Prevalence and associated risk factors of anti-Coxiella burnetii antibodies in dairy cattle herds using bulk tank milk analysis in Kabylia area, north Algeria.

Coxiella burnetii, or Q fever agent, has notable implications for human and livestock health. Infections in cattle primarily manifest through reproductive issues where infected animals shed the bacterium in birth fluids, placental tissues, and milk, serving as potential sources of transmission. Bovine herds become reservoirs, contributing to the environmental contamination of farming areas. Comprehensive studies on the prevalence, transmission routes, and associated risk factors among cattle contribute to the development of effective control strategies, ultimately safeguarding both livestock and public health.Here we determine the prevalence of Coxiella burnetii antibodies against in dairy cattle farms from Kabylia (northern Algeria) and identify the associated risk factors. Bulk tank milk samples from 184 farms were analyzed by indirect ELISA technique, 49 of them were tested positive which corresponds to a prevalence rate of 26.63% (95% CI 20.25-33.01%). Multivariate analysis by logistic regression showed that the risk factors associated with detection of anti-Coxiella burnetii antibodies are: cohabitation of cattle with small ruminants(OR = 3.74 95% CI [1.41-8.92]), exposure to prevailing winds (OR = 5.12 95% CI [2.11-13.45]), and the veterinarian visits frequency(OR = 5.67 95% CI [2.55-13.60]). These findings underscore the susceptibility of dairy cattle to Q fever in the Kabylia region, highlighting practices that pose risks. We recommend the implementation of hygienic measures and adherence to proper farming conditions to mitigate the transmission of Q fever and reduce the associated zoonotic risk.

Risk factors associated with Coxiella burnetii in wild boars: A study in South Korea.

Coxiella burnetii is a Gram-negative bacterium that causes the zoonotic disease Q fever. Wild boars serve as reservoirs for C. burnetii. This study aimed to identify the risk factors associated with C. burnetii infection in wild boars. We analyzed the data from 975 wild boar samples collected from June to November 2021 in South Korea. We utilized the indirect ELISA to detect antibodies against C. burnetii. A sample optical density to positive-control optical density value exceeding 50% was classified as positive. We gathered data on the forestation, terrain, weather, agriculture, and animal density of the region where the samples were collected. Continuous variables were categorized into tertiles. We performed a univariate logistic regression analysis and included variables with a p-value < 0.2 in the final multivariable logistic regression model. In our multivariable logistic regression analysis to identify risk factors for C. burnetii infection in wild boars, we used a forward selection method to enter variables based on the order of their significance. We performed the final multivariable logistic regression analyses using either continuous variables or variables categorized into tertiles. The prevalence of C. burnetii was 14.6% (n=142). Locations with the highest maximum wind speeds (3.92-8.24 m/s) showed a 59% increase in infection odds compared to locations with the lowest speeds (1.45-3.25 m/s)(p=0.044). For each 1 m/s increase in maximum wind speed, infection odds increased by 24.1% (p=0.037). Regions with the highest percentage of paddy fields per area (8.3-45%) showed a 76% increase in infection odds compared to regions with the lowest percentage (0-1.5%)(p=0.011). For each 1% increase in the proportion of paddy fields per area, infection odds increased by 3.3% (p=0.003). High maximum wind speed and a high percentage of paddy field were identified as significant risk factors for C. burnetii infection in wild boars.

The immune response to a Coxiella burnetii vaccine in sheep varies according to their natural pre-exposure.

