Q fever

Lysosomal trafficking regulator restricts intracellular growth of Coxiella burnetii by inhibiting the expansion of Coxiella-containing vacuole and upregulating nos2 expression

Coxiella burnetii is an obligate intracellular bacterium that causes Q fever, a zoonotic disease typically manifests as a severe flu-illness. After invading into the host cells, C. burnetii delivers effectors to regulate the vesicle trafficking and fusion events to form a large and mature Coxiella-containing vacuole (CCV), providing sufficient space and nutrition for its intracellular growth and proliferation. Lysosomal trafficking regulator (LYST) is a member of the Beige and Chediak-Higashi syndrome (BEACH) family, which regulates the transport of vesicles to lysosomes and regulates TLR signaling pathway, but the effect of LYST on C. burnetii infection is unclear. In this study, a series of experiments has been conducted to investigate the influence of LYST on intracellular growth of C. burnetii. Our results showed that lyst transcription was up-regulated in the host cells after C. burnetii infection, but there is no significant change in lyst expression level after infection with the Dot/Icm type IV secretion system (T4SS) mutant strain, while CCVs expansion and significantly increasing load of C. burnetii appeared in the host cells with a silenced lyst gene, suggesting LYST inhibits the intracellular proliferation of C. burnetii by reducing CCVs size. Then, the size of CCVs and the load of C. burnetii in the HeLa cells pretreated with E-64d were significantly decreased. In addition, the level of iNOS was decreased significantly in LYST knockout THP-1 cells, which was conducive to the intracellular replication of C. burnetii. This data is consistent with the phenotype of L-NMMA-treated THP-1 cells infected with C. burnetii. Our results revealed that the upregulation of lyst transcription after infection is due to effector secretion of C. burnetii and LYST inhibit the intracellular replication of C. burnetii by reducing the size of CCVs and inducing nos2 expression.

Genomic detection of Coxiellaburnetii based on plasmid genes in horses

Q fever is a worldwide zoonosis caused by an obligate intra-cellular pathogen called Coxiella burnetii affecting a broad range of animal hosts including horses. Most of the isolates found carry plasmids which genetic studies of C. burnetii strains suggest a critical role in C. burnetii survival. The correlation between an isolated plasmid type and the chronic or acute nature of the disease has always been controversial. This study was conducted to investigate the prevalence of C. burnetii QpH1 and QpDG plasmids in horses and assess the potential role of these species as reservoirs of infection and transmission. Nested-polymerase chain reaction (PCR) assays were performed on 320 blood serum samples drawn from horses in West Azerbaijan province, Iran, in 2020. In total, 26 (8.13%) Q fever-positive samples based on containing the IS1111 gene were tested by nested-PCR approach to amplify QpH1 and QpDG plasmid segments. The QpH1 and QpRS plasmid-specific sequences were identified in 19 (73.07%) and none in the serum samples, respectively. According to the present study, the age of the animal can be considered as an important risk factor for the prevalence of C. burnetii; but, the season, sex, and breed of the horse had no effect on the prevalence of disease. The results indicate that nested-PCR method could be suitable for routine diagnosis, to gather new information about the shedding of C. burnetii, and to improve the knowledge of contamination routes.

Open repair of a Coxiella burnetii-associated abdominal aortic endovascular stent graft infection with a cryopreserved allograft using visceral artery pump perfusion

Coxiella burnetii, the causative organism of Q fever, has been increasingly reported to be associated with infections of abdominal aortic aneurysms and endovascular stent grafts. We have added to the current literature by presenting a case of the surgical management of chronic Q fever that had infected a prior aortic endovascular stent graft placed for a contained rupture of an infrarenal aortic aneurysm in a 68-year-old woman. We presented our case of the surgical management of the excision and explantation of the infected aorta and stent graft, with reconstruction of the aorta using a cryopreserved aortic graft and visceral artery pump perfusion.

