Identification and Characterization of an HtrA Sheddase Produced by Coxiella burnetii

Having previously shown that soluble E-cadherin (sE-cad) is found in sera of Q fever patients and that infection of BeWo cells by C. burnetii leads to modulation of the E-cad/β-cat pathway, our purpose was to identify which sheddase(s) might catalyze the cleavage of E-cad. Here, we searched for a direct mechanism of cleavage initiated by the bacterium itself, assuming the possible synthesis of a sheddase encoded in the genome of C. burnetii or an indirect mechanism based on the activation of a human sheddase. Using a straightforward bioinformatics approach to scan the complete genomes of four laboratory strains of C. burnetii, we demonstrate that C. burnetii encodes a 451 amino acid sheddase (CbHtrA) belonging to the HtrA family that is differently expressed according to the bacterial virulence. An artificial CbHtrA gene (CoxbHtrA) was expressed, and the CoxbHtrA recombinant protein was found to have sheddase activity. We also found evidence that the C. burnetii infection triggers an over-induction of the human HuHtrA gene expression. Finally, we demonstrate that cleavage of E-cad by CoxbHtrA on macrophages-THP-1 cells leads to an M2 polarization of the target cells and the induction of their secretion of IL-10, which "disarms" the target cells and improves C. burnetii replication. Taken together, these results demonstrate that the genome of C. burnetii encodes a functional HtrA sheddase and establishes a link between the HtrA sheddase-induced cleavage of E-cad, the M2 polarization of the target cells and their secretion of IL-10, and the intracellular replication of C. burnetii.

Risk of chronic Q fever in patients with cardiac valvulopathy, seven years after a large epidemic in the Netherlands

BACKGROUND

From 2007 through 2010, a large epidemic of acute Q fever occurred in the Netherlands. Patients with cardiac valvulopathy are at high risk to develop chronic Q fever after an acute infection. This patient group was not routinely screened, so it is unknown whether all their chronic infections were diagnosed. This study aims to investigate how many chronic Q fever patients can be identified by routinely screening patients with valvulopathy and to establish whether the policy of not screening should be changed.

METHODS

In a cross-sectional study (2016-2017) in a hospital at the epicentre of the Q fever epidemic, a blood sample was taken from patients 18 years and older who presented with cardiac valvulopathy. The sample was tested for IgG antibodies against phase I and II of Coxiella burnetii using an immunofluorescence assay. An IgG phase II titre of ≥1:64 was considered serological evidence of a previous Q fever infection. An IgG phase I titre of ≥1:512 was considered suspicious for a chronic infection, and these patients were referred for medical examination.

RESULTS

Of the 904 included patients, 133 (15%) had evidence of a previous C. burnetii infection, of whom 6 (5%) had a chronic infection on medical examination.

CONCLUSIONS

In a group of high-risk patients with a heart valve defect, we diagnosed new chronic Q fever infections seven years after the epidemic, emphasizing the need for screening of this group to prevent complications in those not yet diagnosed in epidemic areas.

Tache Noire in a Patient with Acute Q Fever

OBJECTIVE

To describe a rare case of acute Q fever with tache noire.

CLINICAL PRESENTATION AND INTERVENTION

A 51-year-old man experienced acute Q fever showing tache noire, generally considered a pathognomonic sign of Mediterranean spotted fever (MSF) and MSF-like illness, but not a clinical feature of Q fever. The patient was treated with doxycycline 100 mg every 12 h.

CONCLUSION

In the Mediterranean area, tache noire should be considered pathognomonic of MSF but it should not rule out Q fever. Clinical diagnosis should be supported by accurate laboratory diagnostic tests to guide proper management.

Latent Q fever endocarditis in patients undergoing routine valve surgery

BACKGROUND AND AIM OF THE STUDY

Q fever is a worldwide zoonosis caused by a fastidious bacterium, Coxiella burnetii. A recent major outbreak of which in the Netherlands will most likely lead to the emergence of hundreds of cases of C. burnetii endocarditis during the next decade. Patients undergoing cardiac valve surgery may carry undiagnosed Q fever endocarditis with possible disastrous outcomes, and hence may benefit from a screening strategy. The study aim was to evaluate the frequency of unsuspected latent Q fever endocarditis in patients undergoing routine valve surgery.

METHODS

At the present authors' institution, all resected cardiac valves/prostheses are examined routinely histologically, microbiologically and on a molecular biological basis, in addition to serological testing for fastidious microorganisms. A retrospective review was conducted of data relating to all patients who had unsuspected Q fever endocarditis that had been diagnosed after routine valve/prosthesis replacement/repair between 2000 and 2013 at the authors' institution.