Q fever in humans is caused by Coxiella (C.) burnetii. In 2008 and 2012, cases of Q fever in humans were linked to an infected flock of approximately 650 ewes. Since 2013 gimmers (G'13, G'14, G'15 etc.) were primary vaccinated (two doses) with an inactivated C.burnetii vaccine without any revaccination. In 2013, 30 ewes were primary vaccinated (A'13). Shedding was annually monitored by qPCR-testing of vaginal and nasal swabs collected at lambing. Animals were tested for Phase I- (PhI) and PhII-antibodies (Ab) and for PhII-specific-interferon-γ (IFN-γ) before and after vaccination. The effect of a revaccination was determined in 2018 and 2023. Groups of randomly selected gimmers primary vaccinated in 2015, 2016 and 2017 and a mixed group of older animals (A'13, G'13 and G'14) were revaccinated once in 2018. The trial was repeated in 2023 on groups primary vaccinated in 2019-2023. Major shedding after the outbreak in 2012 ceased in 2014. Thereafter C.burnetii was only sporadically detected at low-level in 2018, 2021 and 2023. Sheep naturally exposed to C.burnetii during the outbreak in 2012 (A'13, G'13) mounted a strong and complete (PhI, PhII, IFN-γ) recall immune response after vaccination. A serological PhI+/PhII+ pattern dominated after vaccination. In contrast, since 2014 a weaker immune response (PhII-titre, IFN-γ) and a dominance of the PhI-/PhII+ pattern was observed in vaccinated gimmers. The number of serologically non-responding gimmers to vaccination increased to 25.0 % in G'16/G'17 and 40.4 % in G'19/G'20. But revaccination even three (G'15 in 2018) and four (G'19 in 2023) years after primary vaccination resulted in a strong and complete immune response. No difference of the immune response nor to more recently primary vaccinated animals (G'23 in 2023) nor to those animals that were present during the outbreak (A'13/G'13/G'14 in 2018) was observed.

Coxiella burnetii infection persistence in a goat herd during seven kidding seasons after an outbreak of abortions: the effect of vaccination.

Coxiella burnetii infection was monitored during seven kidding seasons (2017-2023) in a dairy goat herd that after an outbreak of Q fever abortions was vaccinated with an inactivated phase I vaccine. Due to the high infection rate just after the outbreak, only the replacement stock was vaccinated during the first three kidding seasons, and when the average herd immunity had decreased (fourth kidding season onwards), the whole herd was vaccinated. Vaginal swabs, feces, and milk were analyzed by PCR to monitor infection, and dust and aerosols were analyzed to measure C. burnetii environmental contamination. One year after the onset of the outbreak, a significant reduction in C. burnetii shedding loads was observed, but the percentage of shedding animals remained high until the third kidding season. By the seventh kidding season, no shedders were detected. The bacterial load excreted was significantly lower in vaccinated compared with unvaccinated animals, and in yearlings compared with multiparous. C. burnetii was detected by PCR in aerosols collected inside the animal premises throughout the study period except in the last season; whereas, aerosols collected outdoors tested negative in the last three kidding seasons. Viable C. burnetii was detectable in environmental dust collected inside the barn until the third kidding season following the outbreak. These results indicate that after an outbreak of Q fever, the risk of infection for humans and susceptible animals can remain high for at least three kidding seasons when the number of C. burnetii animal shedders is still high, even when bacterial excretion is low. IMPORTANCE: Q fever is a zoonosis distributed worldwide. Ruminants are the main reservoir, and infection can cause high rates of abortion. After entering a farm, Coxiella burnetii infection can persist in the animal population over several lambing/kidding periods. Once infection is established in a herd, vaccination with the inactivated Phase I vaccine significantly reduces bacterial shedding, but although at low levels, excretion may continue to occur for several lambing/kidding seasons. The time that C. burnetii remains viable in the farm environment after an outbreak of Q fever determines the period when risk of infection is high for the people in close contact. This work showed that this period extends at least three kidding seasons after the outbreak. These results provided valuable information on the epidemiology of C. burnetii infection in goat herds and may help to develop guidelines for controlling the disease and reducing infection risk for susceptible people and animals.

Molecular detection of Coxiella burnetii in tick and blood samples from small ruminants in northwest of Iran.

