Rickettsia Massiliae Research Articles

Spotted fever group rickettsiae in Dermacentor reticulatus and Haemaphysalis punctata ticks in the UK

BackgroundSpotted fever group (SFG) rickettsiae have recently been identified for the first time in UK ticks. This included the findings of Rickettsia helvetica in Ixodes ricinus and Rickettsia raoultii in Dermacentor reticulatus. This paper further investigates the occurrence of SFG rickettsiae in additional geographically distinct populations of D. reticulatus, and for the first time, investigates the occurrence of SFG rickettsiae in UK populations of Haemaphysalis punctata ticks.MethodsQuesting D. reticulatus and H. punctata were collected at a number of sites in England and Wales. DNA from questing ticks was extracted by alkaline lysis and detection of rickettsiae DNA was performed, in addition to detection of A. phagocytophilum, N. mikurensis, C. burnetii and B. burgdorferi sensu lato.ResultsThis paper builds on previous findings to include the detection of spotted fever Rickettsia which showed the highest homology to Rickettsia massiliae in Haemaphysalis punctata, as well as R. helvetica in D. reticulatus. The occurrence of SFG rickettsiae in D. reticulatus in the UK appears to be confined only to Welsh and Essex populations, with no evidence so far from Devon. Similarly, the occurrence of SFG rickettsiae in H. punctata appears confined to one of two farms known to be infested with this tick in North Kent, with no evidence so far from the Sussex populations. Anaplasma phagocytophilum, Neoehrlichia mikurensis, Coxiella burnetii and Borrelia burgdorferi sensu lato DNA was not detected in any of the ticks.ConclusionThese two tick species are highly restricted in their distribution in England and Wales, but where they do occur they can be abundant. Following detection of these SFG rickettsiae in additional UK tick species, as well as I. ricinus, research should now be directed towards clarifying firstly the geographic distribution of SFG rickettsiae in UK ticks, and secondly to assess the prevalence rates in ticks, wild and domesticated animals and humans to identify the drivers for disease transmission and their public health significance.

Scalp Eschar and Neck Lymphadenopathy Caused byRickettsia massiliae

Scalp Eschar and Neck Lymphadenopathy Caused by<i>Rickettsia massiliae</i>

Molecular evidence of Ehrlichia canis and Rickettsia massiliae in ixodid ticks of carnivores from South Hungary

To monitor the emergence of thermophilic, Mediterranean ixodid tick species and tick-borne pathogens in southern Hungary, 348 ticks were collected from shepherd dogs, red foxes and golden jackals during the summer of 2011. Golden jackals shared tick species with both the dog and the red fox in the region. Dermacentor nymphs were collected exclusively from dogs, and the sequence identification of these ticks indicated that dogs are preferred hosts of both D. reticulatus and D. marginatus nymphs, unlike previously reported. Subadults of three ixodid species were selected for reverse line blot hybridisation (RLB) analysis to screen their vector potential for 40 pathogens/groups. Results were negative for Anaplasma, Babesia and Theileria spp. Investigation of D. marginatus nymphs revealed the presence of Ehrlichia canis, Rickettsia massiliae and Borrelia afzelii for the first time in this tick species. These findings broaden the range of those tick-borne agents, which are typically transmitted by Rhipicephalus sanguineus, but may also have Dermacentor spp. as potential or alternative vectors. Ehrlichiacanis was also newly detected in Ixodes canisuga larvae from red foxes. In absence of transovarial transmission in ticks this implies that Eurasian red foxes may play a reservoir role in the epidemiology of canine ehrlichiosis.

Detection ofRickettsia massiliaeinRhipicephalus sanguineusfrom the Eastern United States

We report the first evidence of Rickettsia massiliae in the brown dog tick, Rhipicephalus sanguineus, from the East Coast of the United States. As part of routine pathogen surveillance, DNA samples from ixodid ticks were tested for spotted fever group rickettsiae by nested PCR. A R. massiliae-positive tick was collected off a beagle mix recently rescued from North Carolina. Infection was confirmed by partial sequence analysis of the htrA, gltA, ompB, ompA, and sca4 genes, which had 100% identity to a R. massiliae isolate from Arizona.

