Q Fever, an Under-Recognized and Under-Diagnosed Disease: A Case Report.

Q fever is an illness following infection by the organism Coxiella burnetii. It is usually associated with an asymptomatic infection in animals which lends a hand in how it is easily transmitted to other hosts such as humans who encounter the bodily fluids of infected animals. Its presentation reflects an acute viral illness with malaise, fever/chills, and vomiting seen in acute cases while endocarditis and other severe sequelae can be seen in chronic infections. Here we have a 55-year-old male who presented for further evaluation of his muscular pains following a motor vehicle accident. His physical exam was benign except for tenderness in his left shoulder and cervical musculature. In interviewing the patient, he reported having fevers/chills, night sweats, and episodes of vomiting for several weeks which led him to seek further medical care. After many tests including a complete blood count (CBC), complete metabolic panel (CMP), blood cultures, and stool/ova testing came back normal, a Q fever phase 1 and 2 titer was performed and confirmed the suspected diagnosis of Q fever due to a lack of his symptoms being explained by another etiology. Although his initial symptoms were consistent with acute Q fever, the continuation of his symptoms suggests the possibility of Q fever fatigue syndrome. This case report highlights the under-recognized, uncommon zoonotic infection that plagues those working in the animal industry while also exploring the various presentations of it.

Crescentic Glomerulonephritis and Portal Hypertension with Chronic Q Fever: A Case Report and Comprehensive Literature Review.

Q fever, an infectious zoonotic disease caused by Coxiella burnetii, remains prevalent in China. Systemic infections can result in renal or hepatic complications; however, it is rare for both the kidneys and liver to be simultaneously affected. We present a case of a patient who exhibited fever, rapid deterioration in renal function, thrombocytopenia, and severe ascites. Renal biopsy revealed crescentic glomerulonephritis, while liver biopsy demonstrated non-cirrhotic portal hypertension. Metagenomic next-generation sequencing (mNGS) identified the presence of Coxiella burnetii in both venous blood and liver tissue samples. Notably, the patient's renal insufficiency and ascites showed a positive response to treatment for chronic Q fever. These findings provide valuable insights into the limited understanding of kidney and liver diseases associated with Q fever. Advanced diagnostic technologies, including mNGS and positron emission tomography/computed tomography (PET/CT), have been employed to identify Coxiella burnetii infection.

[Chronic Q fever. Literature review and a case report of culture negative spondylodiscitis]. / Fièvre Q chronique. Revue de la littérature à propos d'un cas de spondylodicite à hémocultures négatives.

INTRODUCTION: Fever is a cosmopolit zoonosis due to Coxiella burnetii. The diagnosis of chronic Q fever can be really misleading. The growth of this bacterium is difficult and blood cultures are often negatives. CASE PRESENTATION: We rapport here the case of a 69-year-old man presenting with an alteration of his general condition and low back pain. He suffered from a well-controlled HIV infection and lower limb arteriopathy treated with a cross-femoral bypass. A computed tomography scan revealed a L3-L4 abscessed spondylodiscitis but multiple blood cultures remained sterile, and the transthoracic echocardiography was normal. PET scan showed a hypermetabolism on L3-L4 vertebrae but also indicated an intense uptake of the cross-femoral bypass. C. burnetii serology was in favour of a chronic Q fever. The management of this chronic Q fever needed a multidisciplinary discussion. Three months after the treatment initiation, C. burnetii serology was reduced by a titer and has stabilized 6months to a year. CONCLUSION: Chronic Q fever and mostly osteoarticular diseases are difficult to diagnose. We have to evoke the diagnosis of osteoarticular chronic Q fever in case of insidious inflammatory syndrome, negatives blood cultures spondylodiscitis especially when associated to endocarditis or vascular infection, and in case of spondylodiscitis with a granulomatous histology without Mycobacterium tuberculosis. Although there are many complementary tests (PET scanner, PCR), serology remains the cornerstone of diagnosis.

Molecular Detection and Characterisation of Coxiella burnetii in Koala (Phascolarctos cinereus) Urogenital Tract Swabs.