RESULTS

Among 6,401 patients undergoing valve surgery, postoperative examinations of the explanted valves/prostheses led to an unexpected diagnosis of Q fever endocarditis in 14 cases (0.2%), who subsequently underwent appropriate medical treatments. Only two of the patients (14%) had intraoperative findings suggestive of endocarditis. On serological analysis of the blood samples, 11 patients (79%) presented an evocative Phase I IgG antibody titer > or =800. Valvular tissue-sample analyses yielded positive cultures and PCR in the same 13 patients (93%), whereas pathological and immunohistochemical examinations alone were suggestive of endocarditis in only seven Cases (50%).

CONCLUSION

This screening strategy led to an unexpected diagnosis of Q fever endocarditis in 0.2% of patients undergoing routine valve surgery, who received subsequent appropriate antibiotic therapy. Systematic serological analysis should be mandatory before performing heart valve surgery in countries where C. burnetii is endemic. A positive serology should lead to appropriate valve-specimen analyses, including microbiological, molecular biological and histological evaluations.

Animal models of Q fever (Coxiella burnetii)

Q fever, caused by the pathogen Coxiella burnetii, is an acute disease that can progress to become a serious chronic illness. The organism leads an obligate, intracellular lifecycle, during which it multiplies in the phagolytic compartments of the phagocytic cells of the immune system of its hosts. This characteristic makes study of the organism particularly difficult and is perhaps one of the reasons why, more than 70 y after its discovery, much remains unknown about the organism and its pathogenesis. A variety of animal species have been used to study both the acute and chronic forms of the disease. Although none of the models perfectly mimics the disease process in humans, each opens a window onto an important aspect of the pathology of the disease. We have learned that immunosuppression, overexpression of IL10, or physical damage to the heart muscle in mice and guinea pigs can induce disease that is similar to the chronic disease seen in humans, suggesting that this aspect of disease may eventually be fully understood. Models using species from mice to nonhuman primates have been used to evaluate and characterize vaccines to protect against the disease and may ultimately yield safer, less expensive vaccines.

[Implication of functional platelet activity in pathogenesis of Q-fever]

AIM

To ascertain the role of platelets in pathogenesis of clinical symptoms in patients with Q-fever.

MATERIAL AND METHODS

We studied hemostasis with estimation of functional platelet activity in 49 patients with Q-fever.

RESULTS

Hemorrhagic syndrome (HS) occurred in 34.4% patients with Q-fever (QF) during seasonal rise of morbidity. HS manifested with petechiae (12%), hematomas (32%), nasal bleeding (17%), stomatorrhagia (9%), melena (12%). Characteristics and duration of such symptoms as weakness (100%), myalgia (72%), arthralgia (52.9%) suggested hemocoagulatory disorders as a cause of the symptoms appearance. At the height of the disease thrombocytopenia was accompanied with inhibition of platelet aggregation activity, but regression of the clinical symptoms was associated with an increase in platelet count and platelet hyperaggregation. Fibrinogen content was elevated during hospitalization in 50% patients.

CONCLUSION

Clinical manifestations of HS are typical for Q-fever prevalent in the Astrakhan Region. Hemostatic disorders because of altered functional activity of platelets were registered in all the cases and evidence for pathogenetic unbalance of homeostasis in Q-fever patients.

Detailed analysis of health status of Q fever patients 1 year after the first Dutch outbreak: a case-control study

BACKGROUND

Q fever is a zoonosis caused by the obligate intracellular bacterium Coxiella burnetii. The two long-term complications, after primary infection, are chronic Q fever in ∼1% of patients, and a chronic fatigue syndrome in 10-20%. However, the existence of a protracted decreased health status after Q fever remains controversial.

AIM

To determine the health status of the patients of the Q fever outbreak in The Netherlands in 2007, 1 year after primary infection.

DESIGN

Cross-sectional case-control study.

METHODS

Health status of the patients from the 2007 Dutch Q fever outbreak was compared to age-, sex- and geographically matched and Q fever seronegative controls. Health status of both patients and controls was assessed with the Nijmegen Clinical Screening Instrument (NCSI).

RESULTS

Fifty-four Q fever patients provided 34 years of age- and sex-matched controls from the same neighbourhood. Eleven controls had positive Q fever serology and were excluded. Q fever patients had significantly more problems on the subdomains of symptoms and functional impairment. Overall quality of life was decreased in both patients and controls, 59% vs. 39%, respectively, ns). Severe fatigue levels were present in 52% of patients vs. 26% in controls (P < 0.05).

CONCLUSION

These data support a sustained decrease in many aspects of health status in Q fever patients in The Netherlands, 1 year after primary infection.

The devil is in the details

The approach to clinical conundrums by an expert clinician is revealed through presentation of an actual patient's case in an approach typical of morning report. Similar to patient care, sequential pieces of information are provided to the clinician who is unfamiliar with the case. The focus is on the thought processes of both the clinical team caring for the patient and the discussant.