Diagnosis and Genotyping of Coxiella burnetii Endocarditis in a Patient with Prosthetic Pulmonary Valve Replacement Using Next-Generation Sequencing of Plasma Microbial Cell-Free DNA

Determining the causative etiology of culture-negative endocarditis can be challenging. We performed next-generation sequencing of plasma microbial cell-free DNA to facilitate rapid diagnosis and genotyping of Coxiella burnetii in a patient with culture-negative endocarditis of a prosthetic pulmonary valve, enabling early targeted treatment prior to valve replacement surgery.

A Q Fever Outbreak with a High Rate of Abortions at a Dairy Goat Farm: Coxiella burnetii Shedding, Environmental Contamination, and Viability

This study describes a Q fever outbreak in a herd of 77 Alpine goats which suffered a high rate of abortions (81% [58/72]) in January 2017 and presents the results of monitoring the contamination and viability of Coxiella burnetii in the farm environment several months after the outbreak. Over the course of 7 months, we studied bacterial shedding by 35 dams with abortions to monitor C. burnetii infection dynamics and the duration of excretion. The highest bacterial shedding load was observed in vaginal mucus, followed by in feces and in milk. Conversely, the duration of C. burnetii shedding was longer through feces (5 months after abortion) than milk (3 months). C. burnetii DNA was detected throughout the study in aerosol samples periodically collected indoors and outdoors from the animal premises. Mouse inoculation and culture in Vero cells demonstrated the presence of viable isolates in dust collected from different surfaces inside the animal facilities during the period of time with the highest number of abortions but not in dust collected 2, 3, and 4 months after the last parturition. Some workers and visitors were affected by Q fever, with attack rates of 78% (7/9) and 31% (4/13), respectively. Affected people mostly showed fever and seroconversion, along with myalgia and arthralgia in two patients and pneumonia in the index case. The genotype identified in animal and environmental samples (SNP1/MST13) turned out to be very aggressive in goats but caused only moderate symptoms in people. After the diagnosis of abortion by Q fever in goats, several control measures were implemented at the farm to prevent contamination inside and outside the animal facilities.IMPORTANCE This work describes a 7-month follow-up of the excretion by different routes of Coxiella burnetii genotype SNP1/MST13 in a herd of goats that suffered high rate of abortions (81%), generating high environmental contamination. Some of the workers and visitors who accessed the farm were infected, with fever as the main symptom but a low incidence of pneumonia. The detected strain (SNP1/MST13 genotype) turned out to be very aggressive in goats. The viability of C. burnetii was demonstrated in the environment of the farm at the time of abortions, but 2 months after the last parturition, no viable bacteria were detected. These results highlighted the importance of implementing good biosafety measures at farms and avoiding the entrance of visitors to farms several months after the end of the kidding period.

Presentation and diagnosis of acute Q fever in Portugal - A case series

Q fever is a worldwide zoonotic infection caused by the obligate intracellular bacterium Coxiella burnetii that can course with acute or chronic disease.

This series describes 7 cases of acute Q fever admitted in a Portuguese University Hospital between 2014 and 2015.

All cases presented with hepatitis and had epidemiological history. Diagnosis was done by PCR on majority (5) and by serology and PCR in only 2.

Serological tests can be negative in the initial period of the disease. Molecular biology methods by polymerase chain-reaction are extremely important in acute disease, allowing timely diagnosis and treatment.

Chronic Q fever: A missed prosthetic valve endocarditis possibly for years

Chronic Coxiella burnetii endocarditis usually develops in people with underlying heart disease and accounts for 60–70% of chronic Q fever. Onset is generally insidious and manifestations are atypical. The authors report a case of Coxiella burnetii prosthetic valve endocarditis in a 53 years- old patient with recurrent mechanical valve dehiscence on mitral position. He lived in a rural area with sheep and goats on the surroundings. During a 9 year- period, he was submitted to three cardiac mitral valve surgeries two of which with no Q fever diagnosis suspicion. Diagnosis was based on a positive serology test (Indirect imunofluorescence). Treatment consisted in a combination of prolonged course of hydroxychloroquine plus doxycycline and surgical replacement of the mitral valve, with a favorable outcome. With this case report, the authors pretend to highlight the not always expected diagnosis of Q fever endocarditis. If not considered, Coxiella burnetii endocarditis may lead to multiple cardiac surgeries, greater morbidity and potentially death.

