Coxiella burnetii in slaughterhouses in Brazil: A public health concern

Molecular Detection of Coxiella burnetii in Vaginal Swab Samples from Sheep That Aborted

Background: Coxiella burnetii, an obligate intracellular bacterium, is the etiological agent of Q fever in humans and one of the causes of abortion in small ruminants. Although coxiellosis is considered an exotic disease, there are a few reports in Mexico. Methods: The objective of this work was to determine the presence of C. burnetii DNA in vaginal samples from sheep that presented abortion and ram semen. A total of 180 vaginal exudate samples and 20 semen samples were obtained from five Central and Southern States of Mexico. Total DNA was extracted from vaginal swabs and C. burnetii was identified by PCR amplification and sequencing of the IS1111 insertion sequence. Results and Conclusion: In total, 110 (110/180) vaginal samples and 12 (12/20) semen samples were positive for C. burnetii. This is the first report of C. burnetii in sheep that aborted and in ram semen in Mexico.

Exposure of small ruminants and humans to Coxiella burnetii in the semi-arid region of Northeastern Brazil

Q fever is a zoonotic disease caused by the obligate intracellular pathogen Coxiella burnetii, for which domestic ruminants are the primary source of infection in humans. Herein, we investigated the presence of C. burnetii in humans, sheep, and goats in the semi-arid region of northeastern Brazil. The presence of anti-C. burnetii antibodies was surveyed using indirect immunofluorescence assay, and detection of C. burnetii DNA was performed by polymerase chain reaction (PCR). Anti-C. burnetii antibodies were detected in 60% of farms, 4.8% of goats, 1.5% of sheep, and 4.5% of human samples. PCR was positive in 18.9% of blood samples, 7.7% of milk samples, and 7.7% of vaginal mucus samples. A DNA sequence of a C. burnetii DNA sample extracted from the goat vaginal mucus showed 99.2-99.4% nucleotide identity with other strains previously reported in Brazil. These results indicate that C. burnetii is present in the surveyed area, where it poses a risk to both public and animal health. These findings indicate an urgent need for educative actions to protect population, as well as better training of veterinarians to detect and report Q fever.

One Health approach to Coxiella burnetii in Brazilian indigenous communities

Indigenous health has posted complex challenges worldwide, particularly due to historical economic, territorial, social and environmental processes, which may lead to emergence and reemergence of pathogens. In addition to few Coxiella burnetii serosurveys in vulnerable populations, especially in developing tropical countries, no comprehensive One Health approach has focused on human-animal infection along with potential environmental determinants. Accordingly, this study aimed to assess the seroprevalence of anti-C. burnetii antibodies in indigenous populations and their dogs from 10 indigenous communities distributed in southern and southeastern Brazil, along with the correspondent healthcare professionals. In overall, 8/893 (0.90%; 95% CI 0.45-1.76) indigenous and 1/406 (0.25%) dog samples were seropositive, with 7/343 (2.04%) individuals the 1/144 (0.69%) dog from the Ocoy community, located in the city of São Miguel do Iguaçu, bordering Argentina at south, and far 10 km at west from Paraguay. All 84 healthcare professionals tested seronegative.

Serosurvey of Coxiella burnetii in Descendants of Former Black Slaves (Quilombola Communities) of Southern Brazil

Brazilian descendants of former Black-slave (quilombola) communities have been predisposed to several zoonotic diseases due to social vulnerability, characterized by subsistence and close contact with livestock and companion animals. Accordingly, the present study has assessed anti-Coxiella burnetii antibodies in 200 individuals and 20 dogs from four quilombola communities located in Paraná State, southern Brazil. Serum samples were tested by indirect immunofluorescence assay (IFA) using in-house and commercial diagnostic protocols, with analysis of seropositive titers and antibody type. Fisher's exact test was used to compare seropositivity to C. burnetti with binary variables, with variables with three or more possible responses submitted to logistic regression. In total, 44/200 (22%; 95% CI 16.82-28.24) people tested positive, and 4.5% had titers higher than 128, indicating a recent onset of C. burnetii infection. Seropositive individuals were statistically associated with the Limitão community (p = 0.0013), urban workers as occupations (p = 0.0475), consumption of undercooked meat (p = 0.0159), and contact with animal abortion (p = 0.0276). No seropositivity association was found for age, sex, education, habit of entering forest areas, consumption of game meat, consumption of raw milk, flea and tick bites, dog contact, or history of female miscarriage. Only one of 20 dogs was seropositive with a titer of 128, probably related to an acute animal infection. Despite the prevalence here being higher than previous Brazilian reports, including with symptomatic populations, the results were within range for worldwide outbreaks and occupational risk populations. To the reader's knowledge, this is the first human survey of Q fever in southern Brazil and should be considered a warning for C. burnetii in vulnerable populations, particularly Quilombola communities.

