Molecular and genotyping techniques in diagnosis of Coxiella burnetii: An overview

Although we live in the genomic era, the accessibility of the complete genome sequence of Coxiella burnetii, the etiological agent of Q fever, has increased knowledge in the field of genomic diversity of this agent However, it is still somewhat of a "question" microorganism. The epidemiology of Q fever is intricate due to its global distribution, repository and vector variety, as well as absence of surveys defining the dynamic interaction among these factors. Moreover, C. burnetii is a microbial agent that can be utilized as a bioterror weapon. Therefore, typing techniques used to recognize the strains can also be used to trace infections back to their source which is of great significance. In this paper, the latest and current typing techniques of C. burnetii spp. are reviewed illustrating their advantages and constraints. Recently developed multi locus VNTR analysis (MLVA) and single-nucleotide polymorphism (SNP) typing methods are promising in improving diagnostic capacity and enhancing the application of genotyping techniques for molecular epidemiologic surveys of the challenging pathogen. However, most of these studies did not differentiate between C. burnetii and Coxiella-like endosymbionts making it difficult to estimate the potential role that ticks play in the epidemiology of Q fever. Therefore, it is necessary to analyze the vector competence of different tick species to transmit C. burnetii. Knowledge of the vector and reservoir competence of ticks is important for taking adequate preventive measures to limit infection risks. The significant prevalence observed for the IS1111 gene underscores its substantial presence, while other genes display comparatively lower prevalence rates. Methodological variations, particularly between commercial and non-commercial kit-based methods, result in different prevalence outcomes. Variations in sample processing procedures also lead to significant differences in prevalence rates between mechanical and non-mechanical techniques.

Occurrence of Coxiella burnetii in wild lagomorphs and their ticks in Spanish Mediterranean ecosystems

BACKGROUND

Coxiella burnetii, the causative agent of Q fever, is a zoonotic multi-host vector-borne pathogen of major public health importance. Although the European Food Safety Authority has recently made the monitoring of this bacterium in wildlife a priority, the role of wild lagomorphs in the transmission and maintenance of C. burnetii is poorly understood.

AIMS

The aims of this study were to determine the prevalence and risk factors associated with C. burnetii circulation in European wild rabbits (Oryctolagus cuniculus) and Iberian hares (Lepus granatensis) and to assess the presence of this pathogen in ticks that feed on them in Mediterranean ecosystems in Spain, the country with the highest number of reported cases of Q fever in Europe.

METHODS

A total of 574 spleen samples were collected from 453 wild rabbits and 121 Iberian hares, and 513 ticks (processed in 120 pools) between the 2017/2018 and 2021/2022 hunting seasons.

RESULTS

C. burnetii DNA was detected in 103 (17.9%; 95% CI: 14.8-21.1) of the 574 wild lagomorphs tested. By species, prevalence was 16.3% (74/453; 95% CI: 12.9-19.7) in the European wild rabbit and 24.0% (29/121; 95% CI: 16.4-31.6) in the Iberian hare. At least one positive lagomorph was found on 47.9% of the 96 hunting estates sampled and in every hunting season since 2018/2019. Two risk factors associated with C. burnetii infection were as follows: outbreak of myxomatosis on the hunting estate in the month prior to sampling and high tick abundance observed by gamekeepers on the hunting estate. C. burnetii DNA was also found in 33 of the 120 (27.5%; 95% CI: 19.5-35.5) tick pools tested. The pathogen was detected in 66.7% (4/6), 29.2% (26/89) and 21.4% (3/14) of Haemaphysalis hispanica, Rhipicephalus pusillus and Hyalomma lusitanicum pools respectively.

CONCLUSIONS

This study provides new epidemiological data on C. burnetii in European wild rabbits and is the first survey on this zoonotic pathogen performed in Iberian hares. Our results indicate widespread endemic circulation of C. burnetii and highlight the importance of both wild lagomorph species as natural reservoirs of this zoonotic bacterium in Mediterranean ecosystems in southern Spain, which may be of public and animal health concern. The high prevalence and wide diversity of positive tick species suggest the possible role of ticks in the epidemiological cycle of C. burnetii, with the potential risk of transmission to sympatric species, including humans.

First detection and a new avian host of the tick Ixodes ventalloi Gil Collado, 1936, in Slovakia

This study describes the first detection of Ixodes ventalloi in Slovakia. Two engorged females of I. ventalloi were collected from Dunnocks (Prunella modularis) captured in eastern Slovakia. The identification of females was based on morphological and molecular 16S rRNA gene features. Phylogenetic analysis revealed a classification of the females into distinct genogroups. Moreover, comparative morphological analysis highlighted variations between the two females, particularly in the curvature of the auriculae, the shape of coxa I, and the internal spur. These findings suggest the potential for varied phenotypes of I. ventalloi correlated with their genogroups. Nonetheless, I. ventalloi population establishment within Slovakia necessitates further investigation through flagging or drag sampling.

