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Olivier Duron - One of the best experts on this subject based on the ideXlab platform.
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microbial community structure reveals instability of nutritional symbiosis during the evolutionary radiation of amblyomma ticks
Molecular Ecology, 2020Co-Authors: Florian Binetruy, Marie Buysse, Quentin Lejarre, Roxanne Barosi, Manon Villa, Nil Rahola, Christophe Paupy, Diego Ayala, Olivier DuronAbstract:Mutualistic interactions with microbes have facilitated the adaptation of major eukaryotic lineages to restricted diet niches. Hence, ticks with their strictly blood-feeding lifestyle are associated with intracellular bacterial symbionts through an essential B vitamin supplementation. In this study, examination of bacterial diversity in 25 tick species of the genus Amblyomma showed that three intracellular bacteria, Coxiella-like endosymbionts (LE), Francisella-LE and Rickettsia, are remarkably common. No other bacterium is as uniformly present in Amblyomma ticks. Almost all Amblyomma species were found to harbour a nutritive obligate symbiont, Coxiella-LE or Francisella-LE, that is able to synthesize B vitamins. However, despite the co-evolved and obligate nature of these mutualistic interactions, the structure of microbiomes does not mirror the Amblyomma phylogeny, with a clear exclusion pattern between Coxiella-LE and Francisella-LE across tick species. Coxiella-LE, but not Francisella-LE, form evolutionarily stable associations with ticks, commonly leading to co-cladogenesis. We further found evidence for symbiont replacements during the radiation of Amblyomma, with recent, and probably ongoing, invasions by Francisella-LE and subsequent replacements of ancestral Coxiella-LE through transient co-infections. Nutritional symbiosis in Amblyomma ticks is thus not a stable evolutionary state, but instead arises from conflicting origins between unrelated but competing symbionts with similar metabolic capabilities.
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Evolutionary changes in symbiont community structure in ticks.
Molecular Ecology, 2017Co-Authors: Olivier Duron, Julie Cremaschi, Céline Arnathau, John A. Goolsby, Olivier Plantard, Valerie Noel, Florian Binetruy, Adalberto A. Pérez De León, Karen D Mccoy, Dieter HeylenAbstract:Ecological specialization to restricted diet niches is driven by obligate, and often maternally inherited, symbionts in many arthropod lineages. These heritable symbionts typically form evolutionarily stable associations with arthropods that can last for millions of years. Ticks were recently found to harbour such an obligate symbiont, Coxiella-LE, that synthesizes B vitamins and cofactors not obtained in sufficient quantities from blood diet. In this study, the examination of 81 tick species shows that some Coxiella-LE symbioses are evolutionarily stable with an ancient acquisition followed by codiversification as observed in ticks belonging to the Rhipicephalus genus. However, many other Coxiella-LE symbioses are characterized by low evolutionary stability with frequent host shifts and extinction events. Further examination revealed the presence of nine other genera of maternally inherited bacteria in ticks. Although these nine symbionts were primarily thought to be facultative, their distribution among tick species rather suggests that at least four may have independently replaced Coxiella-LE and likely represent alternative obligate symbionts. Phylogenetic evidence otherwise indicates that cocladogenesis is globally rare in these symbioses as most originate via horizontal transfer of an existing symbiont between unrelated tick species. As a result, the structure of these symbiont communities is not fixed and stable across the tick phylogeny. Most importantly, the symbiont communities commonly reach high levels of diversity with up to six unrelated maternally inherited bacteria coexisting within host species. We further conjecture that interactions among coexisting symbionts are pivotal drivers of community structure both among and within tick species.
