Spotted fever rickettsioses in southern and eastern Europe

Wild Red Foxes (Vulpes vulpes) as Sentinels of Parasitic Diseases in the Province of Soria, Northern Spain

Four hundred red foxes (Vulpes vulpes) were examined for ecto- (arthropods) and endoparasites (Leishmania spp., Trichinella spp., and intestinal parasites). Different species of flea (total prevalence, 40.50%), tick (16.25%), mite (7.25%), and fly (1.50%) were identified. The most prevalent flea was Pulex irritans (found on 29% of the foxes); the most prevalent tick, mite, and fly were Ixodes canisuga (on 5%), Sarcoptes scabiei (on 5.25%), and Hippobosca equina (on 1%), respectively. The endoparasites identified included Leishmania spp. (found in 12% of the foxes), Trichinella spp. (in 15.5%, with T. britovi the most prevalent species in 15.25%), Cestoda (in 72.75%, with Mesocestoides spp. the most prevalent in 69.50%), and intestinal ascarids (in 73.25%, with Ancylostoma caninum the most prevalent in 12.50%). No animal was free of parasites. The present results suggest that foxes can act as sentinels of diseases transmitted by ecto- and endoparasites.

Survival of rat cerebrocortical neurons after rickettsial infection

Neuroinvasive microorganisms are suspected to play an important role in the etiopathogenesis of neurological diseases. However, direct evidence for the pathogenic function is still missing. The main aim of this study was to investigate biochemical and morphological changes that may occur as a result of an in vitro infection of rat cerebrocortical neurons by selected members of the genus Rickettsia. Our results showed that survival of the neurons is significantly reduced after the infection. Intracellular level of ATP is gradually decreased and inversely correlates with the load of rickettsiae. Immunofluorescence revealed that rickettsiae can enter the neurons and are localized in perinuclear space and also in neuronal processes. Data obtained in this study correspond to the idea of possible involvement of rickettsiae in the etiopathogenesis of various neuropathies.

Spotted fever group rickettsiae detected in immature stages of ticks parasitizing on Iberian endemic lizard Lacerta schreiberi Bedriaga, 1878

Spotted fever rickettsioses are tick-borne diseases of growing public health concern. The prevalence of rickettsia-infected ticks and their ability to parasitize humans significantly influence the risk of human infection. Altogether 466 Ixodes ricinus ticks (428 nymphs and 38 larvae) collected from 73 Lacerta schreiberi lizards were examined by PCR targeting the citrate synthetase gene gltA for the presence of Rickettsia spp. Rickettsial DNA was detected in 47% of nymphs and 31.6% of larvae. They were subsequently subjected to a second PCR reaction using primers derived from the outer membrane protein rOmpA encoding gene (ompA) to detect spotted fever group rickettsiae (SFG). This analysis shows that 41.4% of nymphs and 7.9% of larvae collected from the lizards contain DNA of SFG rickettsiae. Sequencing of 43 randomly selected samples revealed two different haplotypes, both closely related to R. monacensis (39 and 4 samples, respectively). The remaining ompA negative Rickettsia spp. samples were determined to be R. helvetica based on sequencing of ompB and gltA fragments. Our results indicate that the role of Iberian endemic lizard L. schreiberi and its ectoparasites in the ecology and epidemiology of zoonotic SFG rickettsioses may be appreciable.

Acute febrile illness is associated with Rickettsia spp infection in dogs

BACKGROUND

Rickettsia conorii is transmitted by Rhipicephalus sanguineus ticks and causes Mediterranean Spotted Fever (MSF) in humans. Although dogs are considered the natural host of the vector, the clinical and epidemiological significance of R. conorii infection in dogs remains unclear. The aim of this prospective study was to investigate whether Rickettsia infection causes febrile illness in dogs living in areas endemic for human MSF.

