Management of Coxiella burnetii infection in livestock populations and the associated zoonotic risk: A consensus statement

Raw Equid Milk: A Potential Risk for Q Fever?

Equid milk (donkey or mare) has traditionally been consumed raw or fermented due to its distinctive chemical composition, which closely resembles human milk, and its nutritional benefits. Nowadays, interest in it is increasing, despite limited research on its microbiological risk. Coxiella burnetii (C. burnetii), a globally re-emerging zoonotic agent, has rarely been investigated in equid milk. The objective of this study was to demonstrate the applicability of selected analytical methods for detecting C. burnetii in raw equid milk. A commercial molecular assay was tested on three serial dilutions of one donkey milk sample contaminated with a C. burnetii plasmid, which showed no interference of donkey milk with real-time PCR detection. The commercial molecular assay and a serological assay routinely used in the laboratory were also applied to screen a total of 106 equid milks from 16 farms to assess their applicability to diagnostic samples. No C. burnetii DNA or anti-C. burnetii antibodies were detected in these screenings. In our study, the implemented methods appeared to be suitable for C. burnetii investigation in equid milk. While the overall low prevalence recorded in Italy among domestic species is reassuring, strategic surveillance and risk assessment remain essential considering the low infectious dose of C. burnetii and its zoonotic potential.

Zoonotic Abortifacient Agents in Bovine Abortion: Diagnostic Assessment of 125 Cases (2015-2017)

BACKGROUND

The threat of zoonotic diseases is significant to global public health. Campylobacter spp., Coxiella burnetii (C. burnetii), Brucella spp., Listeria monocytogenes (L. monocytogenes), Chlamydia abortus (C. abortus), and Cache Valley virus (CVV) play a role in bovine abortion and are transmitted from animals to humans.

OBJECTIVE

This study aimed to investigate the presence of these zoonotic abortifacient agents in bovine foetuses (n = 125), each from different herds, in a three-year period in Türkiye.

METHODS

The detection and differentiation of Brucella spp. was achieved using a PCR method, while a multiplex PCR assay was used to detect and differentiate Campylobacter spp. Real-time PCR assays were used to detect C. burnetii, C. abortus, and L. monocytogenes. Furthermore, samples were tested for CVV using one-step duplex real-time RT-PCR.

RESULTS

Although L. monocytogenes and C. abortus and CVV were not detected, Brucella spp., Campylobacter spp., and C. burnetii were detected in 19 (15.2%), 4 (3.2%), and 2 (1.6%) of the bovine foetuses, respectively. Brucella and Campylobacter species were identified by molecular testing as B. melitensis (n = 4) and B. abortus (n = 15) and C. jejuni (n = 2) and C. foetus subsp. foetus (n = 2), respectively.

CONCLUSIONS

The findings of this study suggest that Brucella spp., Campylobacter spp., and C. burnetii could pose a threat to both cattle and human health in the studied regions. Further studies are required to determine the exact role of these agents in cattle reproductive losses in Türkiye, as well as the economic impact of these agents on livestock.

National serosurvey and risk mapping reveal widespread distribution of Coxiella burnetii in Kenya

Coxiella burnetii, the causative agent of Q fever, is an emerging pathogen that has the potential to cause severe chronic infections in animals and humans worldwide. The detrimental impact on public health is projected to be higher in the low- and middle-income countries given their lower capacity to sustain effective surveillance and response measures. We implemented a national serosurvey of cattle in Kenya to map the spatial distribution of the pathogen. The study used serum samples that were collected from randomly selected cattle in different ago-ecological zones across the country. These samples were screened for the pathogen using PrioCHECK Ruminant Q Fever AB Plate ELISA kit. The laboratory findings were analyzed using INLA package to identify risk factors for C. burnetii exposure from herd- and animal-level factors, area, and bioclimatic datasets accessed from online databases. A total of 6,593 cattle were recruited for the study; of these, 7.9% (95% CI; 7.2-8.5) were seropositive. Outputs from the multivariable analysis revealed that the animal age and some of the geographical variables including wind speed, area under shrubs and "petric calcisols" type of soil were significantly associated with C. burnetii seropositivity. Being a calf, weaner or subadult was associated with lower odds of exposure compared to being an adult by 0.24 (credibility interval: 2.5% and 97.5%), 0.41 (0.30-0.55) and 0.51 (0.38-0.69), respectively. In addition, a unit increase in the wind speed increased the odds of C. burnetii seropositivity by 1.27 (1.05-1.52) while an increase on the land area under shrubs was associated with lower odds of exposure (0.67 [0.47-0.69]). The effect of petric calcisols was non-linear; an increase of the land area with this soil type was associated with an exponential increase in C. burnetii seropositivity. This study provides new data on C. burnetii seroprevalence, information of its risk factors and a prevalence map that can be used for C. burnetii risk surveillance and control. The identification of environmental risk factors for C. burnetii exposure, and the increasing awareness of the zoonotic potential of the pathogen, calls for the need to enhance the existing collaborations for the surveillance and control of C. burnetii in line with the One Health framework. The evidence generated on the potential role of environmental factors can also be used to design nature-based interventions, such as replacement of vegetation in denuded areas, to reduce potential for the aerosolization of the pathogen. Livestock vaccination in the hotspots would also reduce animal infections and hence the contamination of the environment.

Biosecurity and Infection Control for Veterinarians Caring for Livestock: A Guide for Daily Threats

Biosecurity and infection control are important aspects of veterinary medicine and livestock production. In fact, cattle, sheep, and goat industries all rank biosecurity and disease prevention among the highest priority areas in livestock management. Although attention and planning have improved over the years among producers, the daily activities of a veterinarian can prevent or promote the spread of contagious disease agents. Awareness and knowledge of principles for infection control are the greatest tools to ward off serious consequences related to the spread of contagious disease. Indeed, veterinarians and livestock producers should endeavor to take all necessary precautions to mitigate foreseeable risks.

Characterising the knowledge, attitudes and practices of Australian veterinarians regarding Q fever and the diagnosis and reporting of coxiellosis

Q fever is a serious zoonotic disease that readily transmits from animals to humans. Infection in animals is known as coxiellosis. Veterinarians are in a key position to provide early detection of coxiellosis in animals that can aid the prevention or recognition of human cases. However, there is little information available about veterinary ability and willingness to diagnose and report this disease in animals. This study was conducted to assess the knowledge, attitudes and practices of veterinarians regarding coxiellosis. An online survey was performed that targeted veterinarians in Australia from 2020 to 2021 and 122 responses were obtained. Results showed that veterinarians report a moderate amount of knowledge about Q fever in humans but an overwhelming lack of confidence around recognising and diagnosing the disease in animals with 70-80 % of respondents reporting that they were 'not at all confident' or 'not very confident'. Most respondents (68 %) believed that coxiellosis was an important infection in animals because of its human health consequences and 84 % would report the infection if it were diagnosed. Barriers to diagnosis and reporting identified in this study include disease unfamiliarity, perception of disease insignificance, and futility of disease identification if there are no effective strategies in place for using diagnosis and notification of coxiellosis in controlling infection. Despite a deficit of self-reported knowledge and confidence regarding the diagnosis of coxiellosis, Australian veterinarians consider it to be an important zoonotic disease with implications for human health and are willing to collaborate with human health colleagues in a One Health approach around this issue.

Detection of Coxiella burnetii in Bulk Tank Milk of Dairy Small Ruminant Farms in Greece

The objectives of this work were as follows: (i) the evaluation of the prevalence of detection of genetic material of Coxiella burnetii in the bulk tank milk of sheep and goat farms in Greece and (ii) the investigation of variables related to the management applied in farms as possible predictors for this. The presence of C. burnetii genetic material was studied in the bulk tank milk of 325 sheep and 119 goat farms throughout the country. For qualitative and quantitative identification of the genetic material of the pathogen, a commercially available real-time PCR was used. In total, 45 parameters were assessed for potential association with the detection of the pathogen: these referred to the management system, infrastructure, health management, animals, production characteristics, and human resources on the farms. Genetic material of the pathogen was detected in bulk tank milk samples from nine sheep (2.8%) and six goat (5.0%) farms. Genetic material was at significantly higher median concentrations in samples from goat farms than from sheep farms, 1,078,096 (min: 181,121, max: 2,331,386) versus 15,728 (min: 507, max: 505,852) GE mL-1, respectively. For sheep farms, the intensive or semi-intensive management system applied in farms (p = 0.003), and for goat farms, the intensive or semi-intensive management system applied in farms (p = 0.0007) and the smaller number of annual veterinary visits to farms (p = 0.044) emerged as significant predictors. Among sheep farms managed under the intensive or semi-intensive system, the lack of accessory barns on farms (p = 0.024) emerged as a significant predictor; no significant predictor could be found among goat farms under such management systems. There was no significant difference in production outcomes between farms in which C. burnetii was or was not detected in the bulk tank milk; also, there was no association between the detection of C. burnetii and the annual incidence rate of cases of abortion on the farms. The results suggest that the risk of transfer of C. burnetii to dairy products from sheep and goat milk appears to be small, but not negligible, which indicates that the pasteurization of milk from small ruminants must be carried out consistently and correctly to ensure the safety of the product.

