Comparison between emerging Q fever in French Guiana and endemic Q fever in Marseille, France

Etiology of Acute Febrile Illnesses in Adults in the Defense Community in French Guiana

In tropical countries, acute febrile illnesses represent a complex clinical problem for general practitioners. We describe the prevalence of different etiologies of acute febrile illnesses occurring among French service members and their families, excluding children, in general practice in French Guiana. From June 2017 to March 2020, patients with a fever ≥37.8°C with a duration of less than 15 days who sought medical care at the army medical centers in Cayenne and Kourou were prospectively enrolled. Based on clinical presentation, blood, urine, nasopharyngeal, and stool samples were collected for diagnostic testing for viruses, bacteria, and parasites (by direct examination, microscopic examination of blood smears, culture, serology, or polymerase chain reaction), and standardized biological tests were systematically performed. Among 175 patients retained for analysis, fever with nonspecific symptoms was predominant (46.9%), with 10 Plasmodium vivax malaria cases, 8 dengue infections, and 6 cases of Q fever. The second most frequent cause of acute febrile illness was upper respiratory tract infections (32.0%) due to influenza virus (n = 18) or human rhinovirus (n = 10). Among the causes of acute febrile illness in French Guiana, clinicians should first consider arboviruses and malaria, as well as Q fever in cases of elevated C-reactive protein with nonspecific symptoms and influenza in cases of signs and symptoms associated with upper respiratory tract infections. Despite an expanded microbiological search, the etiology of 51.4% of acute febrile illnesses remain unknown. Further investigations will be necessary to identify the etiology of acute febrile illnesses, including new pathogens, in French Guiana.

Chest CT findings in community-acquired pneumonia due to Coxiella burnetii (Q fever) compared to Streptococcus pneumoniae, a cross sectional study in French Guiana, 2013-2017

OBJECTIVES

Few and small studies previously examined chest CT-scan characteristics of Coxiella burnetii (Cb) community-acquired pneumonia (CAP). Larger studies are needed to guide physicians towards diagnosis of Q fever in case of pneumonia.

METHODS

We conducted a single-center retrospective observational study between 2013 and 2017. All patients with Cb or Streptococcus pneumoniae (Sp) CAP who had a chest CT-scan on admission at Cayenne Hospital (French Guiana) were included. Chest CT-scan were all analyzed by the same expert radiologist.

RESULTS

We included 75 patients with Cb CAP and 36 with Sp CAP. Fifty-nine percent of all patients were men (n = 66) and median age was 52 [IQR = 38-62]. Chest CT-scans of Cb CAP patients revealed 67 alveolar condensations (89 %), 52 ground-glass opacities (69 %), 30 cases of lymphadenopathy(ies) (40 %) and 25 pleural effusions (33 %). Parenchyma lesions caused by Cb were predominantly unilateral (67 %). We found high numbers of alveolar condensations in both Cb and Sp CAP (89 % and 75 %; respectively), but the presence of ground-glass opacities was significantly associated with Cb CAP (69 % versus 30 %; p < 0.01). Cb CAP were associated with more lymphadenopathies (40 % vs 17 %; p = 0.01) while Sp CAP showed more bronchial thickening (19 % versus 3 %; p < 0.01) and (micro)nodule(s) ≤1 cm (25 % vs 3 %, p < 0.01).

CONCLUSIONS

This large study shows that the most typical aspect of chest CT-scan in case of Cb CAP in French Guiana is a unilateral alveolar consolidation associated with ground glass opacities and lymphadenopathies. C. burnetti and S. pneumoniae both most often cause alveolar consolidations, but present some significantly different CT-scan patterns. This could help physicians through therapeutic choices.