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the is1111 insertion sequence used for detection of Coxiella burnetii is widespread in Coxiella like endosymbionts of ticks
Fems Microbiology Letters, 2015Co-Authors: Olivier DuronAbstract:Coxiella is a genus of obligate intracellular bacteria engaged in a variety of interactions with eukaryotes. The type species, Coxiella burnetii , infects several vertebrate species, including humans, and is the causative agent of Q fever. Multiple copies of a specific transposable element, the insertion sequence IS1111, are present in the genome of C. burnetii and are routinely used for confirmation of Q fever cases. Recently, many Coxiella -like bacteria that are closely related but genetically distinct to C. burnetii have been found in ticks. These Coxiella -like bacteria are maternally inherited endosymbionts, present at high prevalence in tick populations and engaged in mutualistic interactions with their arthropod hosts. In this study, the presence of IS1111 was examined in the Coxiella -like endosymbionts and in bacteria of the Coxiella sister-genus, Rickettsiella . This screening reveals that a wide range of IS1111 copies were present in the Coxiella -like endosymbionts of ticks. DNA sequencing further identified genetically divergent IS1111 copies, including degraded copies that constitute an important genomic fossil record of past IS1111 expansions. These results show that IS1111 is not specific to C. burnetii , suggesting that Q fever detection assays based only on this element may lead to misidentification with Coxiella -like endosymbionts.
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The Recent Evolution of a Maternally-Inherited Endosymbiont of Ticks Led to the Emergence of the Q Fever Pathogen, Coxiella burnetii
PLoS Pathogens, 2015Co-Authors: Olivier Duron, Matteo Bonazzi, Karim Sidi-boumedine, Valerie Noel, Fabrice Vavre, Karen D Mccoy, Elsa Jourdain, Olivier Morel, Lionel Zenner, Patrick DurandAbstract:Q fever is a highly infectious disease with a worldwide distribution. Its causative agent, the intracellular bacterium Coxiella burnetii, infects a variety of vertebrate species, including humans. Its evolutionary origin remains almost entirely unknown and uncertainty persists regarding the identity and lifestyle of its ancestors. A few tick species were recently found to harbor maternally-inherited Coxiella-like organisms engaged in symbiotic interactions, but their relationships to the Q fever pathogen remain unclear. Here, we extensively sampled ticks, identifying new and atypical Coxiella strains from 40 of 58 examined species, and used this data to infer the evolutionary processes leading to the emergence of C. burnetii. Phylogenetic analyses of multi-locus typing and whole-genome sequencing data revealed that Coxiella-like organisms represent an ancient and monophyletic group allied to ticks. Remarkably, all known C. burnetii strains originate within this group and are the descendants of a Coxiella-like progenitor hosted by ticks. Using both colony-reared and field-collected gravid females, we further establish the presence of highly efficient maternal transmission of these Coxiella-like organisms in four examined tick species, a pattern coherent with an endosymbiotic lifestyle. Our laboratory culture assays also showed that these Coxiella-like organisms were not amenable to culture in the vertebrate cell environment, suggesting different metabolic requirements compared to C. burnetii. Altogether, this corpus of data demonstrates that C. burnetii recently evolved from an inherited symbiont of ticks which succeeded in infecting vertebrate cells, likely by the acquisition of novel virulence factors.
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Phylogenetic network with concatenated 16S rRNA, 23S rRNA, GroEL, rpoB and dnaK sequences (3009 unambiguously aligned bp), including 71 Coxiella-like strains of ticks, 15 C. burnetii reference strains, and bacterial outgroups.
2015Co-Authors: Olivier Duron, Matteo Bonazzi, Karim Sidi-boumedine, Valerie Noel, Fabrice Vavre, Karen D Mccoy, Elsa Jourdain, Olivier Morel, Lionel Zenner, Patrick DurandAbstract:The four Coxiella clades are labeled A to D. A zoom on the A clade which contains C. burnetii isolates is shown in Supplementary Fig C in S1 Text. Each number corresponds to one tick species as detailed in Table 1. Blue—Coxiella-like organisms; red—C. burnetii; green—Rickettsiella; black- other bacteria. All multi-locus typing of Coxiella and Rickettsiella of ticks are new sequences from this study. The scale bar is in units of substitution/site.
Karen D Mccoy - One of the best experts on this subject based on the ideXlab platform.
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Evolutionary changes in symbiont community structure in ticks.
