Epidemiological,clinical and laboratory features of acute Q fever in a cohort of hospitalized patients in a regional hospital,Israel, 2012-2018

IntroductionAcute Q fever is endemic in Israel, yet the clinical and laboratory picture is poorly defined.MethodsA retrospective study reviewing the medical records of acute Q fever patients, conducted in a single hospital in the Sharon district, Israel. Serum samples from suspected cases were preliminary tested by a qualitative enzyme immunoassay (EIA). Confirmatory testing at the reference laboratory used an indirect immunofluorescence assay (IFA). Positive cases were defined as fever with at least one other symptom and accepted laboratory criteria such as a single-phase II immunoglobulin G (IgG) antibody titer ≥1:200. Cases not fulfilling these criteria and in which acute Q fever was excluded, served as a control group.ResultsBetween January 2012 and May 2018, 484 patients tested positive. After confirmatory testing, 65 (13.4%) were positive for acute Q fever (with requisite clinical picture), 171 (35.3%) were definitely not infected, the remaining 248 were excluded because of past/chronic/undetermined infection. The average age was 58 years and 66% were males. Most resided in urban areas with rare animal exposure. Pneumonia was seen in 57% of cases and a combination with headache/hepatitis was highly suggestive of acute Q fever diagnosis. Syncope/presyncope, fall and arthritis were more common in acute Q fever cases. Laboratory indexes were similar to the control group, except for erythrocyte sedimentation rate (ESR) which was more common and higher in the study group.ConclusionAcute Q fever in the Sharon district could be better diagnosed by using a syndromic approach in combination with improved rapid diagnostic testing.     

Clinical Characteristics of Q Fever and Etiology of Community-Acquired Pneumonia in a Tropical Region of Southern Taiwan: A Prospective Observational Study

Background

The clinical characteristics of Q fever are poorly identified in the tropics. Fever with pneumonia or hepatitis are the dominant presentations of acute Q fever, which exhibits geographic variability. In southern Taiwan, which is located in a tropical region, the role of Q fever in community-acquired pneumonia (CAP) has never been investigated.

Methodology/Principal Findings

During the study period, May 2012 to April 2013, 166 cases of adult CAP and 15 cases of acute Q fever were prospectively investigated. Cultures of clinical specimens, urine antigen tests for Streptococcus pneumoniae and Legionella pneumophila, and paired serologic assessments for Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Q fever (Coxiella burnetii) were used for identifying pathogens associated with CAP. From April 2004 to April 2013 (the pre-study period), 122 cases of acute Q fever were also included retrospectively for analysis. The geographic distribution of Q fever and CAP cases was similar. Q fever cases were identified in warmer seasons and younger ages than CAP. Based on multivariate analysis, male gender, chills, thrombocytopenia, and elevated liver enzymes were independent characteristics associated with Q fever. In patients with Q fever, 95% and 13.5% of cases presented with hepatitis and pneumonia, respectively. Twelve (7.2%) cases of CAP were seropositive for C. burnetii antibodies, but none of them had acute Q fever. Among CAP cases, 22.9% had a CURB-65 score ≧2, and 45.8% had identifiable pathogens. Haemophilus parainfluenzae (14.5%), S. pneumoniae (6.6%), Pseudomonas aeruginosa (4.8%), and Klebsiella pneumoniae (3.0%) were the most common pathogens identified by cultures or urine antigen tests. Moreover, M. pneumoniae, C. pneumoniae, and co-infection with 2 pathogens accounted for 9.0%, 7.8%, and 1.8%, respectively.

Conclusions

In southern Taiwan, Q fever is an endemic disease with hepatitis as the major presentation and is not a common etiology of CAP.     

The 2007–2010 Q fever epidemic in The Netherlands: characteristics of notified acute Q fever patients and the association with dairy goat farming

We describe the Q fever epidemic in the Netherlands with emphasis on the epidemiological characteristics of acute Q fever patients and the association with veterinary factors. Data from 3264 notifications for acute Q fever in the period from 2007 through 2009 were analysed. The patients most affected were men, smokers and persons aged 40–60 years. Pneumonia was the most common clinical presentation (62% in 2007 and 2008). Only 3.2% of the patients were working in the agriculture sector and 0.5% in the meat-processing industry including abattoirs. Dairy goat farms with Coxiella burnetii-induced abortion waves were mainly located in the same area where human cases occurred. Airborne transmission of contaminated dust particles from commercial dairy goat farms in densely populated areas has probably caused this epidemic. In 2010, there was a sharp decline in the number of notified cases following the implementation of control measures on dairy goat and sheep farms such as vaccination, hygiene measures and culling of pregnant animals on infected farms. In combination with a rise in the human population with antibodies against C. burnetii, these have most likely ended the outbreak. Development of chronic Q fever in infected patients remains an important problem for years to come.     