Etiology of acute undifferentiated febrile illness in the Amazon basin of Ecuador

We conducted a longitudinal observational study of 533 patients presenting to two hospitals in the Ecuadorean Amazon basin with acute undifferentiated febrile illness (AUFI) from 2001 through 2004. Viral isolation, reverse transcription-polymerase chain reaction (RT-PCR), IgM seroconversion, and malaria smears identified pathogens responsible for fever in 122 (40.1%) of 304 patients who provided both acute and convalescent blood samples. Leptospirosis was found in 40 (13.2%), malaria in 38 (12.5%), rickettsioses in 18 (5.9%), dengue fever in 16 (5.3%), Q fever in 15 (4.9%), brucellosis in 4 (1.3%), Ilhéus infection in 3 (1.0%), and Venezuelan equine encephalitis (VEE), Oropouche, and St. Louis encephalitis virus infections in less than 1% of these patients. Viral isolation and RT-PCR on another 229 participants who provided only acute samples identified 3 cases of dengue fever, 2 of VEE, and 1 of Ilhéus. None of these pathogens, except for malaria, had previously been detected in the study area.

Q fever in the Netherlands - what matters is seriousness of disease rather than quantity

As the number of detected cases may be closely related to the intensity of the search and the methods and criteria used in the diagnosis, we believe that exhaustive surveillance under pressure from the media could lead to over-diagnosis and unnecessary treatments which, like that of pregnant women, are not free of risk.

Acute Q fever: an emerging and endemic disease in southern Taiwan

Acute Q fever is a worldwide zoonosis caused by Coxiella burnetii infection. In Taiwan, cases of acute Q fever increased during 3 y of observation, especially at Kaohsiung County and City in southern Taiwan. From 15 April 2004 to 15 April 2007, a total of 67 cases of acute Q fever were identified at E-Da hospital located at Kaohsiung County. 19 (28.4%) patients had a history of travel in rural areas and only 1 had been outside southern Taiwan. 21 (31.3%) patients had a history of animal contact. 20 (30.8%) of the 65 examined patients had underlying chronic hepatitis B or hepatitis C virus infection. Fever (98.5%), chills (79.1%), headache (79.1%), relative bradycardia (44.8%), elevated aminotransferases (100%), and thrombocytopenia (74.6%) were common manifestations. 12 (19.0%) cases had abnormal findings on chest X-ray. Fatty liver (50.0%) and hepatomegaly and/or splenomegaly (41.9%) were found by abdominal image examinations. 42 (76.4%) of 55 cases had defervescence within 3 d after treatment, whereas 4 (7.3%) had spontaneous remission. Acute Q fever is an endemic infectious disease with hepatitis rather than pneumonia as the major presentation in southern Taiwan and the emergence of Q fever is due to increased alertness for the disease by physicians.

Epidemiological features of Mediterranean spotted fever, murine typhus, and Q fever in Split-Dalmatia County (Croatia), 1982-2002

We determined the epidemiological features of three zoonoses in hospitalized patients in southern Croatia. Patients were diagnosed by serological testing. Clinical and epidemiological data were also collected. Between 1982 and 2002, Mediterranean spotted fever (MSF) was diagnosed in 126 (incidence rate 1.27/100,000 per year), murine typhus (MT), in 57 (incidence rate 0.57/100,000 per year), and Q fever in 170 (incidence rate 1.7/100,000 per year) patients. MSF and Q fever were characterized by a marked seasonality. Incidences of Q fever and of MSF were higher for males than for females (P<0.0001 and P=0.0024, respectively). The most frequent of the three zoonoses in children was MSF. Q fever and MT cases were mostly seen in the 21-50 years age group. We found no statistically significant differences between season- and gender-specific incidence rates of MT. Whereas infections due to rickettsiae decreased, the incidence of Q fever increased over the last 12 years of the study.

Acute Q fever hepatitis in patients with and without underlying hepatitis B or C virus infection

BACKGROUND

Although hepatitis is one of the major presentations of acute Q fever, the possible influence of viral hepatitis in Q fever has, to our knowledge, never been investigated. It is an important issue in regions where Q fever hepatitis and viral hepatitis are prevalent, such as Taiwan. We conducted a study to investigate the possible influence of viral hepatitis in cases of acute Q fever hepatitis.

METHODS

Cases of acute Q fever confirmed by serologic examination were included in the study. All patients who were found to be positive for Q fever were tested for hepatitis B surface antigen and antibody to hepatitis C virus, and those with positive results had their viral loads determined. Demographic data, clinical manifestations, results of laboratory and imaging examinations, and responses to treatment were recorded retrospectively from charts.