Molecular Ecology, 2017Co-Authors: Olivier Duron, Julie Cremaschi, Céline Arnathau, John A. Goolsby, Olivier Plantard, Valerie Noel, Florian Binetruy, Adalberto A. Pérez De León, Karen D Mccoy, Dieter HeylenAbstract:Ecological specialization to restricted diet niches is driven by obligate, and often maternally inherited, symbionts in many arthropod lineages. These heritable symbionts typically form evolutionarily stable associations with arthropods that can last for millions of years. Ticks were recently found to harbour such an obligate symbiont, Coxiella-LE, that synthesizes B vitamins and cofactors not obtained in sufficient quantities from blood diet. In this study, the examination of 81 tick species shows that some Coxiella-LE symbioses are evolutionarily stable with an ancient acquisition followed by codiversification as observed in ticks belonging to the Rhipicephalus genus. However, many other Coxiella-LE symbioses are characterized by low evolutionary stability with frequent host shifts and extinction events. Further examination revealed the presence of nine other genera of maternally inherited bacteria in ticks. Although these nine symbionts were primarily thought to be facultative, their distribution among tick species rather suggests that at least four may have independently replaced Coxiella-LE and likely represent alternative obligate symbionts. Phylogenetic evidence otherwise indicates that cocladogenesis is globally rare in these symbioses as most originate via horizontal transfer of an existing symbiont between unrelated tick species. As a result, the structure of these symbiont communities is not fixed and stable across the tick phylogeny. Most importantly, the symbiont communities commonly reach high levels of diversity with up to six unrelated maternally inherited bacteria coexisting within host species. We further conjecture that interactions among coexisting symbionts are pivotal drivers of community structure both among and within tick species.
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The Recent Evolution of a Maternally-Inherited Endosymbiont of Ticks Led to the Emergence of the Q Fever Pathogen, Coxiella burnetii
PLoS Pathogens, 2015Co-Authors: Olivier Duron, Matteo Bonazzi, Karim Sidi-boumedine, Valerie Noel, Fabrice Vavre, Karen D Mccoy, Elsa Jourdain, Olivier Morel, Lionel Zenner, Patrick DurandAbstract:Q fever is a highly infectious disease with a worldwide distribution. Its causative agent, the intracellular bacterium Coxiella burnetii, infects a variety of vertebrate species, including humans. Its evolutionary origin remains almost entirely unknown and uncertainty persists regarding the identity and lifestyle of its ancestors. A few tick species were recently found to harbor maternally-inherited Coxiella-like organisms engaged in symbiotic interactions, but their relationships to the Q fever pathogen remain unclear. Here, we extensively sampled ticks, identifying new and atypical Coxiella strains from 40 of 58 examined species, and used this data to infer the evolutionary processes leading to the emergence of C. burnetii. Phylogenetic analyses of multi-locus typing and whole-genome sequencing data revealed that Coxiella-like organisms represent an ancient and monophyletic group allied to ticks. Remarkably, all known C. burnetii strains originate within this group and are the descendants of a Coxiella-like progenitor hosted by ticks. Using both colony-reared and field-collected gravid females, we further establish the presence of highly efficient maternal transmission of these Coxiella-like organisms in four examined tick species, a pattern coherent with an endosymbiotic lifestyle. Our laboratory culture assays also showed that these Coxiella-like organisms were not amenable to culture in the vertebrate cell environment, suggesting different metabolic requirements compared to C. burnetii. Altogether, this corpus of data demonstrates that C. burnetii recently evolved from an inherited symbiont of ticks which succeeded in infecting vertebrate cells, likely by the acquisition of novel virulence factors.
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Phylogenetic network with concatenated 16S rRNA, 23S rRNA, GroEL, rpoB and dnaK sequences (3009 unambiguously aligned bp), including 71 Coxiella-like strains of ticks, 15 C. burnetii reference strains, and bacterial outgroups.
2015Co-Authors: Olivier Duron, Matteo Bonazzi, Karim Sidi-boumedine, Valerie Noel, Fabrice Vavre, Karen D Mccoy, Elsa Jourdain, Olivier Morel, Lionel Zenner, Patrick DurandAbstract:The four Coxiella clades are labeled A to D. A zoom on the A clade which contains C. burnetii isolates is shown in Supplementary Fig C in S1 Text. Each number corresponds to one tick species as detailed in Table 1. Blue—Coxiella-like organisms; red—C. burnetii; green—Rickettsiella; black- other bacteria. All multi-locus typing of Coxiella and Rickettsiella of ticks are new sequences from this study. The scale bar is in units of substitution/site.
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List of tick species and populations included in the analysis, with details on their origin, the population sample size, and the prevalence of Coxiella spp. and Rickettsiella spp.