Zoonotic bacterial meningitis in human adults

OBJECTIVE

To describe the epidemiology, etiology, clinical characteristics, treatment, outcome, and prevention of zoonotic bacterial meningitis in human adults.

METHODS

We identified 16 zoonotic bacteria causing meningitis in adults.

RESULTS

Zoonotic bacterial meningitis is uncommon compared to bacterial meningitis caused by human pathogens, and the incidence has a strong regional distribution. Zoonotic bacterial meningitis is mainly associated with animal contact, consumption of animal products, and an immunocompromised state of the patient. In a high proportion of zoonotic bacterial meningitis cases, CSF analysis showed only a mildly elevated leukocyte count. The recommended antibiotic therapy differs per pathogen, and the overall mortality is low.

CONCLUSIONS

Zoonotic bacterial meningitis is uncommon but is associated with specific complications. The suspicion should be raised in patients with bacterial meningitis who have recreational or professional contact with animals and in patients living in regions endemic for specific zoonotic pathogens. An immunocompromised state is associated with a worse prognosis. Identification of risk factors and underlying disease is necessary to improve treatment.

Selected Zoonoses

Human risks of acquiring a zoonotic disease from animals used in biomedical research have declined over the last decade because higher quality research animals have defined microbiologic profiles. Even with diminished risks, the potential for exposure to infectious agents still exists, especially from larger species such as nonhuman primates, which may be obtained from the wild, and from livestock, dogs, ferrets, and cats, which are generally not raised in barrier facilities and are not subject to the intensive health monitoring performed routinely on laboratory rodents and rabbits. Additionally, when laboratory animals are used as models for infectious disease studies, exposure to microbial pathogens presents a threat to human health. Also, with the recognition of emerging diseases, some of which are zoonotic, constant vigilance and surveillance of laboratory animals for zoonotic diseases are still required.

Serosurvey and observational study of US Army Veterinary Corps officers for Q fever antibodies from 1989 to 2008

Since World War II, the military has experienced outbreaks of Q fever among deploying units including recent case reports of Q fever in US military personnel returning from serving in the Middle East during Operation Iraqi Freedom and Operation Enduring Freedom. Occupational exposure and prevalence of Q fever among US Army Veterinary Corps officers have not been examined. A retrospective serosurvey and observational study of 500 military veterinarians were conducted using archived serum specimens from military veterinarians who entered and served between 1989 and 2008 and were tested for exposure to Coxiella burnetii. Corresponding longitudinal health-related, demographic, medical and deployment data were examined. A total of 69 (13.8%) individuals at military entry and 85 (17%) had late career positive titres. A total of 18 (3.6%) individuals showed seroconversion. Women were more likely to be seropositive after military service [prevalence ratio (PR) 1.96; 95% confidence interval (CI) 1.15–3.35] and were also more likely to seroconvert (incidence rate ratio 3.55; 95% CI 1.19–12.7). Women who deployed to Operation Iraqi Freedom were more likely to be seropositive (PR 3.17; 95% CI 1.03–9.71). Veterinarians with field service and pathology specialties had the highest incidence rates (7.0/1000 PY; 95% CI 4–12 and 3–19, respectively). This is the first report documenting US military veterinarians' exposure to C. burnetii. Military veterinarians are at risk prior to service, with moderate number of new cases developing during service and most maintaining titres for long periods of time. Women consistently demonstrated higher seroprevalence and incidence levels. As increasing numbers of women enter the veterinary profession and subsequently the US Army, this may warrant close monitoring. This study likely underestimates exposure and risk and does not address chronic health effects, which may be valuable to explore in future health studies.

Acute Q fever in Portugal. Epidemiological and clinical features of 32 hospitalized patients

INTRODUCTION

Q fever is a worldwide zoonosis caused by Coxiella burnetii. The main characteristic of acute Q fever is its clinical polymorphism, usually presenting as a febrile illness with varying degrees of hepatitis and/or pneumonia. Q fever is endemic in Portugal, and it is an obligatory notifiable disease since 1999. However, its epidemiological and clinical characteristics are still incompletely described.