Exposure to Coxiella burnetii in Wild Lagomorphs in Spanish Mediterranean Ecosystems

Coxiella burnetii is an important zoonotic pathogen of worldwide distribution that can infect a wide range of wild and domestic species. The European wild rabbit (Oryctolagus cuniculus) can play a role as a reservoir for this bacterium in certain epidemiological scenarios, but, to date, a very limited numbers of large-scale serosurveys have been conducted for this species worldwide. Although exposure in hare species has also been described, C. burnetii in Iberian hare (Lepus granatensis) has never been assessed. Here, we aimed to determine the seroprevalence and risk factors associated with C. burnetii exposure in wild lagomorphs in the Mediterranean ecosystems of southern Spain. Between the 2018/2019 and 2021/2022 hunting seasons, blood samples from 638 wild lagomorphs, including 471 wild rabbits and 167 Iberian hares, were collected from 112 hunting grounds distributed across all eight provinces of Andalusia (southern Spain). The overall apparent individual seroprevalence was 8.9% (57/638; 95% CI: 6.8-11.4). Antibodies against C. burnetii were found in 11.3% (53/471; 95% CI: 8.4-14.1) of the wild rabbits and 2.4% (4/167; 95% CI: 0.1-4.7) of the Iberian hares. Seropositive animals were detected for 16 (14.3%; 95% CI: 7.8-20.8) of the 112 hunting grounds tested and in all the hunting seasons sampled. A generalized estimating equations model showed that the geographical area (western Andalusia) and presence of sheep were risk factors potentially associated with C. burnetii exposure in wild lagomorphs. A statistically significant spatial cluster (p < 0.001) was identified in the south-west of Andalusia. Our results provide evidence of moderate, endemic and heterogeneous circulation of C. burnetii in wild lagomorph populations in Spanish Mediterranean ecosystems. Risk-based strategies for integrative surveillance programs should be implemented in these species to reduce the risk of transmission of the bacterium to sympatric species, including humans.

Identification of zoonotic pathogenic bacteria from blood and ticks obtained from hares and long-eared hedgehogs (Hemiechinus megalofis) in eastern Iran

The role of wildlife in the complex balance of tick-borne diseases within ecosystems is crucial, as they serve as hosts for tick carriers and reservoirs for the pathogens carried by these ticks. This study aimed to investigate the presence of zoonotic pathogenic bacteria in wildlife, specifically in hares and long-eared hedgehogs (Hemiechinus megalofis), in the eastern region of Iran. The focus was on the detection of Borrelia spp., Coxiella burnetii, Anaplasma spp., Francisella spp., and Leptospira spp., using the Nested-PCR method. We analyzed a total of 124 blood samples, and 196 ticks collected from hares and long-eared hedgehogs were analyzed. The Nested-PCR method was employed to identify the presence of zoonotic pathogenic bacteria DNA. Our study revealed the presence of these zoonotic pathogenic bacteria in both wildlife species, indicating their potential role as hosts and reservoirs for the ticks carrying these pathogens. The specific presence and prevalence of Borrelia spp., Coxiella burnetii, Anaplasma spp., Francisella spp., and Leptospira spp. were determined through the Nested-PCR method. This study contributes to the limited knowledge about the involvement of wild animals in the transmission of tick-borne diseases. By using the Nested-PCR method, we successfully identified the presence of zoonotic pathogenic bacteria in hares and long-eared hedgehogs. This study emphasizes the need for further research to better understand the ecological process of tick-borne diseases, particularly the role of wildlife in their spread. Such knowledge is crucial for wildlife conservation efforts and the management of tick-borne diseases, ultimately benefiting both animal and human health.

Seroprevalence of Coxiella burnetii antibodies in wild deer populations in eastern Australia

Coxiella burnetii causes significant reproduction losses in livestock and the disease Q fever in humans. Transmission of C. burnetii is facilitated by the stability of the bacterium in the environment and the susceptibility of a variety of host species to infection. Consequently, inter-species transmission occurs frequently through either direct or indirect contact. Wildlife may represent reservoirs of C. burnetii and could therefore be a source of infection for domestic animals. Understanding the prevalence of C. burnetii infections at the wildlife-livestock interface is important for disease control. This study aimed to investigate the extent of C. burnetii exposure in wild deer in eastern Australia. Serum samples were obtained from 413 wild deer from seven regions in four eastern Australian states from 2017 to 2020. Antibodies were detected using a commercial Q fever antibody kit validated for ruminants. Seroprevalence of C. burnetii antibodies in deer was determined and true prevalence estimated, for each region. The overall seroprevalence of C. burnetii antibodies in wild deer was 3.4% (14 seropositive of 413 deer sampled) with true prevalence estimated to be 4.3% (95% credible interval: 0.6%, 10.9%). Seropositive deer were identified only in Queensland (7/108 seropositive) and northern New South Wales (7/120 seropositive). This geospatial distribution is consistent with seropositivity in other animal species and indicative of the level of C. burnetii in the environment. The low seroprevalence suggests that wild deer are unlikely to be a major reservoir species for C. burnetii in eastern Australia but may still be implicated in inter-species transmission cycles.