Q fever is a zoonosis caused by Coxiella burnetii, primarily affecting those in close contact with domestic ruminants, the main source of human infection. Coxiella burnetii has also been detected in various wildlife species globally. In Australia, serological and molecular studies have shown exposure to and infection by C. burnetii in macropods, bandicoots, and koalas. However, the extent to which these species contribute to human infection remains unclear. An unpublished public health investigation into a Q fever case in a person involved in koala care could not conclusively link the infection to koalas due to the patient's broad animal exposure. This study aimed to explore the potential role of koalas in transmitting C. burnetii to humans by investigating the presence of C. burnetii DNA in urogenital tract (UGT) swabs from koalas. DNA was extracted from UGT swabs from koalas in three regions in New South Wales, Australia. An optimised multiplex qPCR assay detected C. burnetii DNA in 2 out of 225 samples (0.89%) at approximately 10 genome equivalents per reaction. Both positive samples amplified all three gene targets. MLVA genotyping identified two distinct C. burnetii genotypes previously isolated from Australian Q fever cases. These findings highlight the need for vaccination against Q fever for those in close contact with koalas.

Absence of Coxiella burnetii in kangaroo ticks (Amblyomma triguttatum) from a high seroprevalence population of eastern grey kangaroos.

Q fever, caused by Coxiella burnetii, is an important zoonotic and public health concern worldwide. Kangaroos are thought to be a likely wildlife reservoir for C. burnetii in Australia and the kangaroo tick (Amblyomma triguttatum) has often been considered a vector. In this descriptive study of ticks collected from a population of eastern grey kangaroos (Macropus giganteus) with a high serological (84 %) and molecular (65 %) prevalence of C. burnetii in northern New South Wales, a total of 72 A. triguttatum ticks were tested by PCRs targeting the IS1111, htpAB, and com1 genes of the Coxiella genome. Despite the remarkably high prevalence of coxiellosis in the host population, none of the ticks were positive for Coxiella. This finding suggests that the kangaroo tick may not play a significant role in the transmission dynamics of C. burnetii in this particular host population.

Evaluation of the phase-specific antibody response in water buffalo (Bubalus bubalis) after two doses of an inactivated phase I Coxiella burnetii vaccine.

The control and management of Q fever outbreaks in ruminants are currently based on vaccination. Although buffalo (Bubalus bubalis) are intensively farmed in several countries and represent a reservoir for Coxiellosis, no evidence has been described regarding the efficacy of vaccination in this species. This work aimed to evaluate the humoral response, using appropriate phase-specific ELISAs, and the effects on abortion rate in buffalo by a field study. A total of 15 seropositive and 20 seronegative animals were vaccinated twice, three weeks apart, with a commercial phase I vaccine, and phase-specific antibodies were determined in the course of vaccination. Although anti-phase II antibody reactivity predominated after vaccination compared to phase I, both anti-phase I- and -phase II-antibody-reactivity significantly increased after the first (p = 0.001) and again after the second vaccination (p = 0.05). Seroconversion did not significantly depend on age or natural infection status. Once the vaccination cycle was completed, the herd study observed a reduced rate of abortion and placenta retention. Our data demonstrated that the vaccine principally induced a similar antibody response as in goats and sheep. These preliminary data appeared to support vaccination in buffalo, even in seropositive animals, although further studies are needed to better define the dynamics concerning seroconversion in this species.

Molecular detection of Coxiella burnetii in blood and hard tick-infested Egyptian camels and the possibility of coinfections.

Coxiella burnetii, a bacterium that causes Q fever. It can infect mammals and has a global geographical distribution, but data on its occurrence in Egyptian dromedaries and the associated ticks are limited. Therefore, this study aims to detect C. burnetii in the blood of infested camels and associated ticks collected from Egypt by using molecular techniques and to examine the possibility of coinfections with C. burnetii. A total of 133 blood samples and 1260 hard ticks infesting these camels were collected from Egyptian slaughterhouses. Nested PCR and sequencing were used based on the IS1111 gene for molecular detection of C. burnetii. The identification of tick species at the molecular level was performed using the COX1 gene. C. burnetii was detected in Hyalomma (H) dromedarii, H. anatolicum, H. marginatum, Amblyomma (Am) lipidium, and Am. cohaerens with an overall prevalence rate of 1.3% (16/1260), while in the camel blood samples, it was 15.8% (21/133). Out of C. burnetii-positive ticks, there were double infections by Borrelia species and C. burnetii in H. dromedarii and Am. lipidium and triple infections at one Am. cohaerens tick (C. burnetii, Borrelia spp., and Babesia microti). In addition, two positive camel blood samples were found to carry C. burnetii with Borrelia spp. Our research findings indicate the presence of Coxiella burnetii among camels and their associated ticks in Egypt and emphasize the potential of having coinfection. To prevent the transmission of this infection to other animal species or humans, appropriate control measures should be implemented.

