Coxiella burnetii seroprevalence of shepherds and their flocks in the lower Saint-Lawrence River region of Quebec, Canada.

OBJECTIVE: To determine the seroprevalence of Coxiella burnetii among the shepherds and their sheep in the lower Saint-Lawrence River region (LSLRR) of Quebec, Canada. DESIGN: A prospective human-animal comparative study was conducted with 81 shepherds from 46 farms and a control group matched for sex and age. All participants answered a standardized questionnaire to evaluate their risk factors for Q fever, including a specific section on the work practices of the shepherds. All human subjects had a blood sample taken for serology to phase I and phase II antigens of C burnetii performed by indirect immunofluorescence assay. At each participating farm, seven to nine sheep had blood samples taken for C burnetii serology to be assessed by the complement fixation test. RESULTS: The seroprevalence to C burnetii was higher in the group of shepherds (28.4%) than the control group (1.2%) (P<0.005). Among the group of shepherds, spending more than 5 h/week in the sheep barn (P=0.06) and buying and/or trading sheep within the past six months (P=0.004) were associated with positive C burnetii serology. A total of 137 of 334 sheep (41%) were seropositive for C burnetii. These positive sheep were distributed in 41 of the 46 flocks (89%). No correlation could be demonstrated between a serology for C burnetii in the herds and the shepherds. CONCLUSION: Q fever is highly prevalent in the LSLRR of Quebec, affecting 89% of the flocks and 28% of the shepherds. Shepherds in this region are at increased risk for C burnetii infection in comparison to the general population.     

Epidemiology of Q fever in Sweden.

Q fever is known to be a worldwide disease, with Sweden supposed to be one of a few exceptions. The purpose of this pilot study was to elucidate whether or not a potential risk group for obtaining Q fever in Sweden was seropositive to the causative agent Coxiella burnetii. Blood samples were collected from sheep farmers on the island of Gotland, and from members of their families. Serum samples were examined by ELISA for the presence of antibodies against C. burnetii, phases I and II. Positive reactions were confirmed with Western blot analysis. It was found that 30% of the study group were seropositive to C. burnetii, thus indicating that Q fever is endemic in this area of Sweden.     

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.     

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.     

Tick-borne rickettsioses in Pune district, Maharashtra, India

An extensive study on tick-borne rickettsioses in the Pune district of Maharashtra revealed that Indian tick typhus exists as a zoonosis, which only occasionally causes disease in man. By sero-conversion in guinea pigs, presumptive isolates of Rickettsia conori and Coxiella burnetii were recovered from 4 of the 11 species of ticks examined. Boophilus microplus and Rhipicephalus haemaphysalis were found to be harbouring R. conori whereas C. burnetii was isolated from Haemaphysalis intermedia and Hyalomma hussaini in addition to the above mentioned 2 tick species. Complement fixation tests carried out on sera from various species of rodents and gerbils revealed the presence of antibodies against the R. conori antigen in the sera of Rattus blanfordi, R.r. rufescens and Suncus murinus. In the case of large mammals, similar antibodies were detected in the sera from dog, cow, horse and sheep. C. burnetii infection was found to exist in both the sylvan and domestic cycle, as evidenced from the involvement of ticks, large and small mammals and man in its natural history.     

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     

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.     

氯仿-甲醇提取贝氏柯克斯体残存组分Q热疫苗的免疫原性及免疫保护性研究

目的实验评价氯仿-甲醇提取贝氏柯克斯体残存组分(CMR)疫苗的免疫特性及免疫保护性。方法采用国内分离贝氏柯克斯体新桥株制备CMR疫苗,用CMR免疫Balb/c小鼠;采用间接免疫荧光法检测CMR免疫小鼠血清特异性抗体水平和用淋巴细胞增殖试验评价CMR疫苗体外刺激小鼠脾细胞增殖的能力;以贝氏柯克斯体攻击免疫小鼠和用贝氏柯克斯体特异的荧光定量PCR检测感染小鼠血和脾脏样本。结果CMR免疫第4周起,小鼠血清中检出高水平的特异性抗体,CMR加氢氧化铝佐剂免疫小鼠的血清特异性抗体显著高于未加佐剂组。CMR在体外刺激正常小鼠和免疫小鼠脾淋巴细胞增殖水平显著高于对照组,WCV则抑制正常脾淋巴细胞增殖。三种剂量(30μg、10μg、1μg/只)CMR免疫小鼠血和脾脏样本贝氏柯克斯体含量显著低于未免疫组,以30μg组及加佐剂免疫小鼠的样本含菌量更显著低于对照组。结论采用我国分离株制备的CMR疫苗能诱导机体产生高效特异性体液免疫和细胞免疫应答,使机体抵抗大剂量的贝氏柯克斯体感染,具有良好的免疫原性和免疫保护性;氢氧化铝佐剂能显著增强CMR疫苗的免疫保护效能。     