METHODS

We performed a retrospective study of 32 cases admitted in the Infectious Diseases Department, Santa Maria's University Hospital, from January 2001 to December 2010, in whom acute Q fever was diagnosed by the presence of antibodies to phase II Coxiella burnetii antigens associated with a compatible clinical syndrome.

RESULTS

Out of the 32 cases recorded, 29 (91%) were male, with a male:female ratio of 9.7:1. Individuals at productive age were mainly affected (88%, n=28, with ages between 25 and 64 years). Clinically, the most common manifestation of acute Q fever was hepatic involvement (84%, n=27), which occurred isolated in 53% (n=17) of the cases. Hepatitis was more severe, presenting with higher values of liver function tests, in patients presenting both pulmonary and hepatic involvement. Additionally, we report one case of myocarditis and another one with neurological involvement. Empiric but appropriate antibiotic therapy was given in 66% (n=21) of the cases. There was a complete recovery in 94% (n=30) of the patients, and one death. We confirmed the sub-notification of this disease in Portugal, with only 47% (n=15) of the cases notified.

CONCLUSION

In Portugal further studies are needed to confirm our results. From the 32 cases studied, acute Q fever presented more frequently as a febrile disease with hepatic involvement affecting mainly young male individuals. Furthermore, acute Q fever is clearly underdiagnosed and underreported in Portugal, which suggests that an increased awareness of the disease is needed, together with a broader use of serological testing.

Application of a broad-range resequencing array for detection of pathogens in desert dust samples from Kuwait and Iraq

A significant percentage of the human population is exposed to high levels of naturally occurring airborne dusts. Although the link between airborne particulate inhalation and a variety of respiratory diseases has long been established, little is known about the pathogenic role of the microbial component of the dust. In this study, we applied highly multiplexed PCR and a high-density resequencing microarray (RPM-TEI version 1.0) to screen samples of fine topsoil particles and airborne dust collected in 19 locations in Iraq and Kuwait for the presence of a broad range of human pathogens. The results indicated the presence of potential human pathogens, including Mycobacterium, Brucella, Coxiella burnetii, Clostridium perfringens, and Bacillus. The presence of Coxiella burnetii, a highly infectious potential biowarfare agent, was confirmed and detected in additional samples by use of a more sensitive technique (real-time PCR), indicating a high prevalence of this organism in the analyzed samples. The detection of potentially viable pathogens in breathable dusts from arid regions of Iraq and Kuwait underscores the importance of further study of these environments.

Silencing of three Amblyomma americanum (L.) insulin-like growth factor binding protein-related proteins prevents ticks from feeding to repletion

The insulin-like growth factor (IGF) binding proteins (IGFBP) family is the regulatory arm of the IGF signaling system that control mitogenic and anabolic actions of IGF peptide hormones. This study describes cloning and biological characterization of three Amblyomma americanum (L.) (Aam) proteins that show amino-terminal sequence and secondary structure similarity to the IGFBP superfamily. The three molecules here provisionally identified as AamIGFBP-rP1 and short (S) and long (L) AamIGFBP-rP6 are expressed in multiple tick organs and are responsive to tick feeding activity with the former being upregulated and the latter being downregulated. We show that they regulate tick physiological functions that may be related to A. americanum tick feeding success as revealed by RNAi-mediated dual silencing of AamIGFBP-rP6S and AamIGFBP-rP6L or AamIGFBP-rP1 alone, which caused a reduction in blood meal size compared to the controls. Additionally, in the case of AamIGFBP-rP1 silencing, 47% of ticks died while attempting to feed and those that did survive and spontaneously detached from the host failed to lay eggs. Although AamIGFBP-rP6S and AamIGFBP-rP6L show overall identities of 49% and 59%, respectively, to Rhipicephalus microplus C protein, the identity level jumps to ~84% when the comparison is restricted to first 70 amino acids of the mature protein. Similarly, the AamIGFBP-rP1 mature protein is ~72%, 87%, 88% and 92% identical to that of Ixodes scapularis S, R. microplus, R. appendiculatus N and A. variegatum F, respectively. The observed across-tick-species conservation suggests that the three molecules (AamIGFBP-rP1, AamIGFBP-rP6S and AamIGFBP-rP6L) represent target for development of vaccines to protect animals against multiple tick species. The data are discussed with reference to advances in tick molecular biology and the potential of the three proteins as targets for immunizing animals against tick feeding.