Tick-borne rickettsioses in Europe

Rickettsioses are caused by obligate intracellular bacteria within the genus Rickettsia, mainly transmitted by arthropods. Until recently, Mediterranean spotted fever (MSF) caused by Rickettsia conorii was considered the only tick-borne rickettsiosis in Europe. However, ‘new’ TBR have been described in Europe during last years. For instance, other subspecies such as R. conorii caspia and R. conorii israelensis have been involved in MSF. Dermacentor-borne necrosis erythema and lymphadenopathy/tick-borne lymphadenopathy (DEBONEL/TIBOLA) cases caused by Rickettsia slovaca, Rickettsia raoultii, and Rickettsia rioja been described in several countries where Dermacentor marginatus ticks (the mainly implicated vector) are present. Rickettsia helvetica has also been involved as a human pathogen in cases of fever with and without rash and in patients with meningitis and carditis. Other TBR such as lymphangitis-associated rickettsioses (LAR), caused by Rickettsia sibirica mongolitimonae, have been diagnosed in different European countries (France, Spain, Portugal and Greece). Rickettsia massiliae is considered an etiological agent of MSF-like illness in the Mediterranean basin. Furthermore, Rickettsia monacensis that is distributed all along Europe has been isolated from patients with MSF-like illness in Spain. Although Rickettsia aeschlimannii has been associated with MSF-like in Africa and is distributed in the Mediterranean area, no autochthonous human cases have been reported for Europe. Other Rickettsia species detected in ticks and unrelated to human disease (Candidatus Rickettsia kotlanii, Candidatus Rickettsia barbariae, Candidatus Rickettsia vini) could be potentially involved in the next years. Climate changes, among other factors, may contribute to the emergence of other rickettsioses or change their distribution. Lastly, African tick-bite fever (ATBF), caused by Rickettsia africae, is frequently diagnosed in Europe in patients returning from endemic areas.

Rickettsiae of spotted fever group, Borrelia valaisiana, and Coxiella burnetii in ticks on passerine birds and mammals from the Camargue in the south of France

Ticks are obligate hematophagous arthropods that have a limited mobility, but can be transported over large geographical distances by wild and domestic mammals and birds. In this study, we analyze the presence of emerging zoonotic bacteria in ticks collected from passerine birds and mammals present in the Camargue, in the south of France, which is a major rallying point for birds migrating from Eurasia and Africa.The presence of Coxiella burnetii, Rickettsia, Borrelia, and Bartonella was examined by real-time PCR on DNA samples extracted from 118 ticks. Rickettsia massiliae was detected in ticks from Passer domesticus, Ri. aeschlimannii in ticks from Acrocephalus scirpaceus and Luscinia megarhynchos, and Borrelia valaisiana in one tick from Turdus merula. In addition, Ri. massiliae, Ri. slovaca, Candidatus Ri. barbariae, and C. burnetii were detected in ticks from dogs, horses, cats, and humans. No Bartonella DNA was detected in these samples.The migratory birds may play a role in the transmission of infectious diseases and contribute to the geographic distribution of Ri. aeschlimannii, Bo. valaisiana, and C. burnetii. The role of birds in spreading Rh. sanguineus ticks infected with Ri. massiliae needs to be clarified by complementary studies. This is the first detection of Candidatus Ri. barbariae in Rh. sanguineus from the south of France.

Widespread use of real-time PCR for rickettsial diagnosis: Figure 1

We report 2years of experience with rickettsial molecular diagnosis using real-time PCR at the French National Reference Center. All Rickettsia genomes available were compared to discover specific sequences to design new sets of primers and probes. The specificity was verified in silico and against a panel of 30 rickettsial species. Sensitivity was determined using 10-fold serial dilutions. Finally, primers and probes that were both specific and sensitive were routinely used for the diagnosis of rickettsial infections from clinical specimens. We retained sets of primers and probes to detect spotted fever group Rickettsia, typhus group Rickettsia,Rickettsia conorii,Rickettsia slovaca,Rickettsia africae and Rickettsia australis; 643 clinical samples were screened for the presence of Rickettsia DNA. Overall, 45 positive samples were detected, including 15 Rickettsia africae, nine R.conorii, five Rickettsia sibirica mongolitimonae, four R.slovaca, two R.australis, four Rickettsia massiliae, one Rickettsia honei, one Rickettsia typhi and eight Rickettsia sp. Positive samples were detected mainly from cutaneous biopsies and swabs (31/45). Widespread use of real-time PCR is inexpensive and reduces delay in the diagnosis of rickettsial infections. These real-time PCR assays could be implemented easily in laboratories that have molecular facilities and may be added to existing molecular tools as a point-of-care strategy.