This survey sought to molecularly detect Coxiella burnetii in Argasidae and Ixodidae ticks attached to small ruminants in the region of West Azerbaijan (Northwest of Iran) and blood samples collected from the same animals. 451 tick samples and 927 blood samples were obtained from sheep (n = 536) and goats (n = 391) and tested by nested PCR for detection of C. burnetii insertion sequence IS1111 or icd gene sequence. The collected ticks were morphologically classified as Rhipicephalus sanguineus, Rhipicephalus turanicus, Hyalomma asiaticum, Hyalomma anatolicum, or Argas reflexus. 14% of ticks (65 in total 43 for IS1111 and 22 for icd gene) tested positive for C. burnetii, none of which were from the Argas genus. Among the 927 blood samples, 218 (23.5%) tested positive for C. burnetii. The positive result from analysis targeting the genes IS1111 and icd were 131 and 87 respectively. As Q fever is a tickborne zoonosis and endemic to Iran, such information is critical for creating effective, coordinated, and strategic tick and pathogen control programs to prevent disease outbreak in domestic animals and humans.

Molecular examination for Coxiella burnetii and Brucella spp. infections in Iranian women experiencing spontaneous miscarriage.

BACKGROUND: Spontaneous miscarriage, a leading health concern globally, often occurs due to various factors, including infections. Among these, Coxiella burnetii and Brucella spp. may have adverse effects on pregnancy outcomes. While previous research has established a link between infections and spontaneous miscarriage, our study aimed specifically to investigate the presence of these two pathogens in abortion samples from women who experienced spontaneous miscarriages in Iran. Our study can add to the existing knowledge by focusing on Iran, a region with a high prevalence of C. burnetii and Brucella spp. As a result, it could provide a better understanding and unique insights into the relationship of these pathogens with spontaneous miscarriages in endemic regions. METHODS: From March 2021 to March 2022, a total of 728 abortion samples (including placenta and cotyledon) were collected from 409 women who had experienced spontaneous miscarriages in the provinces of Tehran, Fars, and West Azerbaijan in Iran. The specimens included 467 Formalin-Fixed Paraffin-Embedded (FFPE) and 261 fresh frozen samples. After DNA extraction from abortion samples, the quantitative real-time PCR (qPCR) assay targeted a specific fragment of the IS1111 and IS711 elements for molecular identification of C. burnetii and Brucella spp., respectively. Furthermore, the qPCR assay employing specific primers for different species was used to determine the species of Brucella. RESULTS: Among the studied women, 1 out of 409 (0.24%) samples tested positive for Brucella spp., specifically Brucella melitensis. There were no positive specimens for C. burnetii. CONCLUSIONS: Our study contributes to understanding the potential involvement of Brucella species in spontaneous infectious abortion within endemic regions. The identification of B. melitensis in this study highlights the need for further research in this area. However, while our results suggest a relatively low or zero identification of these pathogens in our sample population, this does not rule out the possibility of undetected infections. Therefore, it is critical to acknowledge the limitations of the molecular techniques used (qPCR), which may have potential limitations such as sensitivity and specificity. Moreover, because 64.15% of our samples were FFPE, the sensitivity of the qPCR test may be reduced. These raise concerns about the accuracy of the reported prevalence rates and the potential for false positives or negatives.

Molecular detection and MST genotyping of Coxiella burnetii in ruminants and stray dogs and cats in Northern Algeria.

Aiming at identifying the reservoir and contamination sources of Coxiella burnetii in Northern Algeria, we investigated the molecular presence of the bacterium in 599 samples (blood, placenta, liver, spleen, and uterus) collected from cattle, sheep, dogs and cats. Our qPCR results showed that 15/344 (4.36%) blood samples and six/255 (2.35%) organ specimens were positive for C. burnetii. In cattle, three (4%) blood and liver samples were positive. In sheep, one blood (1.19%) and 3 (8.57%) placenta samples were positive. At the Algiers dog pound, 8 (10%) and 3 (5%) blood samples were qPCR positivein dogs and cats, respectively. In addition, MST genotyping showed that MST 33 was present in cattle and sheep, MST 20 in cattle,andMST 21 in dogs and cats.