Coxiella burnetii Nine Mile phase I primary infection derived protective immunity against C. burnetii reinfection in mice depends on both B and T cells, but T cells play a critical role.

Coxiella burnetii is an obligate intracellular Gram-negative bacterium that causes acute and chronic Q fever in humans. Acute Q fever is usually a flu-like, self-limiting or treatable illness, but some infections can turn into a severe and sometimes fatal chronic disease. There is currently no FDA-approved vaccine available for the prevention of human Q fever in the US, development of a safe and effective vaccine for the prevention of human Q fever remains an important goal for public health. However, there is a fundamental gap in knowledge regarding the mechanism of protective immunity against C. burnetii infection. To understand the mechanism of C. burnetii infection induced protective immunity, we examined if C. burnetii Nine Mile phase I (NMI) infection induces protection against C. burnetii reinfection in mice. Our results indicate that NMI-infected mice conferred significant protection against C. burnetii reinfection. We also found that NMI infection derived protection did not depend on the routes of infection and antibodies are required for NMI infection derived protection. In addition, NMI infection elicited a comparable level of protection in Wild type, CD4+ T cell deficient, and CD8+ T cell deficient mice, partial protection in B cell deficient mice but no protection in T cell deficient mice. These results suggest that both B cells and T cells are required for NMI-infection derived protection, but T cells may play a critical role. Therefore, the new generation vaccine for the prevention of human Q fever should be focused on boosting both humoral and T cell immune responses.

Age-dependent haemogram and sex-dependent serum biochemistry values in semi-feral Konik horses.

INTRODUCTION: Semi-feral, free-roaming Konik polski horses are used in some European countries for preserving semi-open pasture landscapes. The estimation of their health status is still limited by insufficient data on various blood parameters. Therefore, our study aimed at the sex- and age-dependent analysis of haemogram and selected biochemistry parameters in healthy, semi-feral Koniks. In order to reach this aim, we took blood samples from 53 female and 18 male (8 uncastrated, 10 castrated) Koniks living in two Middle German nature reserves. They were of different age (9-266 months) and without signs of illness. Blood samples were analysed by an accredited laboratory. We identified age- but not sex-dependent changes in the white blood cell count (WBC). Higher age mainly caused a decrease in lymphocytes. Therefore, WBC correlated negatively and granulocyte-to-lymphocyte ratio positively with increasing age. Serum values of selected biochemical parameters did not depend on age but showed some sex-related differences. In this regard, serum total protein, triglyceride and the enzymatic activities of alkaline phosphatase, aspartate transaminase and g-glutamyltransferase were higher in males than females. However, the sex dependency of these enzymatic activities was restricted to uncastrated males. They also showed higher serum values for calcium and selenium than castrated males or all females. As far as the respective group sizes permitted, we then calculated age- or sex-dependent reference interval values for all parameters analysed. These values improve now the estimation of the health status of semi-feral, free-roaming Konik horses and provide a stable basis for future studies.

INTRODUCTION: Les chevaux Konik Polski semi-sauvages en liberté sont utilisés dans certains pays européens pour préserver les paysages de pâturages semi-ouverts. L'estimation de leur état de santé est encore limitée par le manque de données sur divers paramètres sanguins. C'est pourquoi notre étude visait à analyser, en fonction du sexe et de l'âge, l'hémogramme et certains paramètres biochimiques chez des Konik semi-sauvages en bonne santé. Pour ce faire, nous avons prélevé des échantillons de sang sur 53 femelles et 18 mâles (8 non castrés, 10 castrés) vivant dans deux réserves naturelles d'Allemagne centrale. Ils étaient d'âges différents (9-266 mois) et ne présentaient aucun signe de maladie. Les échantillons de sang ont été analysés par un laboratoire accrédité. Nous avons identifié des changements dans la numération des globules blancs (WBC) qui dépendent de l'âge mais non du sexe. L'augmentation de l'âge a principalement entraîné une diminution des lymphocytes. Par conséquent, le nombre de globules blancs est corrélé négativement et le rapport granulocytes/lymphocytes positivement avec l'augmentation de l'âge. Les valeurs sériques de certains paramètres biochimiques ne dépendaient pas de l'âge, mais présentaient certaines différences liées au sexe. À cet égard, les protéines totales sériques, les triglycérides et les activités enzymatiques de la phosphatase alcaline, de la transaminase aspartate et de la γ-glutamyltransférase étaient plus élevés chez les mâles que chez les femelles. Cependant, la dépendance de ces activités enzymatiques par rapport au sexe était limitée aux mâles non castrés. Ces derniers présentaient également des valeurs sériques de calcium et de sélénium plus élevées que les mâles castrés ou que toutes les femelles. Dans la mesure où la taille des groupes respectifs le permettait, nous avons ensuite calculé des valeurs d'intervalle de référence dépendant de l'âge ou du sexe pour tous les paramètres analysés. Ces valeurs améliorent désormais l'estimation de l'état de santé des chevaux Konik semi-sauvages en liberté et fournissent une base stable pour les études futures.