Ticks, Fleas, and Harboured Pathogens from Dogs and Cats in Cyprus

Ticks and fleas are blood-sucking ectoparasites that cause irritation and anaemia to their hosts and act as vectors of pathogens (vector-borne pathogens, VBPs) of relevance for animal and human health. In the present study, tick and flea species in dogs and cats from Cyprus were recorded and VBPs were detected in the collected specimens. Ectoparasites were collected from 220 animals (161 dogs and 59 cats), and a questionnaire including demographic, clinical, and other information was filled out for each animal. The ectoparasites were morphologically identified and the detection of VBPs was performed by PCR-coupled sequencing. Rhipicephalus sanguineus sensu lato was found on 108 dogs and 13 cats, and Ixodes gibbosus on 2 dogs. Ctenocephalides felis was the predominant flea species (on 62 dogs and 45 cats), while one dog and one cat were infested by Ctenocephalides canis and Echidnophaga gallinacea, respectively. The VBPs in ticks were Anaplasma platys, Rickettsia massiliae, Rickettsia conorii, Rickettsia felis, Hepatozoon felis and Hepatozoon canis, while Rickettsia felis, Rickettsia sp., Bartonella koehlerae, Bartonella clarridgeiae, and Bartonella henselae were recorded in fleas. Statistical analysis (chi-square test and multiple univariate generalized linear model) showed that animals up to 6 months of age were less likely to be infested with ticks than older animals, but more likely to be infested with fleas. Ticks were more prevalent in sheltered than in owned animals, while the odds ratio of flea presence was higher in owned animals than those living in shelters. The present study is the first investigation on the occurrence of ticks and fleas in dogs and cats from Cyprus, showing the presence of different VBPs in these important ectoparasites. The results point out the importance of systematic ectoparasite control in dogs and cats.

What do we know about the microbiome of I. ricinus?

I. ricinus is an obligate hematophagous parasitic arthropod that is responsible for the transmission of a wide range of zoonotic pathogens including spirochetes of the genus Borrelia, Rickettsia spp., C. burnetii, Anaplasma phagocytophilum and Francisella tularensis, which are part the tick´s microbiome. Most of the studies focus on "pathogens" and only very few elucidate the role of "non-pathogenic" symbiotic microorganisms in I. ricinus. While most of the members of the microbiome are leading an intracellular lifestyle, they are able to complement tick´s nutrition and stress response having a great impact on tick´s survival and transmission of pathogens. The composition of the tick´s microbiome is not consistent and can be tied to the environment, tick species, developmental stage, or specific organ or tissue. Ovarian tissue harbors a stable microbiome consisting mainly but not exclusively of endosymbiotic bacteria, while the microbiome of the digestive system is rather unstable, and together with salivary glands, is mostly comprised of pathogens. The most prevalent endosymbionts found in ticks are Rickettsia spp., Ricketsiella spp., Coxiella-like and Francisella-like endosymbionts, Spiroplasma spp. and Candidatus Midichloria spp. Since microorganisms can modify ticks' behavior, such as mobility, feeding or saliva production, which results in increased survival rates, we aimed to elucidate the potential, tight relationship, and interaction between bacteria of the I. ricinus microbiome. Here we show that endosymbionts including Coxiella-like spp., can provide I. ricinus with different types of vitamin B (B2, B6, B7, B9) essential for eukaryotic organisms. Furthermore, we hypothesize that survival of Wolbachia spp., or the bacterial pathogen A. phagocytophilum can be supported by the tick itself since coinfection with symbiotic Spiroplasma ixodetis provides I. ricinus with complete metabolic pathway of folate biosynthesis necessary for DNA synthesis and cell division. Manipulation of tick´s endosymbiotic microbiome could present a perspective way of I. ricinus control and regulation of spread of emerging bacterial pathogens.

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.

Validation of an Indirect Immunofluorescence Assay and Commercial Q Fever Enzyme-Linked Immunosorbent Assay for Use in Macropods

Kangaroos are considered to be an important reservoir of Q fever in Australia, although there is limited knowledge on the true prevalence and distribution of coxiellosis in Australian macropod populations. Serological tests serve as useful surveillance tools, but formal test validation is needed to be able to estimate true seroprevalence rates, and few tests have been validated to screen wildlife species for Q fever. In this study, we modified and optimized a phase-specific indirect immunofluorescence assay (IFA) for the detection of IgG antibodies against Coxiella burnetii in macropod sera. The assay was validated against the commercially available ID Screen Q fever indirect multispecies enzyme-linked immunosorbent assay (ELISA) kit (IDVet, Grabels, France) to estimate the diagnostic sensitivity and specificity of each assay, using Bayesian latent class analysis. A direct comparison of the two tests was performed by testing 303 serum samples from 10 macropod populations from the east coast of Australia and New Zealand. The analysis indicated that the IFA had relatively high diagnostic sensitivity (97.6% [95% credible interval [CrI], 88.0 to 99.9]) and diagnostic specificity (98.5% [95% CrI, 94.4 to 99.9]). In comparison, the ELISA had relatively poor diagnostic sensitivity (42.1% [95% CrI, 33.7 to 50.8]) and similar diagnostic specificity (99.2% [95% CrI, 96.4 to 100]) using the cutoff values recommended by the manufacturer. The estimated true seroprevalence of C. burnetii exposure in the macropod populations included in this study ranged from 0% in New Zealand and Victoria, Australia, up to 94.2% in one population from New South Wales, Australia.

Diversity of bacterial pathogens and their antimicrobial resistance profile among commensal rodents in Qatar

