intent of this study was to determine the natural history of Coxiella burnetii infection in goats. Twenty-four goats on one farm were followed through the next two kidding seasons following the Q fever outbreak. Antibodies to phases I and II C. burnetii were determined using an indirect immunofluorescence assay and samples of placentas were cultured for C. burnetii and polymerase chain reaction was used to identify C. burnetii DNA. Phase I antibody was present in high levels and was maintained over the study period, while phase II antibody levels declined to the seronegative range in 60% of the infected goats. Molecular studies suggest that excretion of C. burnetii in the placenta of infected goats seems to be limited to the next kidding season following an outbreak. We therefore conclude that C. burnetii infection in goats seems to be limited to two kidding seasons. Phase I antibody levels are maintained, while phase II antibody levels decline.     

Isolation of Coxiella burnetii by a centrifugation shell-vial assay from ticks collected in Cyprus: detection by nested polymerase chain reaction (PCR) and by PCR-restriction fragment length polymorphism analyses

Ticks are the principal vectors and reservoirs of Coxiella burnetii. The identification of isolates is necessary for understanding the clinical diversity of Q fever in different geographic areas. This is the first report of isolation of C. burnetii from ticks by the shell-vial assay and by nested polymerase chain reaction (PCR) assay for the detection of this pathogen in ticks. Of 141 ticks collected in Cyprus (Rhipicephalus sanguineus and Hyalloma spp.), 10% were found to be infected with C. burnetii. Three ticks were positive by hemolymph test, and 11 triturated ticks were positive by nested PCR. Three isolates were obtained by the centrifugation shell-vial technique. Analysis by PCR, then restriction fragment length polymorphism showed that the 3 Cyprus isolates had identical restriction profiles to reference strains Nine Mile and Q212. The methods described are useful in studying the epidemiology and ecology of C. burnetii.     

Q fever in humans and animals in the United States

Coxiella burnetii, the etiologic agent of Q fever, is a worldwide zoonotic pathogen. Although Q fever is present in the United States, little is known about its current incidence or geographic distribution in either humans or animals. Published reports of national disease surveillance, individual cases, outbreak investigations, and serologic surveys were reviewed to better characterize Q fever epidemiology in the United States. In national disease surveillance reports for 1948-1986, 1,396 human cases were reported from almost every state. Among published individual case reports and outbreak investigations, occupational exposures (research facilities, farm environments, slaughterhouses) were commonly reported, and sheep were most frequently implicated as a possible source of infection. In studies conducted on specific groups, livestock handlers had a significantly higher prevalence of antibodies to C. burnetii than did persons with no known risk. Animal studies showed wide variation in seroprevalence, with goats having a significantly higher average seroprevalence (41.6%) than sheep (16.5%) or cattle (3.4%). Evidence of antibody to C. burnetii was reported among various wild-animal species, including coyotes, foxes, rodents, skunks, raccoons, rabbits, deer, and birds. This literature review suggests that C. burnetii is enzootic among ruminants and wild animals throughout much of the United States and that there is widespread human exposure to this pathogen. Sheep and goats appear to be a more important risk for human infection in the United States than cattle or wild animals, and research studies examining the natural history and transmission risk of Q fever in sheep and goats in this country should be encouraged.     

Q fever endocarditis in the United States.

A patient with Q fever endocarditis, which is almost unknown in the United States, was followed for a total of 32 months; the study was begun 3 1/2 months before aortic valve replacement. Diagnosis was confirmed by serology, visualization of Coxiella burnetii in excised aortic valve tissue by direct and immunofluorescence staining, and isolation of C. burnetii from aortic valve tissue. Serum antibodies against phase I and phase II antigens of C. burnetii were identified. Almost all phase I and phase II antibodies were IgG. These findings are compared with those in an uncomplicated case of acute Q fever. New findings on the immune response to chronic Q fever are presented.     

Outbreak of Q fever in Lohra-Rollshausen,Germany, spring 1996

Q fever is an acute (and sometimes chronic) febrile illness caused by the rickettsial organism Coxiella burnetii. The commonest animal reservoirs for C. burnetiiare cattle, sheep, and goats. Infected animals shed the organisms, which resist desiccation, i     

Pigeon pneumonia in provence: a bird-borne Q fever outbreak.

Q fever is a widespread zoonosis caused by Coxiella burnetii, an obligate intracellular bacterium, which humans usually acquire through the inhalation of infected dust from subclinically infected mammals. Human infection commonly takes place when an infected mammal gives birth, since high concentrations of the organism are found in the products of conception. Worldwide, cattle, sheep, and goats are the most common reservoirs for C. burnetii. A few investigators have also reported parturient cats and dogs as the sources of human outbreaks of Q fever. During a 10-day period in May 1996, all five members of one family living on a farm in Provence, in the south of France, became ill with fever, general malaise, and cough. All of them had acute Q fever. An epidemiological investigation suggested that this outbreak resulted from exposure to contaminated pigeon feces and ticks.     