Epidemiological investigation and physician awareness regarding the diagnosis and management of Q fever in South Korea, 2011 to 2017

BackgroundIn South Korea, the number of Q fever cases has rapidly increased since 2015. Therefore, this study aimed to characterize the epidemiological and clinical features of Q fever in South Korea between 2011 and 2017.Methods/Principal findingsWe analyzed the epidemiological investigations and reviewed the medical records from all hospitals that had reported at least one case of Q fever from 2011 to 2017. We also conducted an online survey to investigate physicians’ awareness regarding how to appropriately diagnose and manage Q fever. The nationwide incidence rate of Q fever was annually 0.07 cases per 100,000 persons. However, there has been a sharp increase in its incidence, reaching up to 0.19 cases per 100,000 persons in 2017. Q fever sporadically occurred across the country, with the highest incidences in Chungbuk (0.53 cases per 100,000 persons per year) and Chungnam (0.27 cases per 100,000 persons per year) areas. Patients with acute Q fever primarily presented with mild illnesses such as hepatitis (64.5%) and isolated febrile illness (24.0%), whereas those with chronic Q fever were likely to undergo surgery (41.2%) and had a high mortality rate (23.5%). Follow-up for 6 months after acute Q fever was performed by 24.0% of the physician respondents, and only 22.3% of them reported that clinical and serological evaluations were required after acute Q fever diagnosis.ConclusionsQ fever is becoming an endemic disease in the midwestern area of South Korea. Given the clinical severity and mortality of chronic Q fever, physicians should be made aware of appropriate diagnosis and management strategies for Q fever.     

An epidemiological analysis of hemorrhagic fever with renal syndrome morbidity in the Republic of Bashkortostan in 1997

The outbreak of hemorrhagic fever with renal syndrome (HFRS) in the Republic of Bashkortostan, resulting in 10,057 registered cases of the disease (287 cases per 100,000 of the population), was analyzed. HFRS cases among the population were registered in 52 out of 54 regions of Bashkortostan. 31% of the total number of patients were the inhabitants of rural regions (170 cases per 100,000) and 69% were urban dwellers (295 cases per 100,000), mainly in Ufa (512 cases per 100,000). HFRS morbidity among males was fourfold higher than among females. In 70% of cases persons aged 20-49 years were affected. 5% of the total number of patients were children aged up to 14 years. In 34 cases (0.4%) the severe clinical course of the disease had a fatal outcome. Cases of HFRS were registered from April 1997 till March 1998 with the highest morbidity rate observed during the period of August-December. In most cases (46.8%) both urban and rural dwellers contacted infection during a short-term stay in the forest. As the result of the serological examination of the patients, all HFRS cases were etiologically attributed to hantavirus, serotype Puumala. The main natural reservoir of this virus and the source of human infection in Bashkortostan were bank voles (Clethrionomys glareolus), the domination species among small mammals in this region.     

The epidemic of Q fever in 2018 to 2019 in Zhuhai city of China determined by metagenomic next-generation sequencing

Q fever is a worldwide zoonosis caused by Coxiella burnetii (Cb). From January 2018 to November 2019, plasma samples from 2,382 patients with acute fever of unknown cause at a hospital in Zhuhai city of China were tested using metagenomic next-generation sequencing (mNGS). Of those tested, 138 patients (5.8%) were diagnosed with Q fever based on the presence of Cb genomic DNA detected by mNGS. Among these, 78 cases (56.5%) presented from Nov 2018 to Mar 2019, suggesting an outbreak of Q fever. 55 cases with detailed clinical information that occurred during the outbreak period were used for further analysis. The vast majority of plasma samples from those Cb-mNGS-positive patients were positive in a Cb-specific quantitative polymerase chain reaction (n = 38) and/or indirect immunofluorescence assay (n = 26). Mobile phone tracing data was used to define the area of infection during the outbreak. This suggested the probable infection source was Cb-infected goats and cattle at the only official authorized slaughterhouse in Zhuhai city. Phylogenic analysis based on genomic sequences indicated Cb strains identified in the patients, goat and cattle were formed a single branch, most closely related to the genomic group of Cb dominated by strains isolated from goats. Our study demonstrates Q fever was epidemic in 2018–2019 in Zhuhai city, and this is the first confirmed epidemic of Q fever in a contemporary city in China.     