A Narrative Review of Q Fever in Europe

Coxiella burnetii, the causative agent of Q fever, causes abortions in animals. Its effects on humans and the management of Q fever in certain conditions like pregnancy are undetermined. The World Health Organization has estimated that zoonotic diseases cause around one billion cases of infections and millions of deaths globally each year. It is worth noting that many emerging infectious diseases currently being reported worldwide are zoonoses. We reviewed studies reporting on Q fever prevalence and incidence in Europe. Articles from 1937 to 2023 with the following terms "Coxiella burnetii and Europe and Q fever, and seroprevalence studies" were identified in the PubMed database and reports by organizations such as the European Centre for Disease Prevention and Control (ECDC). We included randomized and observational studies, seroprevalence studies, case series, and case reports. According to the ECDC in 2019, 23 countries reported 1069 cases, the majority of which were classified as confirmed cases. The number of reports per 100,000 inhabitants in the EU/EEA was 0.2 for 2019, the same as the previous four years. The highest report rate (0.7 cases per 100,000 population) was observed in Spain, followed by Romania (0.6), Bulgaria (0.5), and Hungary. Considering the typically asymptomatic nature of Q fever infection, it is imperative to strengthen the existing systems to promote the rapid identification and reporting of Q fever outbreaks in animals, particularly in cases of abortion. It is also essential to consider the facilitation of early information exchange between veterinarians and public health counterparts to ensure the timely detection and prevention of potential zoonotic events, including Q fever.

[Overview of infectious and non-infectious diseases in French Guiana in 2022]

Source of many myths, French Guiana represents an exceptional territory due to the richness of its biodiversity and the variety of its communities. The only European territory in Amazonia, surrounded by the Brazilian giant and the little-known Suriname, Ariane 6 rockets are launched from Kourou while 50% of the population lives below the poverty line. This paradoxical situation is a source of health problems specific to this territory, whether they be infectious diseases with unknown germs, intoxications or chronic pathologies.Some infectious diseases such as Q fever, toxoplasmosis, cryptococcosis or HIV infection are in common with temperate countries, but present specificities leading to sometimes different management and medical reasoning. In addition to these pathologies, many tropical diseases are present in an endemic and / or epidemic mode such as malaria, leishmaniasis, Chagas disease, histoplasmosis or dengue. Besides, Amazonian dermatology is extremely varied, ranging from rare but serious pathologies (Buruli ulcer, leprosy) to others which are frequent and benign such as agouti lice (mites of the family Trombiculidae) or papillonitis. Envenomations by wild fauna are not rare, and deserve an appropriate management of the incriminated taxon. Obstetrical, cardiovascular and metabolic cosmopolitan pathologies sometimes take on a particular dimension in French Guiana that must be taken into account in the management of patients. Finally, different types of intoxication are to be known by practitioners, especially due to heavy metals.European-level resources offer diagnostic and therapeutic possibilities that do not exist in the surrounding countries and regions, thus allowing the management of diseases that are not well known elsewhere.Thanks to these same European-level resources, research in Guyana occupies a key place within the Amazon region, despite a smaller population than in the surrounding countries. Thus, certain pathologies such as histoplasmosis of the immunocompromised patient, Amazonian toxoplasmosis or Q fever are hardly described in neighboring countries, probably due to under-diagnosis linked to more limited resources. French Guiana plays a leading role in the study of these diseases.The objective of this overview is to guide health care providers coming to or practicing in French Guiana in their daily practice, but also practitioners taking care of people returning from French Guiana.

Transmission dynamics of Q fever in French Guiana: A population-based cross-sectional study

Background

Q fever is a zoonosis caused by Coxiella burnetii which is among the major agents of community-acquired pneumonia in French Guiana. Despite its relatively high incidence, its epidemiology in French Guiana remains unclear, and all previous studies have considered transmission from livestock unlikely, suggesting that a wild reservoir is responsible for transmission.

Methods

A country-wide seroprevalence survey of 2697 participants from French Guiana was conducted. Serum samples were tested for phase II IgG antibodies by ELISA and indirect immunofluorescence assays (IFAs). Factors associated with Q fever were investigated, and a serocatalytic model was used to reconstruct the annual force of infection.

Findings

The overall weighted seroprevalence was estimated at 9.6% (95% confidence interval (CI): 8.2%-11.0%). The model revealed constant, low-level circulation across French Guiana, particularly affecting middle-aged males (odds ratio (OR): 3.0, 95% credible interval (CrI): 1.7-5.8) and individuals living close to sheep farms (OR: 4, 95% CrI: 1.5-12). The overall annual number of cases was estimated at 579 (95% CrI: 492-670). In the region around Cayenne, the main urban municipality, the high seroprevalence was explained by an outbreak that may have occurred between 1996 and 2003 and that infected 10% (95% CrI: 6.9%-14%) of the population and males and females alike.

