Q fever, caused by Coxiella burnetii, leads to debilitating human infections that are often recalcitrant to antibiotics. The development of new medical countermeasures is critical, as the only available vaccine has significant limitations that prevent its widespread or rapid use. To address this, we characterized aerosol C. burnetii infection in 16 cynomolgus macaques (Macaca fascicularis), providing the first detailed pathological description of Q fever pneumonia in a nonhuman primate model. Following exposure, all animals developed clinical signs consistent with human Q fever, including sustained fever, respiratory distress, and weight loss. Clinical pathology revealed hematological changes and evidence of systemic inflammation, including elevated C-reactive protein. Although clinical signs resolved by day 28, significant pathology persisted, including granulomatous interstitial pneumonia, pleuritis, carditis, hepatitis, and nephritis. Infection was confirmed in tissues using immunohistochemistry and electron microscopy. The cynomolgus macaque model faithfully replicates key features of human Q fever, validating its utility for studying disease pathogenesis and serving as a pivotal model for evaluating next-generation vaccines and therapies.

Hard ticks are important vectors of zoonotic pathogens, including bacteria that cause rickettsiosis, Q fever, and anaplasmosis. In this study, 167 ticks were collected from vegetation in Chiang Mai Province, northern Thailand, and examined using morphological and molecular methods. Five tick species were identified: Dermacentor tamokensis (n = 81), D. bellulus (n = 49), D. pasteuri (n = 9), Ixodes acutitarsus (n = 26), and Haemaphysalis hystricis (n = 2), with the first three species newly characterized at the molecular level. Moreover, D. tamokensis and D. bellulus are newly recorded in Thailand. Phylogenetic analysis using the multilocus sequence analysis (MLSA) approach revealed two distinct genotypic groups of spotted fever group rickettsiae (SFGRs): a novel Candidatus Rickettsia chiangmaiensis in I. acutitarsus (20/26) and Candidatus Rickettsia laoensis in D. tamokensis (12/81) and D. bellulus (10/49). The latter SFGR was closely related to strains found only in western Thailand and Laos. Additionally, Coxiella-like endosymbionts (CLEs) were detected in D. tamokensis (61/81), D. bellulus (13/49), and H. hystricis (1/2), while Anaplasma sp. was found in D. tamokensis (2/81). Notably, double infections: Ca. R. laoensis-CLEs, Anaplasma-CLEs, and a triple infection: Ca. R. laoensis-CLE-Anaplasma were reported herein. These findings demonstrate the diverse bacterial associations in ticks, suggesting the ecological complexity of forested areas in northern Thailand.

Prosthetic joint infection (PJI) caused by Coxiella burnetii (C. burnetii) remains a rare but clinically significant diagnostic challenge due to its culture-negative characteristics and nonspecific clinical manifestations. Metagenomic next-generation sequencing (mNGS) has emerged as a valuable tool for identifying fastidious pathogens in culture-negative PJI cases. A patient with a history of joint arthroplasty presented with persistent joint pain and swelling. Despite multiple surgical interventions and prolonged empirical antibiotic therapy, routine bacterial cultures remained negative and the infection recurred. mNGS performed on periprosthetic tissue detected C. burnetii in two independent specimens, while all conventional cultures remained negative. Targeted antimicrobial therapy with doxycycline combined with levofloxacin was initiated, resulting in gradual symptom resolution and sustained clinical improvement during follow-up. This case highlights C. burnetii as an underrecognized cause of culture-negative PJI and demonstrates the clinical value of mNGS for early pathogen identification when conventional diagnostics fail. Repeated detection in independent specimens strengthened diagnostic confidence and enabled timely targeted therapy. Our findings support the early incorporation of mNGS into the diagnostic algorithm for suspected culture-negative PJI. In the present case, targeted doxycycline-levofloxacin therapy following mNGS-based pathogen identification was associated with sustained clinical improvement.

Q fever is a zoonotic disease caused by Coxiella burnetii, with domestic ruminants serving as the main reservoir. Infected animals can shed large quantities of the pathogen into the environment after normal parturition or abortion, enabling airborne transmission to humans and potentially triggering outbreaks of variable scale. Effective outbreak management requires the rapid identification of all related cases, tracing of infection source(s), and implementing proportionate control measures that protect human health while considering animal health and ecosystem integrity.