Q Fever in Greece and Factors of Exposure: A Multiregional Seroprevalence Study.

INTRODUCTION: The epidemiology of Q fever, caused by Coxiella burnetii, varies significantly worldwide. This study aimed to document the prevalence of Coxiella burnetii in Greece by measuring specific IgG antibody levels in serum samples from the general population and high-risk groups, including farmers, veterinarians, and laboratory workers. METHODOLOGY: A multiregional, stratified sampling design was employed, with 1,345 participants from Thessaly and Central Macedonia. Serum samples were tested for Coxiella burnetii IgG antibodies, and multivariate analysis was conducted to identify factors associated with seroprevalence. RESULTS: Overall, 8.1% of participants tested positive for Coxiella burnetii antibodies, with the highest seroprevalence in Larissa (22.2%) and Karditsa (16.1%). High-risk occupational groups, particularly those with direct animal contact, showed a higher seroprevalence (13.6%). Multivariate analysis identified significant associations between seroprevalence and factors such as geographic region, occupation, and gender. CONCLUSION: The study reveals regional and occupational disparities in Q fever seroprevalence in Greece, particularly in rural areas. These findings underscore the need for targeted public health measures, including heightened surveillance and preventive interventions for high-risk groups.

Molecular detection of Coxiella burnetii infection (Q fever) in livestock in Makkah Province, Saudi Arabia.

The study aims to investigate the prevalence of Q fever in livestock and ticks in Makkah Province, Saudi Arabia, by molecular methods. Using DNA obtained from (40) blood samples, (60) vaginal swabs and ticks (120) samples. Real-time PCR was used to detect the IS1111 insertion sequence of Coxiella burnetii in aborted animals. Among 40 blood samples only one sample of the camel was found to be infected with an overall prevalence of 2.5 %. The highest prevalence (10 %) was recorded in AL-Laith in one camel blood sample out of 10 samples examined. Of 60 vaginal swabs examined for C. burnetii DNA, four samples were found to be infected with an overall prevalence of 6.6 %. The highest prevalence (10 %) was recorded in Makkah in two camel vaginal swabs out of 20 samples, followed by Jeddah and AL-Laith with a prevalence of (5.6 %) by detection of one sample positive out of 18 samples on each of them, while vaginal swabs from AL-Kamil were negative. Three types of ticks were identified Hyalomma dromedarii, Hyalomma anatolicum, and Hyalomma excavatum. H. dromedarii tick is the most common in aborted camels with a prevalence (6.7 %) in Makkah followed by Jeddah (5 %). The findings of this study revealed that C. burnetii infection is prevalent in agricultural animals especially camels and ticks maintained at livestock farms in Makkah Province. However, these animals and ticks may pass on C. burnetii infections to nearby people and other animals in the study area.

Embracing multiple infection models to tackle Q fever: A review of in vitro, in vivo, and lung ex vivo models.

Multiple animal and cell culture models are employed to study pathogenesis of Coxiella burnetii, the causative agent of acute and chronic human Q fever. C. burnetii is a lung pathogen that is aerosolized in contaminated products and inhaled by humans to cause acute disease that can disseminate to other organs and establish chronic infection. Cellular models of Q fever include a variety of tissue-derived cell lines from mice and humans such as lung alveolar ex vivo cells. These models have the advantage of being cost-effective and reproducible. Similarly, animal models including mice and guinea pigs are cost-effective, although only immunocompromised SCID mice display a severe disease phenotype in response to Nine Mile I and Nine Mile II isolates of C. burnetii while immunocompetent guinea pigs display human-like symptoms and robust immune responses. Non-human primates such as macaques and marmosets are the closest model of human disease but are costly and largely used for adaptive immune response studies. All animal models are used for vaccine development but many differences exist in the pathogen's ability to establish lung infection when considering infection routes, bacterial isolates, and host genetic background. Similarly, while cellular models are useful for characterization of host-pathogen mechanisms, future developments should include use of a lung infection platform to draw appropriate conclusions. Here, we summarize the current state of the C. burnetii lung pathogenesis field by discussing the contribution of different animal and cell culture models and include suggestions for continuing to move the field forward.