Coxiellosis in Dogs-A Hitherto Masked Zoonosis in India: An Insight From Seromolecular Investigation and Risk Factor Analysis

Coxiellaburnetii is an airborne bacterial zoonotic pathogen that causes Q fever/coxiellosis in humans and animals. Although dogs are suspected of transmitting Q fever to humans in past outbreaks, the prevalence of C. burnetii in the Indian dog population and risk factors for infection remain unknown. In this study, 452 dogs from pet clinics in three Indian states were screened for coxiellosis using molecular (Trans-PCR, Com 1-PCR) and serological (IFAT) tests. C. burnetii DNA was detected in 0.44% of blood samples using Trans-PCR, and pathogen-specific antibodies were found in 4.20% of sera using IFAT. Contact with stray dogs and ownership by farmers were identified as risk factors for canine coxiellosis. This study appears to be the first systematic assessment of coxiellosis and associated risk factors among dogs in India. A large-scale assessment of canine coxiellosis and its risk factors is warranted among pets and high-risk occupational groups in India.

Molecular and serological screening of coxiellosis in bovines with reproductive disorders in dairy farms

Coxiella burnetii infection is an emerging/re-emerging public health problem affecting several countries worldwide. In India, the disease is mainly underdiagnosed, creating hindrances in its effective control. This study investigated the occurrence of C. burnetii among apparently healthy cattle and cattle with a history of reproductive disorders by both PCR and indirect-ELISA. A total of 731 clinical samples (serum: 531, and vaginal swabs as well as blood: 100 each) from 531 cattle were screened for coxiellosis. The serum, blood, and vaginal swabs each collected from 100 cattle with a history of reproductive disorders were screened using Com1-PCR, Trans-PCR, and indirect-ELISA. Conversely, serum samples obtained from apparently healthy cattle were exclusively screened using indirect ELISA. None of the samples tested could detect C. burnetii in PCR assays, while 13.37 % of serum samples were found to be seropositive in i-ELISA. Seropositivity noted among clinically healthy and those suffering from reproductive disorders were 12.76 % and 16 %, respectively, exhibiting a non-significant difference observed between these two categories. The obtained results suggested that the occurrence of coxiellosis did not differ significantly between clinically healthy animals and those with reproductive disorders; hence, in farms affected with C. burnetii infection, screening healthy and symptomatic animals is crucial to implement appropriate preventive measures.

Herd-level seroprevalence, molecular prevalence, and trends of Coxiella burnetii (Q fever) in cattle worldwide: A systematic review and meta-analysis

Background and Aim

Cattle are the reservoir host of Coxiella burnetii, a causative agent of Q fever. Pooling herd-level prevalence data from individual studies would help determine the global prevalence of C. burnetii in cattle herds. This study aimed to estimate the global herd-level seroprevalence and molecular prevalence of C. burnetii in cattle, explore sources of heterogeneity, and determine trends and cumulative evidence of the pooled prevalence over time.

Materials and Methods

Relevant studies were retrieved from PubMed, Scopus, and Web of Science and then screened for possible inclusion. A random-effects model was used for all meta-analyses. Subgroup meta-analysis and meta-regression were used to explore some sources of heterogeneity associated with the pooled prevalence and to determine the trends of C. burnetii in cattle herds over the study years (1961-2020). A cumulative meta-analysis was used to determine the cumulative evidence of the pooled prevalence over the publication years.

Results

Of the 1541 citations, 86 studies with 38,057 cattle herds from 42 countries on six continents were included in the meta-analysis. The global herd-level seroprevalence of C. burnetii in cattle was estimated to be 44.4% (95% confidence interval [CI], 37.9%-51.1%), with high heterogeneity among the included studies. The herd-level seroprevalence was significantly higher in dairy than in beef cattle herds (49.0% [95% CI: 41.9%-56.2%] vs. 14.5% [95% CI: 5.8%-32.1%], respectively). The global herd-level molecular prevalence of C. burnetii in cattle was estimated to be 32.3% (95% CI: 25.3%-40.01%), with high heterogeneity among the included studies. Herd-level molecular prevalence was significantly different among continents. The herd-level molecular prevalence ranged from 12.8% (95% CI: 7.1%-21.9%) in Asia to 70.0% (95% CI: 36.3%-90.5%) in North America. Regarding trends, the herd-level seroprevalence of C. burnetii in cattle did not change significantlyover the study years.

Conclusion

The global herd-level seroprevalence and herd-level molecular prevalence of C. burnetii in cattle were high, estimated at 44% and 32%, respectively. The herd-level seroprevalence trend did not significantly change over time. This result indicates that cattle remain a major reservoir host for C. burnetii and pose a potential risk to human health.

Molecular and Serological Findings in Sheep During Two Coxiella burnetii Outbreaks in Sicily (Southern Italy)

Q fever is a widespread zoonotic disease caused by the obligate intracellular bacterium Coxiella burnetii, primarily transmitted through the inhalation of contaminated aerosols. This study aimed to detect C. burnetii in two Sicilian sheep flocks, with no better defined reproductive disorders reported by the farmers. Blood, individual and bulk milk, ticks, and conjunctival swabs were collected from both flocks (A and B). Real-time and traditional PCRs were carried out to detect C. burnetii DNA and anti-C. burnetii antibodies were searched using an ELISA. In terms of Farm A, C. burnetii DNA was detected in 7.1% of blood samples, 20% of individual milk samples, bulk milk, 66.6% of conjunctival swabs, and in all the examined tick pools. Anti-C. burnetii antibodies were found in 77.0% of sera, 92.5% of individual milk samples, and bulk milk. In terms of Farm B, C. burnetii DNA was detected in 3.8% of blood samples, 39.4% of individual milk samples, bulk milk, 100% of conjunctival swabs, and in all tick pools; anti-C. burnetii antibodies were present in 53.6% of sera, 73.2% of milk samples, and in bulk milk. Our results highlight the high diffusion of C. burnetii in the two outbreaks, with widespread pathogen circulation, significant shedding in dairy products, and high environmental contamination, highlighting the need for enhanced surveillance and control measures in dairy sheep farms.

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.

Navigating Q fever: Current perspectives and challenges in outbreak preparedness

Q fever, also known as query fever, is a zoonotic illness brought on by the Coxiella burnetii bacteria. This disease was first discovered in 1935 in Queensland, Australia. Worldwide, Q fever is a disease that requires notification, and certain nations classify it as a national health concern. A feature of C. burnetii is known as cell wall phase fluctuation. Serological testing is the main method used to diagnose Q fever illnesses. Inhalation is the primary method of C. burnetii transmission in both people and animals, with smaller amounts occurring through milk and milk product ingestion. The bacterial strain that is causing the infection determines how severe it is. Q fever is a significant zoonosis that can be dangerous for personnel working in veterinary laboratories, livestock breeding operations, and slaughterhouses due to its high human contagiousness. Coxiella burnetii is a biological weapon that can be sprayed on food, water, or even mail. It can also be employed as an aerosol. Antibiotics work well against this disease's acute form, but as the infection develops into a chronic form, treatment becomes more difficult and the illness frequently returns, which can result in a high death rate. Vaccination has been demonstrated to lower the incidence of animal infections, C. burnetii shedding, and abortion. Several hygienic precautions should be put in place during an outbreak to lessen the spread of disease to animals.