2015Co-Authors: Olivier Duron, Matteo Bonazzi, Karim Sidi-boumedine, Valerie Noel, Fabrice Vavre, Karen D Mccoy, Elsa Jourdain, Olivier Morel, Lionel Zenner, Patrick DurandAbstract:List of tick species and populations included in the analysis, with details on their origin, the population sample size, and the prevalence of Coxiella spp. and Rickettsiella spp.
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Diversity and global distribution of the Coxiella intracellular bacterium in seabird ticks.
Ticks and tick-borne diseases, 2014Co-Authors: Elsa Jourdain, Karen D MccoyAbstract:The obligate intracellular bacterium Coxiella burnetii is the etiological agent of Q fever, a widespread zoonotic disease whose most common animal reservoirs are domestic ruminants. Recently, a variety of Coxiella-like organisms have also been reported from non-mammalian hosts, including pathogenic forms in birds and forms without known effects in ticks, raising questions about the potential importance of non-mammalian hosts as reservoirs of Coxiella in the wild. In the present study, we examined the potential role of globally-distributed seabird ticks as reservoirs of these bacteria. To this aim, we tested for Coxiella infection 11 geographically distinct populations of two tick species frequently found in seabird breeding colonies, the hard tick Ixodes uriae (Ixodidae) and soft ticks of the Ornithodoros (Carios) capensis group (Argasidae). We found Coxiella-like organisms in all O. capensis sensu lato specimens, but only in a few I. uriae specimens of one population. The sequencing of 16S rDNA and GroEL gene sequences further revealed an unexpected Coxiella diversity, with seven genetically distinct Coxiella-like organisms present in seabird tick populations. Phylogenetic analyses show that these Coxiella-like organisms originate from three divergent subclades within the Coxiella genus and that none of the Coxiella strains found in seabird ticks are genetically identical to the forms known to be associated with pathogenicity in vertebrates, including C. burnetii. Using this data set, we discuss the potential epidemiological significance of the presence of Coxiella in seabird ticks. Notably, we suggest that these organisms may not be pathogenic forms, but rather behave as endosymbionts engaged in intricate interactions with their tick hosts.
Elsa Jourdain - One of the best experts on this subject based on the ideXlab platform.
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The Recent Evolution of a Maternally-Inherited Endosymbiont of Ticks Led to the Emergence of the Q Fever Pathogen, Coxiella burnetii
PLoS Pathogens, 2015Co-Authors: Olivier Duron, Matteo Bonazzi, Karim Sidi-boumedine, Valerie Noel, Fabrice Vavre, Karen D Mccoy, Elsa Jourdain, Olivier Morel, Lionel Zenner, Patrick DurandAbstract:Q fever is a highly infectious disease with a worldwide distribution. Its causative agent, the intracellular bacterium Coxiella burnetii, infects a variety of vertebrate species, including humans. Its evolutionary origin remains almost entirely unknown and uncertainty persists regarding the identity and lifestyle of its ancestors. A few tick species were recently found to harbor maternally-inherited Coxiella-like organisms engaged in symbiotic interactions, but their relationships to the Q fever pathogen remain unclear. Here, we extensively sampled ticks, identifying new and atypical Coxiella strains from 40 of 58 examined species, and used this data to infer the evolutionary processes leading to the emergence of C. burnetii. Phylogenetic analyses of multi-locus typing and whole-genome sequencing data revealed that Coxiella-like organisms represent an ancient and monophyletic group allied to ticks. Remarkably, all known C. burnetii strains originate within this group and are the descendants of a Coxiella-like progenitor hosted by ticks. Using both colony-reared and field-collected gravid females, we further establish the presence of highly efficient maternal transmission of these Coxiella-like organisms in four examined tick species, a pattern coherent with an endosymbiotic lifestyle. Our laboratory culture assays also showed that these Coxiella-like organisms were not amenable to culture in the vertebrate cell environment, suggesting different metabolic requirements compared to C. burnetii. Altogether, this corpus of data demonstrates that C. burnetii recently evolved from an inherited symbiont of ticks which succeeded in infecting vertebrate cells, likely by the acquisition of novel virulence factors.