METHODS

Dogs from southern Italy with acute fever (n = 99) were compared with case-control dogs with normal body temperatures (n = 72). Serology and real-time PCR were performed for Rickettsia spp., Ehrlichia canis, Anaplasma phagocytophilum/A. platys and Leishmania infantum. Conventional PCR was performed for Babesia spp. and Hepatozoon spp. Acute and convalescent antibodies to R. conorii, E. canis and A. phagocytophilum were determined.

RESULTS

The seroprevalence rates at first visit for R. conorii, E. canis, A. phagocytophilum and L. infantum were 44.8%, 48.5%, 37.8% and 17.6%, respectively. The seroconversion rates for R. conorii, E. canis and A. phagocytophilum were 20.7%, 14.3% and 8.8%, respectively. The molecular positive rates at first visit for Rickettsia spp., E. canis, A. phagocytophilum, A. platys, L. infantum, Babesia spp. and Hepatozoon spp. were 1.8%, 4.1%, 0%, 2.3%, 11.1%, 2.3% and 0.6%, respectively. Positive PCR for E. canis (7%), Rickettsia spp. (3%), Babesia spp. (4.0%) and Hepatozoon spp. (1.0%) were found only in febrile dogs. The DNA sequences obtained from Rickettsia and Babesia PCRs positive samples were 100% identical to the R. conorii and Babesia vogeli sequences in GenBank®, respectively. Febrile illness was statistically associated with acute and convalescent positive R. conorii antibodies, seroconversion to R. conorii, E. canis positive PCR, and positivity to any tick pathogen PCRs. Fourteen febrile dogs (31.8%) were diagnosed with Rickettsia spp. infection based on seroconversion and/or PCR while only six afebrile dogs (12.5%) seroconverted (P = 0.0248). The most common clinical findings of dogs with Rickettsia infection diagnosed by seroconversion and/or PCR were fever, myalgia, lameness, elevation of C-reactive protein, thrombocytopenia and hypoalbuminemia.

CONCLUSIONS

This study demonstrates acute febrile illness associated with Rickettsia infection in dogs living in endemic areas of human MSF based on seroconversion alone or in combination with PCR.

Spotted fever Rickettsia species in Hyalomma and Ixodes ticks infesting migratory birds in the European Mediterranean area

Background

A few billion birds migrate annually between their breeding grounds in Europe and their wintering grounds in Africa. Many bird species are tick-infested, and as a result of their innate migratory behavior, they contribute significantly to the geographic distribution of pathogens, including spotted fever rickettsiae. The aim of the present study was to characterize, in samples from two consecutive years, the potential role of migrant birds captured in Europe as disseminators of Rickettsia-infected ticks.

Methods

Ticks were collected from a total of 14,789 birds during their seasonal migration northwards in spring 2009 and 2010 at bird observatories on two Mediterranean islands: Capri and Antikythira. All ticks were subjected to RNA extraction followed by cDNA synthesis and individually assayed with a real-time PCR targeting the citrate synthase (gltA) gene. For species identification of Rickettsia, multiple genes were sequenced.

Results

Three hundred and ninety-eight (2.7%) of all captured birds were tick-infested; some birds carried more than one tick. A total number of 734 ticks were analysed of which 353 ± 1 (48%) were Rickettsia-positive; 96% were infected with Rickettsia aeschlimannii and 4% with Rickettsia africae or unidentified Rickettsia species. The predominant tick taxon, Hyalomma marginatum sensu lato constituted 90% (n = 658) of the ticks collected. The remaining ticks were Ixodes frontalis, Amblyomma sp., Haemaphysalis sp., Rhipicephalus sp. and unidentified ixodids. Most ticks were nymphs (66%) followed by larvae (27%) and adult female ticks (0.5%). The majority (65%) of ticks was engorged and nearly all ticks contained visible blood.

Conclusions

Migratory birds appear to have a great impact on the dissemination of Rickettsia-infected ticks, some of which may originate from distant locations. The potential ecological, medical and veterinary implications of such Rickettsia infections need further examination.