Q fever is a neglected zoonotic disease that poses a significant threat to the economy, animal health, and public health sectors worldwide, particularly in developing countries such as Ethiopia. In Ethiopia, where livestock production is the primary source of livelihood and food security for many communities, the implications of Q fever are particularly concerning. Despite its importance as a health issue for both animals and humans, there is insufficient national-level consolidated evidence regarding the burden of Q fever in ticks, domestic ruminants, and humans in Ethiopia. Therefore, this meta-analysis aims to assess the pooled prevalence of Q fever among ticks, ruminants, and humans in the country. A systematic review and meta-analysis were conducted in accordance with PRISMA guidelines, using common databases such as Scopus, ScienceDirect, PubMed, Web of Science, and Google Scholar. The literature search was conducted from January 21 to January 30, 2026, to identify articles published in Ethiopia between January 1, 1990, and January 30, 2026. To evaluate the heterogeneity among studies, a random-effects model was employed to explore the pooled prevalence of Q fever in ticks, ruminants, and humans. Subgroup analysis, meta-regression, and sensitivity analysis were conducted to identify sources of variation between studies. Funnel plots, along with Egger's and Begg's correlation tests, were used to assess publication bias. The overall prevalence of Q fever across ticks, ruminants, and humans was 27.0% (95% CI: 20.0-34.0). The pooled prevalence of Q fever was 9% (95% CI: 2.0-16.0) in ticks, 29% (95% CI: 21.0-38.0) in ruminants, and 20% (95% CI: 5.0-36.0) in humans. The prevalence of Q fever was highest in Eastern Ethiopia at 41.0% (95% CI: 22.0-59.0) and lowest in Southwestern Ethiopia at 7.0% (95% CI: 2.0-13.0). Camels exhibited the highest exposure rate at 48.0% (95% CI: 0.0-1.0), while cattle had the lowest at 12.0% (95% CI: 4.0-21.0). The meta-regression analysis revealed that camel and goat species, along with the geographical regions of Eastern and Central Ethiopia, significantly affected the prevalence of Q fever. The findings highlight that Q fever continues to pose a significant threat to ticks, ruminants, and humans in Ethiopia. Therefore, collaboration among environmental, veterinary, and public health professionals is essential for designing and implementing effective prevention and control programs for Q fever in the context of a One Health approach.

In Hong Kong, the average annual incidence of Q-fever in humans was one case per year from 2008 to 2023. The prevalence of C. burnetii infection in animals in Hong Kong is not reported. This study aimed to identify potential domestic and wild animal reservoirs of C. burnetii to inform human exposure risks from local animals. A cross-sectional study was conducted to detect infection and/or exposure using biological samples from 1118 animals including 377 ruminants (200 feral cattle, 35 water buffalo, 142 goats), 216 rats and 525 owned or unowned dogs and cats between 2020 and 2023. PCR to detect C. burnetii IS1111 DNA was performed on reproductive tissues, liver, faeces, blood, and/or vaginal swabs from 866 animals, and sera from 691 animals were tested for antibodies against C. burnetii by ELISA. C. burnetii DNA was not detected in any sample. While C. burnetii antibodies were not detected in any bovine or canine sera, 2/157 (1.3%) cats and 1/142 (0.7%) goats were seropositive. No evidence of active C. burnetii infection was detected in any of the 866 tested animals. Evidence of exposure was found only in cats and goats, albeit at low frequency. No evidence of a role for rodent reservoirs of C. burnetii in Hong Kong was identified. The sporadic serological evidence and the absence of molecular evidence of active infection in key reservoir species, along with the limited local livestock population, suggest that the risk of acquiring C. burnetii infection from exposure to local animals in Hong Kong is low.

Chronic Q fever can present as culture-negative aortic endograft infection with osteomyelitis. Plasma microbial cell-free DNA sequencing unexpectedly detected Coxiella burnetii before serology, prompting exposure reassessment and targeted therapy. Later operative cultures grew Eikenella corrodens, underscoring the need to pair molecular results with serology and source-control microbiology.