Interpretation

This study reveals for the first time Q fever dynamics of transmission and the role of domestic livestock in transmission in French Guiana and highlights the urgent need to reinforce Q fever surveillance in livestocks of the entire Guianese territory.

Funding

This study was supported by the "European Regional Development Fund" under EPI-ARBO grant agreement (GY0008695), the "Regional Health Agency of French Guiana" and the "National Center of Spatial Studies". The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

High incidence of acute Q fever among incarcerated people in Cayenne, French Guiana

Q fever is a major public health problem in French Guiana. In recent years, a considerable number of cases has been reported in French Guiana's penitentiary center. The main objective of this study was to describe the epidemiology of these cases. A retrospective study was conducted at the prison to identify cases of acute Q fever in people incarcerated between 2010 and 2021. During the study period, 16 patients were diagnosed with acute Q fever. The positivity rate varied between 13 and 57%. The annual incidence rate in 2019, 2020 and 2021 was 269 (95% CI: 0-640) 1,120 (95% CI: 290-1950) and 1,931 (95% CI: 60-3810) per 100,000 person-years, respectively. While several vertebrate species have already been shown to play an important role in the transmission of Coxiella burnetii, the full epidemiology picture in the tropics is far from clear, and the prison context, with its controlled environment, could help provide answers.

High endemicity of Q fever in French Guiana: A cross sectional study (2007–2017)

Q fever (QF) is a zoonosis caused by Coxiella burnetii (Cb). French Guiana (FG) had a high incidence but no data have been published since 2006. The objective of this study was to update the incidence and epidemiological data on QF in FG. A retrospective study of all FG Q fever serodiagnosis between 2007 and 2017 was carried out. Among the 695 patients included, the M/F sex-ratio was 2.0 and the median age of 45.3 years (IQR 33.7–56.3). The annual QF incidence rate was 27.4 cases (95%CI: 7.1–47.7) per 100,000 inhabitants ranging from 5.2 in 2007 to 40.4 in 2010. Risk factors associated with Q fever compared to general population were male gender, being born in mainland France, an age between 30 to 59 years-old and a residence in Cayenne and surroundings. The incidence of QF in FG remains high and stable and the highest in the world.

We present here a study showing the exceptional nature of the incidence of Q fever in French Guiana. Indeed, this zoonosis due to the bacterium Coxiella burnetii, is a real public health problem in French Guiana, a French ultra-marine territory located in the North East of South America. The study found an endemic state with a stable incidence between 2010 and 2017 around 25–30 cases per 100,000 inhabitants per year. More than 90% of cases are concentrated in the territory’s capital, Cayenne, and its surroundings. The risk factors for Q fever are being male, being between 30 and 59 years old, which are risk factors found elsewhere, but also living in Cayenne and its surroundings and being born in mainland France or Europe.

Q Fever: A troubling disease and a challenging diagnosis

Q fever is a disease caused by the bacterial pathogen Coxiella burnetii. This hardy organism can easily spread long distances in the wind, and only a few infectious aerosolized particles are necessary to cause serious illness. Presentations of Q fever disease can be wide-ranging, allowing it to masquerade as other illnesses and highlight the importance of laboratory testing for diagnosis and treatment. This review summarizes Q fever's epidemiology and clinical presentations and presents classical laboratory diagnostic assays and novel approaches to detecting this troubling disease.

Capybara and Brush Cutter Involvement in Q Fever Outbreak in Remote Area of Amazon Rain Forest, French Guiana, 2014

We investigated a Q fever outbreak that occurred in an isolated area of the Amazon Rain Forest in French Guiana in 2014. Capybara fecal samples were positive for Coxiella burnetii DNA. Being near brush cutters in use was associated with disease development. Capybaras are a putative reservoir for C. burnetii.

Human Q Fever on the Guiana Shield and Brazil: Recent Findings and Remaining Questions

Purpose of Review

In this review, we report on the state of knowledge about human Q fever in Brazil and on the Guiana Shield, an Amazonian region located in northeastern South America. There is a contrast between French Guiana, where the incidence of this disease is the highest in the world, and other countries where this disease is practically non-existent.

Recent Findings

Recent findings are essentially in French Guiana where a unique strain MST17 has been identified; it is probably more virulent than those usually found with a particularly marked pulmonary tropism, a mysterious animal reservoir, a geographical distribution that raises questions.