Molecular detection of rickettsial agents in ticks and fleas collected from a European hedgehog (Erinaceus europaeus) in Marseilles, France

The European hedgehog (Erinaceus europaeus) is a synanthropic nocturnal insectivore commonly found in the countryside and in the parks and gardens. Because hedgehogs are already involved in the transmission of a number of zoonoses, including salmonellosis and ringworm, we decided to study their possible role in the epidemiology of the spotted fever group of Rickettsia. We collected ticks and fleas from a hedgehog that was captured in the city of Marseilles in France. Using a genus-specific quantitative PCR (qPCR) analysis followed by a species-specific qPCR analysis for positive samples, we observed that 91.7% (11/12) of the Rhipicephalus sanguineus ticks were positive for Rickettsia massiliae and 99.2% (128/129) of the Archaeopsylla erinacei fleas were positive for Rickettsia felis. Hedgehogs carry infected ectoparasites and then likely ensure the dissemination of spotted fever group Rickettsiae, and their epidemiological role requires further investigation.

Rickettsiae in arthropods collected from red foxes (Vulpes vulpes) in France

The aim of our study was to detect the presence of Rickettsia spp. and Bartonella spp. in ticks and fleas collected from red foxes (Vulpes vulpes) in southeastern France during 2008. Using a genus-specific quantitative PCR (qPCR) assay, which was followed by a species-specific qPCR assay for the positive samples, 45.2% (33/73) of ticks (Rhipicephalus turanicus) were found to be infected with Rickettsia massiliae. 10.5% (2/19) of the fleas (Archaeopsylla erinacei) collected in the study tested positive for Rickettsia felis. A genus-specific qPCR assay did not reveal any Bartonella species in any of the ticks or fleas collected. The role of red foxes in the epidemiology of spotted fever caused by Rickettsiae species requires further investigation.

Spotted Fever Group Rickettsiae in Ticks in Cyprus

In two surveys conducted from March 1999 to March 2001 and from January 2004 to December 2006, a total of 3,950 ticks (belonging to ten different species) were collected from seven domestic and wild animals (goat, sheep, cattle, dog, fox, hare, and mouflon) from different localities throughout Cyprus. In order to establish their infection rate with Spotted Fever Rickettsiae (SFG), ticks were pooled and tested by polymerase chain reaction targeting gltA and ompA genes, followed by sequencing analysis. When tick pools tested positive, individual ticks were then tested one by one, and of the 3,950 ticks screened, rickettsial DNA was identified in 315 ticks (infection rate, 8%). Five SFG Rickettsiae were identified: Rickettsia aeschlimannii in Hyalomma marginatum marginatum, Rickettsia massiliae in Rhipicephalus turanicus and Rhipicephalus sanguineus, Rickettsia sibirica mongolotimonae in Hyalomma anatolicum excavatum, and a Rickettsia endosymbiont of Haemaphysalis sulcata (later described as Rickettsia hoogstraalii) in Haemaphysalis punctata. Two additional genes, 17 kDa and ompB, were targeted to characterize a new genotype of "Candidatus Rickettsia barbariae" genotype in R. turanicus, designated here as "Candidatus Rickettsia barbariae" Cretocypriensis. These results confirm the presence of a spectrum of SFG Rickettsiae on the island. Further studies are necessary to gain better knowledge on the epidemiology of SFG Rickettsiae in Cyprus.

Molecular detection of Rickettsia massiliae, Rickettsia sibirica mongolitimonae and Rickettsia conorii israelensis in ticks from Israel

Rickettsioses are recognized as important emerging vector-borne infections of humans worldwide. Previous reports documented the presence of two spotted fever group rickettsiae in Israel, Rickettsia conorii israelensis and Rickettsia felis. The aim of this study was to characterize the diversity of rickettsiae in ticks collected from vegetation and the ground, from different parts of Israel. Non-engorged questing adult ticks were collected from 13 localities. A total of 131 tick pools, 83 of Rhipicephalus turanicus and 48 of Rhipicephalus sanguineus (each with 2–10 ticks per pool), were included in this study. In addition, 13 Hyalomma sp. ticks were collected. The ticks were molecularly screened for rickettsiae, targeting the citrate synthase (gltA) and the outer membrane protein A (ompA) gene loci. Rickettsia massiliae ompA DNA (100% sequence identity; 180 bp) was detected in 32 Rh. turanicus and 12 Rh. sanguineus tick pools. R. conorii israelensis was detected in three Rh. sanguineus pools. Rickettsia sibirica mongolitimonae ompA DNA (100% sequence identity; 182 bp) was found in one Hyalomma tick. This study reports the first detection of R. massiliae and R. sibirica mongolitimonae in ticks from Israel. This is the first report describing the presence of these human pathogens in the Middle East.