Coxiella burnetii seroprevalence in domestic goat does in the United States: Prevalence, distribution, and associated risk factors.

Infection with the bacterium Coxiella burnetii can cause coxiellosis in animals and Q fever in humans. Coxiellosis a consistently underreported infectious disease. The infection can result in reproductive consequences for humans and animals. Ruminants are a reservoir for infection and humans are generally infected via aerosolized secretions, making it a public health concern. Studies of ruminant seroprevalence are generally limited in size and scope. This study determined seroprevalence in a large-scale U.S. population of female goats using serum samples from 7736 does from 24 states. This study identified C. burnetii seroprevalence in the United States domestic goat population. Overall, 14.5 % (SE = 2.3) of does were seropositive and 21.0 % (SE = 2.4) of operations had at least 1 seropositive doe. Further, operation demographics and herd management practices associated with seropositivity were as follows: the suspected or confirmed presence of caprine arthritis encephalitis (CAE), caseous lymphadenitis (CL), Johne's disease, or sore mouth in the herd in the previous 3 years, not cleaning or disinfecting the kidding areas or removing aborting does from other does, allowing visitors to access the kidding areas, and a lower percentage of adult goat inventory that were adult bucks or wethers. Furthermore, goat breed was associated with seropositivity. These data show C. burnetii seroprevalence in the United States and identify operation and animal characteristics and management practices associated with C. burnetii seropositivity. Together, this information can be used to help limit animal transmission, inform public health measures, and help educate and protect individuals working with goats.

Q fever infection is a preventable risk associated with pet food manufacturing.

OBJECTIVE: This paper highlights the occupational risk of Q fever from exposure to raw animal products in the context of multiple notified Q fever cases from 2020 to 2023 linked to four pet food manufacturing facilities in South-East Queensland, Australia. METHODS: The Queensland Government Notifiable Conditions System was used to identify Q fever cases linked to pet food manufacturing in the Metro North and Gold Coast Hospital and Health Service areas of Brisbane, Australia. Data on each case from routine public health follow-up were collected and descriptively analysed. RESULTS: Between 2020 and 2023, 12 confirmed Q fever infections (17% of total cases) were linked to four pet food manufacturing facilities. Eleven cases reported direct or environmental exposure to raw meat and animal products. None were previously vaccinated for Q fever. CONCLUSION: These cases demonstrate the increased risk of Q fever infection as part of the pet food manufacturing process, highlighting an underappreciated preventable occupational risk, which can be mitigated with the use of pre-screening and vaccination of workers. All occupations should conduct workplace-based risk assessments to identify risks such as Q fever to prevent adverse negative health outcomes.

Seroprevalence of Coxiella burnetii in an Indigenous Population from the Sierra Nevada De Santa Marta, Colombia.

Coxiella burnetii is an underreported zoonotic pathogen in many rural regions globally. We investigated C. burnetii exposure in a remote indigenous tribe residing in the Sierra Nevada de Santa Marta, Colombia. The high seroprevalence of 35% (95% CI, 27-43%) demonstrates the need for One Health studies to identify risk factors, clinical impact, and potential medical, veterinary, and environmental interventions.

Coxiella burnetii infections from animals and ticks in South Africa: a systematic review.