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Phylogenetic network with concatenated 16S rRNA, 23S rRNA, GroEL, rpoB and dnaK sequences (3009 unambiguously aligned bp), including 71 Coxiella-like strains of ticks, 15 C. burnetii reference strains, and bacterial outgroups.
2015Co-Authors: Olivier Duron, Matteo Bonazzi, Karim Sidi-boumedine, Valerie Noel, Fabrice Vavre, Karen D Mccoy, Elsa Jourdain, Olivier Morel, Lionel Zenner, Patrick DurandAbstract:The four Coxiella clades are labeled A to D. A zoom on the A clade which contains C. burnetii isolates is shown in Supplementary Fig C in S1 Text. Each number corresponds to one tick species as detailed in Table 1. Blue—Coxiella-like organisms; red—C. burnetii; green—Rickettsiella; black- other bacteria. All multi-locus typing of Coxiella and Rickettsiella of ticks are new sequences from this study. The scale bar is in units of substitution/site.
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List of tick species and populations included in the analysis, with details on their origin, the population sample size, and the prevalence of Coxiella spp. and Rickettsiella spp.
2015Co-Authors: Olivier Duron, Matteo Bonazzi, Karim Sidi-boumedine, Valerie Noel, Fabrice Vavre, Karen D Mccoy, Elsa Jourdain, Olivier Morel, Lionel Zenner, Patrick DurandAbstract:List of tick species and populations included in the analysis, with details on their origin, the population sample size, and the prevalence of Coxiella spp. and Rickettsiella spp.
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The importance of ticks in Q fever transmission: what has (and has not) been demonstrated?
Trends in Parasitology, 2015Co-Authors: Olivier Duron, Karim Sidi-boumedine, Elodie Rousset, Sara Moutailler, Elsa JourdainAbstract:Q fever is a widespread zoonotic disease caused by Coxiella burnetii, a ubiqui- tous intracellular bacterium infecting humans and a variety of animals. Transmission is primarily but not exclusively airborne, and ticks are usually thought to act as vectors. We argue that, although ticks may readily transmit C. burnetii in experimental systems, they only occasionally transmit the pathogen in the field. Furthermore, we underscore that many Coxiella-like bacteria are widespread in ticks and may have been misidentified as C. burnetii. Our recommendation is to improve the methods currently used to detect and characterize C. burnetii, and we propose that further knowledge of Coxiella-like bacteria will yield new insights into Q fever evolutionary ecology and C. burnetii virulence factors
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Diversity and global distribution of the Coxiella intracellular bacterium in seabird ticks.
Ticks and tick-borne diseases, 2014Co-Authors: Elsa Jourdain, Karen D MccoyAbstract:The obligate intracellular bacterium Coxiella burnetii is the etiological agent of Q fever, a widespread zoonotic disease whose most common animal reservoirs are domestic ruminants. Recently, a variety of Coxiella-like organisms have also been reported from non-mammalian hosts, including pathogenic forms in birds and forms without known effects in ticks, raising questions about the potential importance of non-mammalian hosts as reservoirs of Coxiella in the wild. In the present study, we examined the potential role of globally-distributed seabird ticks as reservoirs of these bacteria. To this aim, we tested for Coxiella infection 11 geographically distinct populations of two tick species frequently found in seabird breeding colonies, the hard tick Ixodes uriae (Ixodidae) and soft ticks of the Ornithodoros (Carios) capensis group (Argasidae). We found Coxiella-like organisms in all O. capensis sensu lato specimens, but only in a few I. uriae specimens of one population. The sequencing of 16S rDNA and GroEL gene sequences further revealed an unexpected Coxiella diversity, with seven genetically distinct Coxiella-like organisms present in seabird tick populations. Phylogenetic analyses show that these Coxiella-like organisms originate from three divergent subclades within the Coxiella genus and that none of the Coxiella strains found in seabird ticks are genetically identical to the forms known to be associated with pathogenicity in vertebrates, including C. burnetii. Using this data set, we discuss the potential epidemiological significance of the presence of Coxiella in seabird ticks. Notably, we suggest that these organisms may not be pathogenic forms, but rather behave as endosymbionts engaged in intricate interactions with their tick hosts.
Yuval Gottlieb - One of the best experts on this subject based on the ideXlab platform.