High Seroprevalence of Mycoplasma pneumoniae IgM in Acute Q Fever by Enzyme-Linked Immunosorbent Assay (ELISA)

Q fever is serologically cross-reactive with other intracellular microorganisms. However, studies of the serological status of Mycoplasma pneumoniae and Chlamydophila pneumoniae during Q fever are rare. We conducted a retrospective serological study of M. pneumoniae and C. pneumoniae by enzyme-linked immunosorbent assay (ELISA), a method widely used in clinical practice, in 102 cases of acute Q fever, 39 cases of scrub typhus, and 14 cases of murine typhus. The seropositive (57.8%, 7.7%, and 0%, p<0.001) and seroconversion rates (50.6%, 8.8%, and 0%, p<0.001) of M. pneumoniae IgM, but not M. pneumoniae IgG and C. pneumoniae IgG/IgM, in acute Q fever were significantly higher than in scrub typhus and murine typhus. Another ELISA kit also revealed a high seropositivity (49.5%) and seroconversion rate (33.3%) of M. pneumoniae IgM in acute Q fever. The temporal and age distributions of patients with positive M. pneumoniae IgM were not typical of M. pneumoniae pneumonia. Comparing acute Q fever patients who were positive for M. pneumoniae IgM (59 cases) with those who were negative (43 cases), the demographic characteristics and underlying diseases were not different. In addition, the clinical manifestations associated with atypical pneumonia, including headache (71.2% vs. 81.4%, p=0.255), sore throat (8.5% vs. 16.3%, p=0.351), cough (35.6% vs. 23.3%, p=0.199), and chest x-ray suggesting pneumonia (19.3% vs. 9.5%, p=0.258), were unchanged between the two groups. Clinicians should be aware of the high seroprevalence of M. pneumoniae IgM in acute Q fever, particularly with ELISA kits, which can lead to misdiagnosis, overestimations of the prevalence of M. pneumoniae pneumonia, and underestimations of the true prevalence of Q fever pneumonia.     

Mixed Methods Survey of Zoonotic Disease Awareness and Practice among Animal and Human Healthcare Providers in Moshi,Tanzania

BackgroundZoonoses are common causes of human and livestock illness in Tanzania. Previous studies have shown that brucellosis, leptospirosis, and Q fever account for a large proportion of human febrile illness in northern Tanzania, yet they are infrequently diagnosed. We conducted this study to assess awareness and knowledge regarding selected zoonoses among healthcare providers in Moshi, Tanzania; to determine what diagnostic and treatment protocols are utilized; and obtain insights into contextual factors contributing to the apparent under-diagnosis of zoonoses.Methodology/ResultsWe conducted a questionnaire about zoonoses knowledge, case reporting, and testing with 52 human health practitioners and 10 livestock health providers. Immediately following questionnaire administration, we conducted semi-structured interviews with 60 of these respondents, using the findings of a previous fever etiology study to prompt conversation. Sixty respondents (97%) had heard of brucellosis, 26 (42%) leptospirosis, and 20 (32%) Q fever. Animal sector respondents reported seeing cases of animal brucellosis (4), rabies (4), and anthrax (3) in the previous 12 months. Human sector respondents reported cases of human brucellosis (15, 29%), rabies (9, 18%) and anthrax (6, 12%). None reported leptospirosis or Q fever cases. Nineteen respondents were aware of a local diagnostic test for human brucellosis. Reports of tests for human leptospirosis or Q fever, or for any of the study pathogens in animals, were rare. Many respondents expressed awareness of malaria over-diagnosis and zoonoses under-diagnosis, and many identified low knowledge and testing capacity as reasons for zoonoses under-diagnosis.ConclusionsThis study revealed differences in knowledge of different zoonoses and low case report frequencies of brucellosis, leptospirosis, and Q fever. There was a lack of known diagnostic services for leptospirosis and Q fever. These findings emphasize a need for improved diagnostic capacity alongside healthcare provider education and improved clinical guidelines for syndrome-based disease management to provoke diagnostic consideration of locally relevant zoonoses in the absence of laboratory confirmation.     