Spotted Fever Group Rickettsiae in Ticks Collected from Wild Animals in Israel

We report molecular evidence for the presence of spotted fever group rickettsiae (SFGR) in ticks collected from roe deer, addax, red foxes, and wild boars in Israel. Rickettsia aeschlimannii was detected in Hyalomma marginatum and Hyalomma detritum while Rickettsia massiliae was present in Rhipicephalus turanicus ticks. Furthermore, a novel uncultured SFGR was detected in Haemaphysalis adleri and Haemaphysalis parva ticks from golden jackals. The pathogenicity of the novel SFGR for humans is unknown; however, the presence of multiple SFGR agents should be considered when serological surveillance data from Israel are interpreted because of significant antigenic cross-reactivity among Rickettsia. The epidemiology and ecology of SFGR in Israel appear to be more complicated than was previously believed.

Tick-borne rickettsioses, neglected emerging diseases in rural Senegal.

BackgroundRickettsioses are one of the most important causes of systemic febrile illness among travelers from developed countries, but little is known about their incidence in indigenous populations, especially in West Africa.Methodology/Principal FindingsOverall seroprevalence evaluated by immunofluorescence using six rickettsial antigens (spotted fever and typhus group) in rural populations of two villages of the Sine-Saloum region of Senegal was found to be 21.4% and 51% for spotted fever group rickettsiae for Dielmo and Ndiop villages, respectively. We investigated the role of tick-borne rickettsiae as the cause of acute non-malarial febrile diseases in the same villages. The incidence of rickettsial DNA in 204 blood samples from 134 (62M and 72F) febrile patients negative for malaria was studied. DNA extracted from whole blood was tested by two qPCR systems. Rickettsial DNA was found in nine patients, eight with Rickettsia felis (separately reported). For the first time in West Africa, Rickettsia conorii was diagnosed in one patient. We also tested 2,767 Ixodid ticks collected in two regions of Senegal (Niakhar and Sine-Saloum) from domestic animals (cows, sheep, goats, donkeys and horses) by qPCR and identified five different pathogenic rickettsiae. We found the following: Rickettsia aeschlimannii in Hyalomma marginatum rufipes (51.3% and 44.8% in Niakhar and Sine-Saloum region, respectively), in Hyalomma truncatum (6% and 6.8%) and in Rhipicephalus evertsi evertsi (0.5%, only in Niakhar); R. c. conorii in Rh. e. evertsi (0.4%, only in Sine-Saloum); Rickettsia massiliae in Rhipicephalus guilhoni (22.4%, only in Niakhar); Rickettsia sibirica mongolitimonae in Hyalomma truncatum (13.5%, only in Sine-Saloum); and Rickettsia africae in Rhipicephalus evertsi evertsi (0.7% and 0.4% in Niakhar and Sine-Saloum region, respectively) as well as in Rhipicephalus annulatus (20%, only in Sine-Saloum). We isolated two rickettsial strains from H. truncatum: R. s. mongolitimonae and R. aeschlimannii.Conclusions/SignificanceWe believe that together with our previous data on the high prevalence of R. africae in Amblyomma ticks and R. felis infection in patients, the presented results on the distribution of pathogenic rickettsiae in ticks and the first R. conorii case in West Africa show that the rural population of Senegal is at risk for other tick-borne rickettsioses, which are significant causes of febrile disease in this area.

A Patient from Argentina Infected with Rickettsia massiliae

The first confirmed case of Rickettsia massiliae infection in the New World (Buenos Aires, Argentina) is described. To date, only two cases of human infection had been reported in Europe. The patient, a woman, had a fever, a palpable purpuric rash on the upper and lower extremities, and a skin lesion (eschar) on the right leg compatible with tache noire. When interviewed, she reported having had contact with dog ticks. After treatment with doxycycline for 12 days, her symptoms resolved. Rickettsia massiliae infection was diagnosed by molecular-based detection of the microorganism in a biopsy specimen of the eschar.

Functional Annotation of Conserved Hypothetical Proteins in Rickettsia Massiliae MTU5

Completed genome sequences are rapidly increasing for Rickettsia but most the genes in them does not have an assigned function. The present investigation mainly focused only on identifying the function of hypothetical proteins of Rickettsia massiliae MTU5 that were conserved in Rickettsia species. Nearly, 114 conserved hypothetical proteins were selected that were conserved in Rickettsia species. Function annotation was carried out by using databases like SMART, Interproscan, Pfam, JAFA, COG, and BLAST. Among 114 conserved hypothetical proteins only 35 proteins were annotated. The study motivated us to thoroughly study the genome of Rickettsia massiliae MTU5 by bioinformatics approach for categorizing the proteins whose function was unknown.

