Q fever is a re-emerging zoonosis whose epidemiological cycle in ruminants is well defined, while the role of other species (including pets) is still debated. In this study, the serological and molecular prevalence of Coxiella burnetii in a sample of dogs in the Campania region, southern Italy was evaluated. A seroprevalence of 5.97 % (16/268) was observed using a commercial multispecies ELISA, compared to only 2.7 % (5/197) at the molecular level. No risk factors correlated with higher levels of exposure except for the size of the animal (small dogs showed significantly higher seroprevalence). Positive samples were further evaluated for reactivity to phase I and II antigens using IFA and phase-specific ELISAs (for specific IgG detection). Two animals showed antibodies against both phases of infection, suggesting that Coxiella burnetii seroconversion in dogs follows similar dynamics to those observed in ruminants. One of the five samples that showed positive results in real-time PCR was confirmed at the PCR endpoint and showed similarity with other Coxiella spp. strains detected in tick and dog samples when sequenced. In this study, we demonstrated exposure to Coxiella burnetii for different categories of dogs in southern Italy, including pet dogs living indoors. Since reports of transmission of infection from pets to humans have been described in both rural and urban areas, careful surveillance of these species is also necessary. In the lack of additional information, comprehending the risk to humans requires monitoring of wild and domestic animal populations.

BACKGROUND: Q fever, caused by the zoonotic pathogen Coxiella burnetii, exhibits a worldwide prevalence. In China, Q fever is not recognized as a notifiable disease, and the disease is overlooked and underestimated in clinical practice, leading to diagnostic challenges.
METHODS: We present a case series of three patients diagnosed with persistent Q fever between 2022 and 2023. The average age of our three cases was 63.33 years old, consisting of two males and one female. The medical history of the individuals included previous valve replacement, aneurysm followed by aortic stent-graft placement and prosthetic hip joint replacement. At the onset of the disease, only one case exhibited acute fever, while the remaining two cases were devoid of any acute symptoms. The etiology was initially overlooked until metagenomic next-generation sequencing test identified Coxiella burnetii from the blood or biopsy samples. Delayed diagnosis was noted, with a duration ranging from three months to one year between the onset of the disease and its confirmation. The epidemiological history uncovered that none of the three cases had direct exposure to domestic animals or consumption of unpasteurized dairy products. Case 1 and 2 resided in urban areas, while Case 3 was a rural resident engaged in farming. All patients received combination therapy of doxycycline and hydroxychloroquine, and no recurrence of the disease was observed during the follow-up period.
CONCLUSIONS: Q fever is rarely diagnosed and reported in clinical practice in our country. We should be aware of persistent Q fever in high-risk population, even with unremarkable exposure history. Metagenomic next-generation sequencing holds great potential as a diagnostic tool for identifying rare and fastidious pathogens such as Coxiella burnetii.

Intracellular bacterial pathogens divert multiple cellular pathways to establish their niche and persist inside their host. Coxiella burnetii, the causative agent of Q fever, secretes bacterial effector proteins via its Type 4 secretion system to generate a Coxiella-containing vacuole (CCV). Manipulation of lipid and protein trafficking by these effectors is essential for bacterial replication and virulence. Here, we have characterized the lipid composition of CCVs and found that the effector Vice interacts with phosphoinositides and membranes enriched in phosphatidylserine and lysobisphosphatidic acid. Remarkably, eukaryotic cells ectopically expressing Vice present compartments that resemble early CCVs in both morphology and composition. We found that the biogenesis of these compartments relies on the double function of Vice. The effector protein initially localizes at the plasma membrane of eukaryotic cells where it triggers the internalization of large vacuoles by macropinocytosis. Then, Vice stabilizes these compartments by perturbing the ESCRT machinery. Collectively, our results reveal that Vice is an essential C. burnetii effector protein capable of hijacking two major cellular pathways to shape the bacterial replicative niche.

Ixodes ricinus is a vector of several pathogens of public health interest. While forests are the primary habitat for I. ricinus, its abundance and infection prevalence are expected to vary within forest stands. This study assesses the spatio-temporal variations in tick abundance and infection prevalence with three pathogens in and around a peri-urban forest where human exposure is high. Ticks were sampled multiple times in 2016 and 2018 in multiple locations with a diversity of undergrowth, using the consecutive drags method. Three zoonotic pathogens were screened for, Borrelia burgdorferi s.l., Coxiella burnetii, and Francisella tularensis. The influence of season, type of site and micro-environmental factors on tick abundance were assessed with negative binomial generalized linear mixed-effects models. We collected 1642 nymphs and 181 adult ticks. Ticks were most abundant in the spring, in warmer temperatures, and where undergrowth was higher. Sites with vegetation unaffected by human presence had higher abundance of ticks. Forest undergrowth type and height were significant predictors of the level of tick abundance in a forest. The consecutive drags method is expected to provide more precise estimates of tick abundance, presumably through more varied contacts with foliage. Borrelia burgdorferi s.l. prevalence was estimated from pooled ticks at 5.33%, C. burnetii was detected in six pools and F. tularensis was not detected. Borrelia afzelii was the dominant B. burgdorferi genospecies. Tick abundance and B. burgdorferi s.l. infection prevalence were lower than other estimates in Belgian forests.