Molecular and serological study of rickettsial infection in humans, and in wild and farm animals, in the province of Burgos, Spain

Limited information is available on the presence of rickettsial infection in humans and animal reservoirs in Spain. Exposure to spotted fever group rickettsia in healthy humans and in farm and wild animals in the Province of Burgos, Spain, was examined by serological methods. Rickettsial DNA was also sought by PCR in animal samples. Of 102 human serum samples examined by indirect immunofluorescence assays (IFA), 5.88% were positive for antibodies against Rickettsia conorii (titers 1/128-1/512). Significant differences were detected in human seroprevalence with respect to age. In further IFAs, 102 out of 375 (27.2%) serum samples from the wild animals reacted with R. conorii antigens (titers 1/64-1/1024); 32 out of 281 (11.38%) samples from farm animals were also positive for R. conorii (titers 1/64-1/2048). The prevalence detected among total wild animals was significantly higher than among total farm animals. No rickettsial DNA was found by PCR in any farm or wild animal sample.

Effects of homologous and heterologous immunization on the reservoir competence of domestic dogs for Rickettsia conorii (israelensis)

A number of spotted fever group (SFG) rickettsiae cause serious infections in humans. Several antigenically related rickettsial agents may coexist within the same geographical area, and humans or vertebrate hosts may be sequentially exposed to multiple SFG agents. We assessed whether exposure of a vertebrate reservoir to one SFG Rickettsia will affect the host's immune response to a related pathogen and the efficiency of transmission to uninfected ticks. Two pairs of dogs were each infected with either Rickettsia massiliae or Rickettsia conorii israelensis, and their immune response was monitored twice weekly by IFA. The four immunized dogs and a pair of naïve dogs were each challenged with R. conorii israelensis-infected Rhipicephalus sanguineus nymphs. Uninfected Rh. sanguineus larvae were acquisition-fed on the dogs on days 1, 7, and 14 post-challenge. These ticks were tested for the presence of rickettsial DNA after molting to the nymphal stage. The naive dogs became infected with R. conorii israelensis and were infectious to ticks for at least 3 weeks, whereas reservoir competence of dogs previously infected with either R. massiliae or R. conorii was significantly diminished. This opens an opportunity for decreasing the efficiency of transmission and propagation of pathogenic Rickettsia in natural foci by immunizing the primary hosts with closely related nonpathogenic SFG bacteria. However, neither homologous immunization nor cross-immunization significantly affected the efficiency of R. conorii transmission between cofeeding infected nymphs and uninfected larvae. At high densities of ticks, the efficiency of cofeeding transmission may be sufficient for yearly amplification and persistent circulation of a rickettsial pathogen in the vector population.

Genome Sequence of Rickettsia gravesii, Isolated from Western Australian Ticks

Rickettsia gravesii is a new Rickettsia species closely related to the human pathogen Rickettsia massiliae. Here, we describe the genome sequence of R. gravesii strain BWI-1, isolated from Amblyomma triguttatum triguttatum ticks collected from humans on Barrow Island, Western Australia.

Next generation sequencing uncovers unexpected bacterial pathogens in ticks in western Europe

Background and Aims

Ticks are highly susceptible to global environmental and socio-economical changes. Several tick-borne pathogens have been reported in new geographical regions while new species, strains or genetic variants of tick-borne microorganisms are continually being detected. However, tick-borne pathogens are still poorly understood, and it is estimated that half of all human tick-borne disease has an unknown origin. Therefore in order to prevent these diseases, more effort is required to identify unknown or unexpected tick-borne pathogens. Ixodes ricinus is the vector for a broad range of bacterial pathogens and the most prevalent tick in Europe. The aim of the present study was to evaluate the capability of Next Generation Sequencing (NGS) to extend the inventory of pathogenic bacteria carried by this species of tick in France.