Longitudinal surveillance of Coxiella burnetii following an abortion storm in domestic goats

Q fever is a disease caused by Coxiella burnetii, which can cause serious illness in humans and abortions in goats. A Q fever outbreak among an unvaccinated goat herd led to a 65% loss of the kid crop in spring 2018. To assess the impact of the outbreak on the herd and environment, longitudinal surveillance of the ranch was conducted across three samplings in September 2018, April 2019, and May 2022. Antibodies against C. burnetii were monitored by an indirect immunofluorescence assay. Shedding was monitored through analysis of vaginal/fecal swabs and milk. Environmental swabs and bulk soil were collected from various locations around the ranch. Animal and environmental samples were analyzed for C. burnetii DNA by PCR. Herd-level seroprevalence decreased from 89% in 2018 to 84.3% in 2019, and 64.5% in 2022. Overall herd shedding was 14.4% in 2018, 7.4% in 2019, and 6.7% in 2022. The percentage of C. burnetii-positive environmental samples was 83.7% in 2018, 51.7% in 2019, and 28.6% in 2022. Serological evidence suggests that new infections were occurring in the herd 4 years post-abortion storm. This study demonstrates the presence of C. burnetii shedding and environmental contamination in a goat operation at least four kidding seasons after an outbreak. A better understanding of management practices that can improve outcomes for infected herds, particularly in areas without access to vaccines against C. burnetii, is needed to better protect operators and the public.

Prevalence and risk factors of coxiellosis in meat goat herds: an epidemiological investigation in Northeastern Thailand

Q fever/coxiellosis poses a significant threat to both human and animal health, with goats serving as important reservoirs for disease transmission. This study aimed to evaluate the prevalence of coxiellosis and identify associated risk factors within meat goat herds in northeastern Thailand. A total of 39 meat goat herds were examined, with 84.61% of these herds experiencing reproductive disorders suggestive of Coxiella burnetii infection. Serum samples (n = 513) and vaginal swabs (n = 334) were collected from 522 goats for serological and molecular analyses, respectively. Results unveiled an overall herd prevalence of 74.35% (29/39), with a within-herd prevalence of 15.49% (95% CI: 10.86-20.12). Univariate analysis indicated that knowledge about the transmission of coxiellosis in herd owners serves as a protective factor against C. burnetii infection at the herd level (OR: 0.10; 95% CI: 0.01-0.92; p = 0.04). Multivariable analysis identified two significant risk factors associated with C. burnetii infection at the herd level, including herd establishment exceeding 5 years (OR: 7.14; 95% CI: 1.05-48.4; p = 0.04), as well as reproductive failures including abortion, infertility, and weak offspring (OR: 17.65; 95% CI: 1.76-177.45; p = 0.01). Individual-level risk factors included female gender (OR: 8.42; 95% CI: 1.14-62.42; p = 0.03), crossbreeding (OR: 2.52; 95% CI: 1.32-4.82; p = 0.005), and clinical signs of anaemia (OR: 1.63; 95% CI: 1.01-2.64; p = 0.04). These findings underscore the widespread prevalence of Q fever in meat goat herds within the study area and emphasize the necessity of implementing targeted control strategies.

Clinical Coxiella burnetii infection in sable and roan antelope in South Africa

Various zoonotic microorganisms cause reproductive problems such as abortions and stillbirths, leading to economic losses on farms, particularly within livestock. In South Africa, bovine brucellosis is endemic in cattle, and from 2013-2018, outbreaks of Brucella melitensis occurred in sable. Coxiella burnetii, the agent responsible for the zoonotic disease known as Q-fever and/or coxiellosis, also causes reproductive problems and infects multiple domestic animal species worldwide, including humans. However, little is known of this disease in wildlife. With the expansion of the wildlife industry in South Africa, diseases like brucellosis and coxiellosis can significantly impact herd breeding success because of challenges in identifying, managing and treating diseases in wildlife populations. This study investigated samples obtained from aborted sable and roan antelope, initially suspected to be brucellosis, from game farms in South Africa using serology tests and ruminant VetMAX™ polymerase chain reaction (PCR) abortion kit. The presence of C. burnetii was confirmed with PCR in a sable abortion case, while samples from both sable and roan were seropositive for C. burnetii indirect enzyme-linked immunosorbent assay (iELISA). This study represents the initial report of C. burnetii infection in sable and roan antelope in South Africa. Epidemiological investigations are crucial to assess the risk of C. burnetii in sable and roan populations, as well as wildlife and livestock in general, across South Africa. This is important in intensive farming practices, particularly as Q-fever, being a zoonotic disease, poses a particular threat to the health of veterinarians and farm workers as well as domestic animals.Contribution: A report of clinical C. burnetii infection in the wildlife industry contributes towards the limited knowledge of this zoonotic disease in South Africa.

Efficacy and Safety of an Inactivated Phase I Coxiella burnetii Vaccine to Control Q Fever in Ruminants: A Systematic Review

Q fever is a disease caused by Coxiella burnetii that affects many animal species and humans. In ruminants, the disease is responsible for several reproductive disorders (such as abortions, stillbirths, premature births, weak offspring, retained foetal membranes and infertility). An inactivated vaccine based on a phase I antigen of C. burnetii is available for cattle, goats and sheep. This review aims to summarise the scientific literature regarding the efficacy and safety of this vaccine to control the infection in these three domestic ruminant species. Forty-five publications and one experimental veterinary thesis reporting on experimental studies, case reports, mathematical modelling and intervention studies were selected according to the PRISMA guidelines. Although some studies lack control groups or statistical analyses, for all three species, published data show that vaccination often results in a reduction in abortions and an improvement in reproductive performance in comparison with absence of vaccination. There is also evidence, including in infected herds and animals, that vaccination is associated with a reduction in bacterial shedding, both in intensity and duration in comparison with absence of vaccination. For these reasons, in case of human outbreaks, vaccination is one of the pillars of control measures. Vaccination is generally well tolerated, despite the rare occurrence of mild, transient side-effects, such as hyperthermia and reduction in milk yield.

Toxoplasmosis and Chlamydophilosis in Small Ruminant Farms in Cameroon: Knowledge, Attitudes, Practices, and Perception of Zoonotic Risks of Farmers

Zoonotic abortive diseases represent a significant health and economic risk for national public health. This cross-sectional survey was conducted from April to October 2021 among 200 selected small ruminant farmers in the three northern regions of Cameroon. Data collection was done through questionnaires administered by exchange with the herder, and responses were coded and recorded on an Excel spreadsheet. The data were then analyzed with R software, version 2.13.0. An ANOVA test was used to assess significant differences in mean of Knowledge, Attitudes, Practices, and Perception of zoonotic risks (KAPP) scores between regions. Pearson correlations were used to calculate the association between KAPP scores within regions. Small ruminant farmers surveyed had low mean scores for knowledge of abortive toxoplasmosis and chlamydophilosis (0.1 ± 0.2), desirable attitude (0.32 ± 0.07), appropriate practice (0.36 ± 0.13) in managing abortion, and positive perception of zoonotic risks of toxoplasmosis and chlamydophilosis in small ruminants (0.12 ± 0.33), respectively. KAPP was significantly (P < 0.01) and positively associated with knowledge (r = 0.98) and risk perception (r = 0.99). However, attitudes (r = 0.06), practices (r = 0.05), and risk perception of toxoplasmosis (r = 0.07) and chlamydophilosis (r = 0.08) were not associated with farmers' knowledge. This study revealed significant knowledge gaps, low levels of desired attitudes, and high-risk behavioral practices. These results therefore call for capacity building of health professionals and farmers to better integrate the One Health concept in the management of neglected zoonotic diseases.

Coxiella burnetii in domestic doe goats in the United States, 2019-2020

Coxiella burnetii is a bacterial pathogen capable of causing serious disease in humans and abortions in goats. Infected goats can shed C. burnetii through urine, feces, and parturient byproducts, which can lead to infections in humans when the bacteria are inhaled. Goats are important C. burnetii reservoirs as evidenced by goat-related outbreaks across the world. To better understand the current landscape of C. burnetii infection in the domestic goat population, 4,121 vaginal swabs from 388 operations across the United States were analyzed for the presence of C. burnetii by IS1111 PCR as part of the United States Department of Agriculture, Animal Plant Health Inspection Service, Veterinary Services' National Animal Health Monitoring System Goats 2019 Study. In total, 1.5% (61/4121) of swabs representing 10.3% (40/388) (weighted estimate of 7.8, 95% CI 4.4-13.5) of operations were positive for C. burnetii DNA. The quantity of C. burnetii on positive swabs was low with an average Ct of 37.9. Factors associated with greater odds of testing positive included suspected Q fever in the herd in the previous 3 years, the presence of wild deer or elk on the operation, and the utilization of hormones for estrus synchronization. Factors associated with reduced odds of testing positive include the presence of kittens and treatment of herds with high tannin concentrate plants, diatomaceous earth, and tetrahydropyrimidines. In vitro analysis demonstrated an inhibitory effect of the tetrahydropyrimidine, pyrantel pamoate, on the growth of C. burnetii in axenic media as low as 1 μg per mL. The final multivariable logistic regression modeling identified the presence of wild predators on the operation or adjacent property (OR = 9.0, 95% CI 1.3-61.6, p value = 0.0248) as a risk factor for C. burnetii infection.