Summary

Q fever is a bacterial zoonosis due to Coxiella burnetii that has been reported worldwide. On the Guiana Shield, a region mostly covered by Amazonian forest, which encompasses the Venezuelan State of Bolivar, Guyana, Suriname, French Guiana, and the Brazilian State of Amapá, the situation is very heterogeneous. While French Guiana is the region reporting the highest incidence of this disease in the world, with a single infecting clone (MST 117) and a unique epidemiological cycle, it has hardly ever been reported in other countries in the region. This absence of cases raises many questions and is probably due to massive under-diagnosis. Studies should estimate comprehensively the true burden of this disease in the region.

Epidemiological, clinical and laboratory characteristics of acute Q fever in an endemic area in Israel, 2006-2016

Our purpose was to describe the clinical, epidemiological and laboratory characteristics of patients hospitalised with acute Q fever in an endemic area of Israel. We conducted a historical cohort study of all patients hospitalised with a definite diagnosis of acute Q fever, and compared them to patients suspected to have acute Q fever, but diagnosis was ruled out. A total of 38 patients had a definitive diagnosis, 47% occurred during the autumn and winter seasons, only 18% lived in rural regions. Leucopaenia and thrombocytopaenia were uncommon (16% and 18%, respectively), but mild hepatitis was common (mean aspartate aminotransferase 76 U/l, mean alanine aminotransferase 81 U/l). We compared them with 74 patients in which acute Q fever was ruled out, and found that these parameters were not significantly different. Patients with acute Q fever had a shorter hospitalisation and they were treated more often with doxycycline than those without acute Q fever (6.4 vs. 14 days, P = 0.007, 71% vs. 38%, P = 0.001, respectively). In conclusion, acute Q fever can manifest as an unspecified febrile illness, with no seasonality. We suggest that in endemic areas, Q fever should be considered in the differential diagnosis in any febrile patient with risk factors for a persistent infection.

New insights in Coxiella burnetii infection: diagnosis and therapeutic update

Introduction: Coxiella burnetii infection is still challenging physicians, mainly because no international coordination has been stated to standardize the therapeutic strategy and improve the clinical outcomes.Areas covered: Based on the recent knowledge on Q fever, we review here the clinical practices from Q fever diagnosis to therapy. We searched PubMed and Google Scholar to perform the qualitative synthesis.Expert opinion: Four major critical points are highlighted in this review. The first point is that Q fever diagnosis has been reviewed in the light of the new diagnosis tools, including molecular biology, transthoracic echocardiography, and 18F-FDG-PET/CT-scan imaging. Q fever diagnosis results from the presence of a microbiological criterion in addition to a lesional criterion. Second, the identification of the anticardiolipin antibodies as a novel biological predictive marker for acute Q fever complications (hemophagocytic syndrome, acute Q fever endocarditis, alithiasic cholecystitis, hepatitis, and meningitis). Third, the observation of a coincidence between Q fever and non-Hodgkin lymphoma that has made persistent C. burnetii infection a risk of non-Hodgkin lymphoma. Finally, we expose here the close follow-up we proposed from the French National Reference Center for patients with Q fever infection to detect relapse and complications.

Ten-year experience of Q fever endocarditis in a tertiary cardiac center in Saudi Arabia

BACKGROUND

Q fever endocarditis (QFE) is considered rare in the Middle East, with only a few cases reported in Saudi Arabia. The aim of this study is to report on the experience of our centre on QFE.

METHODS

We searched the medical records for cases of QFE at our cardiac center from 2009-2018. Demographic data, clinical features, serology and echocardiography results, treatments, and outcomes were assessed.

RESULTS

Five hundred and two cases of infective endocarditis were detected over the 10 years period. Among the 234 patients with blood culture-negative endocarditis (BCNE), 19 (8.10%) had QFE. All patients had a previously diagnosed congenital heart disease except for one patient with rheumatic heart disease. Eleven patients had received a bovine jugular vein-related implant, e.g., a Melody valve (seven patients) or Contegra conduit (four patients). Coinfection was detected in three patients, and immunologic and embolic phenomena were observed in five patients. All patients received a combination of hydroxychloroquine and doxycycline, with good outcomes. Only two patients required surgery while on treatment. Two patients died several months after treatment; the cause of death was not identified.