Methods

RNA and DNA were extracted from 1450 I. ricinus questing nymphs collected by flagging in Alsace, France. RNA was pooled and used for NGS. Following de novo assembly, bacterial contigs were assigned to the closest known taxonomy. DNA was used for real time PCR to confirm taxonomic species assignment of NGS-derived contigs for the doubtful cases, and for determination of prevalence.

Results

We have generated a global in-depth picture of tick-borne bacteria. We identified RNA from the main pathogenic bacterial species known to be transmitted by I. ricinus. In addition we also identified unanticipated bacterial species for which we have estimated the prevalence within those ticks inhabiting the studied areas.

Conclusions

The data obtained from this study has proven that NGS has an enormous potential to detect the unexpected and provides the means to monitor pathogen occurrence.

Rickettsia slovaca in immature Dermacentor marginatus and tissues from Apodemus spp. in the northern Apennines, Italy

Immature Dermacentor marginatus ticks and tissues from small rodents were tested for infection with Rickettsia slovaca in the northern Apennines, Lucca Province, where tick-borne lymphadenopathy (TIBOLA) was previously reported in people. Prevalence of infestation with D. marginatus was 30.5% (n=131, 95% CI: 22.8-39.2%) in Apodemus spp. and 26.5% (n=34, 95% CI: 12.9-44.4%) in Myodes glareolus, which were captured during 1980 trap nights in 2009 and 2010. Rickettsia slovaca was identified by polymerase chain reaction, targeting the gltA and OmpA genes, in ear biopsies from 8 out of 37 tested Apodemus (22%, 95% CI: 9.8-38.2%), but not from 9 M. glareolus. The prevalence of R. slovaca in D. marginatus feeding on Apodemus spp. was 53% in larvae (n=51, 95% CI: 38.5-67.1%) and 47.5% in nymphs (n=59, 95% CI: 34.3-60.9%). No larvae (0.0%, 95% CI: 0-36.9%), but one nymph removed from M. glareolus was positive (10%, 95% CI: 0.3-44.5%). Prevalence of R. slovaca in host-seeking D. marginatus larvae, collected in the same area, was 42% (n=38; 95% CI: 26.3-59.2%). Prevalence of R. slovaca was greater in larvae feeding on PCR-positive Apodemus than in those feeding on negative mice (78.6% vs. 37.1%). Furthermore, levels of infestation with D. marginatus larvae were greater for R. slovaca-positive mice. The infection of Apodemus spp. was probably the result of repeated bites by transovarially infected larvae. On the other hand, the finding of R. slovaca in mice tissues would be compatible with transmission from these hosts to feeding D. marginatus. Based on such a hypothesis, the most heavily infested Apodemus might play a role as amplifiers of the infection.

Old and new tick-borne rickettsioses

The field of rickettsiology is rapidly evolving. Rickettsiae are small Gram-negative bacteria that can be transmitted to humans by arthropods. In most cases they are transmitted transovarially in the arthropod; human beings are incidental hosts. In recent years the use of cell culture and molecular biology has profoundly changed our knowledge of rickettsiae and has led to the description of several new species. New rickettsial diseases have been found in three main situations: firstly, in places where no new species have been identified, typical rickettsial symptoms have been observed (Japan, China); secondly, typical rickettsioses have been found to be caused by different organisms - in such cases a new Rickettsia species has been misdiagnosed as a previously identified bacterium (for example, R. parkeri was confused with R. rickettsii); thirdly, atypical clinical symptoms have been found to be caused by rickettsial organisms such as R. slovaca. These findings challenge the old dogma that only one tick-borne rickettsiosis is prevalent in one geographical area. Many Rickettsia spp. have been identified in ticks, but have not yet been implicated in human pathology. These rickettsiae should be considered as potential pathogens. All known or suspected rickettsial diseases should be treated (including in children) with doxycycline.