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.

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.

Drosophila melanogaster Sting mediates Coxiella burnetii infection by reducing accumulation of reactive oxygen species

The Gram-negative bacterium Coxiella burnetii is the causative agent of query fever in humans and coxiellosis in livestock. C. burnetii infects a variety of cell types, tissues, and animal species including mammals and arthropods, but there is much left to be understood about the molecular mechanisms at play during infection in distinct species. Human stimulator of interferon genes (STING) induces an innate immune response through the induction of type I interferons (IFNs), and IFN promotes or suppresses C. burnetii replication, depending on tissue type. Drosophila melanogaster contains a functional STING ortholog (Sting) which activates NF-κB signaling and autophagy. Here, we sought to address the role of D. melanogaster Sting during C. burnetii infection to uncover how Sting regulates C. burnetii infection in flies. We show that Sting-null flies exhibit higher mortality and reduced induction of antimicrobial peptides following C. burnetii infection compared to control flies. Additionally, Sting-null flies induce lower levels of oxidative stress genes during infection, but the provision of N-acetyl-cysteine (NAC) in food rescues Sting-null host survival. Lastly, we find that reactive oxygen species levels during C. burnetii infection are higher in Drosophila S2 cells knocked down for Sting compared to control cells. Our results show that at the host level, NAC provides protection against C. burnetii infection in the absence of Sting, thus establishing a role for Sting in protection against oxidative stress during C. burnetii infection.

Serological Evidence and Coexposure of Selected Infections among Livestock Slaughtered at Eastern Cape Abattoirs in South Africa

Zoonotic infections were investigated in a cross-sectional study on asymptomatic livestock slaughtered in abattoirs in the Eastern Cape. Antibodies against Brucella spp., Coxiella burnetii, Toxoplasma gondii, and the coexposure were investigated in sera using serological tests. A total of 565 animals comprising of 280 cattle, 200 sheep, and 85 pigs were screened using RBT, iELISA, CFT, and AMOS-PCR. The Mast® Toxoreagent test and iELISA were used for the detection of T. gondii and C. burnetii, respectively. The Brucella positivity based on at least two tests was 4.3% (12/280), 1.0% (2/200), and 0.0% (0/85) in cattle, sheep, and pigs, respectively. Toxoplasma gondii seropositivity of 37.90% (106/280), 1.50% (3/200), and 7.10% (6/85) was observed in cattle, sheep, and pigs, respectively. Coxiella burnetii seropositivity of 26.40% (74/280), 15.00% (30/200), and 2.40% (2/85) was observed in cattle, sheep, and pigs, respectively. Coexposure was detected in cattle for positivity against C. burnetii and T. gondii 40.54%, Brucella spp. and T. gondii 1.35%, and Brucella spp. and C. burnetii 4.05%. Coexposure for Brucella spp., C. burnetii, and T. gondii 4.05% was detected in cattle. Coexposure of Brucella spp. and C. burnetii 6.67% was detected in sheep. The AMOS-PCR identified B. abortus in cattle and a mixed infection of B. abortus and B. melitensis in sheep in 64.71% seropositive samples. To our knowledge, the coexposure of Brucella spp., T. gondii, and C. burnetii in cattle has not been reported. Coexposure of Brucella spp. and C. burnetii in cattle and sheep is significant as it results in reproductive losses and constitutes an infectious risk to humans. The detection of antibodies against multiple zoonotic infections in livestock from abattoirs has implications for public health.

The lower Saint Lawrence River region of Quebec, a hot spot for sheepfold-associated Q fever in Canada: Review of 258 cases

Background

The lower Saint Lawrence river region (LSLRR), in Quebec, has a 10-fold higher incidence of Q fever compared to the provincial rate. This study aimed to review clinical cases and the Q fever risk exposure in this region.

Methods

Data were retrieved from microbiology laboratory, medical records from Rimouski Regional Hospital and Public Health reports between 1991 and 2018. They were analyzed with Epi Info 7.2.2.6. Patients with confirmed acute, probable acute, and chronic Q fever were classified using standard case definitions and mapped according to the postal code, to assess the correlation between cases and sheep distribution.

Results

Out of 295 cases, 258 were included (241 confirmed acute, seven probable acute, 10 chronic). Median age was 49 years, 76% were male. For acute cases, the prominent symptoms were fever (99%), headache (83%), chills (80%), sweating (72%), myalgia (69%), and fatigue (67%). Clinical presentation was mostly febrile syndrome with mild hepatitis (84%). A seasonal peak was observed from May to July (56% of acute cases). Most cases (56%) occurred within the two counties where sheep production was highest. Exposure to sheep was prominent 93%, including 64% direct contact (15% shepherds, 49% sheepfold visitors), 14% indirect contact, and 15% sheepfold neighbors.

Conclusions

To our knowledge, this is one of the largest retrospective studies of Q fever cases reported in Canada. Q fever in Quebec LSLRR is associated mainly with sheep exposure. Fever and hepatitis were the most common manifestations. Preventive measures should be considered in this region to protect sheepfold workers, visitors, and their neighbors.

Genome-wide epitope mapping across multiple host species reveals significant diversity in antibody responses to Coxiella burnetii vaccination and infection

Coxiella burnetii is an important zoonotic bacterial pathogen of global importance, causing the disease Q fever in a wide range of animal hosts. Ruminant livestock, in particular sheep and goats, are considered the main reservoir of human infection. Vaccination is a key control measure, and two commercial vaccines based on formalin-inactivated C. burnetii bacterins are currently available for use in livestock and humans. However, their deployment is limited due to significant reactogenicity in individuals previously sensitized to C. burnetii antigens. Furthermore, these vaccines interfere with available serodiagnostic tests which are also based on C. burnetii bacterin antigens. Defined subunit antigen vaccines offer significant advantages, as they can be engineered to reduce reactogenicity and co-designed with serodiagnostic tests to allow discrimination between vaccinated and infected individuals. This study aimed to investigate the diversity of antibody responses to C. burnetii vaccination and/or infection in cattle, goats, humans, and sheep through genome-wide linear epitope mapping to identify candidate vaccine and diagnostic antigens within the predicted bacterial proteome. Using high-density peptide microarrays, we analyzed the seroreactivity in 156 serum samples from vaccinated and infected individuals to peptides derived from 2,092 open-reading frames in the C. burnetii genome. We found significant diversity in the antibody responses within and between species and across different types of C. burnetii exposure. Through the implementation of three different vaccine candidate selection methods, we identified 493 candidate protein antigens for protein subunit vaccine design or serodiagnostic evaluation, of which 65 have been previously described. This is the first study to investigate multi-species seroreactivity against the entire C. burnetii proteome presented as overlapping linear peptides and provides the basis for the selection of antigen targets for next-generation Q fever vaccines and diagnostic tests.

Distribution and Prevalence of Coxiella burnetii in Animals, Humans, and Ticks in Nigeria: A Systematic Review

'Query' (Q) fever is a neglected but emerging or re-emerging zoonotic disease caused by the bacterium Coxiella (C.) burnetii. Several host species are considered or speculated to be the primary reservoir hosts for human infection. In the past, several research groups in Nigeria have evaluated the prevalence of C. burnetii in various vertebrate and invertebrate hosts. Currently, there is a paucity of knowledge regarding the epidemiology of the pathogen in Nigeria with limited or no attention to control and prevention programs. Therefore, this review was undertaken to comprehend the current situation of C. burnetii infection in human, domestic and peri-domestic animals, and some tick species in Nigeria since 1960 with the aim to help identify future research priorities for the country. A comprehensive literature search was performed using the PRISMA guidelines on five scientific databases including Google Scholar, PubMed, AJOL, Science Direct, and Scopus for articles published from Nigeria dealing with the screening of blood, milk, or tick DNA for evidence of C. burnetii using any standard diagnostic approach. Of the 33 published articles subjected to full-text evaluation, more than 48% of the articles met the inclusion criteria and were thus included in this review. We observed different ranges of prevalence for C. burnetii antibodies from four vertebrate hosts including cattle (2.5-23.5%), sheep (3.8-12.0%), goats (3.1-10.9%), and humans (12.0-61.3%). Additionally, the use of molecular diagnostics revealed that the DNA of C. burnetii has been amplified in eight tick species including Hyalomma (Hy) dromedarii, Hy. truncatum, Hy. impeltatum, Hy. rufipes, Hy. impressum, Amblyomma (Am.) variegatum, Rhipicephalus (Rh.) evertsi evertsi, and Rh. annulatus. Two rodent's species (Rattus rattus and Rattus norvegicus) in Nigeria were documented to show evidence of the bacterium with the detection of the DNA of C. burnetii in these two mammals. In conclusion, this review has provided more insight on the prevalence of C. burnetii and its associated host/vector in Nigeria. Domestic animals, peri-domestic animals, and ticks species harbor C. burnetii and could be a source of human infections. Due to the paucity of studies from southern Nigeria, we recommend that research groups with interest on vector-borne diseases need to consider more epidemiological studies in the future on C. burnetii prevalence in diverse hosts to help unravel their distribution and vector potentials in Nigeria as a whole.