CONCLUSION

This study indicates that Q fever exists in our population. The majority of the patients had congenital heart disease (CHD) and underwent bovine jugular vein implants. Patients with CHD are at increased risk of infective endocarditis. Bovine jugular vein implants increase the risk of infective and possibly QFE. Proper exclusion of Q fever is warranted in all BCNE and possibly in culture-positive endocarditis cases in areas endemic to Q fever.

KEY POINTS

We presented the largest series of Q fever endocarditis cases in Saudi Arabia. We showed that Q fever is not rare in the Middle East and suggest that it should be considered in all blood culture-negative endocarditis cases.

Infections tropicales graves dans les départements français d’Amérique, Antilles françaises et Guyane

Les Antilles-Guyane (AG) sont les départements français du continent américain, situés en zone intertropicale. La diversité des écosystèmes ainsi que le climat tropical à très forte pluviosité exposent à un vaste panel de pathologies infectieuses. Ces territoires sont de plus l’objet de mouvements importants de populations, voyageurs ou migrants, ce qui joue un rôle significatif dans le développement d’épidémies et/ou de pathologies émergentes. Ces pathologies infectieuses dites « tropicales » peuvent nécessiter une prise en charge en réanimation. Nous rapportons ici les principales données récentes concernant ces pathologies (hors infection liée au VIH) ainsi que les stratégies diagnostiques et thérapeutiques, à l’usage des réanimateurs amenés à exercer en zone tropicale AG ou recevant en métropole des patients issus de cette région.

The hypervirulent Coxiella burnetii Guiana strain compared in silico, in vitro and in vivo to the Nine Mile and the German strain

OBJECTIVE

Q fever epidemic outbreaks have been reported in French Guiana and in The Netherlands. To determine whether the C. burnetii strains involved in these epidemics had a peculiar virulence pattern, we compared the pathogenicity of the Guiana and the German strain (a clone of The Netherlands strain), in silico, in vitro, and in vivo versus the Nine Mile strain.

METHOD

The pan-genomes of the Guiana (Cb175), German (Z3055), and the referent Nine Mile (RSA 493) C. burnetii strains were compared. In vitro, the growth rate and the morphological presentation were compared. In vivo (SCID and Balb/c mice), weight loss, histological lesions, C. burnetii bacterial load in deep organs, and serological response were reported according to each C. burnetii strain studied.

RESULTS

The Guiana strain had 77 times more missing genes and 12 times more unique genes than the German strain. The Guiana strain presented as large cell variants (LCVs) and led to the most pronounced fatality rate in SCID mice (100% at 4 weeks). The German strain presented as small cell variants (SCVs), and had an intermediate fatality rate (75% at 4 weeks). Both the Guiana and the German strains led to a significant higher serological response at 2 and 4 weeks post infection (p <0.05).

CONCLUSION

The Guiana strain was the most virulent strain, followed by the German strain and the referent Nine Mile strain. Unique and missing genes could be implicated but further investigations are necessary to specify their role.

Zoonoses under our noses

One Health is an effective approach for the management of zoonotic disease in humans, animals and environments. Examples of the management of bacterial zoonoses in Europe and across the globe demonstrate that One Health approaches of international surveillance, information-sharing and appropriate intervention methods are required to successfully prevent and control disease outbreaks in both endemic and non-endemic regions. Additionally, a One Health approach enables effective preparation and response to bioterrorism threats.

Coxiella burnetii infection with women's febrile spontaneous abortion reported in Algiers

We investigated Q fever infection in Febrile Spontaneous Abortions in women by using a serologic method (Immuno-Fluorescence Assay, IFA) and a molecular method (real-time quantitative PCR, qPCR) in Obstetric-Gynaecology (OB-GYN) services in two hospitals in Algiers. We included in the case group 380 women who experienced Febrile Spontaneous Abortion; the control group comprised 345 women who gave birth without any other infections or complications. Among the 725 women included, antibodies against Coxiella burnetii were detected by IFA in three (03) cases patients; all control group samples were IFA negative. In other hand, only four (04) placental samples among the case group came back with q PCR positive for IS1111 and IS30a too. A relationship between C. burnetii infection and febrile spontaneous abortion exists in OB-GYN services in Algiers.