Mediterranean spotted fever in southeastern Romania

Although cases of Mediterranean spotted fever (MSF) have been reported for decades in southeastern Romania, there are few published data. We retrospectively studied 339 patients, diagnosed with MSF at the National Institute of Infectious Diseases “Prof. Dr. Matei Bals” between 2000 and 2011, in order to raise awareness about MSF in certain regions of Romania. According to the Raoult diagnostic criteria 171 (50.4%) had a score >25 points. Mean age was 52.5 years. One hundred and fifty-five (90.6%) patients were from Bucharest and the surrounding region. Almost all patients presented with fever (99.4%) and rash (98.2%), and 57.9% had evidence of a tick bite. There were no recorded deaths. Serologic diagnosis was made by indirect immunofluorescence assay. Of the 171 patients, serology results for R. conorii were available in 147. One hundred and twenty-three (83.7%) of them had a titer IgG ≥1 : 160 or a fourfold increase in titer in paired samples. MSF is endemic in southeastern Romania and should be considered in patients with fever and rash even in the absence of recognized tick exposure. Since the disease is prevalent in areas highly frequented by tourists, travel-associated MSF should be suspected in patients with characteristic symptoms returning from the endemic area.

Evaluation of the presence of Rickettsia slovaca infection in domestic ruminants in Catalonia, Northeastern Spain

Rickettsia slovaca is the etiological agent of the human disease tick-borne lymphadenopathy (TIBOLA) transmitted by Dermacentor spp. ticks. In our area, Dermacentor marginatus is the most important tick vector; adult ticks feed on mammals, especially ungulates such as wild boars and domestic ruminants. The epidemiology of tick-transmitted diseases describes a wild cycle and a domestic cycle and both are connected by ticks. To identify the role of domestic ruminants in the transmission and maintenance of R. slovaca infection, blood samples from sheep (n=95), goats (n=91), and bullfighting cattle (n=100) were collected during a herd health program, and livestock grazing was selected to ensure tick contact. Samples were analyzed by serology using an indirect immunofluorescent assay (IFA) and molecular techniques (real-time PCR). Seroprevalence was 15.7% in sheep, 20.8% in goats, and 65.0% in bullfighting cattle. On the basis of molecular methods, R. slovaca infection was demonstrated in a goat blood sample with an antibody titer of 1:160. This is the first time that R. slovaca has been identified in a goat blood sample. These results suggest that domestic ruminants are exposed to R. slovaca infection and, because the domestic cycle is close to the human environment, this could increase the risk of transmitting the pathogen to human beings.

Human rickettsioses in the Batna area, eastern Algeria

In order to investigate the prevalence of rickettsioses in febrile exanthemas in eastern Algeria, we conducted a prospective serological analysis of all patients presenting with this clinical picture at the Infectious Diseases Department in the Batna Hospital from January 2000 to September 2006. One hundred and eight adult patients were included in the study, 46% of whom younger than 25 years, and 72.5% were admitted from May to September. Patients were tested for antibodies to Rickettsia conorii conorii, R. conorii israelensis, R. aeschlimannii, R. felis, R. sibirica mongolitimonae, R. africae, R. massiliae, R. typhi, and R. prowazekii using microimmunofluorescence and Western blot as confirmation procedure. Both methods confirmed the diagnosis of Mediterranean spotted fever in 5 patients (4.6%), flea spotted fever in 2 patients (1.9%), and R. aeschlimannii infection in 2 patients (1.9%). In addition, 4 patients were diagnosed as having murine typhus (3.7%) and one with epidemic typhus (0.9%). To the best of our knowledge, this is the first report of R. felis infection and R. aeschlimannii infection in Algeria. In conclusion, at least 5 different kinds of rickettsiosis coexist in eastern Algeria and, being responsible for 13% of cases of febrile exanthemas, should be considered among major causes of this clinical picture in this area. In addition, we emphasize the high incidence of typhus group rickettioses, including epidemic typhus, in this area.