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.     

检测贝氏柯克斯体的实时荧光定量PCR

目的采用新型TaqMan-MGB探针建立检测贝氏柯克斯体的实时荧光定量PCR(real-timequantitativePCR)方法。方法根据贝氏柯克斯体特异的23SrRNA插入基因序列设计引物和探针,以克隆的23SrRNA插入基因片段作DNA模板,在荧光定量PCR检测仪(ABI7900型)上建立实时荧光定量检测方法。结果建立的定量标准曲线的循环阈值(Ct)与模板拷贝数呈良好的线性关系(r=0.997);与套式PCR相比较,荧光定量PCR检测敏感性是其100倍。用荧光定量PCR检测其它相关立克次体,检出结果均为0。用荧光定量PCR检测贝氏柯克斯体感染的小鼠脾脏标本,脾脏中贝氏柯克斯体的感染量与感染过程具有相关性。结论本研究建立的检测贝氏柯克斯体的实时荧光定量PCR具有很高的特异性和敏感性,特别适合样本中微量贝氏柯克斯体DNA的检测,其定量检测可用于动物实验中的贝氏柯克斯体感染程度的分析。     

Coxiella burnetii,the causative agent of Q fever in Saudi Arabia:molecular detection from camel and other domestic livestock

Objective:To detect Coxiella burnetii(C.burnetii)DNA in clinical specimens from camel,goats,cattle and sheep in the Kingdom of Saudi Arabia.Methods:A total of 367 clinical samples including blood,milk,faeces and urine were collected from different livestock and subjected to PCR amplification using primers which amplify transposon-like region and transposase gene.Results:Positive amplification from both regions was obtained from camel,goats and cattle but not from sheep.A percentage of 10.8%samples yielded positive PCR amplification from both blood and milk,where 15 of 139 blood and 16 of 148 milk samples were positive.Faeces and urine showed higher percentages of positive samples reaching 40.8%and 23.8%respectively.Conclusions:The preferred route of shedding in camel appeared to be the faeces followed by urine,while that of goats appeared to be the faeces and that of the cattle appeared to be the milk.     

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).     

Effect of sex on Coxiella burnetii infection: protective role of 17beta-estradiol

Q fever is a zoonosis caused by Coxiella burnetii and recently has been recognized as a potential agent of bioterrorism. In Q fever, men are symptomatic more often than women, despite equal seroprevalence. We hypothesized that sex hormones play a role in the pathogenesis of C. burnetii infection. When C57/BL6 mice were injected with C. burnetii, bacteria load and granuloma numbers were lower in females than in males. Ovarectomized mice showed increased bacteria load in the spleen and the liver, similar to that found in males. The granuloma number was also increased in ovarectomized mice and reached the levels found in males. Tissue infection and granulomatous response are largely under the control of estrogens: treatment of ovarectomized mice with 17beta-estradiol reduced both bacteria loads and granuloma numbers. These results show that sex hormones control host response to C. burnetii infection and may account for host-dependent clinical presentation of Q fever.     

Short report: seroprevalence of human infection by Coxiella burnetii in Barcelona (northeast of Spain)

Coxiella burnetii is the causal agent of Q fever, a worldwide-distributed zoonosis, which is endemic in Spain. C. burnetii has an extensive reservoir, including farm animals and pets. The aim of this study was to determine the seroprevalence of C. burnetii in humans in Vallés Occidental (Barcelona, northeast of Spain) and its possible related risk factors. The prevalence of phase II antibodies from 216 subjects was determined by indirect immunofluorescence assay (IFA). Age, sex, living place, occupation, and contact with animals were surveyed. A 15.3% seroprevalence was found (> or = 1/40), and 8.8% of samples had titers > or = 1/80. Seropositive cases were significantly higher in patients > 44 years of age. No statistically significant correlation was found between seropositivity and the remaining variables studied. Therefore, infection by C. burnetii seems to be endemic in our region, with a prevalence ranging from 9% to 15%, depending on the titers that are to be considered significant.     

