Publications

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experimental transmission of langat (tick-borne encephalitis virus complex) virus by the soft tick ornithodoros sonrai (acari: argasidae).laboratory studies determined that the soft tick ornithodoros sonrai sautet & witkowski is a competent vector of langat (tick-borne encephalitis virus complex) virus. when ticks fed on suckling mice having a mean viremia of 10(7.2) plaque-forming units per ml, 52% (n = 208) became infected, and 84% (n = 87) of the infected ticks transmitted virus by bite when fed individually on suckling mice > or = 27 d after the infectious blood meal. overall, 79 of 184 (43%) of ticks exposed to the original v ...19948158617
association of ticks (acari: ixodoidea) with rodent burrows in northern senegal.four species of ticks were retrieved from burrows of 64 multimammate rats, mastomys erythroleucus (temminck), 55-gerbils, taterillus gracilis (thomas) or t. pygargus (cuvier), 13 nile rats, arvicanthis niloticus (demarest), and five geoffroy's ground squirrels, xerus erythropus (geoffroy) from may 1987 through august 1988 at two study sites in northern senegal. ornithodoros sonrai sautet & witkowski were recovered from 95% (74/78) of burrows near bandia and 6% (4/66) of burrows near yonofere. ei ...19938360905
experimental vector incompetence of a soft tick, ornithodoros sonrai (acari: argasidae), for crimean-congo hemorrhagic fever virus.adults and nymphs of a soft tick, ornithodoros sonrai sautet & witkowski, were allowed to feed on suckling mice that had been experimentally infected with crimean-congo hemorrhagic fever (cchf) virus (ibar 10200 strain). the mean viral titer of mouse blood at the time of tick feeding was 10(3.2) plaque-forming units (pfu) per ml. samples of ticks were assayed on 12 occasions between days 0 and 31 after the viremic blood meal. mean cchf viral titers were 10(2.1) pfu per tick immediately after the ...19938459431
the spread of tick-borne borreliosis in west africa and its relationship to sub-saharan drought.in west africa, tick-borne relapsing fever is due to the spirochete borrelia crocidurae and its geographic distribution is classically limited to the sahel and saharan regions where the vector tick alectorobius sonrai is distributed. we report results of epidemiologic investigations carried out in the sudan savanna of senegal where the existence of the disease was unknown. a two-year prospective investigation of a rural community indicated that 10% of the study population developed an infection ...19968600768
tick-borne borreliosis in west africa: recent epidemiological studies.tick-borne borreliosis in west africa is classically considered a rare disease whose geographic distribution is limited to saharan and sahelian regions. we report results of epidemiological investigations which indicate that tick-borne borreliosis is endemic in all regions of senegal north to the 13 degrees 30'n latitude and is a major cause of morbidity in these areas. our findings indicate a considerable range extension for the vector tick alectorobius sonrai and suggest that the persistence o ...19968673799
short report: lack of virus replication in arthropods after intrathoracic inoculation of ebola reston virus.to evaluate the potential for arthropods to serve as reservoir hosts of ebola virus, three mosquito species, aedes albopictus, aedes taeniorhynchus, and culex pipiens, and a soft tick, ornithodoros sonrai, were inoculated with 1o2.5 plaque-forming units of ebola reston virus. after incubation at 22 degrees c for 11 days, at least six specimens of each species were triturated and examined for evidence of viral replication by enzyme-linked immunosorbent assay and plaque assay. there was no evidenc ...19968702028
tick-borne relapsing fever imported from west africa: diagnosis by quantitative buffy coat analysis and in vitro culture of borrelia crocidurae.west african tick-borne relapsing fever (tbrf) is difficult to diagnose due to the low number of spirochetes in the bloodstream of patients. previously, the causative microorganism, borrelia crocidurae, had never been cultured in vitro. tbrf was rapidly diagnosed for two patients returning from western africa with fever of unknown origin by quantitative buffy coat (qbc) analysis. diagnosis was confirmed by intraperitoneal inoculation of blood specimens from patients into laboratory mice. in vitr ...199910325370
[west african tick-borne relapsing fever].west african tick-borne relapsing fever is an endemic disease due to borrelia crocidurae. the tick alectorobius sonrai is the only known vector of this bacterium. several species of rodents and insectivores may be reservoir for this spirochete. the geographic distribution of borrelia crocidurae is not well known. the zone where the presence of the vector has been recorded is situated in sahelian regions, from mauritania and northern senegal up to chad. in senegal, it has been shown that the pers ...200314671751