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.

Endemic infectious diseases of Afghanistan

The current crisis in Afghanistan has resulted in an influx of Western military personnel, peacekeepers, humanitarian workers, and journalists. At the same time, unprecedented numbers of internally displaced persons and refugees have overwhelmed much of the already fragile infrastructure, setting the stage for outbreaks of infectious diseases among both foreigners and local populations. This review surveys the literature concerning the infectious diseases of Afghanistan and south-central Asia, with particular emphasis on diseases not typically seen in the Western world.

Tularemia and Q fever

The zoonotic infections caused by Francisella tularensis and Coxiella burnetii, tularemia and Q fever, respectively, are two less commonly encountered clinical illnesses that are becoming increasingly recognized as epidemiologically important human diseases. The prevalence of tularemia and Q fever can be positively impacted by increased awareness of the clinical entities that arise from infection by these arthropod-borne organisms. Improved recognition of these clinical syndromes will lead to greater diagnostic accuracy in recognizing these diseases in patients. Ultimately, more stringent measures to prevent infection may be required, through raising public awareness, since current therapeutic regimens for these two diseases are limited, and knowledge of the pathogenesis of these two organisms are still in developing stages.

Changing epidemiology of Q fever in Germany, 1947-1999

The epidemiology of Q fever in Germany was examined by reviewing relevant studies since 1947 and by analyzing available surveillance data since 1962. The average annual Q fever incidence nationwide from 1979 to 1989 was 0.8 per million and from 1990 to 1999, 1.4 per million. The mean annual incidence from 1979 to 1999 ranged from a minimum of 0.1 per million in several northern states to 3.1 per million in Baden-Württemberg, in the South. We identified 40 documented outbreaks since 1947; in 24 of these sheep were implicated as the source of transmission. The seasonality of community outbreaks has shifted from predominantly winter- spring to spring-summer, possibly because of changes in sheep husbandry. The location of recent outbreaks suggests that urbanization of rural areas may be contributing to the increase in Q fever. Prevention efforts should focus on reducing sheep-related exposures, particularly near urban areas.

Goat-associated Q fever: a new disease in Newfoundland

In the spring of 1999 in rural Newfoundland, abortions in goats were associated with illness in goat workers. An epidemiologic investigation and a serologic survey were conducted in April 1999 to determine the number of infections, nature of illness, and risk factors for infection. Thirty-seven percent of the outbreak cohort had antibody titers to phase II Coxiella burnetii antigen >1:64, suggesting recent infection. The predominant clinical manifestation of Q fever was an acute febrile illness. Independent risk factors for infection included contact with goat placenta, smoking tobacco, and eating cheese made from pasteurized goat milk. This outbreak raises questions about management of such outbreaks, interprovincial sale and movement of domestic ungulates, and the need for discussion between public health practitioners and the dairy industry on control of this highly infectious organism.

Lymphadenopathy

Lymphadenopathy can occur in any age group, in symptomatic or asymptomatic patients, and in a single site or at multiple sites. Lymphadenopathy is associated with numerous disorders. An abnormal lymph node may be observed or palpated by the patient, found by a health care worker, or discovered through radiologic evaluation. Lymphadenopathy may be a part of a complex case presentation, or the clinical cause may be straightforward. Patients with potentially curable malignant disorders may have lymphadenopathy as the first sign of their disease. This review of lymphadenopathy summarizes general considerations, discusses which patients might be considered for biopsy, reviews which nodes are most likely to be diagnostic, outlines initial diagnostic considerations on a region-by-region basis, and reviews a broad differential diagnosis for adenopathy.

Long term vascular complications of Coxiella burnetii infection in Switzerland: cohort study

OBJECTIVE

To evaluate the range of long term vascular manifestations of Coxiella burnetii infection.