Cross-protection among Rickettsia species and subspecies in a guinea pig model of cutaneous infection

Pathogenic rickettsiae of the spotted fever group (SFG) induce skin lesions called "eschars" at the sites of arthropod bites. We recently described a guinea pig model based on eschar formation to predict the eventual pathogenicity of new Rickettsia species, and in this study, we used the model to study cross-protection among SFG Rickettsia species and subspecies. We showed that the intradermal inoculation of guinea pigs with Rickettsia conorii subsp. conorii significantly reduced, but not completely prevented, the number of eschars after sub-challenges with the same pathogen (P=0.0004). The same effect was also observed for other subspecies of the R. conorii complex. Additionally, the bacterial load in the eschars was significantly lower in immunized animals than in naïve animals. No protection was observed when sub-challenges were performed with other Rickettsia species, such as R. africae, R. sibirica subsp. mongolitimonae, R. aeschlimannii and R. massiliae. Our data suggest that patients may experience several episodes of infection with related or with the same species of Rickettsia. Moreover, the absence of cross-protection between Rickettsia species may explain the co-existence of two or more tick-borne rickettsioses in the same geographic areas.

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.

Life cycle, growth characteristics and host cell response of Rickettsia helvetica in a Vero cell line

Rickettsia helvetica, a spotted fever rickettsia and emerging pathogen with Ixodes ricinus ticks as the main vector, is an agent of human disease and may cause febrile illness as well as meningitis. In three parallel series the isolated standard type of R. helvetica, obtained from a PCR-positive I. ricinus tick, was high-passaged and propagated in a Vero cell line. By using quantitative real-time PCR, the generation time from inoculation to stationary phase of growth was calculated to 20-22 h. In the static cultivation system the stationary phase was observed from the seventh day after inoculation, and there was no observed degradation of R. helvetica DNA during the 14 days studied. Microscopy showed that the organisms invaded the host cells rapidly and were primarily found free in the cytoplasm and only occasionally located in the nucleus. Four days after inoculation some of the host cells were broken and many indifferent stages of cytoplasmic organic decomposition were seen. However the R. helvetica organism did not show any morphologic alterations and the number of organisms was stable after the replication peak which may indicate that R. helvetica is adapted to growth in a Vero cell line and/or that the phase of degradation occurs later than the 14 days studied. The findings differ from what has been reported for other rickettsiae of the spotted fever group and may be of importance for invasiveness and virulence of R. helvetica.

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.

Coinfection with Rickettsia helvetica and Herpes Simplex Virus 2 in a Young Woman with Meningoencephalitis

Herpes virus type 2 DNA was detected by PCR in the cerebrospinal fluid in a young woman presenting with headache, stiff neck and pleocytosis, and serological findings consistent with reactivation. Since she was exposed to ticks, Lyme disease and tick-borne encephalitis were excluded. Further investigation in an ongoing project, using PCR and sequencing of the amplified products, showed the presence of Rickettsia helvetica in the cerebrospinal fluid. The bacteria were also isolated in Vero cell culture, and microimmunofluorescence confirmed the development of antibodies against Rickettsia spp. with predominance of IgM reactivity consistent with recent infection. She was treated with antibiotics and improved rapidly. The patient could easily have been judged to have isolated herpes meningitis. Because Sweden and other European countries are endemic areas for rickettsioses, the paper reaffirms the importance of investigating for the presence of rickettsial infections in endemic areas in cases of meningitis of uncertain aetiology.