Q Fever Outbreak among Workers at a Waste-Sorting Plant

An outbreak of Q fever occurred in February–April 2014 among workers at a waste-sorting plant in Bilbao (Spain). The outbreak affected 58.5% of investigated employees, 47.2% as confirmed cases (PCR and/or serology) and 11.3% as probable cases (symptoms without laboratory confirmation). Only employees who had no-access to the waste processing areas of the plant were not affected and incidence of infection was significantly higher among workers not using respiratory protection masks. Detection by qPCR of Coxiella burnetii in dust collected from surfaces of the plant facilities confirmed exposure of workers inside the plant. Animal remains sporadically detected among the residues received for waste-sorting were the most probable source of infection. After cleaning and disinfection, all environmental samples tested negative. Personal protection measures were reinforced and made compulsory for the staff and actions were taken to raise farmers’ awareness of the biological risk of discharging animal carcasses as urban waste.     

Q fever in Croatia: war-induced changes in epidemiological characteristics

The article describes the epidemiological characteristics of Q fever in Croatia, during the period before and after the Homeland War. In the ten years prior to the Homeland War (1983-1992) 1053 cases of Q fever were recorded, 16.2% (171) of which on islands and in coastal areas. In the period after the Homeland War (1995-2008), a total of 654 cases was recorded, 59.9% (392) of which on islands and in coastal areas. In addition to reduced incidence, geographic distribution of the disease also changed. Before the war, the highest morbidity rate was recorded in the Sisak-Moslavina County. After the war, the Split-Dalmatia County recorded the highest morbidity rate because in the post-war period sheep from Bosnia and Herzegovina went to this county for winter grazing. The disease might be relevant to the Croatian Army and other armed forces that stay in Croatia as part of NATO forces.     

Q fever in the Mordvinian ASSR]

In the serological (CFT) examination of patients with elevated temperature for Q fever positive results were obtained in 8.2--14% of cases. The number of positive results of the CFT in rural districts was higher (16%) than in urban districts (10.2%). A considerable percentage of positive results was observed among the workers of a meat-packing plant (25%) and among persons who regularly received milk at their work as a special diet (25--39.2%). In the Mordovian ASSR the infection seemed to be transmitted mainly by the alimentary and contact ways.     

Serotyping Coxiella burnetii isolates from acute and chronic Q fever patients by using monoclonal antibodies

Abstract Four mouse monoclonal antibodies reacting with Coxiella burnetii lipopolysaccharide antigens were produced and used in serotyping 17 C. burnetii isolates from acute Q fever and Q fever endocarditis patients in France. Two monoclonal antibodies (1B2 and 3B6) were considered specific for the Priscilla strain, a representative of Q fever endocarditis isolates, and did not react with the Nine Mile strain, which is representative of acute Q fever isolates. Monoclonal antibodies Nos. 1B2 and 3B6 reacted with 75% (3/4) acute Q fever isolates and 85% (11/13) of endocarditis isolates from France. It is reasonable to conclude that Priscilla-like strains cause both acute Q fever and Q fever endocarditis. The hypothesis that Priscilla-like strains only are associated with Q fever endocarditis should be reconsidered.     

Q fever: hazard from sheep used in research.

The recent recognition that Q fever is endemic in Ontario and the known occupational risk of Q fever to research personnel working with sheep prompted a study to determine the prevalence of antibodies to the causative organism, Coxiella burnetti, in animals and staff at a Toronto animal research institute. Of 37 sheep 34 (92%) were found to be seropositive--that is, to have a titre of complement-fixing antibody to the phase II antigen of 1:8 or greater. Of 331 staff members tested, 18% were found to be seropositive, compared with 0.6% of a random sample of Toronto blood donors. The highest rate of seropositivity, 68%, was in the 28 animal attendants tested. Seropositivity was associated with working with sheep or fetal lamb tissue (p less than 0.0001) and with visiting the animal facility (p less than 0.001). Of the 59 seropositive staff members 63% had had no direct contact with sheep. There were 12 clinically apparent cases of Q fever, 2 of which required admission to hospital. Q fever remains a serious occupational hazard to staff working in research laboratories using sheep, even to those with indirect exposure to infected animals.     