experimental transmission of karshi and langat (tick-borne encephalitis virus complex) viruses by ornithodoros ticks (acari: argasidae).selected species of mosquitoes and ornithodoros ticks were evaluated for their potential to transmit karshi and langat (tick-borne encephalitis virus complex) viruses in the laboratory. although there was no evidence of replication of karshi virus in either of the two mosquito species tested [ochlerotatus taeniorhynchus (wiedemann) or culex pipiens (l.)], karshi virus replicated in and was transmitted by all three species of ornithodoros ticks tested (ornithodoros parkeri cooley, ornithodoros so ...200415535630
incidence of tick-borne relapsing fever in west africa: longitudinal study.the ongoing drought in sub-saharan countries has led to the colonisation of west african savanna by ornithodoros sonrai; this tick acts as a vector for borrelia crocidurae, which causes tick-borne relapsing fever (tbrf). our aim was to ascertain the incidence of tbrf in west africa.200616815378
molecular divergences of the ornithodoros sonrai soft tick species, a vector of human relapsing fever in west africa.the soft tick ornithodoros sonrai is recognized as the only vector of borrelia crocidurae causing human relapsing fever in west africa. its determination has been exclusively based on morphological features, geographical distribution and vector competence. some ambiguities persist in its systematics and may cause misunderstanding about west african human relapsing fevers epidemiology. by amplifying and aligning 16s and 18s rdna genes in o. sonrai specimens collected from 14 distinct sites in sen ...200616962358
african swine fever virus dna in soft ticks, senegal.african swine fever is a highly contagious disease of pigs in africa. although its persistence in senegal may be caused by asymptomatic carriers involved in the domestic transmission cycle, we demonstrated that the soft tick ornithodoros sonrai can be naturally infected with the causative agent.200718258050
cell lines from the soft tick ornithodoros moubata.primary cell cultures (n = 16) were initiated from tissues of embryonic and neonatal larval ornithodoros moubata following methods developed for hard ticks. after maintenance for 20-25 months in vitro, cell multiplication commenced in surviving cultures, leading to the establishment of six cell lines designated ome/ctvm21, 22, 24, 25, 26 and 27. all lines are maintained at 28 degrees c, with subculture at 2-8 week intervals. the cultures comprise heterogeneous populations of large cells of 15-10 ...200919252822
new concepts for the old challenge of african relapsing fever borreliosis.relapsing fever, caused by spirochaetes belonging to the genus borrelia, was once the cause of worldwide epidemic disease. this was largely through infection with the louse-borne form of the disease, caused by borrelia recurrentis (louse-borne relapsing fever (lbrf)). during the last century, we have witnessed the demise of this infection, largely owing to improved standards of living and the introduction of the insecticide ddt, resulting in a reduction in the incidence of the body louse, the ve ...200919489922
coxiella burnetii in humans and ticks in rural senegal.q fever is a worldwide zoonotic disease caused by coxiella burnetii. epidemiologically, animals are considered reservoirs and humans incidental hosts.201020386603
phylogenetic analysis of a virulent borrelia species isolated from patients with relapsing fever.multilocus sequence analysis (mlsa) was used to clarify the taxonomic status of a virulent borrelia organism previously isolated from patients with relapsing fever and from ticks in spain that is designated the spanish relapsing fever (srf) borrelia. this species has been used extensively in experimental infection models because of its continued virulence. seven genes were amplified to analyze the phylogenetic relationships among several spanish isolates of srf borrelia and other relapsing fever ...201020463158
bloodmeal size and spirochete acquisition of ornithodoros hermsi (acari: argasidae) during feeding.ornithodoros hermsi wheeler (acari: argasidae) is the vector of borrelia hermsii, the primary cause of tick-borne relapsing fever in north america. this tick is one of the smallest ornithodoros species involved with the biological transmission of spirochetes; yet, the amount of blood ingested while feeding is unknown. therefore, we determined the amount of blood o. hermsi ingested during a bloodmeal to establish its potential for spirochete acquisition while feeding on an infected host. ticks at ...201021175068
seroprevalence of african swine fever in senegal, 2006.in senegal, during 2002-2007, 11 outbreaks of african swine fever (asf) were reported to the world organisation for animal health. despite this, little was known of the epidemiology of asf in the country. to determine the prevalence of asf in senegal in 2006, we tested serum specimens collected from a sample of pigs in the 3 main pig-farming regions for antibodies to asf virus using an elisa. of 747 serum samples examined, 126 were positive for asf, suggesting a prevalence of 16.9%. the estimate ...201121192854