An unusual cause of headache: Expanding your differential.

Giant cell arteritis (GCA) is an inflammatory vasculitis that affects larger blood vessels, like the temporal arteries and the aorta. It is systemic and tends to affect individuals over 50. Common symptoms include headache, jaw pain provoked by chewing, and fever. We present an interesting case of a GCA variant.

Surgical management of infected endovascular aortic stent graft secondary to Coxiella burnetii infection.

The management of an endograft infection with Coxiella burnetti (Q fever) is presented. In this case report, we describe a unique case of an endovascular aneurysm repair (EVAR) that was originally placed for a 6.4-cm abdominal aortic aneurysm with an aorto-left renal vein fistula. In retrospect, the abdominal aortic aneurysm was most likely infected at the time of EVAR. The patient presented 2 years later with a virulent infection of the stent graft requiring explantation and reconstruction. This case highlights surgical management of an infected EVAR with homograft reconstruction and subsequent antibiotic management.

First Insight into the Prevalence of Coxiella burnetii Infection among Veterinary Medicine Students in Bulgaria.

The aim of this study was to assess the prevalence of Coxiella burnetii infection among veterinary medicine students from two Bulgarian Universities, located in Sofia and Stara Zagora. Blood samples were collected from a total of 185 veterinary students for the detection of C. burnetii phase II antibodies and presence of DNA using an enzyme-linked immunosorbent assay (ELISA) and end-point PCR test. Out of all samples, 29.7% were positive for at least one C. burnetii phase II antibody marker or by the result of the PCR test. Veterinary students from Stara Zagora showed a significantly high seropositivity for Q fever (33.6%), as compared to the students in Sofia (23%; p < 0.05). Evidence of recent exposure with detection of anti-C. burnetii phase II IgM (+) antibodies was observed in 14.6% of the students under study. Seroprevalence among students in Stara Zagora was higher (15.3%). Anti-C. burnetii phase II IgG antibodies were detected in 21.6% of examined samples. Our study revealed a higher seropositivity among the male students (32.8%) as compared to females (16.0%; p < 0.05). The end-point PCR assay detected 5.9% blood samples as positive. The relative risk (RR) of Q fever exposure for male students was 40.7%, whereas it was 24.6% in females (p < 0.05). The findings from this study indicate that the C. burnetii infection is widely distributed amongst veterinary students in Bulgaria. This study emphasizes the need for improved safety protocols and infection control measures in veterinary training programs.

Molecular detection of Coxiella burnetii in ticks infesting wild and domestic animals in the Eastern region of Punjab, Pakistan.

Tick-borne pathogens are significant for human, veterinary, and wildlife health. Coxiella burnetii is an example that is widely distributed across various hosts and can cross species boundaries. In Pakistan, there is a scarcity of data regarding C. burnetii at the intersection of wildlife and livestock. Ticks were collected from ruminants and wildlife from the districts of Kasur, Pakpattan, and Okara in Pakistan. Five tick species totaling 571 ticks were collected, with the following distribution: 56.4% Hyalomma anatolicum, 22.4% Rhipicephalus microplus, 10.5% Hyalomma marginatum, 7.9% Rhipicephalus sanguineus, and 2.8% Rhipicephalus turanicus. Fifty tick pools were screened for C. burnetii to amplify a segment of the IS1111 using real-time PCR assays. Ticks collected from sheep and goats had a greater rate of positivity for C. burnetii (40% and 38%, respectively) compared to Indian long-eared hedgehogs with a prevalence of 2%. Coxiella burnetii was prominent in Rhipicephalus microplus (92.3%) and Hyalomma anatolicum (88.9%), followed by Rhipicephalus turanicus (66.6%), Rhipicephalus sanguineus (33.3%), and Hyalomma marginatum (25.0%). Ticks from Pakpattan district displayed the highest prevalence of C. burnetii (88.9%), whereas the lowest was observed in ticks from Kasur district (77.3%). There was no significant association between tick gender and C. burnetii infection. Female host animals were more likely to harbor ticks containing C. burnetii, with a prevalence rate of 81.8%. The research underscores the urgent need for comprehensive studies on C. burnetii in Pakistan, especially at the interface of wildlife and livestock. The high prevalence rates observed in certain tick species and geographic regions emphasize the importance of targeted public health interventions. Future research should focus on elucidating the transmission dynamics and implementing effective control measures to mitigate the impact of these pathogens on human, veterinary, and wildlife health in the region.