Epidemiology of hemorrhagic fever with renal syndrome in the north Volga-Viatka region

The results of the ecological and epidemiological study of hemorrhagic fever with the renal syndrome (HFRS) in the Kirov region for the period of 1987-2000 are presented. HFRS morbidity rate varied from 1.3 to 13.7 per 100,000 population, which corresponded to the figures registered in the Volga Vyatka region. Cases of HRFS were mainly (90%) registered in three southern districts of the region. The moderate degree of correlation between morbidity rate and the number of wild mammals (r = 0.55) was established. Periodic morbidity rise occurred every 3 years. In 1998-2000 the contamination of wild mammals with HFRS virus increased and reached 7.6-9.5%. Infection factors connected with everyday human activities somewhat prevailed, industrial and agricultural types of infection constituting 43.8%. Males aged 20-49 years prevailed among the patients. Morbidity rate among urban dwellers exceeded that among town residents.     

Shifts in Geographic Distribution and Antimicrobial Resistance during a Prolonged Typhoid Fever Outbreak — Bundibugyo and Kasese Districts,Uganda, 2009–2011

Background

Salmonella enterica serovar Typhi is transmitted by fecally contaminated food and water and causes approximately 22 million typhoid fever infections worldwide each year. Most cases occur in developing countries, where approximately 4% of patients develop intestinal perforation (IP). In Kasese District, Uganda, a typhoid fever outbreak notable for a high IP rate began in 2008. We report that this outbreak continued through 2011, when it spread to the neighboring district of Bundibugyo.

Methodology/Principal Findings

A suspected typhoid fever case was defined as IP or symptoms of fever, abdominal pain, and ≥1 of the following: gastrointestinal disruptions, body weakness, joint pain, headache, clinically suspected IP, or non-responsiveness to antimalarial medications. Cases were identified retrospectively via medical record reviews and prospectively through laboratory-enhanced case finding. Among Kasese residents, 709 cases were identified from August 1, 2009–December 31, 2011; of these, 149 were identified during the prospective period beginning November 1, 2011. Among Bundibugyo residents, 333 cases were identified from January 1–December 31, 2011, including 128 cases identified during the prospective period beginning October 28, 2011. IP was reported for 507 (82%) and 59 (20%) of Kasese and Bundibugyo cases, respectively. Blood and stool cultures performed for 154 patients during the prospective period yielded isolates from 24 (16%) patients. Three pulsed-field gel electrophoresis pattern combinations, including one observed in a Kasese isolate in 2009, were shared among Kasese and Bundibugyo isolates. Antimicrobial susceptibility was assessed for 18 isolates; among these 15 (83%) were multidrug-resistant (MDR), compared to 5% of 2009 isolates.

Conclusions/Significance

Molecular and epidemiological evidence suggest that during a prolonged outbreak, typhoid spread from Kasese to Bundibugyo. MDR strains became prevalent. Lasting interventions, such as typhoid vaccination and improvements in drinking water infrastructure, should be considered to minimize the risk of prolonged outbreaks in the future.     

Large Regional Differences in Serological Follow-Up of Q Fever Patients in The Netherlands

Background

During the Dutch Q fever epidemic more than 4,000 Q fever cases were notified. This provided logistical challenges for the organisation of serological follow-up, which is considered mandatory for early detection of chronic infection. The aim of this study was to investigate the proportion of acute Q fever patients that received serological follow-up, and to identify regional differences in follow-up rates and contributing factors, such as knowledge of medical practitioners.

Methods

Serological datasets of Q fever patients diagnosed between 2007 and 2009 (N = 3,198) were obtained from three Laboratories of Medical Microbiology (LMM) in the province of Noord-Brabant. One LMM offered an active follow-up service by approaching patients; the other two only tested on physician''s request. The medical microbiologist in charge of each LMM was interviewed. In December 2011, 240 general practices and 112 medical specialists received questionnaires on their knowledge and practices regarding the serological follow-up of Q fever patients.

Results

Ninety-five percent (2,226/2,346) of the Q fever patients diagnosed at the LMM with a follow-up service received at least one serological follow-up within 15 months of diagnosis. For those diagnosed at a LMM without this service, this was 25% (218/852) (OR 54, 95% CI 43–67). Although 80% (162/203) of all medical practitioners with Q fever patients reported informing patients of the importance of serological follow-up, 33% (67/203) never requested it.

Conclusions

Regional differences in follow-up are substantial and range from 25% to 95%. In areas with a low follow-up rate the proportion of missed chronic Q fever is potentially higher than in areas with a high follow-up rate. Medical practitioners lack knowledge regarding the need, timing and implementation of serological follow-up, which contributes to patients receiving incorrect or no follow-up. Therefore, this information should be incorporated in national guidelines and patient information forms.     