Coxiella burnetii shedding and serological status in pregnant and postpartum ewes

This study aimed to evaluate the occurence C. burnetii-DNA shedding by pregnant (vaginal mucus and feces) and postpartum (vaginal mucus, feces and milk) meat breed ewes from Saint Kitts. Additionally, antibodies anti-C. burnetii were detected in serum, and milk. Barbados Blackbelly ewes (n=187) were sampled using stratified convenience cross-sectional sampling. There were two animal groups: pregnant (n=96) and postpartum (n=91). Vaginal mucus (n=187), feces (n=177) and milk (n=83) samples were subjected to a TaqMan real time qPCR assay for C. burnetii based on the IS1111 multi copy element. IgG antibodies against C. burnetii were tested in blood serum (n=187) and milk (n=61) samples, via indirect ELISA. McNemar and Fischer exact tests were used to compare occurrence between routes and between groups, respectively. Overall, 86.6% of all the animals (162/187) were shedding C. burnetti DNA through at least one route (vaginal and/or fecal and/or milk). The DNA shedding occurrence via vaginal (73% vs 51%, p-value=0.003) and fecal routes (64% vs 47%, p-value=0.001) was higher in the pregnant compared to the postpartum animals. There was no prevalent shedding route among vaginal, fecal or milk in all ewes. Overall, 38% of the ewes were seropositive for C. burnetii IgG and a total of 19.7% of the tested postpartum ewes had IgG antibodies in milk. The vaginal and fecal DNA shedding were not associated with the blood serology, nor was milk DNA shedding related to the milk serology status, thus there was no association between C. burnetii seropositivity and bacterial DNA shedding. In short, high occurrence of C. burnetii DNA shedding was observed within ewes in St. Kitts, and represents the first detection of the Q fever agent within the Caribbean islands. Bacterial shedding was more prevalent in pregnant ewes, highlighting the importance of gestating animals as a source of C. burnetii.

Prevalence and risk factors of Q fever (Coxiella burnetii) in cattle on farms of Limpopo province, South Africa

Q fever in animals and humans and its economic and public health significance has been widely reported worldwide but in South Africa. There are few studies on the prevalence of this zoonosis and its associated risk factors in South African livestock. Therefore, a cross-sectional study was conducted to determine the seroprevalence, molecular prevalence, and risk factors associated with C. burnetii in cattle on farms in South Africa's Limpopo province. Out of 383 cattle tested for antibodies, the overall seroprevalence was 24.28%. Herd size of >150 (OR: 9.88; 95%CI: 3.92-24.89; p < 0.01) remained associated with C. burnetii seropositivity in cattle. For PCR detection, targeting IS1111 fragment, cattle with no abortion history (OR: 0.37; 95%CI: 0.18-0.77; p < 0.01) and herd size of >150 (OR: 3.52; 95%CI: 1.34-9.24; p < 0.01) remained associated with C. burnetii positivity. The molecular prevalence in sheath scrapings and vaginal swabs by IS1111 PCR was 15.67%. Cohen's kappa agreement test revealed a fair agreement between the PCR and ELISA results (k = 0.40). Sequence analysis revealed that the amplicons had similarities to the C. burnetii transposase gene fragment, confirming the presence of the pathogen. The higher seroprevalence than molecular prevalence indicated a past C. burnetii infection, no bacterial shedding through vaginal mucus in cows, or preputial discharge in bulls. Similarly, the detection of C. burnetii by PCR in the absence of antibodies could be partly explained by recent infections in which antibodies have not yet been produced against the bacteria, or the level of these antibodies was below the detectability threshold. The presence of the pathogen in cattle and the evidence of exposure, as shown by both PCR and ELISA suggests an active circulation of the pathogen. This study demonstrated that C. burnetii is widespread in the study area and that a herd size of >150 is associated with C. burnetii seroprevalence and molecular prevalence.

Tracking the Source of Human Q Fever from a Southern French Village: Sentinel Animals and Environmental Reservoir

Coxiella burnetii, also known as the causal agent of Q fever, is a zoonotic pathogen infecting humans and several animal species. Here, we investigated the epidemiological context of C. burnetii from an area in the Hérault department in southern France, using the One Health paradigm. In total, 13 human cases of Q fever were diagnosed over the last three years in an area comprising four villages. Serological and molecular investigations conducted on the representative animal population, as well as wind data, indicated that some of the recent cases are likely to have originated from a sheepfold, which revealed bacterial contamination and a seroprevalence of 47.6%. However, the clear-cut origin of human cases cannot be ruled out in the absence of molecular data from the patients. Multi-spacer typing based on dual barcoding nanopore sequencing highlighted the occurrence of a new genotype of C. burnetii. In addition, the environmental contamination appeared to be widespread across a perimeter of 6 km due to local wind activity, according to the seroprevalence detected in dogs (12.6%) and horses (8.49%) in the surrounding populations. These findings were helpful in describing the extent of the exposed area and thus supporting the use of dogs and horses as valuable sentinel indicators for monitoring Q fever. The present data clearly highlighted that the epidemiological surveillance of Q fever should be reinforced and improved.

Efficacy of Phase I and Phase II Coxiella burnetii Bacterin Vaccines in a Pregnant Ewe Challenge Model

The bacterium Coxiella burnetii can cause the disease Q-fever in a wide range of animal hosts. Ruminants, including sheep, are thought to play a pivotal role in the transmission of C. burnetii to humans; however, the only existing livestock vaccine, namely, Coxevac® (Ceva Animal Health Ltd., Libourne, France), a killed bacterin vaccine based on phase I C. burnetii strain Nine-Mile, is only approved for use in goats and cattle. In this study, a pregnant ewe challenge model was used to determine the protective effects of Coxevac® and an experimental bacterin vaccine based on phase II C. burnetii against C. burnetii challenge. Prior to mating, ewes (n = 20 per group) were vaccinated subcutaneously with either Coxevac®, the phase II vaccine, or were unvaccinated. A subset of pregnant ewes (n = 6) from each group was then challenged 151 days later (~100 days of gestation) with 106 infectious mouse doses of C. burnetii, Nine-Mile strain RSA493. Both vaccines provided protection against C. burnetii challenge as measured by reductions in bacterial shedding in faeces, milk and vaginal mucus, and reduced abnormal pregnancies, compared to unvaccinated controls. This work highlights that the phase I vaccine Coxevac® can protect ewes against C. burnetii infection. Furthermore, the phase II vaccine provided comparable levels of protection and may offer a safer and cost-effective alternative to the currently licensed vaccine.

Coxiella burnetii and Co-Infections with Other Major Pathogens Causing Abortion in Small Ruminant Flocks in the Iberian Peninsula

Coxiella burnetii is an intracellular bacterium causing human Q fever and reproductive disorders in domestic ruminants. We analyzed the occurrence of C. burnetii and co-infections with six other major pathogens causing abortion in sheep (1242 cases) and goat (371 cases) flocks from Spain and Portugal. After real-time PCR detection, co-infections were established by principal component and cluster analysis that grouped cases based on the joint presence/absence of several microorganisms. C. burnetii and Chlamydia abortus were the most common abortifacient agents with approximately 75% of cases from both hosts testing positive, followed by Toxoplasma gondii, Campylobacter sp., Salmonella enterica, border disease virus and Neospora caninum. C. burnetii was significantly more common than C. abortus in goat abortions (p < 0.001). Co-infections with at least two pathogens were found in more than 66% cases of ovine abortions and 36% cases of caprine abortions testing positive for C. burnetii, mostly including mixed infections with only C. abortus. These findings indicate that both pathogens are the most significant ones to be readily prevented by vaccination in this geographical area. Biosecurity and biocontainment measures are also steadfastly recommended to prevent both the economic losses and public health risks associated with most of these abortifacient agents.