Coxiella burnetii is a zoonotic intracellular bacterium that is widely distributed and affects domestic animals, wildlife, humans and non-mammalian species. This systematic review was aimed at synthesizing research findings on C. burnetii in both domestic and wild animals of South Africa. The systematic review protocol was registered with Open Society Foundations of systematic reviews ( https://doi.org/10.17605/OSF.IO/8WS ). PRISMA guidelines were followed to collect and evaluate relevant scientific articles published on C. burnetii infecting domestic and wild animals in South Africa. Published articles were sourced from five electronic databases, namely, Google Scholar, PubMed and ScienceDirect, EBSCO and Scopus. Results showed 11 eligible studies involving four domestic animals, three wild animals and one ectoparasite species from seven provinces across South Africa. The occurrence of C. burnetii infection was high in Ceratotherium simum (white rhinoceros) (53.9%), medium in sheep (29.0%) and low in pigs (0.9%). Limpopo province (26%) had the most recorded infections followed by KwaZulu-Natal (19%) and Free State (3%) had the least reported occurrence of C. burnetii. The current study discovered that there is scarcity of published research on prevalence and distribution of C. burnetii infecting domestic and wild animals in South Africa, and this is of concern as this bacterium is an important zoonotic pathogen of "One Health" importance.

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.

Molecular prevalence of Coxiella burnetii in cheese samples: Systematic review and meta-analysis.

BACKGROUND: Cheese is a popular dairy product consumed worldwide, and it has been implicated as a source of Coxiella burnetii infections. OBJECTIVES: The present study aimed to describe the molecular prevalence and source analysis of C. burnetii in cheese samples. METHODS: A systematic literature search was conducted using the Medline/PubMed, Science Direct, Web of Science, Scopus, and Google Scholar databases to identify studies reporting the molecular prevalence of C. burnetii in cheese samples. The pooled prevalence of C. burnetii in cheese samples was estimated using a random-effects model. RESULTS: A meta-analysis was conducted using the mean and standard deviation values obtained from 13 original studies. The overall molecular prevalence of C. burnetii in cheese was estimated to be 25.2% (95% confidence interval [CI]: 13.1%-39.7%). The I2 value of 96.3% (CI95% 94.9-97.3) suggested high heterogeneity, with a τ2 of 0.642 (CI95% -0.141 to 0.881), and an χ2 statistic of 323.77 (p < 0.0001). CONCLUSIONS: In conclusion, our meta-analysis provides a thorough assessment of the molecular prevalence and source analysis of C. burnetii in cheese samples.

Molecular epidemiology of Coxiella burnetii infection in sheep and goats in Henan province, China.

Q fever is a significant zoonotic disease caused by Coxiella burnetii, an obligate intracellular gram-negative bacterium. Although C. burnetii infection has been identified in various animal species, domestic ruminants serve as the primary reservoirs and main sources of human infection. Understanding of the epidemiology of C. burnetii in domestic ruminants is crucial for preventing and controlling of C. burnetii infection in humans. In this study, spleen tissues from sheep and goats were collected in Hennan province, China. Through PCR screening, C. burnetii was detected in sheep and goats in Henan province with an overall infection rate of 6.8 %. Sequence comparison and phylogenetic analysis revealed that all newly identified C. burnetii strains shared a close genetic relationship with those found in humans worldwide. These findings highlight the high risk of C. burnetii infection among slaughterhouse workers and emphasize the importance of epidemiological studies that investigate samples from both humans and animals within the "One Health" framework. Such surveillance will contribute to a better understanding of the epidemic situation and aid in the development of effective prevention and control strategies for C. burnetii infections in humans.

Interdisciplinary studies on Coxiella burnetii: From molecular to cellular, to host, to one health research.

The Q-GAPS (Q fever GermAn interdisciplinary Program for reSearch) consortium was launched in 2017 as a German consortium of more than 20 scientists with exceptional expertise, competence, and substantial knowledge in the field of the Q fever pathogen Coxiella (C.) burnetii. C. burnetii exemplifies as a zoonotic pathogen the challenges of zoonotic disease control and prophylaxis in human, animal, and environmental settings in a One Health approach. An interdisciplinary approach to studying the pathogen is essential to address unresolved questions about the epidemiology, immunology, pathogenesis, surveillance, and control of C. burnetii. In more than five years, Q-GAPS has provided new insights into pathogenicity and interaction with host defense mechanisms. The consortium has also investigated vaccine efficacy and application in animal reservoirs and identified expanded phenotypic and genotypic characteristics of C. burnetii and their epidemiological significance. In addition, conceptual principles for controlling, surveilling, and preventing zoonotic Q fever infections were developed and prepared for specific target groups. All findings have been continuously integrated into a Web-based, interactive, freely accessible knowledge and information platform (www.q-gaps.de), which also contains Q fever guidelines to support public health institutions in controlling and preventing Q fever. In this review, we will summarize our results and show an example of how an interdisciplinary consortium provides knowledge and better tools to control a zoonotic pathogen at the national level.