Rodents are sources of many zoonotic pathogens that are of public health concern. This study investigated bacterial pathogens and assessed their antimicrobial resistance (AMR) patterns in commensal rodents in Qatar. A total of 148 rodents were captured between August 2019 and February 2020, and blood, ectoparasites, and visceral samples were collected. Gram-negative bacteria were isolated from the intestines, and blood plasma samples were used to detect antibodies against Brucella spp., Chlamydophila abortus, and Coxiella burnetii. PCR assays were performed to detect C. burnetii, Leptospira spp., Rickettsia spp., and Yersinia pestis in rodent tissues and ectoparasite samples. Antimicrobial resistance by the isolated intestinal bacteria was performed using an automated VITEK analyzer. A total of 13 bacterial species were isolated from the intestine samples, namely Acinetobacter baumannii, Aeromonas salmonicida, Citrobacter freundii, Citrobacter koseri, Enterobacter aerogenes, Enterobacter cloacae, Escherichia coli, Hafnia alvei, Klebsiella pneumoniae, Providencia stuartii, Proteus mirabilis, Pseudomonas aeruginosa, and Salmonella enterica. The majority of them were E. coli (54.63%), followed by P. mirabilis (17.59%) and K. pneumoniae (8.33%). Most of the pathogens were isolated from rodents obtained from livestock farms (50.46%), followed by agricultural farms (26.61%) and other sources (22.94%). No antibodies (0/148) were detected against Brucella spp., C. abortus, or C. burnetii. In addition, 31.58% (6/19) of the flea pools and one (1/1) mite pool was positive for Rickettsia spp., and no sample was positive for C. burnetii, Leptospira spp., and Y. pestis by PCR. A total of 43 (38%) bacterial isolates were identified as multidrug resistant (MDR), whereas A. salmonicida (n = 1) did not show resistance to any tested antimicrobials. Over 50% of bacterial MDR isolates were resistant to ampicillin, cefalotin, doxycycline, nitrofurantoin, and tetracycline. The presence of MDR pathogens was not correlated with rodent species or the location of rodent trapping. Seven (11.86%) E. coli and 2 (22.2%) K. pneumoniae were extended-spectrum beta-lactamases (ESBL) producers. These findings suggest that rodents can be a source of opportunistic bacteria for human and animal transmission in Qatar. Further studies are needed for the molecular characterization of the identified bacteria in this study.

Molecular identification of zoonotic Rickettsia species in Ixodidae parasitizing wild lagomorphs from Mediterranean ecosystems

A survey study was carried out to identify tick species parasitizing wild lagomorphs in Mediterranean ecosystems in southern Spain and to determine the occurrence of Rickettsia species present in these ticks in this region. A total of 1304 European wild rabbits (Oryctolagus cuniculus) and 58 Iberian hares (Lepus granatensis) were individually examined for the presence of ticks. Ticks were found in 42.9% and 50% of the wild rabbits and hares sampled, respectively. A total of 1122 ticks were collected and five species, including Rhipicephalus pusillus, Hyalomma lusitanicum, Haemaphysalis hispanica, Ixodes ventalloi and Rhipicephalus sanguineus sensu lato (s.l.), were microscopically and molecularly identified at the 16S rRNA gene. This is the first study on Ixodidae parasitizing Iberian hares. The presence of Rickettsia DNA was assessed in 254 tick pools (according to hunting states, lagomorph species, tick species and tick development stage) using PCR assays targeting the rOmpA, rOmpB and gltA. Twenty-seven pools (10.6%) were positive to Rickettsia DNA. Five zoonotic Rickettsia species were identified, being Rickettsia massiliae the most frequent (4.7%), followed by Rickettsia sibirica subsp. mongolitimonae (2.8%), Rickettsia slovaca (2.0%), Rickettsia aeschlimannii (0.8%) and Rickettsia africae (0.4%). The results suggest that wild rabbits and Iberian hares are parasitized by a wide range of tick species and that these lagomorphs may play an important role in the sylvatic cycle of some zoonotic Rickettsia species in Mediterranean ecosystems. Our data represent the first report of R. massiliae, R. aeschlimannii, R. slovaca and R africae in ticks collected in wild lagomorphs in Europe, and the first report of not imported R. africae in this continent. Since R. slovaca and R. africae DNA was detected in tick species different to their main vectors, further studies are warranted to unravel the role of wild lagomorphs in the epidemiology of these vector-borne pathogens.

MOLECULAR INVESTIGATION OF VECTOR-BORNE PATHOGENS IN RED FOXES (VULPES VULPES) FROM SOUTHERN FRANCE

Because of their free-ranging nature, the probability of wild animals being exposed to vector-borne pathogens is likely higher than that of humans and pets. Recently, the red fox (Vulpes vulpes) has been suspected as being a reservoir or host of several pathogens of veterinary and public health importance. We conducted a molecular survey on 93 red foxes hunted in 2008-18, in the departments of Bouches-du-Rhône and Var, in southeastern France, for pathogens including Leishmania infantum, Piroplasmida, Hepatozoon spp., nematodes, Coxiella burnetii, Borrelia spp., Rickettsia spp., and Anaplasmataceae. Spleen samples were screened for the presence of vector-borne pathogens by PCR followed by sequencing. Pathogens were detected in 94% (87/93) of red foxes, and coinfections were identified in 24% (22/93) of foxes. We identified DNA from Hepatozoon canis, L. infantum, and Babesia vogeli in 92% (86/93), 15% (14/93), and 3% (3/93) of red foxes, respectively. We also found DNA of nematodes in 3% (3/93) of foxes; Spirocerca vulpis was identified in one fox and Dirofilaria immitis in the two others. Interestingly, C. burnetii genotype 3, previously described in humans from the same region, was identified in 3% (3/93) of foxes and Anaplasma platys in 2% (2/93) of foxes. We did not detect DNA of Borrelia spp., Bartonella spp., or Rickettsia spp. In our study, the prevalence of pathogens did not vary by fox origin, sex, or tick carriage. Molecular evidence of B. vogeli, H. canis, S. vulpis, D. immitis, C. burnetii, and A. platys in red foxes has not previously, to our knowledge, been reported from southern France. We propose that red foxes are potential reservoirs for several pathogens, including major zoonotic agents such as L. infantum. They could be incidental hosts for pathogens, such C. burnetii. The high prevalence for H. canis suggests an important role of foxes in domestic dog (Canis lupus familiaris) infection. These animals may pose a threat to human and animal health.