Application of trichloroacetic acid-treated antigen for serodiagnosis of Q fever by indirect immunofluorescence technique]

It is well known that the etiologic agent, Coxiella burnetii, exhibits an antigenic phase variation (phase I to phase II), and the diagnostic significance of the relative antibody titers against phase I and phase II antigens is pointed out. Therefore both phase I and phase II antigens are necessary for the serological examination of Q fever. But it is not so easy to prepare and maintain the phase II antigen by the conventional method. In the present study we tried to prepare the phase II antigen for immunofluorescence test by chemical treatment of the phase I antigen. As a result, treatment of the TK-1 strain of C. burnetii (phase I) with 10% trichloroacetic acid for 4 hr at 4 degrees C modified the antigenicity. The modified antigen reacted strongly with anti-phase II antibody.     

Prevalence of Coxiella burnetii in Hungary: Screening of Dairy Cows, Sheep, Commercial Milk Samples, and Ticks

Abstract Q fever is an important zoonotic disease caused by Coxiella burnetii. There are few reliable data about C. burnetii infection available. The aim of this study was to assess the importance and potential infectious sources of Q fever in Hungary. A total of 215 milk samples (10 individual samples from each herd and 1 bulk tank milk sample from each cattle herd), and 400 serum samples (20 from each herd) were tested from 15 dairy cattle herds and 5 sheep flocks located in different parts of Hungary. The study found 19.3% (58/300) and 38.0% (57/150) seropositivity in cattle, and 0% (0/100) and 6.0% (3/50) seropositivity in sheep, by complement fixation test (CFT) and enzyme-linked immunosorbent assay (ELISA), respectively. C. burnetii DNA was detected by IS1111 element-based TaqMan real-time polymerase chain reaction (PCR) in 8.7% (13/150) of individual dairy cow milk samples, 4.0% (2/50) of individual sheep milk samples, and 66.7% (10/15) of dairy bulk tank milk samples. Samples taken from nine different commercially-available pasteurized cow milk products from different Hungarian producers were also tested for the presence of C. burnetii DNA, and eight of these samples were found to be positive (88.9%). The real-time PCR examination of 5402 ixodid ticks collected from different parts of the country yielded negative results. Knowledge of the true prevalence of Q fever is crucial for policymakers involved in evidence-based decision making.     

Q fever: current concepts

Persons with Q fever usually present with severe retrobulbar headache, a fever to 104 degrees F or higher with shaking chills, general malaise, myalgia, chest pain, and sometimes pneumonia and hepatitis. Cattle, sheep, goats, and ticks are the primary reservoirs of the etiologic agent, Coxiella burnetii. Humans are usually infected by inhaling infectious aerosols. Because C. burnetii can survive for long periods in the environment, it poses a continuing health hazard once it is disseminated. Q fever usually occurs sporadically, but large outbreaks are frequently observed throughout the world, particularly among abattoir workers and personnel working in research centers. Q fever endocarditis follows a chronic course and is frequently fatal. Tests for antibodies to C. burnetii are required for confirmation of the diagnosis. Tetracyclines remain the mainstay of treatment for acute Q fever, and tetracyclines in combination with other antibiotics have been advocated for patients with Q fever endocarditis. Vaccines for Q fever have been proven effective in clinical trials.     

Outbreak of Q fever associated with a horse-boarding ranch, Colorado, 2005

Coxiella burnetii is a bacterium located worldwide that can cause Q fever when inhaled. We describe an outbreak of Q fever associated with a horse-boarding ranch that had acquired two herds of goats. We conducted case finding and cohort studies among persons who boarded horses on the ranch and ranchers and among residents in the surrounding community, and conducted sampling of the goats and environment, to determine risk factors for infection and guide public health interventions. Sixty-six ranchers and persons who boarded horses on the ranch were interviewed; 62 (94%) were not professional ranchers. Twenty persons (53%) of 38 persons tested had evidence of infection with C. burnetii. Contact with goats was associated with seropositivity, including having helped birth goats (relative risk [RR] 2.4, 95% confidence interval [CI] 1.6-3.6), having had contact with newborn goats (RR 2.3, CI 1.2-4.3), having vaccinated goats (RR 2.1, CI 1.3-3.5), having had contact with stillbirths or newborns that died (RR 2.1, CI 1.2-3.7), and having fed goats (RR 2.1, CI 1.0-4.3). Among 138 tested persons living within 1 mile of the ranch, 11 (8%) demonstrated evidence of C. burnetii infection; eight seropositive persons (73%) had no direct contact with the ranch. Testing of the soil and goats with an IS1111 polymerase chain reaction (PCR) assay confirmed the presence of C. burnetii among the herd and in the environment. This outbreak of Q fever was caused by exposure to infected goats, but exposure to the environment likely played a secondary role. Laypersons should not participate in the birthing process of goats; professionals who come into contact with birthing goats should be educated on reducing their infection risk. This is the first time an IS1111 PCR assay has been used in an outbreak investigation in the United States.     