molecular identification of borrelia crocidurae in a patient returning from senegal.borrelia spp. are pathogens responsible for worldwide tickborne relapsing fever (tbrf). in west africa, tbrf is due to a single species, borrelia crocidurae, transmitted by the soft-body tick ornithodoros sonrai. we report a case of b crocidurae infection in a french tourist in senegal, diagnosed by molecular biology using 16s rdna, flab, and the 16s-23s intergenic spacer. we found six imported cases reported in travellers (since 1999). we review here clinical and molecular aspects and pathophys ...200921691399
cotransmission of divergent relapsing fever spirochetes by artificially infected ornithodoros hermsi.the soft tick ornithodoros hermsi, which ranges in specific arboreal zones of western north america, acts as a vector for the relapsing fever spirochete borrelia hermsii. two genomic groups (genomic group i [ggi] and ggii) of b. hermsii are differentiated by multilocus sequence typing yet are codistributed in much of the vector's range. to test whether the tick vector can be infected via immersion, noninfected, colony-derived o. hermsi larvae were exposed to reduced-humidity conditions before im ...201121965393
personal protection against biting insects and ticks.recent events with the first cases of local transmission of chikungunya and dengue fever virus in southern france by aedes albopictus, adding to the nuisance and potential vectors that can be encountered when traveling in tropical or sub-tropical countries, has shown the value of a reflection on the personal protection against vectors (ppav). it is seen during an outbreak of vector-borne disease, or simply because of nuisance arthropods, that our fellow citizens try to protect themselves individ ...201121395212
endemic foci of the tick-borne relapsing fever spirochete borrelia crocidurae in mali, west africa, and the potential for human infection.tick-borne relapsing fever spirochetes are maintained in endemic foci that involve a diversity of small mammals and argasid ticks in the genus ornithodoros. most epidemiological studies of tick-borne relapsing fever in west africa caused by borrelia crocidurae have been conducted in senegal. the risk for humans to acquire relapsing fever in mali is uncertain, as only a few human cases have been identified. given the high incidence of malaria in mali, and the potential to confuse the clinical dia ...201223209863
maldi-tof mass spectrometry detection of pathogens in vectors: the borrelia crocidurae/ornithodoros sonrai paradigm.in africa, relapsing fever borreliae are neglected vector-borne pathogens that cause mild to deadly septicemia and miscarriage. screening vectors for the presence of borreliae currently requires technically demanding, time- and resource-consuming molecular methods. matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (maldi-tof-ms) has recently emerged as a tool for the rapid identification of vectors and the identification of cultured borreliae. we investigated whether m ...201425058611
laboratory diagnosis of tick-borne african relapsing fevers: latest developments.in africa, relapsing fevers caused by ectoparasite-borne borrelia species are transmitted by ticks, with the exception of borrelia recurrentis, which is a louse-borne spirochete. these tropical diseases are responsible for mild to deadly spirochetemia. cultured borrelia crocidurae, borrelia duttonii, and borrelia hispanica circulate alongside at least six species that have not yet been cultured in vectors. direct diagnosis is hindered by the use of non-specific laboratory tools. indeed, microsco ...201526618151
blood-borne candidatus borrelia algerica in a patient with prolonged fever in oran, algeria.to improve the knowledge base of borrelia in north africa, we tested 257 blood samples collected from febrile patients in oran, algeria, between january and december 2012 for borrelia species using flagellin gene polymerase chain reaction sequencing. a sequence indicative of a new borrelia sp. named candidatus borrelia algerica was detected in one blood sample. further multispacer sequence typing indicated this borrelia sp. had 97% similarity with borrelia crocidurae, borrelia duttonii, and borr ...201526416117
tick-borne infections in human and animal population worldwide.the abundance and activity of ectoparasites and its hosts are affected by various abiotic factors, such as climate and other organisms (predators, pathogens and competitors) presenting thus multiples forms of association (obligate to facultative, permanent to intermittent and superficial to subcutaneous) developed during long co-evolving processes. ticks are ectoparasites widespread globally and its eco epidemiology are closely related to the environmental conditions. they are obligatory hematop ...201527047089