Investigating the Role of Micromammals in the Ecology of Coxiella burnetii in Spain

Coxiella burnetii, the causal agent of human Q fever and animal Coxiellosis, is a zoonotic infectious bacterium with a complex ecology that results from its ability to replicate in multiple (in)vertebrate host species. Spain notifies the highest number of Q fever cases to the ECDC annually and wildlife plays a relevant role in C. burnetii ecology in the country. However, the whole picture of C. burnetii hosts is incomplete, so this study seeks to better understand the role of micromammals in C. burnetii ecology in the country. Spleen samples from 816 micromammals of 10 species and 130 vaginal swabs from Microtus arvalis were analysed by qPCR to detect C. burnetii infection and shedding, respectively. The 9.7% of the spleen samples were qPCR positive. The highest infection prevalence (10.8%) was found in Microtus arvalis, in which C. burnetii DNA was also detected in 1 of the 130 vaginal swabs (0.8%) analysed. Positive samples were also found in Apodemus sylvaticus (8.7%), Crocidura russula (7.7%) and Rattus rattus (6.4%). Positive samples were genotyped by coupling PCR with reverse line blotting and a genotype II+ strain was identified for the first time in one of the positive samples from M. arvalis, whereas only partial results could be obtained for the rest of the samples. Acute Q fever was diagnosed in one of the researchers that participated in the study, and it was presumably linked to M. arvalis handling. The results of the study are consistent with previous findings suggesting that micromammals can be infected by C. burnetii. Our findings additionally suggest that micromammals may be potential sources to trace back the origin of human Q fever and animal Coxiellosis cases in Europe.

First isolation and molecular phylogenetic analysis of Coxiella burnetii in lactating cows

Q fever is an infectious disease of animals and humans, caused by globally distributed C. burnetii. In Iraq, there are no previous studies associated with the detection of the organism in cattle. An overall of 130 lactating cows were submitted to direct collection of milk samples. Initially, the samples of milk were tested using the molecular polymerase chain reaction (PCR) assay targeting three genes (16S rRNA, IS1111a transposase, and htpB). However, positive results (18.46%; 24/130) were detected only with the 16s rRNA gene. Concerning risk factors, the highest prevalence of C. burnetii was showed in the district of Badra (42.86%), whereas the lowest - in Al-Numaniyah and Al-Suwaira districts (P=0.025). There was no significant variation in positivity between the months of sampling period (P=0.082) and between age groups (P=0.076). Crossbred cows (20.69%) showed a higher positivity than local and pure breeds (P=0.043). Milk of positive samples (n=24) was used for cultivation of C. burnetii into specific pathogen free-embryonated chicken eggs (SPF-ECEs). After three passages into SPF-ECEs, contents of yolk sac were collected, subjected for DNA extraction, and re-tested by PCR assay using the primer of 16s rRNA gene only. Of 24 cultivated milk samples, 12.5% (3/24) were positive for C. burnetii. Finally, the positive local isolates were analysed phylogenetically and reported in NCBI-Genbank under the accession numbers of MN121700.1, MN121701.1, and MN121702.1. In conclusion, this is a unique study as it detected C. burnetii in Iraqi lactating cows, and confirmed that organism was shed actively through milk, suggesting that these animals can play a role as a reservoir for organism with potential risk for transmission of infection from these animals to humans as well as to other animal species.

Coexistence of Tick-Borne Pathogens in Ticks Collected from their Hosts in Sardinia: an Update

PURPOSE

In recent decades, the incidence and distribution of tick-borne diseases have increased worldwide, attracting the attention of both clinicians and veterinarians. In Sardinia, notifiable tick-borne diseases are spreading and Mediterranean spotted fever (MSF) rickettsiosis continues to be endemic with an incidence of 10/10,000 inhabitants per year. Furthermore, ticks can transfer more than one pathogen after a single blood meal from a coinfected host or after multiple feeding on different infected hosts. The aim of this study was to update information on ticks and tick-borne diseases, focusing also on the presence of coinfection in Sardinian ticks.

METHODS

The presence of protozoan (Theileria and Babesia species) and bacterial pathogens (Rickettsia spp., Anaplasma spp., Ehrlichia canis, Chlamydia spp., Bartonella spp., and Coxiella burnetii) was evaluated in 230 ticks collected from different hosts in Sardinia.

RESULTS

PCR and sequencing analyses highlighted that the 59% of ticks were infected with at least one pathogen while the 15% resulted in coinfection by double and triple pathogens. Among the double co-infections, those of E. canis/C. burnetii, Babesia sp. Anglona/Ch. psittaci and Babesia sp. Anglona/C. burnetii revealed a statistically significant index of coinfection.

CONCLUSION

This study identifies new pathogens in Sardinian ticks and updates the information about tick-borne diseases in the island. We also provide new results on the presence of coinfections in collected ticks. The knowledge about the diversity of ticks and tick-borne diseases circulating in Sardinia is a necessary step toward implementing effective tick-borne disease prevention and control programs.

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

Coxiella burnetii is widespread in ticks (Ixodidae) in the Xinjiang areas of China

Background

The gram-negative Coxiella burnetii bacterium is the pathogen that causes Q fever. The bacterium is transmitted to animals via ticks, and manure, air, dead infected animals, etc. and can cause infection in domestic animals, wild animals, and humans. Xinjiang, the provincial-level administrative region with the largest land area in China, has many endemic tick species. The infection rate of C. burnetii in ticks in Xinjiang border areas has not been studied in detail.