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Tissue tropism and vertical transmission of Coxiella in Rhipicephalus sanguineus and Rhipicephalus turanicus ticks.
Environmental microbiology, 2014Co-Authors: Itai Lalzar, Yael Friedmann, Yuval GottliebAbstract:Arthropod symbionts present tissue tropism that corresponds to the nature of the association and the mode of transmission between host generations. In ticks, however, our knowledge of symbiont tissue tropism and function is limited. Here, we quantified and localized previously described Coxiella-like symbionts in several organs of the tick Rhipicephalus turanicus. Quantitative polymerase chain reaction revealed high densities of Coxiella in the female gonads, and both male and female Malpighian tubules. Using fluorescence in situ hybridization and transmission electron microscopy, we further showed that in the gonads of both Rh. turanicus and Rh. sanguineus, Coxiella does not colonize the primary oocytes but is found later in young and mature oocytes in a specific distribution, suggesting controlled vertical transmission. This method revealed the presence Coxiella in the distal part of the Malpighian tubules, suggesting a possible role in nitrogen metabolism. While testing Rickettsia symbionts, no specific tissue tropism was found, but a slightly higher densities in the tick gut. The low density of Rickettsia in the female ovaries suggests competition between Rickettsia and Coxiella for vertical transmission. The described tissue distribution supports an obligatory role for Coxiella in ticks.
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composition and seasonal variation of rhipicephalus turanicus and rhipicephalus sanguineus bacterial communities
Applied and Environmental Microbiology, 2012Co-Authors: Itai Lalzar, Shimon Harrus, Kosta Y Mumcuoglu, Yuval GottliebAbstract:A 16S rRNA gene approach, including 454 pyrosequencing and quantitative PCR (qPCR), was used to describe the bacterial community in Rhipicephalus turanicus and to evaluate the dynamics of key bacterial tenants of adult ticks during the active questing season. The bacterial community structure of Rh. turanicus was characterized by high dominance of Coxiella and Rickettsia and extremely low taxonomic diversity. Parallel diagnostic PCR further revealed a novel Coxiella species which was present and numerically dominant in all individual ticks tested (n = 187). Coxiella sp. densities were significantly higher in female versus male ticks and were overall stable throughout the questing season. In addition, we revealed the presence of the novel Coxiella sp. in Rh. sanguineus adult ticks, eggs, and hatched larvae, indicating its vertical transmission. The presence of both spotted fever group Rickettsia spp. (SFGR) and non-SFGR was verified in the various individual ticks. The prevalence and density of Rickettsia spp. were very low compared to those of Coxiella sp. Furthermore, Rickettsia sp. densities were similar in males and females and significantly declined toward the end of the questing season. No correlation was found between Coxiella sp. and Rickettsia sp. densities. These results suggest different control mechanisms in the tick over its different bacterial populations and point to an obligatory and facultative association between the two tick species and Coxiella sp. and Rickettsia spp., respectively.
Annie Rodolakis - One of the best experts on this subject based on the ideXlab platform.
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Q Fever in Dairy Animals
Annals of the New York Academy of Sciences, 2009Co-Authors: Annie RodolakisAbstract:This review evaluates the threat to human health--with the shedding of C. burnetii in dairy animals with reproductive disorders or those without clinical signs. The review also discusses the diagnosis of Q fever in livestock and the possibility of Coxiella-free herds, and it reports the available methods for controlling Q fever. C. burnetii shedding seems to occur frequently in milk taken from asymptomatic dairy cows. The number of Coxiella shed in milk is generally low. The phase I vaccine prevented abortion and greatly decreased the shedding of C. burnetii in milk.
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Shedding routes of Coxiella burnetii in dairy cows : implications for detection and control
Veterinary research, 2006Co-Authors: Raphaël Guatteo, François Beaudeau, A. Joly, Mustapha Berri, Annie Rodolakis, Henri SeegersAbstract:Reliable detection of Coxiella burnetii shedders is a critical point for the control of the spread of this bacterium among animals and from animals to humans. Coxiella burnetii is shed by ruminants mainly by birth products (placenta, birth fluids), but may also be shed by vaginal mucus, milk, and faeces, urine and semen. However, the informative value of these types of samples to identify shedders under field conditions is unknown. Our aim was then to describe the responses obtained using a real-time PCR technique applied to milk, vaginal mucus and faeces samples taken from 242 dairy cows in commercial dairy herds known to be naturally infected with Coxiella burnetii, and to assess their putative associations. Positive results were found in all types of tested samples even in faeces. No predominant shedding route was identified. Among the shedder cows, 65.4% were detected as shedders by only one route. By contrast, cows with positive results for all three samples were scarce (less than 7%). Testing a cow based on only one type of biological sample may lead to misclassify it with regards to its shedding of Coxiella burnetii and thereby underestimate the risk of bacterial spread within a herd.