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.     

Cynomolgus monkey model for experimental Q fever infection.

A subhuman primate model was developed for study of the pathogenesis of infection with Coxiella burnetii. Cynomolgus monkeys (Macaca fascicularis) that were exposed to 10(5) mouse median infectious intraperitoneal doses of C. burnetii in a small-particle aerosol developed clinical signs of illness and pathologic changes characteristic of Q fever infection in humans. All monkeys had radiologic evidence of pneumonia by day 9. Antibodies to C. burnetii were detectable by the indirect fluorescent antibody test by day 7. These data indicate that the cynomolgus monkey is a suitable model for study of the pathogenesis of Q fever infection and may prove valuable in the evaluation of C. burnetii vaccines.     

An outbreak of Q fever probably due to contact with a parturient cat

Thirty-three cases (24 definite, nine probable) of Q fever were diagnosed in Victoria County, Cape Breton, Nova Scotia from May to August, 1985. Twenty-six of the cases occurred in residents of Baddeck (population 900, attack rate 2.8 percent), and 21 of the cases occurred during the month of June. There was geographic clustering of the cases: 14 of the 33 (42 percent) lived or worked in four buildings located side by side in the center of town. A case control study revealed that 25 of 29 cases were exposed to a cat that gave birth to stillborn kittens on June 8, 1985 and had bled per vaginum for three weeks prior to delivery. The cat lived in one of the buildings where geographic clustering occurred and frequently visited the other buildings. None of the 40 control subjects was so exposed (p less than 0.001). This cat had an antibody titer of 1:512 to Coxiella burnetii phase 1 antigen and a titer of 1:1024 to phase 2 antigen. Exposure to cattle, sheep and goats, the traditional reservoirs of Q fever, was uncommon among patients and control subjects and none of eight cattle tested had antibodies to C burnetii phase I antigen. We conclude that the infected parturient cat was probably responsible for this outbreak of Q fever affecting 2.8 percent of the population of the town of Baddeck.     

Q fever in an American tourist returned from Australia

Q fever was diagnosed in a previously healthy man who had recently traveled to the East Coast of Australia. The patient experienced fever and headache accompanied by lymphopenia and elevated liver enzymes but not pneumonia. He had no known direct exposures to animals, exhibited IgM and IgG seroconversion to phase II antigen of Coxiella burnetii and IgM only to phase I antigen, and responded to doxycycline treatment. This case serves as a reminder to clinicians to consider Q fever in the differential diagnosis of acute febrile illness in travelers returning from endemic areas.     

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。     

Coxiella burnetii pneumonia.

This report reviews the pulmonary and extrapulmonary manifestation of infections due to Coxiella burnetii. Q fever, a zoonosis, is due to infection with C. burnetii. This spore-forming microorganism is a small gram-negative coccobacillus that is an obligate intracellular parasite. The most common animal reservoirs are goats, cattle, sheep, cats, and occasionally dogs. The organism reaches high concentrations in the placenta of infected animals. Aerosolisation occurs at the time of parturition and infection follows inhalation of this aerosol. There are three distinct clinical syndromes of the acute form of the illness: nonspecific febrile illness, pneumonia, and hepatitis. The chronic form of Q fever is almost always endocarditis, but occasionally it is manifest as hepatitis, osteomyelitis or endovascular infection. The pneumonic form of the illness can range from very mild-to-severe pneumonia requiring assisted ventilation. Multiple round opacities are a common finding on chest radiography. Treatment with doxycycline or a fluoroquinolone is preferred. Susceptibility to macrolides is variable. In conclusion, Coxiella burnetii pneumonia should be considered when there is a suitable exposure history and when outbreaks of a pneumonic illness are being investigated.     

Complete genome sequence of the Q-fever pathogen Coxiella burnetii

The 1,995,275-bp genome of Coxiella burnetii, Nine Mile phase I RSA493, a highly virulent zoonotic pathogen and category B bioterrorism agent, was sequenced by the random shotgun method. This bacterium is an obligate intracellular acidophile that is highly adapted for life within the eukaryotic phagolysosome. Genome analysis revealed many genes with potential roles in adhesion, invasion, intracellular trafficking, host-cell modulation, and detoxification. A previously uncharacterized 13-member family of ankyrin repeat-containing proteins is implicated in the pathogenesis of this organism. Although the lifestyle and parasitic strategies of C. burnetii resemble that of Rickettsiae and Chlamydiae, their genome architectures differ considerably in terms of presence of mobile elements, extent of genome reduction, metabolic capabilities, and transporter profiles. The presence of 83 pseudogenes displays an ongoing process of gene degradation. Unlike other obligate intracellular bacteria, 32 insertion sequences are found dispersed in the chromosome, indicating some plasticity in the C. burnetii genome. These analyses suggest that the obligate intracellular lifestyle of C. burnetii may be a relatively recent innovation.