Genotyping and phylogenetic analysis of Coxiella burnetii in domestic ruminant and clinical samples in Iran: insights into Q fever epidemiology.

Coxiella burnetii, a zoonotic pathogen, is the causative agent of Q fever, an endemic disease in Iran. However, there is currently a lack of available data on the genotypes of C. burnetii in the country. Here, we typed 26 C. burnetii isolates detected in milk, abortion, cotylodon, and cardiac valve samples from various geographical areas and hosts (7 cattle, 8 goats, 10 sheep, and 1 human) using Multilocus Variable Number Tandem Repeat Analysis (MLVA/VNTR) with five loci:ms24, ms27, ms28, ms33, and ms34. As IS1111 was observed to be spontaneously inserted in locus ms23 across all of our examined C. burnetii samples, five loci were employed for MLVA/VNTR genotyping. Among the 26 C. burnetii strains, 22 distinct genotypes (A-V) were identified in the discriminative loci. In silico analysis categorized Iranian C. burnetii strains into five genomic groups along with seven singletons, representing 11 exiting clonal complexes worldwide. Clusters 10 and 11 exclusively consisted of Iranian samples. These findings revealed high genotyping diversity among C. burnetii isolates in Iran. The genotypes circulating in Iran differed significantly from those found in other regions worldwide. To gain a comprehensive understanding of Q fever epidemiology in Iran, it is crucial to conduct large-scale studies that assess the distribution of C. burnetii genotypes across different geographical areas, hosts, and sources.

Q fever awareness in Australia: A scoping review.

OBJECTIVE: To investigate the level of Q fever awareness in Australia. METHODS: A scoping review was conducted by searching the electronic databases Medline, PubMed and Web of Science using keywords for Q fever, awareness, knowledge, and Australian locations. The search was initially limited to articles published in the 10 years prior to June 2022 and then extended up to and including August 2023; yielding 387 records. RESULTS: Fifteen articles were assessed as being eligible. These articles reported on surveys and interviews conducted with farmers, veterinary practitioners and nurses, medical practitioners, policy makers, researchers, industry representatives, animal science students, cat breeders, wildlife rehabilitators, and agriculture show attendees. Farmers were the largest group represented. Level of Q fever awareness amongst these communities, including those at high-risk, was generally low. The need for increased awareness was recognised. General practitioner awareness levels were low and recognised to be so by high-risk groups. Awareness of preventive measures including vaccination was greater among those with greater awareness and risk. CONCLUSION: With the availability of a highly effective vaccine in Australia, there is a need to increase Q fever knowledge and awareness among high-risk groups and primary health care practitioners. IMPLICATIONS FOR PUBLIC HEALTH: Strategies to increase awareness and knowledge of Q fever risks and prevention strategies may assist with reducing Q fever burden in Australia.

Increased recognition of Q fever aortitis as a chronic manifestation of Q fever in tropical North Queensland, Australia.

Aortitis is a life-threatening, manifestation of chronic Q fever. We report a series of 5 patients with Q fever aortitis who have presented to our hospital in tropical Australia since 2019. All diagnoses were confirmed with polymerase chain reaction (PCR) testing of aortic tissue. Only one had a previous diagnosis of acute Q fever, and none had classical high-risk exposures that might increase clinical suspicion for the infection. All patients underwent surgery: one died and 3 had significant complications. Q fever aortitis may be underdiagnosed; clinicians should consider testing for Coxiella burnetii in people with aortic pathology in endemic areas.