UNASSIGNED: Identifying and treating patients with acute Q fever who are at an increased risk of progressing to persistent disease is crucial for preventing future complications. In this study, we share our decade-long clinical experience with acute Q fever, highlighting the challenges that clinicians encounter from making an initial diagnosis and performing risk stratification to determining the appropriate prophylaxis regimen and duration.
UNASSIGNED: We retrieved records of adult Mayo Clinic patients (≥18 years) with positive Coxiella burnetii serology results between 1 January 2012 and 31 March 2022. Patients with Q fever anti-phase II immunoglobulin G ≥1:256 by indirect immunofluorescence were further analyzed.
UNASSIGNED: Thirty-one patients were included. Their median age was 58 years (IQR, 50-64), and the majority were men (84%). Acute hepatitis (29%), flu-like illness (25.8%), and pneumonia (16%) were the most common presentations. Thirteen patients (42%) received antibiotic prophylaxis to prevent disease progression, with significant variation in the indications and duration across physicians. The combination of doxycycline and hydroxychloroquine was the preferred regimen. Prophylaxis was administered for a median 333 days (IQR, 168-414). Four patients (13%) progressed to Q fever native valve infective endocarditis, with elevated anticardiolipin immunoglobulin G levels being the sole risk factor in 2 cases. The small sample size precluded drawing conclusions on the impact of prophylaxis in preventing disease progression.
UNASSIGNED: Management of acute Q fever is complicated by the lack of comprehensive clinical guidelines leading to varied clinical practices. There is a critical need for randomized trials to establish robust evidence-based protocols for management.

BACKGROUND: Q fever, a zoonotic disease caused by Coxiella burnetii (C. burnetii), presents diagnostic challenges due to its clinical and radiological nonspecificity, which often mimics community-acquired pneumonia, coupled with the limitations of traditional diagnostic methods. Metagenomic next-generation sequencing (mNGS) has become an indispensable tool in clinical diagnostics for its high-throughput pathogen identification capabilities. Herein, we detail a case of acute Q fever pneumonia diagnosed with mNGS.
METHODS: The patient exhibited symptoms of fever, cough, expectoration, and diarrhea for three days, with the pathogen undetected in initial laboratory assessments. Bronchoscopy and bronchoalveolar lavage (BAL) were conducted, leading to the identification of C. burnetii in the lavage fluid via mNGS. Consequently, the patient was promptly initiated on a treatment regimen of 100 mg doxycycline, administered orally every 12 hours.
RESULTS: Post-treatment, the patient\'s temperature normalized, and a full recovery was observed. The follow-up chest CT scan revealed complete resolution of the right lower lobe consolidation.
CONCLUSIONS: The clinical presentation of Q fever pneumonia lacks specificity, making diagnosis based solely on symptoms and imaging challenging. mNGS offers a superior alternative for identifying elusive or rarely cultured pathogens.

Some dipteran flies play an important role in the transmission of pathogens such as viruses, bacteria, fungi, protozoan and metazoan parasites in humans and other animals. Despite this importance, knowledge of the prevalence and molecular characteristics of some pathogens in flies is limited, and no data are available for Türkiye. In this study, we investigated the possible vector role of muscid fly species for the transmission of Enterocytozoon bieneusi Desportes (Chytridiopsida: Enterocytozoonidae), Encephalitozoon spp., Coxiella burnetii Derrick (Legionellales: Coxiellaceae) and Thelazia spp. using polymerase chain reaction (PCR) and sequence analysis. The flies were trapped in different animal-related places and surroundings from two different geographical regions of Türkiye including Central Anatolia and Middle Black Sea. According to the morphological keys, 850 (85%), 141 (14.1%) and 6 (0.6%) of the total of 1000 fly specimens identified as Musca domestica Linnaeus (Diptera: Muscidae), Stomoxys calcitrans Linnaeus (Diptera: Muscidae) and Musca autumnalis De Geer (Diptera: Muscidae), respectively. The other species including Haematobia irritans Linnaeus (Diptera: Muscidae), Muscina stabulans Fallén (Diptera: Muscidae) and Hydrotaea ignava Harris (Diptera: Muscidae) were each represented by a single specimen. Screening of the pathogens identified E. bieneusi only in M. domestica with a prevalence of 2.4%. Sequence analyses identified three known genotypes, Type IV, BEB6 and BEB8, and one novel genotype named AEUEb of E. bieneusi in M. domestica. Coxiella burnetii was detected in M. domestica and S. calcitrans with prevalences of 2.9% and 2.8%, respectively. The one specimen of H. ignava was also positive for C. burnetii. Encephalitozoon spp. and Thelazia spp. were not found in the examined specimens. Our results contribute to the current knowledge on the vector potential of muscid flies and their possible role in the transmission dynamics of certain pathogens, especially in regions where diseases are prevalent and affect public and animal health.