RESULTS

A total of 58 patients with acute Q fever hepatitis were studied, of whom 16 (27.6%) had viral hepatitis (hepatitis B virus infection in 12 and hepatitis C virus infection in 4). Patients with and patients without viral hepatitis did not differ with regard to clinical manifestations and responses to treatment, except that chills (100% vs. 73.8%; P=.02) and nausea and/or vomiting (18.8% vs. 2.4%; P=.03) were significantly more common among patients with viral hepatitis. The change in hepatitis B and C virus loads between the acute and convalescent phase was <1.0 log(10).

CONCLUSIONS

The clinical manifestations of acute Q fever hepatitis differ little in patients with and patients without underlying viral hepatitis, and replication of hepatitis virus is not influenced by acute Q fever hepatitis.

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 endocarditis masquerading as Mixed cryoglobulinemia type II. A case report and review of the literature

Background

The clinical manifestations of Q fever endocarditis are protean in nature. Mixed cryoglobulinemia type II is rarely a facet of the presenting clinical manifestations of Q fever endocarditis.

Case presentation

We report a case of a 65-year-old pensioner with such an association and review the literature. As transesophageal echocardiograms are usually normal and blood cultures are usually negative in Q fever endocarditis, many of the manifestations (fever, rash, glomerulonephritis/evidence of renal disease, low serum C4 complement component, presence of mixed type II cryoglobulin, constitutional symptoms as arthralgias and fatigue) can be attributed to Mixed cryoglobulinemia type II per se. The use of Classic Duke Endocarditis Service criteria does not always suffice for the diagnosis of Q fever.

Conclusion

The application of the modified criteria proposed by Fournier et al for the improvement of the diagnosis of Q fever endocarditis will help to reach the diagnosis earlier and thus reduce the high mortality of the disease. We would like to stress the importance of ruling out the diagnosis of Q fever endocarditis in cases of mixed type II cryoglobulinemia.

Genome Analysis of Coxiella burnetii Species: Insights into Pathogenesis and Evolution and Implications for Biodefense

Coxiella burnetii, the etiological agent of Q fever, is a class B biodefense agent. We are continuing the momentum of discovery generated by the first Coxiella genome sequences by extending the breadth of genomics to include four additional heterogeneous C. burnetii strains. We are also sequencing the genome of Rickettsiella grylli, an intracellular parasite of grasshoppers and the closest known phylogenetic relative to the Coxiella group. These data will enable the investigation of fundamental questions about Coxiella pathogenicity and virulence as well as broader evolutionary questions about the transition to obligate intracellular life. Specifically, sequence comparisons will permit examination of genetic differences, allowing us to address key questions: What core genes are necessary for an obligate intracellular lifestyle and developmental cycle of the genus? What specific genetic determinants can be linked to virulence properties such as host preference, disease severity, and pathology (i.e., acute vs. chronic disease)? What are the frequencies of mutation and intragenomic recombination, and levels of genome reduction? What specific factors are relevant to colonization and virulence in human hosts (based on comparisons with R. grylli)? From a public health and biodefense perspective, exposure to different strains, either natural or due to illegitimate release, may have different outcomes. With extensive genomic-level information from diverse strains, investigators can determine effective drug and vaccine targets and design methods to accurately type Coxiella based on a subset of genes, opening the way for cost-effective targeted PCR- or antibody-based tests.

Immunization Experiments with Recombinant Coxiella burnetii Proteins in a Murine Infection Model

Previous attempts to develop Q fever vaccines were less successful in that the vaccines caused unacceptable side effects or failed to be protective. In this study, we tested the efficacy of a mixture of eight recombinant Coxiella burnetii (C. b.) proteins in sublethal challenge infections with mice. Eight potential C. b. virulence genes (Omp, Pmm, HspB, Fbp, Orf410, Crc, CbMip, and MucZ) were overexpressed in E. coli as his-tagged fusion proteins and partially purified. All recombinant proteins but rPmm proved to be antigenic in BALB/c mice when administered as protein mixtures. For efficacy testing, mice were immunized with an adjuvanted mixture of the eight recombinant proteins and subsequently challenged intraperitoneally with the C. b. isolate Nine Mile RSA493 (1.8 x 10(8) C. b.). Only animals vaccinated with the licensed Q fever vaccine Q-Vax (vaccination control) exhibited milder symptoms and minor gain of spleen and liver weights. In summary, clinical examinations and dissection of mice immunized with the eight recombinant C. b. proteins did not indicate a protective immune response after test infection.