Results

For the current study, 1507 ticks were collected from livestock at 22 sampling sites in ten border regions of the Xinjiang Uygur Autonomous region from 2018 to 2019. C. burnetii was detected in 205/348 (58.91%) Dermacentor nuttalli; in 110/146 (75.34%) D. pavlovskyi; in 66/80 (82.50%) D. silvarum; in 15/32 (46.90%) D. niveus; in 28/132 (21.21%) Hyalomma rufipes; in 24/25 (96.00%) H. anatolicum; in 219/312 (70.19%) H. asiaticum; in 252/338 (74.56%) Rhipicephalus sanguineus; and in 54/92 (58.70%) Haemaphysalis punctata. Among these samples, C. burnetii was detected in D. pavlovskyi for the first time. The infection rate of Rhipicephalus was 74.56% (252/338), which was the highest among the four tick genera sampled, whereas the infection rate of H. anatolicum was 96% (24/25), which was the highest among the nine tick species sampled. A sequence analysis indicated that 63 16S rRNA sequences could be found in four newly established genotypes: MT498683.1 (n = 18), MT498684.1 (n = 33), MT498685.1 (n = 6), and MT498686.1 (n = 6).

Conclusions

This study indicates that MT498684.1 might represent the main C. burnetii genotype in the ticks in Xinjiang because it was detected in eight of the tick species studied. The high infection rate of C. burnetii detected in the ticks found in domestic animals may indicate a high likelihood of Q fever infection in both domestic animals and humans.

Investigation of the Role of the European Brown Hare in the Epidemiology of Bacterial Zoonotic Pathogens: A Serological and Molecular Survey in Greece

The aim of this study was to investigate the occurrence of Bartonella spp, Brucella spp, Coxiella burnetii, and Francisella tularensis in European Brown hares (Lepus europaeus) hunter harvested during 2-year hunting periods in northern and central Greece. Serum samples were examined for the presence of IgG antibodies by using an immune fluorescence test and/or an enzyme-linked immunosorbent assay. PCR was used to detect Bartonella spp DNA in blood samples and Brucella spp, C. burnetii, and F. tularensis DNA in liver samples. Antibodies against Bartonella spp were detected in 12 hares (12/105); whereas none of the hares examined was seropositive for Brucella spp, C. burnetii, and F. tularensis. The presence of Bartonella spp, Brucella spp, C. burnetii, and F. tularensis DNA was not detected in the samples examined. This study did not provide any evidence that the European Brown hare is involved in the epidemiology of Brucella spp, C. burnetii, and F. tularensis in Greece. However, our results suggest that this species is exposed to Bartonella spp, which gives the impetus for further investigation of its role as another host of this bacterium.

Coxiella burnetii Antibody Prevalence and Risk Factors of Infection in the Human Population of Estonia

Q fever is an emerging health problem in both humans and animals. To estimate the prevalence of Coxiella burnetii (C. burnetii) antibodies in the Estonian population, we analyzed plasma samples from 1000 individuals representing the general population and 556 individual serum samples from five population groups potentially at a higher risk (veterinary professionals, dairy cattle, beef cattle, and small ruminant stockbreeders and hunters). Additionally, 118 dairy cow bulk tank milk samples were analyzed to establish the infection status of the dairy cattle herds and the participating dairy cattle keepers. Questionnaires were used to find the potential risk factors of exposure. The effects of different variables were evaluated using binary logistic regression analysis and mixed-effects logistic analysis. The prevalence in veterinary professionals (9.62%; p = 0.003) and dairy cattle farmers (7.73%; p = 0.047) was significantly higher than in the general population (3.9%). Contact with production animals in veterinary practice and being a dairy stockbreeder in C. burnetii positive farms were risk factors for testing C. burnetii seropositive (p = 0.038 and p = 0.019, respectively). Results suggest that C. burnetii is present in Estonia and the increased risk of infection in humans is associated with farm animal contact.

Comprehensive literature review of the sources of infection and transmission routes of Coxiella burnetii, with particular regard to the criteria of "evidence-based medicine"

The present review aims to compile the currently available literature since 1936 according the sources of infection of the Q fever pathogen (Coxiella (C.) burnetii) as well as the transmission from animal to man and also from human to human. In terms of quality and validity, the existing publications were reviewed systematically. For this purpose, firstly a structured literature search was carried out using various databases and search engines supplemented by a manual literature search. For critical appraisal, 1444 relevant publications were identified for the moment and evaluated. A total of 73 publications describing a transmission of C. burnetii from animals to man or a human-to-human transmission were discovered. The identified publications are 29 case series, two case reports, 21 cohort studies and 21 case-control studies. With regard to the sources of infection, 25 publications describing the transmission of C. burnetii from sheep to humans could be identified.