DESIGN

Cohort study in Switzerland of people affected in 1983 by the largest reported outbreak of Q fever and who were followed up 12 years later. Follow up information about possible vascular disease and endocarditis was obtained through a mailed questionnaire and death certificates.

SETTING

Val de Bagnes, a rural Alpine valley in Switzerland.

PARTICIPANTS

2044 (87%) of 2355 people who had serum testing for Coxiella burnetii infection in 1983: 1247 were classed as not having been infected, 411 were classed as having been acutely infected, and 386 were classed as having been infected before 1983.

MAIN OUTCOME MEASURES

Relative risk controlled for age and sex and 12 year risk of vascular diseases and endocarditis among infected participants as compared with those who had never been infected.

RESULTS

The 12 year risk of endocarditis or venous thromboembolic disease was not increased among those who had been acutely infected. The 12 year risk of arterial disease was significantly higher among those who had been acutely infected (7%) as compared with those who had never been infected (4%) (relative risk 2.2, 95% confidence interval 1.4 to 3.6). Specifically, there was an increased risk of developing a cerebrovascular accident (relative risk 3.7, 1.6 to 8.4) and cardiac ischaemia (relative risk 1.9, 1.04 to 3.4). 12 year mortality was significantly higher among the 411 people who had been acutely infected in 1983 (9.7%; age adjusted relative risk 1.8, 1.2 to 2.6) when compared with the 1247 participants who had remained serologically negative in 1983 (7.0%).

CONCLUSIONS

Coxiella burnetii infection may cause long term complications including vascular disease.

The diverse habitats of obligate intracellular parasites

Bacterial obligate intracellular parasites have evolved diverse mechanisms for evasion of host cellular defenses. These mechanisms involve adaptations for survival in distinct intracellular compartments. Intracellular niches inhabited by obligate intracellular parasites include the cytoplasm, arrested early endosomes, lysosomes, and vesicles that do not fuse with the endosomal compartment but intersect with an exocytic pathway.

[Community acquired pneumonia. Reliability of the criteria for deciding ambulatory treatment]

To determine whether criteria for not admitting community-acquired pneumonia (CAP) patients diagnosed in the emergency room are appropriate, and to characterize the symptoms, etiology and course of CAP. This one-year prospective, protocol study of immunocompetent CAP patients diagnosed in the emergency room of our hospital enrolled patients not considered to require hospital admission according to the recommendations of the Spanish Society of Respiratory Disease (SEPAR). Medical histories, chest X-rays and blood analysis were obtained for all patients. Blood cultures were analyzed for antibodies against Legionella pneumophila, Mycoplasma pneumoniae, Coxiella burnetii, Chlamydia pneumoniae, Chlamydia psittaci and influenza virus types A and B. The patients received erythromycin for 14 days and were regularly checked by the pulmonologist in the outpatient clinic until signs and symptoms had disappeared. One hundred six patients were enrolled. Mean age was 36 +/- 13 years. Only 3 patients had to be admitted to hospital, after which outcome was good. The main symptoms were fever (106, 100%) and cough (83, 78%). In 46 (43.4%) chest sounds were normal. Microbiologic diagnoses were achieved for 28 (26.4%) and Coxiella burnetii was the agent most often found (19, 17.9%). Outcome was good in all cases, with faster disappearance of symptoms than of radiological signs. The SEPAR criteria for admitting patients with CAP are appropriate. The clinical symptoms of such patients are non specific, a noteworthy finding being that many patients had normal chest sounds. Coxiella burnetii was the most common causative agent. Both clinical and radiological outcomes were excellent.