First report of an outbreak of "Q" fever IN an abattoir from Argentina

In late October 2021, one of the veterinarians and the occupational physician of a bovine and swine abattoir from Entre Ríos Province, Argentina were alerted about workers with atypical pneumonia symptoms, raising suspicious of a possible Q fever outbreak. An outbreak epidemiological investigation was carried out. Analysis was based on the description of the study population, according to gender, age, symptoms, and position within the abattoir, as well as on outbreak epidemic curve and its probable origin. Cases of Q fever in the workers were confirmed by serology. Measurements of the association between the evaluated variables and the risk of exposure were investigated and calculated as attack rates. The outbreak occurred between October and November 2021, symptomatically affecting 11 workers, out of a total exposed population of 49 individuals. The index case was a 33-year-old male who started with symptoms on 27 October 2021, and the outbreak extended for at least 17 days. Workers in the clean zone of the slaughter floor had a 4.68 times higher risk of contracting Q fever than people located in other areas. Importantly, two pregnant cows were slaughtered a few days before the outbreak began, which could have been the origin of the outbreak. The present study demonstrates the urgent need to consider Q fever when diagnosing abortive diseases of ruminants in Argentina, as well as in zoonotic disease epidemiological surveillance to inform all actors of the health system.

Overview of Q fever in Brazil: an underestimated zoonosis

This review aims to provide current information about Q fever, elucidating the etiological, epidemiological, pathogenic, clinical, diagnostic, therapeutic, and prophylactic aspects of the disease for the medical community. We discuss the main forms of presentation of the agent, its ability to persist in the body, the infinite possibilities of susceptible hosts, the main known forms of transmission, its importance in populations at occupational risk, and the role of arthropods in the natural history of the disease. Focusing on Brazil, we present the cases already described and studies developed since its first report, and how there is still much to unravel. We are aware of the possibilities of the persistence of the agent and the development of severe clinical pictures and the specific treatments currently instituted. We also wish to raise awareness about the future, the new genotypes that are emerging, the need to study the effects of vaccines, and the impact of Q fever on the population. Q fever is a poorly understood disease in Latin America, and recent studies, especially in Brazil, have revealed the importance of developing new studies.

Coxiella burnetii Pathogenesis: Emphasizing the Role of the Autophagic Pathway

Coxiella burnetii (C. burnetii), the etiological agent of the Q fever disease, ranks among the most sporadic and persistent global public health concerns. Ruminants are the principal source of human infections and diseases present in both acute and chronic forms. This bacterium is an intracellular pathogen that can survive and reproduce under acidic (pH 4 to 5) and harsh circumstances that contain Coxiella-containing vacuoles. By undermining the autophagy defense system of the host cell, C. burnetii is able to take advantage of the autophagy pathway, which allows it to improve the movement of nutrients and the membrane, thereby extending the vacuole of the reproducing bacteria. For this method to work, it requires the participation of many bacterial effector proteins. In addition, the precise and prompt identification of the causative agent of an acute disease has the potential to delay the onset of its chronic form. Moreover, to make accurate and rapid diagnoses, it is necessary to create diagnostic devices. This review summarizes the most recent research on the epidemiology, pathogenesis, and diagnosis approaches of C. burnetii. This study also explored the complicated relationships between C. burnetii and the autophagic pathway, which are essential for intracellular reproduction and survival in host cells for the infection to be effective.