Identification of a new serotype of Rickettsia heilongjiangensis in wild rats from Guangdong Province, China

Spotted fever (SF) rickettsioses are acute febrile, mostly tick-borne infections caused by obligate intracellular bacteria of the genus Rickettsia. In China, three rickettsiae SF groups, including Rickettsia sibirica subsp. sibirica, R. sibirica subsp. mongolitimonae, and Rickettsia heilongjiangensis, have been isolated in humans [1]. In addition, several SF rickettsiae have been detected in ticks. R. sibirica was first isolated from Dermacentor nuttallii in Xinjiang Province in 1974. Later, up to 20 R. sibirica strains were isolated from ticks in different parts of continental China. In Guangdong Province, R. sibirica was initially identified in Dermacentor ticks in Lianping County in 1999 (Fig. 1). Subsequently, we identified Rickettsia honei, Rickettsia africae and Rickettsia slovaca in Boophilus microplus, Haemaphysalis cornigera and Ixodes granulatus ticks, respectively, that were collected in the same area. In another investigation, we detected R. heilongjiangensis and Rickettsia massiliae in Haemaphysalis longicornis, which is the main tick in this area. In order to further study the prevalence of SF rickettsiae in Lianping County, we investigated their presence in rodents, which are the ticks’ hosts. Herein, we detail the characterization of six rickettsial isolates obtained from wild rats trapped in this area.

First description of Rickettsia monacensis in Ixodes ricinus in Algeria

Tick-borne spotted fever group (SFG) rickettsioses are caused by obligate intracellular Gram-negative bacteria belonging to the genus Rickettsia. Although some rickettsias have been known as human pathogens since the beginning of the century, tick-borne SFG rickettsioses are also recognized as important emerging worldwide zoonoses [1]. In Algeria, three species of SFG rickettsia have been detected in ticks, including Rickettsia conorii conorii (the agent of Mediterranean spotted fever) in Rhipicephalus sanguineus, and two emerging pathogens, i.e. Rickettsia aeschlimannii in Hyalomma marginatum marginatum, and Rickettsia massiliae in Rhipicephalus sanguineus and Rhipicephalus turanicus [2]. We present here the detection and characterization of rickettsiae in more ticks collected in Algeria using PCR and sequence analysis of amplified products.

Spotted fever group rickettsioses documented in Morocco

Mediterranean spotted fever (MSF) is caused by Rickettsia conorii conorii transmitted by the brown dog tick Rhipicephalus sanguineus. It is endemic in the Mediterranean area, where most of the cases are encountered during the summer, when the tick vectors are highly active [1]. In Morocco, MSF has been the sole human tick-borne rickettsiosis known by clinicians, and cases that are clinically recognized are rarely documented [2]. Our aim is to describe the clinical and epidemiological characteristics of confirmed cases of MSF in Casablanca and in the surrounding regions of Morocco.

Molecular survey for spotted fever group rickettsiae in ticks from Morocco

The number of representatives of the genus Rickettsia and the number of newly described rickettsioses have increased in recent decades as a result of improved cell culture isolation techniques and of the extensive use of bacterial detection and identification based on molecular biology techniques [1]. Comparison of the sequences of PCR-amplified fragments of rickettsial genes has become a reliable method for the identification of rickettsiae in arthropods, including ticks. As a consequence, from 1984 to 2008, more than a dozen rickettsial species or subspecies were identified as emerging agents of tickborne rickettsioses throughout the world. As an illustration, in Morocco five rickettsial species, all human pathogens, have been identified from ticks in the Taza region, including: Rickettsia massiliae in Rhipicephalus sanguineus, R. slovaca and R. raoultii in Dermacentor marginatus, R. aeschlimannii in Hyalomma marginatum, and finally R. monacensis and R. helvetica in Ixodes ricinus [2]. We present here the detection and characterisation of rickettsiae in more ticks collected in different areas of Morocco using PCR and sequence analysis of amplified products.

First detection of Rickettsia aeschlimannii in Hyalomma aegyptium from Algeria

Tick-borne spotted fever group (SFG) rickettsioses are zoonoses caused by obligate intracellular Gram-negative bacteria belonging to the genus Rickettsia [1]. In Algeria, three species of SFG rickettsia transmitted by ticks are known to occur, including Rickettsia conorii conorii (the agent of Mediterranean spotted fever), transmitted by Rhipicephalus sanguineus, Rickettsia aeschlimannii, an emerging pathogen transmitted by Hyalomma marginatum marginatum, and Rickettsia massiliae, another emerging pathogen transmitted by Rh. sanguineus and Rhipicephalus turanicus [2]. We report here the detection of SFG rickettsiae in Hyalomma aegyptium ticks collected in Algeria.