Molecular Evidence of Q Fever Agent Coxiella Burnetii in Ixodid Ticks Collected from Stray Dogs in Belgrade (Serbia)

Q fever is a zoonotic disease caused by Coxiella burnetii, a gram-negative coccobacillus, which has been detected in a wide range of animal species, mostly domestic ruminants, but also in wild mammals, pets, birds, reptiles, arthropods (especially ticks), as well as in humans. Although the exposure to domestic animals in rural areas is regarded as the most common cause of the disease in humans, recent studies have shown that the role of pets in the epidemiology of Q fever has been increasingly growing. Although the primary route of infection is inhalation, it is presumed that among animals the infection circulates through ticks and that they are responsible for heterospecifi c transmission, as well as spatial dispersion among vertebrates. The aim of this study was to determine the presence and prevalence of C. burnetii in ticks removed from stray dogs, as well as to examine the distribution of tick species parasitizing dogs on the territory of Belgrade city. A PCR protocol targeting IS1111 repetitive transposon-like region of C. burnetii was used for the detection of C. burnetii DNA in ticks and the results were confi rmed by sequence analysis. In total, 316 ticks were collected from 51 stray dogs - 40 females (78.43%) and 11 males (21.57%). Three species of ticks were identifi ed: Rhipicephalus s anguineus (72.15%), Ixodes ricinus (27.53%) and Dermacentor reticulatus (0.32%). Out of 316 examined ticks, C. burnetii DNA was detected only in the brown dog tick R. sanguineus, with a total prevalence of 10.53% (24/228) . The high prevalence of C. burnetii in R. sanguineus, which is primarily a dog tick, indicates the importance of dogs in the epidemiology of Q fever in the territory of Belgrade.

Airborne geographical dispersal of Q fever from livestock holdings to human communities: a systematic review and critical appraisal of evidence

BACKGROUND

Q fever is a zoonotic disease caused by Coxiella burnetii. This bacterium survives harsh conditions and attaches to dust, suggesting environmental dispersal is a risk factor for outbreaks. Spatial epidemiology studies collating evidence on Q fever geographical contamination gradients are needed, as human cases without occupational exposure are increasing worldwide.

METHODS

We used a systematic literature search to assess the role of distance from ruminant holdings as a risk factor for human Q fever outbreaks. We also collated evidence for other putative drivers of C. burnetii geographical dispersal.

RESULTS

In all documented outbreaks, infective sheep or goats, not cattle, was the likely source. Evidence suggests a prominent role of airborne dispersal; Coxiella burnetii travels up to 18 km on gale force winds. In rural areas, highest infection risk occurs within 5 km of sources. Urban outbreaks generally occur over smaller distances, though evidence on attack rate gradients is limited. Wind speed / direction, spreading of animal products, and stocking density may all contribute to C. burnetii environmental gradients.

CONCLUSIONS

Q fever environmental gradients depend on urbanization level, ruminant species, stocking density and wind speed. While more research is needed, evidence suggests that residential exclusion zones around holdings may be inadequate to contain this zoonotic disease, and should be species-specific.

Molecular survey on the occurrence of arthropod-borne pathogens in wild brown hares (Lepus europaeus) from Central Italy

Data about the spreading of arthropod-borne pathogens among hare populations are very scant, so the aim of the present preliminary study was to investigate, through molecular analysis, the occurrence of Anaplasma phagocytophilum, Bartonella sp., Borrelia burgdorferi sensu lato, Coxiella burnetii, Francisella tularensis, Leishmania spp. and piroplasms DNA in blood of 51 wild hares (Lepus europaeus) living in protected areas in Tuscany. All hares resulted negative for A. phagocytophilum, Bartonella sp., B. burgdorferi s.l., C. burnetii and F. tularensis. Five animals (9.8%) were positive for Leishmania and one hare (1.9%) tested positive for piroplasms. Sequencing of this sample showed a piroplasm similar to one Babesia isolate from the same animal species in Turkey. Therefore, to the best of our knowledge, this is the first molecular report of piroplasms occurring in wild hares from Italy, and the second worldwide. The examined hares appeared to be in good health status, corroborating the hypothesis of a chronic carrier state of some vector borne agents for this animal species.

A Molecular Survey of Tick-Borne Pathogens from Ticks Collected in Central Queensland, Australia

Central Queensland (CQ) is a large and isolated, low population density, remote tropical region of Australia with a varied environment. The region has a diverse fauna and several species of ticks that feed upon that fauna. This study examined 518 individual ticks: 177 Rhipicephalus sanguineus (brown dog tick), 123 Haemaphysalis bancrofti (wallaby tick), 102 Rhipicephalus australis (Australian cattle tick), 47 Amblyomma triguttatum (ornate kangaroo tick), 57 Ixodes holocyclus (paralysis tick), 9 Bothriocroton tachyglossi (CQ short-beaked echidna tick), and 3 Ornithodoros capensis (seabird soft tick). Tick midguts were pooled by common host or environment and screened for four genera of tick-borne zoonoses by PCR and sequencing. The study examined a total of 157 midgut pools of which 3 contained DNA of Coxiella burnetii, 13 Rickettsia gravesii, 1 Rickettsia felis, and 4 other Rickettsia spp. No Borrelia spp. or Babesia spp. DNA were recovered.

Molecular detection of tick-borne pathogens in wild red foxes (Vulpes vulpes) from Central Italy

Spleen samples from 153 red foxes, shot during regular hunting season in the province of Pisa (Central Italy), were examined to detect DNA of Anaplasma phagocytophilum, Ehrlichia canis, Coxiella burnetii, Francisella tularensis, Hepatozoon canis and Babesia sp./Theileria sp. DNA of vector-borne pathogens was detected in 120 (78.43%; 95% CI: 71.06-84.66%) foxes. Specifically, 75 (49%; 95% CI: 40.86-57.22%) animals scored PCR-positive per H. canis, 68 (44.44%; 95% CI: 36.42-52.69%) for E. canis, 35 (22.88%; 95% CI: 16.48-30.35%) for piroplasms (Theileria annae), 3 (1.96%; 95% CI: 0.41-5.62%) for C. burnetii and 1 (0.65%; 95% CI: 0.02-3.59%) for A. phagocytophilum. No positive reaction was observed for F. tularensis. Fifty-six animals (36.6%; 95% CI: 28.97-44.76%) were positive for two or three pathogens. Red foxes result to be involved in the cycle of vector-borne pathogens that are associated to disease in dogs and humans.