The Importance of the Slaughterhouse in Surveilling Animal and Public Health: A Systematic Review

From the point of public health, the objective of the slaughterhouse is to guarantee the safety of meat in which meat inspection represent an essential tool to control animal diseases and guarantee the public health. The slaughterhouse can be used as surveillance center for livestock diseases. However, other aspects related with animal and human health, such as epidemiology and disease control in primary production, control of animal welfare on the farm, surveillance of zoonotic agents responsible for food poisoning, as well as surveillance and control of antimicrobial resistance, can be monitored. These controls should not be seen as a last defensive barrier but rather as a complement to the controls carried out on the farm. Regarding the control of diseases in livestock, scientific research is scarce and outdated, not taking advantage of the potential for disease control. Animal welfare in primary production and during transport can be monitored throughout ante-mortem and post-mortem inspection at the slaughterhouse, providing valuable individual data on animal welfare. Surveillance and research regarding antimicrobial resistance (AMR) at slaughterhouses is scarce, mainly in cattle, sheep, and goats. However, most of the zoonotic pathogens are sensitive to the antibiotics studied. Moreover, the prevalence at the slaughterhouse of zoonotic and foodborne agents seems to be low, but a lack of harmonization in terms of control and communication may lead to underestimate its real prevalence.

Seroprevalence and Risks Factors Associated with Coxiella burnetii Infection in Slaughterhouse Zebu Cattle (Bos indicus) from Northern Regions of Cameroon

A study was conducted to determine the seroprevalence and risks factors of Coxiella burnetii in zebu cattle from the northern regions of Cameroon. From a total of 2016 (1754 females and 262 males) sera sampled, 801, 762 and 453 were collected, respectively, from Adamawa, North and Far North, and screened for Coxiella burnetii using indirect enzyme-linked immunosorbent assay (iELISA). A total of 23.76% (479/2016) were serologically positive. The seroprevalence of Adamawa, North and Far North were 29.09% (233/801), 19.95% (152/762) and 20.75% (94/453); respectively. The seropositivity of male and female were 4.58% and 26.62%; respectively. Cattle from Adamawa region were more likely to have been exposed to C. burnetii than animals from Far North region (OR = 3.28; 95%CI: 1.13-7.85; p = 0.02). The Gudali breed was significantly more infected than Aku (OR =2.52; 95%CI: 1.06-5.99; p = 0.03), and animals aged of (6-9) years were 1.89 times more likely to have been infected to C. burnetii than young animals (p = 0.03). The seropositivity to this bacterium was significantly associated to pregnant cattle than non-pregnant (OR = 1.71; 95%CI: 1.01-2.90; p = 0.04). Female cattle were more likely to have been infected by C. burnetii than male and the rainy season were 1.66 more associated to this disease than dry season. The linear regression model indicated that C. burnetii seropositivity were positively correlated to the regions (0.09, CI: 0.04; 0.18; p = 0.007), age (0.01, CI: -0.01; 0.04; p = 0.02), sex (0.19, CI: 0.08-0.32, p = 0.001) and physiological status (0.11, CI: -0.04; 0.26; p = 0.006). This study revealed that C. burnetii infection is widespread among zebu cattle of Adamawa, North and Far North of Cameroon.

Molecular detection of Coxiella-like endosymbionts and absence of Coxiella burnetii in Amblyomma mixtum from Veracruz, Mexico

Ticks are obligate ectoparasites associated with a wide range of vertebrate hosts, including domestic animals. Moreover, ticks are capable of transmitting many pathogens such as Coxiella. To date, Coxiella burnetii, the etiological agent of coxiellosis or Q fever, is the only valid species of the genera. Nevertheless, a wide range of agents denominated Coxiella-like have been detected in recent studies, mainly associated with ticks. The pathogenicity of these Coxiella-like agents is controversial as some of them can infect both birds and humans. In Mexico, knowledge about Q fever is scarce and limited to historical serological records, and there is an overall lack of molecular proof of any agent of the genus Coxiella circulating in the country. Therefore, the aim of this study was to detect the presence of Coxiella in ticks associated with cattle in all 10 regions of Veracruz, Mexico. To accomplish this objective, first, we identified ticks collected from cattle and horses in Veracruz. Then, for Coxiella detection, DNA extraction from ticks and PCR amplification of the 16S-rDNA of Coxiella was performed. Finally, we performed a phylogenetic reconstruction to determine the Coxiella lineages detected. From the 10 regions sampled we collected 888 ticks grouped in 180 pools, and only five Amblyomma mixtum from the locality of Castán, and one from Los Angeles from Tuxpan were found positive, which represents a frequency of 20% for each locality. This study represents the first attempt at molecular detection of Coxiella in ticks associated with cattle in the state of Veracruz, the major livestock producer in the country. The findings of the present study are relevant as they establish a precedent regarding the circulation of Coxiella-like agents, as well as the absence in three municipalities of the state of Veracruz of C. burnetii, an abortive agent of livestock importance.