monoclonal antibodies for the diagnosis of borrelia crocidurae.relapsing fever borreliae, produced by ectoparasite-borne borrelia species, cause mild to deadly bacteremia and miscarriage. in the perspective of developing inexpensive assays for the rapid detection of relapsing fever borreliae, we produced 12 monoclonal antibodies (mabs) against borrelia crocidurae and characterized the two exhibiting the highest titers. p3a10 mab reacts with the 35.6-kda flagellin b (flab) of b. crocidurae while p6d9 mab recognizes a 35.1-kda variable-like protein (vlp) in b ...201626598566
meningoencephalitis complicating relapsing fever in traveler returning from senegal. 201222469185
the recent evolution of a maternally-inherited endosymbiont of ticks led to the emergence of the q fever pathogen, coxiella burnetii.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 ...201525978383
health effects of drought: a systematic review of the evidence.introduction. climate change projections indicate that droughts will become more intense in the 21 century in some areas of the world. the el niño southern oscillation is associated with drought in some countries, and forecasts can provide advance warning of the increased risk of adverse climate conditions. the most recent available data from emdat estimates that over 50 million people globally were affected by drought in 2011. documentation of the health effects of drought is difficult, given t ...201323787891
identification of bartonellae in the soft tick species ornithodoros sonrai in senegal.ticks, belonging to the soft ticks species ornithodorus sonrai, have been collected from six sites in senegal and were tested for the presence of bartonella spp. initial screening by pcr revealed the presence of these bacteria in ticks from two villages, soulkhou thissé (5/8, 62.5%) and maka gouye (1/24, 4.2%). three bacterial strains were isolated from live ticks, and the genetic characterization of these strains suggests that they belong to two previously unknown species. the pathogenicity of ...201324359424
multiple pathogens including potential new species in tick vectors in côte d'ivoire.our study aimed to assess the presence of different pathogens in ticks collected in two regions in côte d'ivoire.201626771308
the epidemiology and geographic distribution of relapsing fever borreliosis in west and north africa, with a review of the ornithodoros erraticus complex (acari: ixodida).relapsing fever is the most frequent bacterial disease in africa. four main vector / pathogen complexes are classically recognized, with the louse pediculus humanus acting as vector for b. recurrentis and the soft ticks ornithodoros sonrai, o. erraticus and o. moubata acting as vectors for borrelia crocidurae, b. hispanica and b. duttonii, respectively. our aim was to investigate the epidemiology of the disease in west, north and central africa.201324223812
genomic characterization of the genus nairovirus (family bunyaviridae).nairovirus, one of five bunyaviral genera, includes seven species. genomic sequence information is limited for members of the dera ghazi khan, hughes, qalyub, sakhalin, and thiafora nairovirus species. we used next-generation sequencing and historical virus-culture samples to determine 14 complete and nine coding-complete nairoviral genome sequences to further characterize these species. previously unsequenced viruses include abu mina, clo mor, great saltee, hughes, raza, sakhalin, soldado, and ...201627294949
common epidemiology of rickettsia felis infection and malaria, africa.this study aimed to compare the epidemiology of rickettsia felis infection and malaria in france, north africa, and sub-saharan africa and to identify a common vector. blood specimens from 3,122 febrile patients and from 500 nonfebrile persons were analyzed for r. felis and plasmodium spp. we observed a significant linear trend (p<0.0001) of increasing risk for r. felis infection. the risks were lowest in france, tunisia, and algeria (1%), and highest in rural senegal (15%). co-infections with r ...024188709
ubiquitous bacteria borrelia crocidurae in western african ticks ornithodoros sonrai.in west africa, tick-borne relapsing fever is a neglected arthropod-borne infection caused by borrelia crocidurae transmitted by the argasid tick ornithodoros sonrai. from an epidemiological point of view, it is of interest to know whether some genotypes of the vector are specialized in carrying certain genotypes of the pathogen.201526382232
occurrence and genotyping of coxiella burnetii in ixodid ticks in oromia, ethiopia.this study was conducted from september 2011 to march 2014 to address the occurrence and genotypes of coxiella burnetii using molecular methods in ticks collected from domestic animals in ethiopia. ticks were tested for c. burnetii by quantitative real-time polymerase chain reaction (qpcr) targeting two different genes followed by multispacer sequence typing (mst). an overall prevalence of 6.4% (54/842) of c. burnetii was recorded. c. burnetii was detected in 28.6% (14/49) of amblyomma gemma, 25 ...201526392155