The epidemiological and infectious characteristics of novel types of Coxiella burnetii co-infected with Coxiella-like microorganisms from Xuyi County, Jiangsu province, China.

Coxiella burnetii (C. burnetii) is the causative agent of Q fever, a type of zoonoses withwidespread distribution. In 2019, a case of Q fever was diagnosed by metagenomic next-generation sequencing (mNGS) method in Xuyi County (Jiangsu province, China). The seroprevalence of previous fever patients and the molecular epidemiology of Coxiella in wild hedgehogs and harbouring ticks around the confirmed patient were detected to reveal the genetic characteristics and pathogenicity of the Coxiella strains. Four of the 90 serum samples (4.44%) were positive for specific C. burnetii IgM antibody, suggesting that local humans are at risk of Q fever. The positive rates of C. burnetii in hedgehogs and ticks were 21.9% (7/32) and 70.5% (122/173), respectively. At least 3 strains of Coxiella were found prevalent in the investigated area, including one new genotype of pathogenic C. burnetii (XYHT29) and two non-pathogenic Coxiella-like organisms (XYHT19 and XYHT3). XYHT29 carried by ticks and wild hedgehogs successfully infected mice, imposing a potential threat to local humans. XYHT19, a novel Coxiella-like microorganism, was first discovered in the world to co-infect with C. burnetii in Haemaphysalis flava. The study provided significant epidemic information that could be used for prevention and control strategies against Q fever for local public health departments and medical institutions.

Epidemiology of Q Fever in Southeast Europe for a 20-Year Period (2002-2021).

This study aimed to assess epidemiological trends of Q fever in six countries of Southeast Europe by analysing surveillance data for 2002-2021 period. In this descriptive analysis, we collected and analysed data on confirmed human Q fever cases, obtained from the national Public Health Institutes of Bosnia and Herzegovina, Croatia, Greece, Montenegro, North Macedonia and Serbia. Overall, 2714 Q fever cases were registered during the 20-year period. The crude average annual notification rate was 0.82 (± 2.06) (95% CI: 0.47-1.16) per 100,000 inhabitants, ranged from 0.06 (± 0.04) (95% CI: 0.04-0.08) /100,000 in Greece to 2.78 (± 4.80) (95% CI: 0.53-5.02) /100,000 in the Republic of Srpska (entity of Bosnia and Herzegovina). Significant declining trends of Q fever age standardized rates were registered in Croatia, the Federation of Bosnia and Herzegovina, North Macedonia and Serbia, with an average annual change of -30.15%; -17.13%; -28.33% and - 24.77%, respectively. An unequal spatial distribution was observed. The highest average age-specific notification rate was reported in the 20-59 age group (0.84 (± 0.40) (95% CI: 0.65-1.02) /100,000). Most cases (53.69%) were reported during the spring. Q fever remains a significant public health threat in this part of Europe. The findings of this study revealed the endemic maintenance of this disease in the including countries, with large regional and subnational disparities in notification rates. A downward trend was found in Q fever notification rates across the study countries with the average notification rate higher than in the EU/EEA, during the same period.

A novel bacterial effector protein mediates ER-LD membrane contacts to regulate host lipid droplets.

Effective intracellular communication between cellular organelles occurs at dedicated membrane contact sites (MCSs). Tether proteins are responsible for the establishment of MCSs, enabling direct communication between organelles to ensure organelle function and host cell homeostasis. While recent research has identified tether proteins in several bacterial pathogens, their functions have predominantly been associated with mediating inter-organelle communication between the bacteria containing vacuole (BCV) and the host endoplasmic reticulum (ER). Here, we identify a novel bacterial effector protein, CbEPF1, which acts as a molecular tether beyond the confines of the BCV and facilitates interactions between host cell organelles. Coxiella burnetii, an obligate intracellular bacterial pathogen, encodes the FFAT motif-containing protein CbEPF1 which localizes to host lipid droplets (LDs). CbEPF1 establishes inter-organelle contact sites between host LDs and the ER through its interactions with VAP family proteins. Intriguingly, CbEPF1 modulates growth of host LDs in a FFAT motif-dependent manner. These findings highlight the potential for bacterial effector proteins to impact host cellular homeostasis by manipulating inter-organelle communication beyond conventional BCVs.