Diffuse Abdominal Uptake Mimicking Peritonitis in Gallium Inflammatory Scan: An Unusual Feature of Acute Q Fever

The clinical features in patients with acute Q fever are variable. We present a patient with fever, abdominal distension, pericardial effusion, and diffuse gallium uptake in the abdominal cavity, mimicking peritonitis or peritoneum carcinomatosis. Serologic surveys revealed acute infection by Coxiella burnetii. The patient responded poorly to doxycycline and improved with oral levofloxacin. During the afebrile period, gallium inflammatory scan showed resolution of previous diffuse uptake in the abdomen, and cardiac echo resolution of pericardial effusion, which was suggestive of peritoneal inflammation related to acute C. burnetii infection. Therefore, clinicians in Taiwan should be alert to the possibility of acute Q fever in patients with fever of unknown cause, especially with clinical evidence of peritoneal and/or pericardial inflammation.

Natural history and pathophysiology of Q fever

Q fever is a zoonosis caused by Coxiella burnetii. Infection with C burnetii can be acute or chronic, and exhibits a wide spectrum of clinical manifestations. The extreme infectivity of the bacterium results in large outbreaks and makes it a potential bioweapon. In the past decade, the complete genome sequencing of C burnetii, the exploration of bacterial interactions with the host, and the description of the natural history of the disease in human beings and in experimental models have all added to our knowledge about this fascinating disease. Advances in understanding the pathophysiology and natural history of Q fever are reviewed.

Identification and characterization of an immunodominant 28-kilodalton Coxiella burnetii outer membrane protein specific to isolates associated with acute disease

Coxiella burnetii causes acute Q fever in humans and occasional chronic infections that typically manifest as endocarditis or hepatitis. Isolates associated with acute disease were found to be distinct from a group of chronic disease isolates by a variety of biochemical parameters and in a guinea pig fever model of acute disease, suggesting a difference in virulence potential. We compared antigenic polypeptides among C. burnetii isolates and found an immunodominant 28-kDa protein in acute group isolates but not in chronic group isolates (T. Ho, A. Hotta, G. Q. Zhang, S. V. Nguyen, M. Ogawa, T. Yamaguchi, H. Fukushi, and K. Hirai, Microbiol. Immunol. 42:81-85, 1998). In order to clone the adaA gene, the N-terminal amino acid sequence of adaA was determined and a 59-bp fragment was amplified from Nine Mile phase I DNA by PCR. The putative gene fragment was used to screen a lambda ZAP II genomic DNA library, and an open reading frame expressing a 28-kDa immunoreactive protein was identified. Sequence analysis predicted a gene encoding an approximately 28-kDa mature protein with a typical signal sequence. The adaA (acute disease antigen A) gene was detected in acute group C. burnetii isolates but not identified in chronic group isolates by PCR and Southern blotting. A typical signal peptide was predicted in adaA, and specific antibody to adaA reacted with the purified membrane fraction of acute group isolates by Western blotting, suggesting that adaA is exposed on the outer surface of C. burnetii. adaA was overexpressed in pET23a as a fusion protein in Escherichia coli to develop anti-recombinant adaA (anti-radaA) specific antibody, which recognized a approximately 28-kDa band in acute group isolates but not in chronic group isolates. In addition, immunoblotting indicates that radaA reacted with sera derived from animals infected with acute group isolates but did not react with sera from animals infected with chronic group isolates. These results support the idea that an adaA gene-targeted PCR assay and an radaA antigen-based serodiagnostic test may be useful for differential diagnosis of acute and chronic Q fever.

Genetic control of natural resistance of mouse macrophages to Coxiella burnetii infection in vitro: macrophages from restrictive strains control parasitophorous vacuole maturation

Macrophages from A/J and BALB/c mice were more susceptible to Coxiella burnetii phase II infection than were those from C57BL/6, C57BL/10, B10.A, C3H/HePas, and Swiss mice. Resistant macrophages effectively controlled the development of large replication vacuoles (LRVs), which accounted for the restriction of bacterial multiplication within the cultures. However, compared to fibroblasts, all macrophages controlled bacterial multiplication within LRVs.

[Q fever pericarditis]

Q fever is a zoonotic disease caused by Coxiella burnetii--an obligate, gram negative, intracellular bacteria. The term Q (Query) was first used because at the time the disease was named its etiology was unknown. Q fever is divided into acute and chronic infections characterized by different evolution, serological profiles and treatment. Pericarditis, as a manifestation of Q fever is rare and difficult to diagnose. This is due to the following: firstly, the clinical presentation of acute Q fever is pleomorphic, nonspecific and self limited, and secondly, the diagnosis relies on the physician's interest and the presence of a reliable diagnostic laboratory. The objective of that review is to increase the physician's awareness of the clinical presentation of Q fever, to discuss the importance of the diagnosis and laboratory tests and to guide the physician as to when to provide treatment and the relevant patient population to be treated.