Seroprevalence of Brucellosis,Leptospirosis, and Q Fever among Butchers and Slaughterhouse Workers in South-Eastern Iran

Zoonotic diseases can be occupational hazards to people who work in close contact with animals or their carcasses. In this cross-sectional study, 190 sera were collected from butchers and slaughterhouse workers in different regions of the Sistan va Baluchestan province, in Iran in 2011. A questionnaire was filled for each participant to document personal and behavioural information. The sera were tested for detection of specific IgG antibodies against brucellosis, leptospirosis, and Q fever (phase I and II) using commercial enzyme-linked immunosorbent assays (ELISA). The seroprevalence of brucellosis was 7.9%, leptospirosis 23.4%, and phase I and II of Q fever were 18.1% and 14.4%, respectively. The seroprevalence of Q fever and leptospirosis, but not brucellosis, varied among regions within the province (p = 0.01). Additionally, a significant relationship was found between seropositivity of Q fever and camel slaughtering (p = 0.04). Reduced seropositivity rate of brucellosis was associated with use of personal protective equipment (PPE) (p = 0.004). This study shows that brucellosis, leptospirosis and Q fever occur among butchers and slaughterhouse workers in this area.     

Incidence of Q fever in two inadequately investigated occupational groups.

In 1973 the authors investigated the incidence of Q fever serologically by means of the reaction of complement fixation (RCF) and the method of immunofluorescent titration (MIFT) in two inadequately investigated occupational groups--communal workers from the town of Russe and medical workers in obstetric departments of several towns in North Bulgaria. In addition, they carried out comparative studies in order to characterize the incidence and the degree of affection from the same disease in other persons exposed and not exposed at work in the same area--transport workers and blood donors. Out of 198 communal workers, 91 (45.95 +/- 3.54%) had positive titres for Q fever (1:8--1:512). A high incidence of Q fever was established in dustmen (61.40%), sweepers (46.55%) and drivers of dust cars (38.00%), i.e. persons collecting and rendering harmless the garbage of big town. Out of 174 medical workers in obstetric departments 65 (37.36% +/- 3.78%) were positive in titres 1:8--1:512. A high incidence of Q fever was established in obstetricians (57.14%), midwives (38.11%) and hospital attendants (34.38%), i.e. persons providing medical care for pregnant women or women in childbirth. In both groups the occupational hazard increases with the length of service. Out of 244 transport workers 82 (33.60% +/- 3.02%) were positive for Q fever, and out of 237 blood donors 19 (8.01 +/- 2.54%) were serologically positive for Q fever. The authors suggest continued investigation of these two occupational groups.     

Effects of ubiquinones on spontaneous membrane hyperpolarizations in a cloned monkey kidney cell line

The effects of ubiquinones on spontaneous membrane hyperpolarizations in JTC-12 cells were examined. There were three types of spontaneous hyperpolarizations; rhythmic, sporadic and oscillatory types. The oscillatory type was not observed in the standard medium, whereas it was observed in sodium-free medium or in the medium containing 300 nM coenzyme Q10. The number of the cells showing spontaneous hyperpolarizations significantly increased in the medium containing coenzyme Q10 (47.7%) as compared to the control (18.9%). However, coenzyme Q1 (500 nM) showed no effects.     

Protein candidates for Q fever serodiagnosis

The discriminatory diagnosis of Q fever remains difficult because of the unspecific clinical presentations of the disease. Additionally, the diagnosis is often delayed because serodiagnosis is not sensitive enough in the early stages of the disease when the immune response is not yet efficient. Similarly, the diagnosis of Q fever endocarditis can only be performed in approximately 35%, mainly via serology, which was a criterion postulated by Duke. Owing to the discriminatory diagnosis of Q fever and the high number of tests requested, we focused on expressing several proteins for ELISA studies with Coxiella burnetii-infected sera. Previously, we selected a list of 31 candidates [Sekeyova et?al. (2009) Eur J Clin Microbiol Infect Dis 28: 287-295], of which we have successfully cloned and expressed 21. Finally, 15 recombinant proteins were prescreened with the sera of patients with acute Q fever and Q fever endocarditis, respectively. Sera from a control group were also screened. The nine most immunoreactive proteins from the first assay were tested with the sera from a larger group of patients. Our study identified CBU_0092 as the best marker of acute Q fever but failed to isolate a highly specific and sensitive marker of Q fever endocarditis.