Since 1999, doxycycline and hydroxychloroquine have been the recommended treatment for chronic Q fever, a life-threatening disease caused by the bacterial pathogen, Coxiella burnetii. Despite the duration of its use, the treatment is not ideal due to the lengthy treatment time, high mortality rate, resistant strains, and the potential for contraindicated usage. A literature search was conducted to identify studies that screened large panels of drugs against C. burnetii to identify novel targets with potential efficacy against C. burnetii. Twelve candidate antimicrobials approved for use in humans by the US Food and Drug Administration were selected and minimum inhibitory concentrations (MICs) were determined against the low virulence strain Nine Mile phase II. Rifabutin and rifaximin were the best performing antibiotics tested with MICs of ≤0.01 µg mL-1. Further screening of these top candidates was conducted alongside two drugs from the same class, rifampin, well-characterized, and rifapentine, not previously reported against C. burnetii. These were screened against virulent strains of C. burnetii representing three clinically relevant genotypes. Rifapentine was the most effective in the human monocytic leukemia cell line, THP-1, with a MIC ≤0.01 µg mL-1. In the human kidney epithelial cell line, A-498, efficacy of rifapentine, rifampin, and rifabutin varied across C. burnetii strains with MICs between ≤0.001 and 0.01 µg mL-1. Rifampin, rifabutin, and rifapentine were all bactericidal against C. burnetii; however, rifabutin and rifapentine demonstrated impressive bactericidal activity as low as 0.1 µg mL-1 and should be further explored as alternative Q fever treatments given their efficacy in vitro.
OBJECTIVE: This work will help inform investigators and physicians about potential alternative antimicrobial therapies targeting the causative agent of Q fever, Coxiella burnetii. Chronic Q fever is difficult to treat, and alternative antimicrobials are needed. This manuscript explores the efficacy of rifamycin antibiotics against virulent strains of C. burnetii representing three clinically relevant genotypes in vitro. Importantly, this study determines the susceptibility of C. burnetii to rifapentine, which has not been previously reported. Evaluation of the bactericidal activity of the rifamycins reveals that rifabutin and rifapentine are bactericidal at low concentrations, which is unusual for antibiotics against C. burnetii.

Q fever is a zoonotic infection caused by Coxiella burnetii. In rare cases, it can lead to vascular complications, including infected aneurysms. Successful treatment involves surgery and antibiotics, but there is no established consensus or clear recommendation for the choice of material graft. We report a case of abdominal aortic aneurysm infected by C. burnetii treated by open surgery with complete resection of the aneurysm and homemade bovine pericardial bifurcated graft reconstruction and long-term antibiotherapy using doxycycline. One year postoperatively, the patient had no sign of persistent infection or vascular complication. Moreover, C. burnetii immunoglobulins titers decreased 6 months postoperatively.

Coxiella burnetii is the worldwide zoonotic infectious agent for Q fever in humans and animals. Farm animals are the main reservoirs of C. burnetii infection, which is mainly transmitted via tick bites. In humans, oral, percutaneous, and respiratory routes are the primary sources of infection transmission. The clinical signs vary from flu-like symptoms to endocarditis for humans\' acute and chronic Q fever. While it is usually asymptomatic in livestock, abortion, stillbirth, infertility, mastitis, and endometritis are its clinical consequences. Infected farm animals shed C. burnetii in birth products, milk, feces, vaginal mucus, and urine. Milk is an important source of infection among foods of animal origin. This study aimed to determine the prevalence and molecular characterization of C. burnetii in milk samples of dairy animals from two districts in Punjab, Pakistan, as it has not been reported there so far. Using a convenience sampling approach, the current study included 304 individual milk samples from different herds of cattle, buffalo, goats, and sheep present on 39 farms in 11 villages in the districts of Kasur and Lahore. PCR targeting the IS1111 gene sequence was used for its detection. Coxiella burnetii DNA was present in 19 of the 304 (6.3%) samples. The distribution was 7.2% and 5.2% in districts Kasur and Lahore, respectively. The results showed the distribution in ruminants as 3.4% in buffalo, 5.6% in cattle, 6.7% in goats, and 10.6% in sheep. From the univariable analysis, the clinical signs of infection i.e. mastitis and abortion were analyzed for the prevalence of Coxiella burnetii. The obtained sequences were identical to the previously reported sequence of a local strain in district Lahore, Sahiwal and Attock. These findings demonstrated that the prevalence of C. burnetii in raw milk samples deserves more attention from the health care system and veterinary organizations in Kasur and Lahore of Punjab, Pakistan. Future studies should include different districts and human populations, especially professionals working with animals, to estimate the prevalence of C. burnetii.