Coxiella burnetii in ticks, livestock, pets and wildlife: A mini-review

Coxiella burnetii is a zoonotic bacterium with an obligatory intracellular lifestyle and has a worldwide distribution. Coxiella burnetii is the causative agent of Q fever in humans and coxiellosis in animals. Since its discovery in 1935, it has been shown to infect a wide range of animal species including mammals, birds, reptiles, and arthropods. Coxiella burnetii infection is of public and veterinary health and economic concern due to its potential for rapid spread and highly infectious nature. Livestock are the primary source of C. burnetii infection in most Q fever outbreaks which occurs mainly through inhalation of contaminated particles. Aside from livestock, many cases of Q fever linked to exposure to wildlife. Changes in the dynamics of human-wildlife interactions may lead to an increased potential risk of interspecies transmission and contribute to the emergence/re-emergence of Q fever. Although C. burnetii transmission is mainly airborne, ticks may act as vectors and play an important role in the natural cycle of transmission of coxiellosis among wild vertebrates and livestock. In this review, we aim to compile available information on vectors, domestic, and wild hosts of C. burnetii, and to highlight their potential role as bacterial reservoirs in the transmission of C. burnetii.

Longitudinal Study of Selected Bacterial Zoonoses in Small Ruminants in Tana River County, Kenya

Brucellosis, Q fever, and leptospirosis are priority zoonoses worldwide, yet their epidemiology is understudied, and studies investigating multiple pathogens are scarce. Therefore, we selected 316 small ruminants in irrigated, pastoral, and riverine settings in Tana River County and conducted repeated sampling for animals that were initially seronegative between September 2014 and June 2015. We carried out serological and polymerase chain reaction tests and determined risk factors for exposure. The survey-weighted serological incidence rates were 1.8 (95% confidence intervals [CI]: 1.3–2.5) and 1.3 (95% CI: 0.7–2.3) cases per 100 animal-months at risk for Leptospira spp. and C. burnetii, respectively. We observed no seroconversions for Brucella spp. Animals from the irrigated setting had 6.83 (95% CI: 2.58–18.06, p-value = 0.01) higher odds of seropositivity to C. burnetii than those from riverine settings. Considerable co-exposure of animals to more than one zoonosis was also observed, with animals exposed to one zoonosis generally having 2.5 times higher odds of exposure to a second zoonosis. The higher incidence of C. burnetii and Leptospira spp. infections, which are understudied zoonoses in Kenya compared to Brucella spp., demonstrate the need for systematic prioritization of animal diseases to enable the appropriate allocation of resources.

Identifying scenarios and risk factors for Q fever outbreaks using qualitative analysis of expert opinion

Q fever is an important zoonotic disease perceived to be an occupational hazard for those working with livestock. Outbreaks involving large numbers of people are uncommon, but the increasing case incidence coupled with changing environmental and industry conditions that promote transmission of Q fever has raised concerns that large and serious outbreaks could become more frequent. The aim of this study was to use expert opinion to better understand how large Q fever outbreaks might occur in an Australian context and to document factors believed to be drivers of disease transmission. Focus groups were conducted with human and animal health professionals across several Australian states. All discussions were recorded, transcribed verbatim and imported into NVIVO for thematic analysis. Four anthropogenic risk factors (disease awareness, industry practices, land use, human behaviour) and three ecological risk factors (physical environment, agent dissemination, animal hosts) emerged from the data. Analysis of expert opinions pointed to the existence of numerous scenarios in which Q fever outbreaks could occur, many of which depict acquisition in the wider community outside of traditional at-risk occupations. This perception of the expansion of Q fever from occupational-acquisition to community-acquisition is driven by greater overarching economic, political and socio-cultural influences that govern the way in which people live and work. Findings from this study highlight that outbreaks are complex phenomena that involve the convergence of diverse elements, not just that of the pathogen and host, but also the physical, political and socioeconomic environments in which they interact. A review of the approaches to prevent and manage Q fever outbreaks will require a multisectorial approach and strengthening of community education, communication and engagement so that all stakeholders become an integrated part of outbreak mitigation and response.

Shedding and extensive and prolonged environmental contamination of goat farms of Q fever patients by Coxiella burnetii

BACKGROUND

A majority (>70%) of Q fever patients in South Korea do not have a history of animal contact. Therefore, unconscious environmental exposure is suspected. The aim of this study was to investigate exposure of Q fever patients to environmental contamination and animal shedding.

METHODS

Two goat farmers were enrolled. One was diagnosed with Q fever 3 years ago (Farm 1). Among 20 goats on Farm 1, five were tested randomly and found to be Q fever PCR-positive. Three of the five were Q fever ELISA-positive. Two of five environmental samples taken in 2015 were PCR-positive. In 2018, 17 of 18 environmental samples were PCR-positive. On Farm 2, 54 of the 77 goats were PCR-positive, and 63 were ELISA-positive. Twelve of 14 environmental samples were PCR-positive. Repeat administration of oxytetracycline to goats led to a gradual reduction in PCR-positive tests over a 5-month period. However, PCR-positivity of the farm environment persisted for 5 months.

CONCLUSION

The environment on farms owned by Q fever patients was contaminated extensively and persistently, even after antibiotic treatment of goats and environmental decontamination. Undetected environmental contamination can be a major source of sporadic Q fever infection in South Korea.

Ticks and prevalence of tick-borne pathogens from domestic animals in Ghana

Background

Ticks are important vectors of various pathogenic protozoa, bacteria and viruses that cause serious and life-threatening illnesses in humans and animals worldwide. Estimating tick-borne pathogen prevalence in tick populations is necessary to delineate how geographical differences, environmental variability and host factors influence pathogen prevalence and transmission. This study identified ticks and tick-borne pathogens in samples collected from June 2016 to December 2017 at seven sites within the Coastal, Sudan and Guinea savanna ecological zones of Ghana.

Methods

A total of 2016 ticks were collected from domestic animals including cattle, goats and dogs. Ticks were morphologically identified and analysed for pathogens such as Crimean-Congo haemorrhagic fever virus (CCHFV), Alkhurma haemorrhagic fever virus (AHFV), Rickettsia spp. and Coxiella burnetii using polymerase chain reaction assays (PCR) and sequence analysis.

Results

Seven species were identified, with Amblyomma variegatum (60%) most frequently found, followed by Rhipicephalus sanguineus sensu lato (21%), Rhipicephalus spp. (9%), Hyalomma truncatum (6%), Hyalomma rufipes (3%), Rhipicephalus evertsi (1%) and Rhipicephalus (Boophilus) sp. (0.1%). Out of 912 pools of ticks tested, Rickettsia spp. and Coxiella burnetii DNA was found in 45.6% and 16.7% of pools, respectively, whereas no CCHFV or AHFV RNA were detected. Co-infection of bacterial DNA was identified in 9.6% of tick pools, with no statistical difference among the ecozones studied.

Conclusions

Based on these data, humans and animals in these ecological zones are likely at the highest risk of exposure to rickettsiosis, since ticks infected with Rickettsia spp. displayed the highest rates of infection and co-infection with C. burnetii, compared to other tick-borne pathogens in Ghana.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05208-8.

Evidence of exposure to C. burnetii among slaughterhouse workers in western Kenya

Q fever, caused by C. burnetii, has been reported in slaughterhouse workers worldwide. The most reported risk factor for seropositivity is the workers' role in the slaughterhouse. This study examined the seroprevalence and risk factors for antibodies to C. burnetii in slaughterhouse workers in western Kenya to fill a data gap relating to this emerging disease in East Africa.

Individuals were recruited from all consenting slaughterhouses in the study area between February and November 2012. Information was collected from participating workers regarding demographic data, animals slaughtered and role in the slaughterhouse. Sera samples were screened for antibodies to C. burnetii using a commercial ELISA and risk factors associated with seropositivity were identified using multi-level logistic regression analysis.

Slaughterhouse workers (n = 566) were recruited from 84 ruminant slaughterhouses in western Kenya. The seroprevalence of antibodies to C. burnetii was 37.1% (95% Confidence Interval (CI) 33.2–41.2%). The risk factors identified for C. burnetii seropositivity included: male workers compared to female workers, odds ratio (OR) 5.40 (95% CI 1.38–21.22); slaughtering cattle and small ruminants compared to those who only slaughtered cattle, OR 1.52 (95% CI 1.06–2.19). In addition, specific roles in the slaughterhouse were associated with increased odds of being seropositive, including cleaning the slaughterhouse, OR 3.98 (95% CI 1.39–11.43); cleaning the intestines, OR 3.24 (95% CI 1.36–7.73); and flaying the carcass OR 2.63 (95% CI 1.46–4.75) compared to being the slaughterman or foreman.