Acute hepatitis with or without jaundice: a predominant presentation of acute Q fever in southern Taiwan

Acute Q fever was previously regarded as an uncommon infectious disease in Taiwan but has been increasingly recognized recently. Acute febrile illness, hepatitis, and pneumonia are the 3 most common manifestations of this condition, whereas jaundice is rarely reported among patients with acute Q fever. We report 2 cases of acute Q fever with jaundice and multi-organ involvement. The first patient presented with fever, severe headache, and acute abdomen necessitating laparotomy and was complicated with acute cholestatic hepatitis, acute non-oliguric renal failure and disseminated intravascular coagulation. The second patient had acute cholestatic hepatitis and thrombocytopenia, and the latter was likely related to the infection of bone marrow by Coxiella burnetii, as evidenced by the presence of C. burnetii DNA detected by nested polymerase chain reaction. The incidence and clinical significance of hyperbilirubinemia was also determined by review of medical records of 35 cases of acute Q fever cases diagnosed serologically at National Cheng Kung University Hospital from 1994 to 2001. All had biochemical hepatitis and 23% had hyperbilirubinemia (serum bilirubin > or =2 mg/dL). The febrile course before admission and the period between the initiation of effective medication to defervescence were longer in patients with hyperbilirubinemia than in patients without hyperbilirubinemia, although this difference was not significant. Our results suggest that the predominant presentation of acute Q fever in southern Taiwan is acute febrile illness with hepatitis and that jaundice is not uncommon. Due to the clinical polymorphism of acute Q fever, the threshold of surveys for C. burnetii infections should be low for febrile patients with elevated transaminases or hyperbilirubinemia of unknown cause.

Comparison of PCR and serology assays for early diagnosis of acute Q fever

Q fever is a potentially severe disease which can occur in large outbreaks of acute infections and is a possible bioterrorism agent. In order to lessen the delay in diagnosing acute Q fever, we compared LightCycler Nested PCR (LCN-PCR), a rapid nested PCR assay that uses serum sampled early during the disease as a specimen and the LightCycler as a thermal cycler, to serology by indirect immunofluorescence. We used the 20-copy htpAB-associated element as the DNA target. The detection sensitivity of this method was one Coxiella burnetii DNA copy. We applied this method to the first serum samples taken from 100 patients diagnosed in our laboratory as having acute Q fever on the basis of clinical manifestations and serology and to 80 controls. The LCN-PCR had a specificity of 100%. The sensitivity was 26% when no antibodies were detected but only 5% with seropositive patients (P < 10(-2)). The technique was most efficient in the first 2 weeks following the onset of symptoms (P = 0.02), when its sensitivity was 24% compared with 14% for serology. With combined use of LCN-PCR and serology within the first 2 weeks, the sensitivity was significantly increased over that with serology alone (P < 10(-2)). Thus, we propose a strategy for improving the early diagnosis of acute Q fever where LCN-PCR should be performed together with serology in the first 2 weeks of the disease but should be reserved for seronegative patients in the next 2 weeks and not used later than 4 weeks following onset, when serology is highly sensitive.

Q fever: a biological weapon in your backyard

Coxiella burnetii, which causes Q fever, is a highly infectious agent that is widespread among livestock around the world. Although the culture process for coxiella is laborious, large amounts of infectious material can be produced. If used as an aerosolised biological weapon, coxiella may not cause high mortality, but could provoke acute disabling disease. In its late course, Q fever can be complicated by fatal (eg, endocarditis) or debilitating (eg, chronic fatigue syndrome) disorders. The diagnosis of Q fever might be delayed because of non-specific and protean presentations. Effective antibiotic treatment is available for the acute form of disease but not for the chronic complications. Vaccination and chemoprophylaxis in selected individuals may be used in the event of bioterrorism.

Significance of Q fever serologic diagnosis in clinically suspect patients

Q fever is caused by C. burnetii, an intracellular obligate bacterium. For clinical confirmation of Q fever, diagnosis of interstitial pneumonia is of significance. The acute disease varies in severity from minor to fatal, with the possibility of serious complications. Chronic endocarditis is a well-known outcome. Symptoms of Q fever can vary; fixing diagnosis is done by serology with the phase I and the phase II antibody. We tested 44 sera of 31 clinically suspect patients. From these, 22 patients were taken to the infection clinic, 8 to the pulmonary clinic, and one to the general hospital. From the 31 patients, 21 patients had one serum, 7 patients, 2 sera, and 3 patients, 3 sera. Blood samples were collected by vein puncture, and serum samples were kept at -20 degrees C until testing. All sera were processed by indirect immunofluorescent assay (IFA) Q fever IgM and IgG. Of 44 processed sera, 21 were seropositive. Specific IgM antibody was found in sera of 6 patients (19.4%), and specific IgG antibody in sera of 16 patients (51.2%). In sera of 15 clinically suspect patients (48.3%), no specific anticoxiella antibody was found. From these results we can confirm the importance of serology in laboratory diagnosis and clinical affirmation of suspect Q fever. Indirect immunofluorescent assay (IFA) is reliable and appropriate for daily, routine diagnosis of human Q fever.