Seropositivity for Coxiella burnetii in suspected patients with dengue in São Paulo state, Brazil

Q fever and brucellosis are zoonoses that cause fever and other systemic clinical signs in humans; their occurrences are neglected and the differential diagnosis for some diseases is disregarded. This study aimed to investigate the seropositivity for Coxiella burnetii and Brucella spp. antibodies in patients suspected of dengue from 38 municipalities in the state of São Paulo, Brazil. The samples (n = 604) were obtained by convenience from the Adolfo Lutz Institute serum bank. Sera were subjected to an indirect immunofluorescence assay (IFA) using in-house and commercial diagnostic protocols to evaluate C. burnetii positivity. For Brucella spp., sera were subjected to rapid plate serum agglutination with buffered acidified antigen (AAT), slow tube serum agglutination (SAL), and 2-mercaptoethanol (2-ME) techniques. Associations and statistical inferences of the results were performed by logistic regression according to the clinical and demographic variables collected from the patients. Statistical analyses were performed using Statistical Analysis Software (SAS) and associations were considered when p value was <0.05. In all, 129 patients showed positive results for Q fever, indicating a seropositivity of 21.4% (95% CI 18.15–24.85). Patients with 14–20 days of symptoms had 2.12 (95% CI 1.34–3.35) times more chances of being seropositive for Q fever than patients with 7–13 days, and patients with 21–27 days of fever had 2.62 (95% CI 1.27–5.41) times more chances of being seropositive for Q fever than patients with 7–13 days. For the other variables analyzed, there were no significant associations between the groups. No positivity for brucellosis was observed. This is the most comprehensive study of people seropositive for Q fever in São Paulo state and provides additional data for the medical community in Brazil. It is suggested that Q fever may be an important differential diagnosis of febrile illnesses in the region, demanding the government’s attention and investment in health.

Brazil is a tropical country with a warm climate and large animal herds that favor many zoonotic agents that circulate in the territory. Due to the high prevalence of some tropical diseases, such as dengue, malaria, and chikungunya, important zoonoses have been neglected during the clinical evaluation of patients, resulting in misdiagnosis. Examples include Q fever and brucellosis, zoonoses that occur in animals in Brazil and are easily transmitted to humans through contaminated air and food products. There is not much data on these diseases in humans in the country representing their actual health situation. The current knowledge is supported by a few serological surveys developed by research groups and case reports. In this study, sera from patients with fever of unknown origin were positive for Q fever and brucellosis. The authors found that, contrary to brucellosis, Q fever has affected many people in São Paulo, the most populous state in the country. In addition, other findings regarding patient profile and disease behavior have been established. This research highlights the need for surveillance and control of Q fever in humans and animals to prevent acute cases and treat chronic patients.

The Symbiotic Continuum Within Ticks: Opportunities for Disease Control

Among blood-sucking arthropods, ticks are recognized as being of prime global importance because of their role as vectors of pathogens affecting human and animal health. Ticks carry a variety of pathogenic, commensal, and symbiotic microorganisms. For the latter, studies are available concerning the detection of endosymbionts, but their role in the physiology and ecology of ticks remains largely unexplored. This review paper focuses on tick endosymbionts of the genera Coxiella, Rickettsia, Francisella, Midichloria, and Wolbachia, and their impact on ticks and tick-pathogen interactions that drive disease risk. Tick endosymbionts can affect tick physiology by influencing nutritional adaptation, fitness, and immunity. Further, symbionts may influence disease ecology, as they interact with tick-borne pathogens and can facilitate or compete with pathogen development within the vector tissues. Rickettsial symbionts are frequently found in ticks of the genera of Ixodes, Amblyomma, and Dermacentor with relatively lower occurrence in Rhipicephalus, Haemaphysalis, and Hyalomma ticks, while Coxiella-like endosymbionts (CLEs) were reported infecting almost all tick species tested. Francisella-like endosymbionts (FLEs) have been identified in tick genera such as Dermacentor, Amblyomma, Ornithodoros, Ixodes, and Hyalomma, whereas Wolbachia sp. has been detected in Ixodes, Amblyomma, Hyalomma, and Rhipicephalus tick genera. Notably, CLEs and FLEs are obligate endosymbionts essential for tick survival and development through the life cycle. American dog ticks showed greater motility when infected with Rickettsia, indirectly influencing infection risk, providing evidence of a relationship between tick endosymbionts and tick-vectored pathogens. The widespread occurrence of endosymbionts across the tick phylogeny and evidence of their functional roles in ticks and interference with tick-borne pathogens suggests a significant contribution to tick evolution and/or vector competence. We currently understand relatively little on how these endosymbionts influence tick parasitism, vector capacity, pathogen transmission and colonization, and ultimately on how they influence tick-borne disease dynamics. Filling this knowledge gap represents a major challenge for future research.