High incidence of Coxiella burnetii markers in a rural population in France

Since Coxiella burnetii, the causative agent of Q fever, is often transmitted from goats and sheep to humans through aerosols, we examined the sera from 168 persons involved in goat breeding in the Centre region of France and 40 members of veterinary and medical staff from the same region for the presence of antibodies against C. burnetii. An immunofluorescence assay was used to detect the presence of antibodies of the IgG isotope against epitopes from phase II of C. burnetii, which are the first antibodies to appear in infected people, and from phase I, which reflect more chronic stages of the infection. Our serological survey showed that most of the tested sera were positive for C. burnetii markers, indicating at least an encounter with the bacterium. In the overall population of 208 subjects, 71% of the sera had antibodies against phase II epitopes (titres > or = 1:40). Among the goat farmers and their immediate families, 78% had antibodies against phase II and 33% against phase I (titres > or = 1:40). Considering only high titres (> or = 1:320), though, only 37% of the farmers had antibodies against phase II and 15% against phase I. Only 3 out of 12 veterinarians working in the field had high titres of antibodies against phase II and phase I, while none of 28 members of veterinary and medical laboratories had significant levels of antibodies. These results emphasize the need for closer surveillance of populations at risk for Q fever, to prevent the infection by C. burnetii from reaching chronic stages of the disease.

Seroepidemiological survey of Q fever in León province, Spain

A seroepidemiological survey, using an indirect immunofluorescence test against Coxiella burnetii (antigenic phase II), was carried out in León province, north-western Spain. A total of 406 serum samples was collected from people (from 15 to more than 65 years old) living in a rural environment during the winter and spring of 1994. The overall prevalence was 40.6%, titres ranged from 1:80 to 1:640, and a titre of 1:80 was encountered among 60.6% of positive samples. A significant higher prevalence was observed among males globally, as well as among those aged 15-44 and 45-64 years old; however, no difference was encountered among males and females older than 64 years. In the same way, a significant higher Q fever prevalence was observed among individuals having occupations related to agriculture and among those having close relationship with animals.

Isolation of Coxiella burnetii from heart valves of patients treated for Q fever endocarditis

Coxiella burnetii was isolated from the valve material of two patients who underwent valvectomy because of progressive congestive heart failure due to endocarditis. In each case antibiotic therapy was administered for several months prior to valvectomy. Classical histopathological examination of the valves did not reveal an etiology. However, coxiella-like organisms were demonstrated in valvular material with Köster, Stamp, and Giemsa stains, and the organisms were grown in cell culture. Antibody titers were consistent with the diagnosis of chronic C. burnetii infection. This report illustrates the advantage of simple and fast staining techniques and cell culture for the demonstration and isolation of C. burnetii in the heart valve tissue of patients with Q fever endocarditis.

Coxiella burnetii infection in subjects with HIV infection and HIV infection in patients with Q fever

The objective of the study was to determine whether HIV infection favors the acquisition of Coxiella burnetii infection or increases the frequency of symptomatic Coxiella infections. A total of 754 subjects were tested for Coxiella antibodies: 596 intravenous drug users (IVDUs) (306 HIV-infected IVDUs matched by aged and sex with 291 non-HIV-infected IVDUs), and 157 healthy puerperal women matched to the IVDU women. A total of 520 patients with Q fever were tested for HIV antibodies. The seroprevalence of Coxiella antibodies was similar in the 2 groups of IVDUs (19.3% of HIV + IVDUs vs 22.9% of HIV - IVDUs). Likewise, there was no difference in the prevalence of Coxiella antibodies in the groups of IVDU women and healthy women. Of the 520 subjects with acute Q fever, diagnosed between 1987 and 1992, only 4 (0.77%) had HIV infection. The proportions of HIV-infected subjects in the population of patients, with Q fever, of 20-39 years of age (the age of maximum incidence of both HIV and Coxiella infection in our region), coincided with the estimated proportions of HIV subjects in the respective general populations of the province. In conclusion, infection by Coxiella burnetii was not more frequent among HIV-infected subjects. It is not likely that Coxiella infection produces symptomatic infections more often in HIV-infected subjects.

Heart transplantation for Q fever endocarditis

A 30-year-old man underwent aortic and mitral valve replacement for the treatment of Q fever endocarditis. Postoperatively, paravalvular leak of the mitral prosthesis, progressive deterioration in cardiac function, and intractable heart failure developed. As a result, the patient underwent orthotopic heart transplantation 15 months after his initial valve operation. The patient is clinically well 14 months after transplantation.