Q fever--still a query and underestimated infectious disease

Coxiella burnetii (C.b.) is a strictly intracellular, Gram-negative bacterium. It causes Q fever in humans and animals worldwide. The animal Q fever is sometimes designated "coxiellosis". This infection has many different reservoirs including arthropods, birds and mammals. Domestic animals and pets, are the most frequent source of human infections. Q fever may appear basically in two forms, acute and chronic (persistent). The latter form of Q fever in animals is characteristic by shedding C.b. into the environment during parturition or abortion. Human Q fever results usually from inhalation of contaminated aerosols originating mostly from tissue and body fluids of infected animals. Q fever may appear in humans either in an acute form accompanied mainly by fever (pneumonia, flu-like disease, hepatitis) or in a chronic form (mainly endocarditis). Diagnosis of Q fever is based on isolation of the agent in cell culture, its direct detection, namely by PCR, and serology. Detection of high phase II antibodies titers 1-3 weeks after the onset of symptoms and identification of IgM antibodies are indicative to acute infection. High phase I IgG antibody titers >800 as revealed by microimmunofluorescence offer evidence of chronic C.b. infection. For acute Q fever, a two-weeks-treatment with doxycycline is recommended as the first-line therapy. In the case of Q fever endocarditis a long-term combined antibiotic therapy is necessary to prevent relapses. Application of Q fever vaccines containing or prepared from phase I C.b. corpuscles should be considered at least for professionally exposed groups of the population. Infections caused by C.b. are spread worldwide and may pose serious and often underestimated health problems in human but also in veterinary medicine. Though during the last decades substantial progress in investigation of C.b. has been achieved and many data concerning this pathogen has been accumulated, some questions, namely those related to the pathogenesis of the disease, remain open.

Acute Q fever and brachial neuritis: case report and literature review

Peripheral nervous system complications of Q fever are uncommon. A case of electrophysiologically documented brachial neuritis occurring during acute Coxiella burnetii infection is reported. The relevant literature is reviewed.

[Tick-borne neurological diseases]

Some microorganisms transmitted to man via tick bite are responsible for infections, which can be associated with neuro-meningeal complications. TBE virus is the most frequent virus associated with potentially severe neurological lesions. No treatment is available so far. The most frequent bacterial diseases in which neurological complications may appear are Lyme borreliosis, Q fever and some rickettsial infections. More recently ehrlichiosis have emerged as new infections that may be associated with neuro-meningeal complications. Appropriate antibiotic therapy may be used for the treatment of these bacterial infections, but no vaccine is available so far.

Gastrointestinal and hepatic manifestations of tickborne diseases in the United States

Signs and symptoms related to the gastrointestinal tract and liver may provide important clues for the diagnosis of various tickborne diseases prevalent in different geographic areas of the United States. We review clinical and laboratory features that may be helpful in detecting a tickborne infection. Physicians evaluating patients who live in or travel to areas where tickborne diseases are endemic and who present with an acute febrile illness and gastrointestinal manifestations should maintain a high index of suspicion for one of these disease entities, particularly if the patient has received a tick bite. If detected early, many of these potentially serious illnesses can be easily and effectively treated, thereby avoiding serious morbidity and even death.

Neurological involvement in acute Q fever: a report of 29 cases and review of the literature

BACKGROUND

Q fever is characterized by its clinical polymorphism; neurological involvement has occasionally been described. In the course of acute Q fever, neurological manifestations may include aseptic meningitis, encephalitis or encephalomyelitis, and peripheral neuropathy.

OBJECTIVE

To review and evaluate cases of acute Q fever with neurological symptoms diagnosed in our laboratory.

METHODS

A total of 1269 acute Q fever cases were recorded from January 1985 to January 2000 in our laboratory and were reviewed for neurological complications. Patients were considered to have acute Q fever when serological procedures showed Coxiella burnetii phase II titers of 1:200 or higher for IgG and 1:50 or higher for IgM. Those patients who underwent a lumbar puncture for cerebrospinal fluid analysis or who had abnormal neurological symptoms were selected for this study. We describe the clinical, epidemiological, and biological features of these cases. We also review the literature and compare our cases with those previously reported.

RESULTS

Among the 45 patients selected, 14 were excluded because they had normal cerebrospinal fluid and no neurological symptoms. Two were excluded because there were no clinical or epidemiological data. Three major clinical syndromes were observed: meningoencephalitis or encephalitis in 17 cases; meningitis in 8; and myelitis and peripheral neuropathy in 4. Encephalitic signs were not specific, but behavior or psychiatric disturbances were common.