Clinical Features and Complications of Coxiella burnetii Infections From the French National Reference Center for Q Fever

IMPORTANCE

Q fever remains widespread throughout the world; the disease is serious and causes outbreaks and deaths when complications are not detected. The diagnosis of Q fever requires the demonstration of the presence of Coxiella burnetii and the identification of an organic lesion.

OBJECTIVE

To describe the hitherto neglected clinical characteristics of Q fever and identifying risk factors for complications and death.

DESIGN, SETTING, AND PARTICIPANTS

This prospective cohort study conducted from January 1, 1991, through December 31, 2016, included patients treated at the French National Reference Center for Q fever with serologic findings positive for C burnetii and clinical data consistent with C burnetii infection. Clinical data were prospectively collected by telephone. Patients with unavailable clinical data or an unidentified infectious focus were excluded.

MAIN OUTCOMES AND MEASURES

Q fever complications and mortality.

RESULTS

Of the 180 483 patients undergoing testing, 2918 had positive findings for C burnetii and 2434 (68.8% men) presented with clinical data consistent with a C burnetii infection. Mean (SD) age was 51.8 (17.4) years, and the ratio of men to women was 2.2. At the time of inclusion, 1806 patients presented with acute Q fever, including 138 with acute Q fever that progressed to persistent C burnetii infection, and 766 had persistent focalized C burnetii infection. Rare and hitherto neglected foci of infections included lymphadenitis (97 [4.0%]), acute Q fever endocarditis (50 [2.1%]), hemophagocytic syndrome (9 [0.4%]), and alithiasic cholecystitis (11 [0.4%]). Vascular infection (hazard ratio [HR], 3.1; 95% CI, 1.7-5.7; P < .001) and endocarditis (HR, 2.4; 95% CI, 1.1-5.1; P = .02) were associated with an increased risk of death. Independent indicators of lymphoma were lymphadenitis (HR, 77.4; 95% CI, 21.2-281.8; P < .001) and hemophagocytic syndrome (HR, 19.1; 95% CI, 3.4-108.6; P < .001). The presence of anticardiolipin antibodies during acute Q fever has been associated with several complications, including hepatitis, cholecystitis, endocarditis, thrombosis, hemophagocytic syndrome, meningitis, and progression to persistent endocarditis.

CONCLUSIONS AND RELEVANCE

Previously neglected foci of C burnetii infection include the lymphatic system (ie, bone marrow, lymphadenitis) with a risk of lymphoma. Cardiovascular infections were the main fatal complications, highlighting the importance of routine screening for valvular heart disease and vascular anomalies during acute Q fever. Routine screening for anticardiolopin antibodies during acute Q fever can help prevent complications. Positron emission tomographic scanning could be proposed for all patients with suspected persistent focused infection to rapidly diagnose vascular and lymphatic infections associated with death and lymphoma, respectively.

Q fever epidemic in Cayenne, French Guiana, epidemiologically linked to three-toed sloth

A Q fever epidemic occurred in 2013 in a small military residential area in Cayenne, French Guiana. A retrospective cohort study was conducted to identify Q fever risk factors. Confirmed acute Q fever case was defined as positive serology (IgM ≥ 50 and phase II IgG ≥ 200) and/or positive qPCR on serum or blood. In addition, wild mammals were captured at the study site and tested by serology and real-time PCR performed on blood, vaginal swabs and ticks. The attack rate was 20 percent (11/54). All the cases were symptomatic with fever >38.5 °C and community-acquired pneumonia for four cases. Log binomial multivariate models identified two independent risk factors associated with Q fever: to clean the house (RRa = 7.5 CI95% [1.03-55.3]) and to carry a three-toed sloth in arms (RRa = 2.6 CI95% [1.1-5.8]). Eighteen marsupial individuals were captured, all PCRs were negative but 17% (3/18) had a positive serology. Another study conducted after the epidemic found only one (1/4) three-tooth sloth (Bradypus tridactylus) with feces highly infectious for C. burnetii MST17. The same strain C. burnetii genotype 17 has been laboratory- confirmed in this mammal and in human cases. These results support the implication of three-toed-sloth in this epidemic. Human contamination mainly occurs through inhalation of infectious aerosols as suggested by high relative risk associated with house cleaning activities and pulmonary forms of the disease, and through direct contact with three- toed-sloth. Positive serological results among marsupials confirm wildlife exposure and suggest a more complex sylvatic transmission cycle among wild mammals.