Iran's strategic geographic position, its historical role in major trade routes such as the Silk Road, and its proximity to plague-endemic regions have repeatedly exposed it to plague outbreaks. The most recent documented epidemic occurred in 1966 in Sarab, East Azerbaijan Province. Historically, these outbreaks have significantly influenced demographic patterns, socioeconomic structures, and political developments. In response, extensive research has been conducted to investigate the diversity of Yersinia pestis-vectoring fleas (Siphonaptera) in Iran, resulting in the identification of 119 species and subspecies across diverse ecological zones. Despite these efforts, a comprehensive, up-to-date, and user-friendly set of morphological identification keys-covering taxa from superfamily to subspecies level-has been limited to outdated or regionally restricted resources. The present study addressed this critical gap by presenting fully illustrated dichotomous keys for Iranian fleas, based on detailed morphological characteristics of both male and female adults. High-resolution images, accompanied by precise annotations, emphasize diagnostic features essential for distinguishing sibling species and other morphologically similar taxa. The primary objective of this work is to enhance the accuracy of flea taxonomy and to strengthen surveillance and control programs targeting flea-borne diseases, particularly in Iran's plague-endemic areas.

Coxiella burnetii is a zoonotic bacterium that affects human and animal health globally and has detrimental socioeconomic effects on the livestock industry. This organism is known to cause abortion in sheep, goats, and cattle that is characterized by placentitis with minimal to no fetal lesions. In April 2025, the Diagnostic Services Unit at the University of Calgary Faculty of Veterinary Medicine (Alberta) received 11 aborted fetuses from a single herd of farmed plains bison (Bison bison bison). Initial submissions lacked placenta, delaying diagnosis. The 5th submission, which included placenta, revealed a necrotizing placentitis with intracellular bacteria within trophoblasts, highly suggestive of coxiellosis. In 4 of 11 cases, a definitive diagnosis of C. burnetii abortion was made, based on compatible histopathologic lesions in the placenta and detection of high numbers of organisms as evidenced by qPCR values. Coxiella burnetii was suspected in the remaining cases but could not be confirmed due to the absence of placenta. This report documents the first association of C. burnetii with abortion in plains bison and describes the histopathology and qPCR results observed during this outbreak. These cases underscored diagnostic challenges posed by incomplete submissions in abortion investigations. Key clinical message: This report highlights diagnostic challenges associated with abortion cases and the need for submission of both fresh and formalin-fixed placenta. Clinicians and diagnosticians should now include C. burnetii as a differential diagnosis for fetal loss in bison and ensure that appropriate biosafety measures are in place when handling specimens from ruminant abortions.

Background Granulomatous lung diseases include a spectrum of disorders, both infectious and noninfectious, unified by the presence of granulomas in the lung parenchyma. Granulomas are microscopic, organized collections of immune cells that arise as a response to persistent antigenic stimulation. Infectious granulomatous lung diseases arise from a variety of microbial agents, that include most frequently Mycobacterium tuberculosis, non-tuberculous mycobacteria, Nocardia, and Borrelia, as well as a wide range of fungal pathogens including Histoplasma, Cryptococcus, Pneumocystis, and Aspergillus species. Methods and Results: Definitive diagnosis is achieved through direct identification and subsequent culture of the causative pathogen in appropriate clinical specimens, including sputum, bronchoscopic samples, gastric aspirates, or pleural fluid. Imaging is fundamental for the detection and characterization of pulmonary granulomas. HRCT allows precise assessment of the number, size, and distribution of granulomatous lesions, can suggest an infectious etiology based on specific imaging patterns, and is essential for monitoring response to therapy over time. Differential diagnosis is challenging due to the numerous different imaging appearances with whom granulomatous lung diseases may manifest. Conclusions: The purpose of our review is to describe the spectrum of infectious granulomatous lung diseases caused by bacterial pathogens, highlighting their diverse radiologic presentations in order to assist radiologists in recognizing these entities and improving diagnostic accuracy.

Q fever has been considered a worldwide zoonosis caused by Coxiella burnetii, mostly transmitted by respiratory routes in contaminated environments with bio logical waste. Although urban recycling facilities may concentrate contaminated materials, their significance as potential environmental sources for C. burnetii infection has not been investigated to date.