First detection of spotted fever group rickettsiae inIxodes ricinusandDermacentor reticulatusticks in the UK

A preliminary study was conducted to determine the presence of spotted fever rickettsiae in two species of British tick (Ixodes ricinusandDermacentor reticulatus). The 16S rRNA gene ofRickettsiaspp. was detected in 39/401 (9·7%) of ticks tested, including 22/338 (6·5%)I. ricinusand 17/63 (27%)D. reticulatus. Some positiveI. ricinussamples showed 100% homology withRickettsia helvetica(10/22), and most positiveD. reticulatusshowed 100% homology withR. raoultii(13/17). Five otherRickettsiaspp. were detected exhibiting 96–99% homology. Ticks positive for rickettsiae were collected from various hosts and from vegetation from eight counties across Great Britain. The distribution ofR. helveticain various engorged and unfed stages ofI. ricinussuggests thatR. helveticais widespread.R. raoultiiwas found in questing adultD. reticulatusin Wales and England. This is the first evidence of potentially pathogenic spotted fever rickettsiae in British ticks.

Involvement of TLR2 and TLR4 in cell responses to Rickettsia akari

A better understanding of the pathogenesis of rickettsial disease requires elucidation of mechanisms governing host defense during infection. TLRs are primary sensors of microbial pathogens that activate innate immune cells, as well as initiate and orchestrate adaptive immune responses. However, the role of TLRs in rickettsia recognition and cell activation remains poorly understood. In this study, we examined the involvement of TLR2 and TLR4 in recognition of Rickettsia akari, a causative agent of rickettsialpox. Transfection-based complementation of TLR2/4-negative HEK293T cells with human TLR2 or TLR4 coexpressed with CD14 and MD-2 enabled IκB-α degradation, NF-κB reporter activation, and IL-8 expression in response to heat-killed (HK) R. akari. The presence of the R753Q TLR2 or D299G TLR4 polymorphisms significantly impaired the capacities of the respective TLRs to signal HK R. akari-mediated NF-κB reporter activation in HEK293T transfectants. Blocking Ab against TLR2 or TLR4 markedly inhibited TNF-α release from human monocytes stimulated with HK R. akari, and TNF-α secretion elicited by infection with live R. akari was reduced significantly only upon blocking of TLR2 and TLR4. Live and HK R. akari exerted phosphorylation of IRAK1 and p38 MAPK in 293/TLR4/MD-2 or 293/TLR2 stable cell lines, whereas only live bacteria elicited responses in TLR2/4-negative HEK293T cells. These data demonstrate that HK R. akari triggers cell activation via TLR2 or TLR4 and suggest use of additional TLRs and/or NLRs by live R. akari.

A clear and present danger: tick-borne diseases in Europe

Ticks can transmit a variety of viruses, bacteria or parasites that can cause serious infections or conditions in humans and animals. While tick-borne diseases are becoming an increasing and serious problem in Europe, tick-borne diseases are also responsible for major depressions in livestock production and mortality in sub-Saharan Africa, Latin America and Asia. This review will focus on the most important circulating tick-transmitted pathogens in Europe (Borrelia spp., Anaplasma phagocytophilum, Babesia spp., tick-borne encephalitis virus, Rickettsia spp. and Crimean-Congo hemorrhagic fever virus).

Severe Mediterranean spotted fever complicated by acute renal failure and herpetic oesophagitis

Mediterranean spotted fever (MSF) is a tick-borne disease caused by Rickettsia conorii. Recently, complicated cases have been more frequently reported, even in previously healthy patients. We describe a case of severe MSF complicated by acute renal failure and associated with herpetic oesophagitis. Acyclovir therapy resulted in remission of oesophageal symptoms within 48 h.

Diversity of life-threatening complications due to Mediterranean spotted fever in returning travelers

BACKGROUND

Mediterranean spotted fever (MSF) is a tick-borne infection caused by Rickettsia conorii conorii mainly endemic in the Mediterranean Basin. Although usually considered as a benign disease, severe forms of MSF have been sporadically reported.

METHODS

We report on three patients who developed severe MSF complications after a stay in Morocco. Literature was reviewed to assess the frequency and pattern of MSF complications in the largest reported case series in endemic countries.