We identified that slaughterhouse workers have a higher seroprevalence of antibodies to C. burnetii compared to published values in the general population from the same area. Slaughterhouse workers therefore represent an occupational risk group in this East African setting. Workers with increased contact with the viscera and fluids are at higher risk for exposure to C. burnetii. Education of workers may reduce transmission, but an alternative approach may be to consider the benefits of vaccination in high-risk groups.

Analysis of environmental dust in goat and sheep farms to assess Coxiella burnetii infection in a Q fever endemic area: Geographical distribution, relationship with human cases and genotypes

Real-time PCR analysis of environmental samples (dust and aerosols) is an easy tool to investigate the presence of Coxiella burnetii in the farm environment. The aim of this study was to assess the distribution of C. burnetii DNA in dust collected inside animal premises from 272 small ruminant farms in Bizkaia (northern Spain), a region with recent reports of human Q fever cases and outbreaks. Within each farm, 5 samples of dust were collected from difference surfaces, and data on animal census, management procedures, characteristics of the premises and geographic location were collected. Real-time PCR analysis of the dust samples detected presence of C. burnetii DNA in 98 farms (36.0%), flock-prevalence being higher in sheep (38.9%) or mixed ovine-caprine production systems (36.8%), compared to goats (25.0%). Larger bacterial burdens were observed in mixed farms, compared to sheep (p < .05). Single nucleotide polymorphism (SNP) analysis identified 5 different genotypes, with SNP8 being the predominant genotype (73%), followed by SNP6 (11%), SNP2 (9%), SNP4 (5%) and SNP1 (2%). Proportion of farms where C. burnetii DNA was detected differed among the different agricultural counties, and a higher proportion of C. burnetii DNA positive farms was associated with the occurrence of recent human Q fever outbreaks at several geographical locations. Dust sampling in domestic ruminant farms coupled with real-time PCR to screen for the presence of C. burnetii and estimate bacterial load can be a useful tool to identify herds and regions with high prevalence, define priority actions and monitor the effect of control measures. If combined with molecular genotyping and spatial distribution maps, it can help to identify farm contamination sources and trace the origin of human outbreaks.

SEROLOGICAL EVIDENCE OF COXIELLA BURNETII INFECTION IN THE WHITE RHINOCEROS (CERATOTHERIUM SIMUM) IN SOUTH AFRICA

Coxiellosis, or Query (Q) fever, a disease caused by the intracellular bacteria Coxiella burnetii, was recently described in a managed breeding herd of white rhinoceros (Ceratotherium simum) in the southeastern United States. Clinical disease often results in abortion and could represent a conservation challenge for this species. In addition to the reproductive and herd management consequences, coxiellosis is also a zoonotic disease. Infection or clinical disease in any free-ranging rhinoceros species in a national park setting has not been previously described. In this study, evidence of prior infection was measured by immunofluorescent antibody titers in 89 serum samples collected from white rhinoceros within private reserves and a national park in South Africa. Total seropositivity was 48/89 (53.9% [95% CI, 43.6-63.9%]). Animals on private reserves had a seropositivity of 21/51 (41.1% [95% CI, 27.1-55.2%]), and national park rhinoceros had a higher rate of seropositivity at 71.0% [95% CI, 55.9-86.2%] (27/38; P= 0.004). Adults had a higher seropositivity compared with subadults (P= 0.03). There was no difference in seropositivity between sexes (P > 0.05). Results demonstrate that South African white rhinoceros populations are exposed to Coxiella, which could result in underrecognized reproductive consequences. Further studies should investigate potential implications for public health and conservation management of this species.

Real-time PCR biochip for on-site detection of Coxiella burnetii in ticks

BACKGROUND

Q fever, a zoonosis caused by Coxiella burnetii, has adverse effects on public health. Ticks are vectors of C. burnetii and they contribute to the transmission of the pathogen. A tool for rapid, sensitive, and accurate detection of C. burnetii from ticks is important for the prevention of Q fever.

METHODS

Ultra-rapid real-time PCR (UR-qPCR) as a chip-based real-time PCR system was developed for the detection of C. burnetii from ticks. The UR-qPCR system was established and evaluated for the rapidity, sensitivity, and specificity of C. burnetii detection.

RESULTS

C. burnetii was detected using UR-qPCR from 5644 larval, nymphal, and adult ticks from 408 pools collected from livestock and epidemiologically linked environments in two provinces, Gangwon and Jeju, in Korea. Ticks from three species were identified; Haemaphysalis longicornis accounted for the highest number, present in 333 of 408 pools (81.62%), followed by Haemaphysalis flava in 62 pools (15.19%) and Ixodes nipponensis in 13 pools (3.19%). The rapidity and sensitivity of PCR detection was demonstrated with the sufficient amplification and detection of approximately 56 copies of C. burnetii DNA with only 20 min of PCR amplification. The kappa value for the diagnostic agreement between UR-qPCR and stationary qPCR was in perfect agreement (κ = 1). PCR detection and sequencing indicated that C. burnetii was present in 5 of the 408 pools (1.23%), in which four pools contained H. longicornis and one pool contained H. flava. The infection rates of C. burnetii in the tick pools collected from Gangwon and Jeju Provinces were 1.70% and 0.58%, respectively. Phylogenetic analysis indicated a close relationship between the detected C. burnetii and those originating from goats, humans, and ticks in different countries, such as the USA, France, Germany, and Serbia.

CONCLUSIONS

The methods described in this study could be important for the prevention and control of Q fever in the two provinces. The UR-qPCR, with its features of mobility, sensitivity, and rapidity, is helpful for constructing early alert systems in the field for C. burnetii in ticks and could help alleviate the transmission of and economic damage due to Q fever.

Current perspectives on the occurrence of Q fever: highlighting the need for systematic surveillance for a neglected zoonotic disease in Indian subcontinent

Coxiellosis or Q fever is an important global occupational zoonotic disease caused by one of the most contagious bacterial pathogens - Coxiella burnetii, which ranks one among the 13 global priority zoonoses. The detection of C. burnetii infection is exhibiting an increasing trend in high-risk personnel around the globe. It has increasingly been detected from foods of animal origin (including bulk milk, eggs, and meat) as well as tick vectors in many parts of the world. Coxiellosis is reported to be an important public health threat causing spontaneous abortions in humans and potential reproductive failure, which would result in production losses among livestock. Further, comprehensive coverage of the reports and trends of Q fever in developing countries, where this infection is supposed to be widely prevalent appears scarce. Also, the pathogen remains grossly neglected and underreported. Moreover, policymakers and funding agencies do not view it as a priority problem, especially in the Indian subcontinent, including Sri Lanka, Bhutan, Pakistan, Nepal, Bangladesh and Maldives. Here, we review the occurrence and epidemiology of the disease in a global context with special emphasis on its status in the Indian subcontinent.

Concept of an Active Surveillance System for Q Fever in German Small Ruminants-Conflicts Between Best Practices and Feasibility

Q fever is a zoonotic disease caused by the bacterium Coxiella burnetii. Inhalation of contaminated dust particles or aerosols originating from animals (esp. small ruminants) is the main source of human infection. Hence, an active early warning system for Q fever in German small ruminant livestock was conceptualized to prevent human infections. First, we describe the best practice for establishing this system before evaluating its feasibility, as the combination of both evokes conflicts. Vaginal swabs from all husbandry systems with a focus on reproductive females should pooled and investigated by PCR to detect C. burnetii-shedding animals. Multistage risk-based sampling shall be carried out at the flock level and within-flock level. At the flock level, all flocks that are at risk to transmit the pathogen to the public must be sampled. At the within-flock level, all primi- and multiparous females after lambing must be tested in order to increase the probability of identifying a positive herd. Sampling should be performed during the main lambing period and before migration in residential areas. Furthermore, individual animals should be tested before migration or exhibition to ensure a negative status. If a flock tests positive in at least one individual sample, then flock-specific preventive measures should be implemented. This approach implies huge financial costs (sample testing, action/control measures). Hence, taking the step to develop more feasible and affordable preventive measures, e.g., vaccinating small ruminant flocks, should replace testing wherever justifiable.