Biochemical stratagem for obligate parasitism of eukaryotic cells by Coxiella burnetii.

Coxiella burnetti, the etiologic agent of Q fever, is an oligate intracellular parasite of eukaryotes. Unlike the majority of successful bacterial parasites, which escape the bactericidal environment of the phagolysosome by various means, C. burnetii multiplies only in the phagolysosome. In view of the relatively harsh environment inhabited by C. burnetii, we have examined (i) the in vitro metabolism of glucose and glutamate by whole cells of C. burnetii under conditions designed to approximate the pH within the phagolysosome and (ii) the effect of manipulation of the phagolysosomal pH by lysosomotropic amines on the replication of C. burnetii in chicken embryo fibroblasts. The transport, catabolism, and incorporation of both glucose and glutamate were found to be highly stimulated by acidic conditions, whereas at pH 7.0 metabolism of these substrates was minimal. The transport processes were shown to be energy dependent and highly sensitive to inhibition by uncouplers of oxidative phosphorylation. Increasing the phagolysosomal pH of infected chicken embryo fibroblasts by use of the lysosomotropic agents chloroquine, methylamine, or ammonium chloride inhibited the multiplication of C. burnetii, thus demonstrating the in vivo requirement for the acidic conditions of the phagolysosome. This apparent dependence upon phagosome--lysosome fusion to generate pH conditions favorable to C. burnetii replication suggests a unique biochemical mechanism of parasite activation. A pathogenic mechanism based on regulation of microbial metabolism by H+-dependent stimulation of cell function is proposed.     

Urban outbreak of Q fever,Briancon, France,March to June 1996

Q fever is an ubiquitous zoonosis caused by the rickettsial organism Coxiella burnetii. Both sporadic cases and epidemics occur in areas where sheep and goats are bred. The main route of transmission is by inhalation of aerosols from the environment (soil     

Coxiella burnetii antigen-stimulated dendritic cells mediated protection against Coxiella burnetii in BALB/c mice

Coxiella burnetii is the etiological agent of human Q fever. In this study, adaptive transfer of mouse bone marrow-derived dendritic cells (BMDCs) stimulated with C. burnetii antigen, phase I whole-cell antigen (PIAg), lipopolysaccharide (LPS)-removed PIAg (PIIAg), protein antigen Com1, or SecB significantly reduced coxiella burden in recipient mice compared with control mice. Mice that received PIIAg-pulsed BMDCs displayed substantially lower coxiella burden than recipient mice of PIAg-pulsed BMDCs after C burnetii challenge. The protection offered by the antigen-activated BMDCs was correlated with the increased proliferation of helper T (T(H)) T(H)1 CD4(+) cells, preferential development of T(H)17 cells, and impaired expansion of regulatory T lymphocytes. Our results suggest that PIIAg is far superior to PIAg in activating BMDCs to confer protection against C. burnetii in vivo, whereas Com1 and SecB are protective antigens because Com1- or SecB-pulsed BMDCs confer partial protection.     

宁夏回族自治区奶牛感染贝氏柯克斯体的血清流行病学调查

目的调查宁夏回族自治区奶牛感染贝氏柯克斯体状况。方法通过酶联免疫吸附试验(ELISA)检出奶牛血清贝氏柯克斯体抗体,总体阳性率为11.37%(103/906)。结果吴忠市和青铜峡市奶牛贝氏柯克斯体抗体阳性率分别为12.28%和10.44%;不同年龄组的抗体阳性率为9.86%至13.21%;未生育过的奶牛抗体阳性率最高为11.99%。结果显示地区、年龄和胎次均与贝氏柯克斯体感染无统计学差异(P0.05)。结论揭示了宁夏地奶牛贝氏柯克斯体感染普遍存在,对该地区人群健康构成潜在威胁。     

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.