faustovirus-like asfarvirus in hematophagous biting midges and their vertebrate hosts.faustovirus, a new asfarviridae-related giant virus, was recently isolated in vermamoeba vermiformis, a protist found in sewage water in various geographical locations and occasionally reported in human eye infection cases. as part of a global metagenomic analysis of viral communities existing in biting midges, we report here for the first time the identification and isolation of a faustovirus-like virus in hematophagous arthropods and its detection in their animal hosts. the dna virome analysis ...201526733117
high quality draft genome sequence and description of occidentia massiliensis gen. nov., sp. nov., a new member of the family rickettsiaceae.the family rickettsiaceae currently includes two genera: orientia that contains one species, orientia tsutsugamushi, and rickettsia that contains 28 species. occidentia massiliensis gen. nov., sp. nov. strain os118(t) is the type strain of o. massiliensis gen. nov., sp. nov., the type species of the new genus occidentia gen. nov. within the family rickettsiaceae. this strain, whose genome is described here, was isolated in france from the soft tick ornithodoros sonrai collected in senegal. o. ma ...201425780502
genome sequence of borrelia crocidurae strain 03-02, a clinical isolate from senegal.the draft genome sequence of borrelia crocidurae strain 03-02, a blood isolate from a febrile senegalese patient, comprises a 920,021-bp linear chromosome (27.7% g+c content), 32 trnas, 818 open reading frames, and one cluster of regularly interspaced short palindromic repeats. its genotype differs from that of the achema reference strain.201425377717
horizontal transfers and gene losses in the phospholipid pathway of bartonella reveal clues about early ecological niches.bartonellae are mammalian pathogens vectored by blood-feeding arthropods. although of increasing medical importance, little is known about their ecological past, and host associations are underexplored. previous studies suggest an influence of horizontal gene transfers in ecological niche colonization by acquisition of host pathogenicity genes. we here expand these analyses to metabolic pathways of 28 bartonella genomes, and experimentally explore the distribution of bartonellae in 21 species of ...201425106622
non-contiguous finished genome sequence and description of bartonella senegalensis sp. nov.bartonella senegalensis sp. nov. strain os02(t) is the type strain of b. senegalensis sp. nov., a new species within the genus bartonella. this strain, whose genome is described here, was isolated in senegal from the soft tick ornithodoros sonrai, the vector of relapsing fever. b. senegalensis is an aerobic, rod-shaped, gram-negative bacterium. here we describe the features of this organism, together with the complete genome sequence and its annotation. the 1,966,996 bp-long genome contains 1,71 ...201323991259
complete genome sequence of borrelia crocidurae.we announce the draft genome sequence of borrelia crocidurae (strain achema). the 1,557,560-bp genome (27% gc content) comprises one 919,477-bp linear chromosome and 638,083-bp plasmids that together carry 1,472 open reading frames, 32 trnas, and three complete rrnas, with almost complete colinearity between b. crocidurae and borrelia duttonii chromosomes.022740657
borrelia infection in small mammals in west africa and its relationship with tick occurrence inside burrows.tick-borne relapsing fever (tbrf) is a zoonotic disease caused by several borrelia species transmitted to humans by ornithodoros tick vectors. in west africa, borrelia crocidurae is a common cause of disease in many rural populations. small mammals act as reservoirs of infection. we report here the results of surveys that investigated the occurrence of b. crocidurae infection in rodents and insectivores from eight countries of west and central africa. animals were identified at the species level ...201526327444
borrelia crocidurae in ornithodoros ticks from northwestern morocco: a range extension in relation to climatic change?tick-borne relapsing fever (tbrf) is caused by borrelia spirochetes transmitted to humans by argasid soft ticks of the genus ornithodoros. we investigated the presence of ornithodoros ticks in rodent burrows in nine sites of the gharb region of northwestern morocco where we recently documented a high incidence of tbrf in humans. we assessed the borrelia infection rate by nested pcr and sequencing. all sites investigated were colonized by ticks of the ornithodoros marocanus complex and a high pro ...201425424260
detection of a novel rickettsia sp. in soft ticks (acari: argasidae) in algeria.argasid ticks are vectors of viral and bacterial agents that can infect humans and animals. in africa, relapsing fever borreliae are neglected arthropod-borne pathogens that cause mild to deadly septicemia and miscarriage. it would be incredibly beneficial to be able to simultaneous detect and identify other pathogens transmitted by argasid ticks. from 2012 to 2014, we conducted field surveys in 4 distinct areas of algeria. we investigated the occurrence of soft ticks in rodent burrows and yello ...201626408401
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