Parturient Cat As a Potential Reservoir for Coxiella burnetii: A Hidden Threat to Pet Owners

Background: Q fever is a worldwide zoonosis caused by Coxiella burnetii. This study was carried out to investigate the occurrence of C. burnetii among apparently healthy pregnant, parturient, and postparturient dogs and cats to highlight their role in the transmission of such disease to humans. Materials and Methods: A total of 88 apparently healthy pet animals (48 dogs and 40 cats) were enrolled in this study, vaginal swabs were obtained from pregnant and postparturient animals while birth fluids were collected from parturient ones. All samples were subjected to DNA extraction followed by nested PCR for molecular detection of C. burnetii. Results: Out of 40 cats, 3 were positive for C. burnetii with an overall prevalence of 7.5%, all positive samples were birth fluids of parturient queens with a prevalence of 15.8% (3/19) while all pregnant and postparturient animals were negative. In contrast, none of 48 dogs yielded positive result. Moreover, the phylogenetic analysis and sequence identity matrix of the obtained sequence from a parturient cat showed high genetic relatedness to strains derived from human cases rather than those of ruminants to indicate the public health burden of such strain. Conclusion: This study underscores the occurrence of C. burnetii among parturient cats to point out the possible zoonotic transmission to human contacts.

Serological and Molecular Phylogenetic Detection of Coxiella burnetii in Lactating Cows, Iraq

This study is carried out to investigate the prevalence of Coxiella burnetii (C. burnetii) infections in cattle using an enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR) assay targeting IS1111A transposase gene. A total of 130 lactating cows were randomly selected from different areas in Wasit province, Iraq and subjected to blood and milk sampling during the period extended between November 2018 and May 2019. ELISA and PCR tests revealed that 16.15% and 10% of the animals studied were respectively positive. Significant correlations (P<0.05) were detected between the positive results and clinical data. Two positive PCR products were analyzed phylogenetically, named as C. burnetii IQ-No.5 and C. burnetii IQ-No.6; and then recorded in the National Center for Biotechnology Information (NCBI) under an accession numbers of MN473204.1 and MN473205.1. Comparative identity of the local strains with NCBI-BLAST strains/isolates revealed 97% similarity and 0.1-0.6% of total genetic mutations/changes. NCBI-BLAST Homology Sequence reported high significant identity (P<0.05) between the local, C. burnetii IQ-No.5 and C. burnetii IQ-No.6; strains and C. burnetii 3345937 (CP014354.1) Netherlands isolate at 99.10% and 99.06%, respectively. The current study concluded that the percentage of infected cows with coxiellosis is relatively high, and Coxiella should be listed as abortive pathogen. Therefore, additional studies should be performed including different animals, samples, and regions.

Seroprevalence and Molecular Characterization of Coxiella burnetii in Cattle in the Republic of Korea

This study was conducted to determine the prevalence of Coxiella burnetii in cattle and how that prevalence is influenced by cattle breed and growth type. A total of 491 cattle [cattle breed: 216 dairy cattle and 275 beef cattle; growth type: indoor housed (n = 294) and grazing (n = 197)] were used. The presence of C. burnetii DNA and antibodies was detected from blood and serum samples using polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. The overall prevalence of C. burnetii was: 10.8% (95% CI: 8.0–13.5%) using PCR and 8.8% (95% CI: 6.3–11.3%) using ELISA. The prevalence of C. burnetii was significantly higher in beef cattle than in dairy cattle using both PCR (13.5% vs. 7.4%; P = 0.032) and ELISA (14.5% vs. 1.4%; P = 0.000), respectively. Comparison by growth type revealed that C. burnetii infection was significantly higher in grazing cattle than in housed cattle when using both PCR (24.9% vs. 1.4%; P = 0.000) and ELISA (21.3% vs. 0.3%; P = 0.000). Beef cattle were at a significantly higher risk of contracting C. burnetii compared with dairy cattle (odds ratio = 3.20, 95% CI: 1.80–5.67; P = 0.000). The risk of contracting C. burnetii in grazing cattle was increased by 32.57-fold (95% CI: 12.84–82.61; P = 0.000) compared with indoor housed cattle. The phylogenetic analysis based on the IS1111 gene revealed that our sequences grouped with human, tick, goat, and cattle isolates/strains found in several countries. C. burnetii sequences circulating in the Republic of Korea exhibit genetic variations. Thus, grazing is a high risk factor for the prevalence and transmission of C. burnetii.

Detection of Coxiella burnetii antibodies in sheep and cattle on a veterinary campus in St. Kitts: Implications for one health in the Caribbean region

Coxiella burnetii is a ubiquitous zoonotic bacterium reported worldwide that causes Q-fever. Infections result in profound economic losses to livestock producers by causing abortions and low birth weights. Current information about the disease in the Caribbean region is scarce. With multiple small islands and territories, it is often considered that the bacterium is absent or circulates at a low prevalence. Our study aimed to determine whether sheep and cattle housed at a veterinary campus in St Kitts had previous exposure to C. burnetii. Blood samples were taken from cattle (n = 63; 72% of the herd) and sheep (n = 133; 71% of the flock). Antibodies to C. burnetii were detected by a commercial indirect enzyme-linked immunosorbent assay (IDvet® ELISA) test. The seroprevalence was estimated at 26.3% (95% CI: 19.1–34.7%) in sheep and 0% (95% CI: 0–5.7%) in cattle. Sheep importation to St. Kitts is very rare, thus, these results suggest that C. burnetii is present on the island. The seronegativity of all the cattle highlights the absence of the bacterium on the veterinary campus. The high seroprevalence in sheep, however, has potentially important implications for animal health and public health as well as for wildlife conservation. Further investigation about animal seroprevalence and human exposure are warranted in St. Kitts and in the Caribbean region.

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Seroprevalence in sheep from a veterinary university was 26.3%

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No cattle from the university were seropositive

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Risk for human and animal health is likely to be important in St. Kitts

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There is a need to investigate the prevalence of Coxiella burnetii in Caribbean region

Monitoring Coxiella burnetii Infection in Naturally Infected Dairy Sheep Flocks Throughout Four Lambing Seasons and Investigation of Viable Bacteria

Progression of Coxiella burnetii infection in four naturally infected sheep flocks, and in their farm environment, was monitored throughout four lambing seasons. Flocks with an active infection were selected based on the presence of C. burnetii DNA in bulk-tank milk (BTM) and a high seroprevalence in yearlings during the previous milking period (Spring 2015). During four consecutive lambing seasons (2015/16–2018/19), samples were collected within 1 week after each lambing period from animals (vaginal swabs, milk and feces from ewes, and yearlings) and the environment (dust indoor sheep premises). BTM samples and aerosols (outdoors and indoors) were monthly collected between lambing and the end of milking. Real-time PCR analyses showed different trends in C. burnetii shedding in the flocks, with a general progressive decrease in bacterial shedding throughout the years, interrupted in three flocks by peaks of reinfection associated with specific management practices. A significant relationship was found between C. burnetii fecal shedding and the bacterial burden detected in dust, whereas shedding by vaginal route affected the detection of C. burnetii in indoor aerosols. Three genotypes were identified: SNP8 (three flocks, 52.9% of the samples), SNP1 (two flocks, 44.8% samples), and SNP5 (one flock, two environmental samples). Coxiella burnetii viability in dust measured by culture in Vero cells was demonstrated in two of the flocks, even during the fourth lambing season. The results showed that infection can remain active for over 5 years if effective control and biosafety measures are not correctly implemented.

Prevalence of C. burnetii DNA in sheep and goats milk in the northwest of Iran

Q fever is a common zoonotic disease with worldwide distribution. The causative agent of Q fever is Coxiella burnetii, a gram-negative and polymorphic rod bacterium. Sheep and goats are the primary reservoirs of this disease, although a variety of animal species can be infected. The main route of Q fever transmission from animals to humans is the inhalation of contaminated aerosols with C. burnetii. The bacterium is excreted in milk of infected animals and therefore; the consumption of unpasteurized milk and dairy products might be a route of coxiella burnetii transmission from animals to humans. The present study was conducted to determine the prevalence of C. burnetii in milk samples collected from sheep and goats in west Azerbaijan province, Iran. During 2018, a total number of 420 milk samples were collected from sheep (n = 210) and goats (n = 210) of different regions of the province. All milk samples were subjected to DNA extraction and examined by a highly and specific nested-PCR method. The results showed that 51 (12.1%) (95% CI: 9.3%-15.6%) examined samples [sheep; n = 16 (7.6%) and goat; n = 35 (16.6%)] were positive for C. burnetii. The prevalence of C. burnetii in goat milk samples was significantly higher than sheep milk samples (P < 0.05). The shedding of C. burnetii in milk was significantly higher in summer (25%) (P < 0.05, 95% CI: 17.7%-34%) than the other seasons. It was concluded that sheep and goat populations in west Azerbaijan play an important role in the epidemiology of Q fever.