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effect of vaccination with phase i and phase ii Coxiella burnetii vaccines in pregnant goats
Vaccine, 2005Co-Authors: Nathalie Arricaubouvery, C Bodier, Armel Souriau, Elodie Rousset, Philippe Dufour, Annie RodolakisAbstract:Livestock is considered to be the major “source” of human Q fever. The efficacy of two currently available vaccines (Coxevac, phase I, CEVA Sante Animale and Chlamyvax FQ, phase II, MERIAL) against Coxiella excretion was investigated in terms of risks to human health. Two months before mating, 17 goats were vaccinated subcutaneously against Coxiella burnetii with an inactivated phase I vaccine and 16 goats were vaccinated with an inactivated phase II Coxiella mixed with Chlamydophila abortus vaccine. Fourteen goats were left unvaccinated. At 84 days of gestation, the goats were subcutaneously challenged with 104 bacteria of C. burnetii strain CbC1. Phase I vaccine was effective and dramatically reduced both abortion and excretion of bacteria in the milk, vaginal mucus and feces. In contrast, the phase II vaccine did not affect the course of the disease or excretion.
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experimental Coxiella burnetii infection in pregnant goats excretion routes
Veterinary Research, 2003Co-Authors: Nathalie Arricau Bouvery, Armel Souriau, Patrick Lechopier, Annie RodolakisAbstract:Q fever is a widespread zoonosis caused by Coxiella burnetii. Infected animals, shedding bacteria by different routes, constitute contamination sources for humans and the environment. To study Coxiella excretion, pregnant goats were inoculated by the subcutaneous route in a site localized just in front of the shoulder at 90 days of gestation with 3 doses of bacteria (10 8 , 10 6 or 10 4 I.D.). All the goats aborted whatever the dose used. Coxiella were found by PCR and immunofluorescence tests in all placentas and in several organs of at least one fetus per goat. At abortion, all the goats excreted bacteria in vaginal discharges up to 14 days and in milk samples up to 52 days. A few goats excreted Coxiella in their feces before abortion, and all goats, excreted bacteria in their feces after abortion. Antibody titers against Coxiella increased from 21 days post inoculation to the end of the experiment. For a Q fever diagnostic, detection by PCR and immunofluorescence tests of Coxiella in parturition products and vaginal secretions at abortion should be preferred to serological tests. Coxiella burnetii / goat / experimental infection / abortion / shedding
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shedding of Coxiella burnetii in ewes in two pregnancies following an episode of Coxiella abortion in a sheep flock
Veterinary Microbiology, 2002Co-Authors: Mustapha Berri, Armel Souriau, Milton Crosby, Annie RodolakisAbstract:Coxiella burnetii infection in pregnant sheep typically causes abortion or the birth of weak lambs. Two C. burnetii-related abortions in a group of 34 pregnant ewes were reported at their first lambing in our research institute. The seroprevalence of C. burnetii infection and bacteria shedding were investigated using an ELISA and PCR, respectively, during the course of two subsequent pregnancies. None of the ewes examined seroconverted from negative to positive at the time of the second and the third parturition and most of the ewes that were seropositive at the abortion episode remained positive throughout the investigation. The two successive pregnancies resulted in the birth of healthy lambs without PCR evidence of Coxiella infection from placenta and vaginal swabs taken postpartum. PCR assay performed on vaginal swabs taken from all animals 1, 5 or 12 days after the second lambing were also negative for Coxiella. However, one ewe that had previously experienced C. burnetii shedding at the first lambing excreted the bacteria in the genital tract after the third parturition. The bacteria could not be detected by PCR in milk and faecal samples taken up to 12 days after both parturitions.