CONCLUSIONS

Q fever should be included in the differential diagnosis of acute neurological disease in a patient with a fever. Serological testing should be performed in cases of meningoencephalitis, lymphocytic meningitis, and peripheral neuropathy, including Guillain-Barré syndrome and myelitis.

Changing clinical presentation of Q fever endocarditis

Fifteen cases of Q fever endocarditis that occurred in 1999-2000 in southern France are described and compared with 15 cases from the same area reported in 1987. Significant decreases were found in the prevalences of heart failure, hepatomegaly, inflammatory syndrome, anemia, leukopenia, and abnormal liver function test results in patients who had Q fever endocarditis after 1997. This was probably the result of a reduction in the delay before diagnosis of the disease and of the use of novel, effective antibiotic regimens.

Atypical manifestations of chronic Q fever

Chronic Q fever is uncommon, with the majority of cases manifesting as culture-negative endocarditis. In this report, we describe 3 patients who present with atypical manifestations of chronic Q fever. These were a 43-year-old man whose site of chronic Q fever was the central nervous system, a 53-year-old woman who underwent coronary angioplasty 6 days before the onset of symptoms of acute Q fever and within 4 months had serologic evidence consistent with chronic Q fever, and a 66-year-old man with fever of unknown origin, a pancreatic mass, and aorto-bifemoral grafts.

Intractable Q fever treated with recombinant gamma interferon

A 3-year-old boy with Q fever received several kinds of antibiotics including minocycline, but spiking fever and positive PCR of Coxiella burnetii continued for several months. He became asymptomatic and his abnormal laboratory data normalized after the administration of gamma interferon three times a week.

Coxiella burnetii pericarditis: report of 15 cases and review

Q fever is characterized by its clinical polymorphism, and pericarditis associated with Q fever has occasionally been described. Herein we report 15 cases of Coxiella burnetii pericarditis, 9 from our data bank and 6 encountered within the past 12 months. Three patients presented with life-threatening tamponade. We compare our cases with the 18 previously reported and with 60 Q fever-matched controls at our center. This study showed that Q fever pericarditis can present as acute as well as chronic disease; we describe relapse after 6 months in association with a serological profile compatible with the chronic form of disease (phase I C. burnetii IgG titer of > or = 800). Discriminant factors among patients and controls are age of > 52 years (adjusted odds ratio [OR], 5.66), the occurrence of general symptoms such as arthralgias or myalgias (adjusted OR, 6.54), and a normal erythrocyte sedimentation rate (adjusted OR, 16.37). No specific symptoms or underlying cardiac predispositions are observed.

Acute glomerulonephritis associated with acute Q fever: case report and review of the renal complications of Coxiella burnetii infection

We report a case of acute glomerulonephritis associated with acute Q fever. An abattoir worker with a nonspecific febrile illness and pneumonia and abnormal liver function test results developed hematuria, proteinuria, and acute renal failure that resolved with appropriate antimicrobial therapy. Renal biopsy demonstrated diffuse proliferative and exudative glomerulonephritis. Serological tests confirmed recent infection with Coxiella burnetii, with a fourfold rise in the titer of phase II antibody, positive phase II IgM antibody, and negative phase I antibody. Other known causes of glomerulonephritis were excluded. Most reports of renal complications of C. burnetii infection describe glomerulonephritis associated with endocarditis due to chronic Q fever. Renal involvement in patients with acute C. burnetii infection has been rarely described. Glomerulonephritis should be recognized as a complication of acute C. burnetii infection and endocarditis due to chronic Q fever.

Prevalence of Q fever in a rural practice

BACKGROUND

Q fever is a world-wide condition caused by the rickettsia Coxiella burnetii. It appears more prevalent in agrarian communities and may have serious sequelae.

METHODS

A descriptive, cross-sectional, observational study using a randomly selected group of the adult working practice population in a rural practice in West Wales was devised. An immunofluorescence test, which identified past infection, was used to look for associations between C. burnetii seropositivity and farm-related or social activities, and to compare the findings with those of other studies. An attempt was made to establish a clinical profile for the illness Q fever.

RESULTS

Twenty-one subjects were found to be seropositive to C. burnetii. No definite consistent clinical features were identified. Farming was undoubtedly a risk factor for the disease, maybe with other related factors also important. There was a possibility that alcohol had a protective effect. No sinister sequelae were described.

CONCLUSIONS

Q fever occurs more frequently in farmers than in non-farmers, but was less common than previously thought. Is Q fever accurately described in medical textbooks? A case is made for a more co-operative approach between primary carers and epidemiologists in the study of illnesses in populations.