Canine tick-borne pathogens in Cyprus and a unique canine case of multiple co-infections

Canine tick-borne pathogens such as Ehrlichia canis and Hepatozoon canis are widespread in the Mediterranean basin but have never been reported or investigated in Cyprus. We describe herein the presence of canine tick-borne pathogens in three dogs with clinical signs compatible with vector-borne diseases from Paphos area of Cyprus. Molecular and phylogenetic analysis revealed the presence of E. canis, Anaplasma platys, H. canis, Babesia vogeli and Mycoplasma haemocanis in Cyprus. One dog co-infected with E. canis, H. canis, B. vogeli and M. haemocanis is, to the best of our knowledge, the first report of this multiple co-infection in dogs. The tick-borne pathogens reported in the current study should be considered in the differential diagnoses in dogs exposed to ticks in Cyprus.

Bacterial pathogens and endosymbionts in ticks

Ticks collected from goats in northern Greece were tested for the presence of tick-borne bacteria. Among adult ticks, 37 (57.8%) were Rhipicephalus bursa, 11 (17.2%) Dermacentor marginatus, 10 (15.6%) Ixodes ricinus, 3 (4.7%) Rhipicephalus sanguineus sensu lato and 2 (3.1%) Haemaphysalis parva; one (1.6%) Rhipicephalus spp. tick was nymph. Rickettsia monacensis, Rickettsia massilae, Anaplasma phagocytophilum and Anaplasma platys were detected in I. ricinus and Rh. bursa ticks. A variety of Coxiella-like endosymbionts were detected in all tick genera tested, forming distinct clades from Coxiella burnetii in the phylogenetic tree based on the 16S rRNA gene. An additional endosymbiont, Candidatus Midichloria mitochondrii, was detected in most of the I. ricinus ticks. Surveillance for human pathogens in ticks provides knowledge helpful for the public health, while further studies are needed to determine the role of endosymbionts in tick physiology, vector competence and probably in public health.

Serological survey of Coxiella burnetii at the wildlife-livestock interface in the Eastern Pyrenees, Spain

BACKGROUND

Coxiella burnetii is a zoonotic bacterium that infects a wide range of animal species and causes the disease Q fever. Both wild and domestic ruminants may be relevant in the epidemiology of C. burnetii infection. In order to investigate the significance of the ruminant host community in the alpine and subalpine ecosystems of the Eastern Pyrenees, Northeastern Spain, in the epidemiology of Q fever, a serological survey was performed on samples from 599 wild and 353 sympatric domestic ruminants.

RESULTS

Specific antibodies against C. burnetii were detected with a commercial enzyme-linked immunosorbent assay (ELISA). Domestic sheep showed the highest prevalence (12.7 %, CI 95 % 8.6-16.9), followed by European mouflon (Ovis orientalis musimon) with a 6.8 % prevalence (CI 95 % 1.6-12.1), red deer (Cervus elaphus) with 2.4 % (CI 95 % 0-5.6), and cattle with a prevalence of 1.1 % (CI 95 % 0-3.2). No positive domestic goats, fallow deer (Dama dama), roe deer (Capreolus capreolus) and Southern chamois (Rupicapra pyrenaica) were detected. Sheep flock prevalence was 75 % (nine of the 12 sheep flocks sampled were positive, within-flock prevalence ranging from 11.1 to 25.0 %), whereas cattle herd prevalence was 11.1 % (one out of the nine cattle herds sampled was positive, within-herd prevalence of 10.0 %.

CONCLUSIONS

Both domestic and wild ruminants from the alpine and subalpine ecosystems of the Eastern Pyrenees were exposed to C. burnetii. The higher seroprevalence in sheep and its relative abundance suggest that this species may have a major contribution to the ecology of C. burnetii. Conversely, wild ruminants do not seem to represent a relevant host community for C. burnetii maintenance in the Eastern Pyrenees.

Coxiella burnetii Seroprevalence and Risk Factors in Cattle Farmers and Farm Residents in Three Northeastern Provinces and Inner Mongolia Autonomous Region, China

Little is known about Coxiella burnetii infection among cattle farmers and farm residents in China. Thus, the present study was conducted to detect the seroprevalence of C. burnetii infection and estimate associated risk factors among cattle farmers and farm residents in China. A cross-sectional study was designed, and sera of 362 people living or working on 106 cattle farms were tested for C. burnetii IgG and IgM antibodies by immunofluorescence assay. Overall C. burnetii seroprevalence was 35.6% (129/362, 95% CI: 30.70–40.57), and 112 participants had experienced a past infection and seventeen (4.7%) had experienced a relatively recent infection. In the final combined multilevel model, the following activities were significantly associated with presence of antibodies against C. burnetii: milking cattle, providing general healthcare to cattle, providing birth assistance, contact dead-born animals, urbanization, and presence of mice and/or rats in the stable. Moreover, presence of disinfection equipment was a significant protective factor. This is the first study addressing the seroprevalence and risk factors of C. burnetii infection in cattle farmers and farm residents in three northeastern provinces and Inner Mongolia Autonomous Region, China.