Infective Endocarditis in French West Indies: A 13-Year Observational Study

We conducted an observational study to describe the characteristics of infective endocarditis (IE) in French West Indies (FWI) and to identify variables associated with in-hospital case fatality. The records of the patients admitted for IE to the University Hospital of Martinique between 2000 and 2012 were collected using an electronic case report form. Only Duke-Li definite cases were considered for this analysis. Variables associated with in-hospital mortality were tested using univariate logistic regression analysis. The analysis included 201 patients (median age 58 years, sex ratio: two males to one female). There was no previously known heart disease in 45.8%, a prosthetic valve in 21.4%, and previously known native valve disease in 32.8% of the cases. Community-acquired IE represented 59.7% of all cases, health-care-associated IE represented 38.3% and injection-drug-use-acquired IE represented 1.5%. Locations of IE were distributed as follows: 42.3% were mitral valve IE, 34.8% were aortic valve IE, and 7% were right-sided IE. Microorganisms recovered from blood cultures included 30.4% streptococci, 28.9% staphylococci, and 5% enterococci. Blood cultures were negative in 20.9% of the cases. Surgical treatment was performed in 53% of the patients. In-hospital case fatality rate was 19%. Advanced age, Staphylococcus aureus IE, and health-care-associated IE were associated with in-hospital case fatality. The epidemiological and microbiological profile of IE in FWI is in between those observed in developed countries and developing countries: patients were younger, blood cultures were more frequently negative, and IE due to group D streptococci and enterococci were less common than in industrialized countries.

From Q Fever to Coxiella burnetii Infection: a Paradigm Change

Coxiella burnetii is the agent of Q fever, or "query fever," a zoonosis first described in Australia in 1937. Since this first description, knowledge about this pathogen and its associated infections has increased dramatically. We review here all the progress made over the last 20 years on this topic. C. burnetii is classically a strict intracellular, Gram-negative bacterium. However, a major step in the characterization of this pathogen was achieved by the establishment of its axenic culture. C. burnetii infects a wide range of animals, from arthropods to humans. The genetic determinants of virulence are now better known, thanks to the achievement of determining the genome sequences of several strains of this species and comparative genomic analyses. Q fever can be found worldwide, but the epidemiological features of this disease vary according to the geographic area considered, including situations where it is endemic or hyperendemic, and the occurrence of large epidemic outbreaks. In recent years, a major breakthrough in the understanding of the natural history of human infection with C. burnetii was the breaking of the old dichotomy between "acute" and "chronic" Q fever. The clinical presentation of C. burnetii infection depends on both the virulence of the infecting C. burnetii strain and specific risks factors in the infected patient. Moreover, no persistent infection can exist without a focus of infection. This paradigm change should allow better diagnosis and management of primary infection and long-term complications in patients with C. burnetii infection.

Absence of convincing evidence of Coxiella burnetii infection in Chile: a cross-sectional serosurvey among healthy adults in four different regions

Background

Coxiella burnetii is an important zoonotic pathogen of global distribution. Still, in most parts of South America including Chile, systematic epidemiological data are lacking. The presented study aims to determine the seroprevalence of Coxiella burnetii antibodies in healthy adults of four different regions in Chile.

Methods

A cross-sectional study was performed, which included healthy adults living in rural and urban areas of four cities located in different regions in northern, central, and southern Chile. In urban sectors, households were chosen by double stratified random sampling, while in rural areas convenience sampling was performed. Serum specimens were taken and screened for the presence of IgG antibodies against C. burnetii phase II antigen using a commercial ELISA kit. Positive and indeterminate results were confirmed by a reference laboratory using indirect immunofluorescence assay (IFA).

Results

A total of 1112 individuals were included. Of those, 8 were positive by ELISA, but only one sample was confirmed using IFA. Statistical analysis for population freedom from disease revealed a high probability that C. burnetii was absent in our study population.

Conclusion

Our work provides the first epidemiological data on human Q fever in Chile indicating either a very low endemicity or the absence of this pathogen in the studied areas.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1880-9) contains supplementary material, which is available to authorized users.