Molecular detection of Coxiella burnetii in aborted bovine fetuses in Brazil

In the past decade, cases of Q fever have been reported in Brazil. Although the previous report of Coxiella burnetii in humans and animals, the knowledge about the occurrence of this pathogen in livestock in Brazil is scarce. This study aimed to search C. burnetii and possible coinfections in tissues of aborted bovine fetuses from Brazil. Tissue samples from seventy-six aborted bovine fetuses sent to the laboratory of molecular diagnosis of infectious diseases from 2013 to 2019 were evaluated by real-time PCR for C. burnetii. Overall, 9.2% (7/76) of the samples were positive for C. burnetii. Moreover, the molecular diagnostic history of our lab revealed the coinfection with Neospora spp. in three fetuses and the presence of histopathological features suggestive with fetal neosporosis in another one. The previous report of C. burnetii in humans and animals in the country, with the detection of C. burnetii from tissues of aborted bovine fetuses reported here, reinforces the neglected state of the disease in Brazil and raises the question of the role of the pathogen in reproductive disorders in national livestock.

Identification of Immunogenic Linear B-Cell Epitopes in C. burnetii Outer Membrane Proteins Using Immunoinformatics Approaches Reveals Potential Targets of Persistent Infections

Coxiella burnetii is a global, highly infectious intracellular bacterium, able to infect a wide range of hosts and to persist for months in the environment. It is the etiological agent of Q fever—a zoonosis of global priority. Currently, there are no national surveillance data on C. burnetii’s seroprevalence for any South American country, reinforcing the necessity of developing novel and inexpensive serological tools to monitor the prevalence of infections among humans and animals—especially cattle, goats, and sheep. In this study, we used immunoinformatics and computational biology tools to predict specific linear B-cell epitopes in three C. burnetii outer membrane proteins: OMP-H (CBU_0612), Com-1 (CBU_1910), and OMP-P1 (CBU_0311). Furthermore, predicted epitopes were tested by ELISA, as synthetic peptides, against samples of patients reactive to C. burnetii in indirect immunofluorescence assay, in order to evaluate their natural immunogenicity. In this way, two linear B-cell epitopes were identified in each studied protein (OMP-H_(51–59), OMP-H_(91–106), Com-1_(57–76), Com-1_(191–206), OMP-P1_(197–209), and OMP-P1_(215–227)); all of them were confirmed as naturally immunogenic by the presence of specific antibodies in 77% of studied patients against at least one of the identified epitopes. Remarkably, a higher frequency of endocarditis cases was observed among patients who presented an intense humoral response to OMP-H and Com-1 epitopes. These data confirm that immunoinformatics applied to the identification of specific B-cell epitopes can be an effective strategy to improve and accelerate the development of surveillance tools against neglected diseases.

Pattern Recognition Receptors in Innate Immunity to Obligate Intracellular Bacteria

Host pattern recognition receptors (PRRs) are crucial for sensing pathogenic microorganisms, launching innate responses, and shaping pathogen-specific adaptive immunity during infection. Rickettsia spp., Orientia tsutsugamushi, Anaplasma spp., Ehrlichia spp., and Coxiella burnetii are obligate intracellular bacteria, which can only replicate within host cells and must evade immune detection to successfully propagate. These five bacterial species are zoonotic pathogens of clinical or agricultural importance, yet, uncovering how immune recognition occurs has remained challenging. Recent evidence from in-vitro studies and animal models has offered new insights into the types and kinetics of PRR activation during infection with Rickettsia spp., A. phagocytophilum, E. chaffeensis, and C. burnetii, respectively. However, much less is known in these regards for O. tsutsugamushi infection, until the recent discovery for the role of the C-type lectin receptor Mincle during lethal infection in mice and in primary macrophage cultures. This review gives a brief summary for clinical and epidemiologic features of these five bacterial infections, focuses on fundamental biologic facets of infection, and recent advances in host recognition. In addition, we discuss knowledge gaps for innate recognition of these bacteria in the context of disease pathogenesis.