Mouse Model of Coxiella burnetii Aerosolization

Coxiella burnetii is mainly transmitted by aerosols and is responsible for multiple-organ lesions. Animal models have shown C. burnetii pathogenicity, but long-term outcomes still need to be clarified. We used a whole-body aerosol inhalation exposure system to mimic the natural route of infection in immunocompetent (BALB/c) and severe combined immunodeficient (SCID) mice. After an initial lung inoculum of 10(4) C. burnetii cells/lung, the outcome, serological response, hematological disorders, and deep organ lesions were described up to 3 months postinfection. C. burnetii-specific PCR, anti-C. burnetii immunohistochemistry, and fluorescent in situ hybridization (FISH) targeting C. burnetii-specific 16S rRNA completed the detection of the bacterium in the tissues. In BALB/c mice, a thrombocytopenia and lymphopenia were first observed, prior to evidence of C. burnetii replication. In all SCID mouse organs, DNA copies increased to higher levels over time than in BALB/c ones. Clinical signs of discomfort appeared in SCID mice, so follow-up had to be shortened to 2 months in this group. At this stage, all animals presented bone, cervical, and heart lesions. The presence of C. burnetii could be attested in situ for all organs sampled using immunohistochemistry and FISH. This mouse model described C. burnetii Nine Mile strain spread using aerosolization in a way that corroborates the pathogenicity of Q fever described in humans and completes previously published data in mouse models. C. burnetii infection occurring after aerosolization in mice thus seems to be a useful tool to compare the pathogenicity of different strains of C. burnetii.

Coxiella burnetii Endocarditis in a Child Caused by a New Genotype

Coxiella burnetii endocarditis is a rare diagnosis in children. We present a case of Q fever endocarditis due to a new genotype, MST 54, and review recent literature on Q fever infections in children. Practitioners should consider Q fever in culture-negative endocarditis, particularly in children with congenital heart disease and history of travel or residence in endemic regions.

The contribution of genomics to the study of Q fever

Coxiella burnetii is the etiological agent of Q fever, a worldwide zoonosis that can result in large outbreaks. The birth of genomics and sequencing of C. burnetii strains has revolutionized many fields of study of this infection. Accurate genotyping methods and comparative genomic analysis have enabled description of the diversity of strains around the world and their link with pathogenicity. Genomics has also permitted the development of qPCR tools and axenic culture medium, facilitating the diagnosis of Q fever. Moreover, several pathophysiological mechanisms can now be predicted and therapeutic strategies can be determined thanks to in silico genome analysis. An extensive pan-genomic analysis will allow for a comprehensive view of the clonal diversity of C. burnetii and its link with virulence.

The genome of Coxiella burnetii Z3055, a clone linked to the Netherlands Q fever outbreaks, provides evidence for the role of drift in the emergence of epidemic clones

Coxiella burnetii is a pathogen causing Q fever. The aim of our work was to study Z3055, a strain that is genotypically related to the strain causing the Netherlands outbreak. We compared Z3055 to 5 other completed genomes available in GenBank. We calculated the blast score ratio (BSR) to analyze genetic differences among the strains. The ratio core genome/pangenome was 98% likely other bacteria with closed pangenomes. Differences between Z3055 and the reference NMI consisted only of point mutations and insertion/deletion (INDELs). Non-synonymous mutations significantly increased in genes coding for membrane proteins (16/156 vs 103/1757, bilateral Chi(2) test, p<0.05), ankyrin repeat domains containing proteins (2/9 vs 117/1904, bilateral Chi(2) test, p<0.05), transcription factors (7/53 vs 112/1860, bilateral Chi(2) test, p<0.05) and translation proteins (15/144 vs 109/1655, bilateral Chi(2) test, p<0.05). The evolution of this strain may have been driven by mutations in critical genes.

Q fever in French Guiana

Coxiella burnetii, the causative agent of Q fever, is present worldwide. Recent studies have shown that this bacterium is an emerging pathogen in French Guiana and has a high prevalence (24% of community-acquired pneumonia). In this review, we focus on the peculiar epidemiology of Q fever in French Guiana. We place it in the context of the epidemiology of the disease in the surrounding countries of South America. We also review the clinical features of Q fever in this region, which has severe initial presentation but low mortality rates. These characteristics seem to be linked to a unique genotype (genotype 17). Finally, we discuss the issue of the animal reservoir of C. burnetii in French Guiana, which is still unknown. Further studies are necessary to identify this reservoir. Identification of this reservoir will improve the understanding of the Q fever epidemic in French Guiana and will provide new tools to control this public health problem.