RESULTS

Each of our three patients diagnosed with MSF presented with a different complicated course: one with meningoencephalitis, one with lung embolism and one with septic shock and multi organ failure. In published series, rate of complications (defined as severe organ involvement) ranged from 1% to 20%. However, study designs and settings were highly variable and did not allow for relevant comparisons. Meningoencephalitis and shock with multi organ failure were the most frequently observed complications. Mortality of severe course was up to 20% in some series.

CONCLUSION

Severe organ involvement is not infrequent in patients with Mediterranean spotted fever and fatal outcome is regularly reported. Because presentations of complicated course may be extremely diverse, a high index of suspicion is required in febrile patients with potential exposure, in particular if skin rash and/or eschar are found. Early appropriate antibiotherapy is crucial to improve outcome.

The potential role of migratory birds in transmission cycles of Babesia spp., Anaplasma phagocytophilum, and Rickettsia spp

Babesia spp., Anaplasma phagocytophilum, and Rickettsia spp. are potentially emerging tick-borne pathogens, whereas many issues about their ecology, e.g. reservoir host specificity, are still unclear. In spring 2007, we collected 191 feeding Ixodes ricinus ticks from 99 birds of 11 different species on a German bird conservation island in the Baltic Sea. Babesia spp. were detected in 4.7% (9/191), A. phagocytophilum was present in 2.6% (5/191), and Rickettsia spp. were identified in 7.3% (14/191) of the investigated ticks. Further characterization of Babesia spp. infections resulted in B. divergens and B. microti. Among the Rickettsia spp. infections, we identified at least 2 different species: R. monacensis and R. helvetica. Furthermore, 2 ticks harboured mixed infections. Our study provides first interesting insights into the role of migratory birds in the distribution of several emerging tick-borne pathogens.

Detection of Rickettsia spp. and Anaplasma phagocytophilum in Ixodes ricinus ticks in a region of Middle Germany (Thuringia)

Rickettsia spp. and Anaplasma spp. are regarded as potentially emerging tick-borne pathogens, but so far data on prevalence rates in questing ticks and reports on human diseases in several parts of Europe are rarely available. In this study, 430 nymphs and 570 adult Ixodes (I.) ricinus ticks were collected from a frequently visited forest region of Thuringia (Zeitzgrund, near Stadtroda) in 2006 (n=506) and 2007 (n=494). Individual ticks were investigated for a part of the citrate synthase gene (gltA) of Rickettsia spp. and the 16S rRNA gene of Anaplasma phagocytophilum. Positive amplicons were identified with restriction fragment length polymorphism (RFLP) and/or sequencing. Overall, 14.7% (147/1000) of investigated ticks were infected with Rickettsia spp. After sequencing of 64/147 positive amplicons R. helvetica (29/64) was detected predominantly. Prevalence varied in different developmental stages between 9.3% (40/430) in nymphs and 18.8% (107/570) in adults. A. phagocytophilum-specific DNA was detected in 5.4% (54/1000) of ticks with an infection rate of 4.7% (20/430) in nymphs and 6.0% (34/570) in adults. In 1% (10/1000) of ticks coinfections with Rickettsia spp. and A. phagocytophilum were found. Our study provides interesting insights into the circulation and cocirculation of different rickettsial species and A. phagocytophilum in the same biotope.

Mediterranean spotted fever, a diagnostic challenge in travellers

Mediterranean spotted fever or boutonneuse fever is caused by Rickettsia conorii and transmitted by the brown dog tick. The commonest symptoms are pyrexia, a maculopapular rash, lymphadenopathies and an inoculation eschar. Increasingly, it is recognised as a cause of serious illness in southern Europe. Rickettsial infections of the spotted fever group are rarely reported in Belgium. We report the case of a 20-year-old traveller returning from Morocco who presented with fever and a markedly swollen inguinal lymph node. Our case report illustrates the challenges rickettsioses can pose to physicians facing febrile travellers. Awareness of the epidemiology and the spectrum of clinical manifestations of this acute zoonosis can help physicians to promptly start appropriate empiric antibiotic therapy.

Occurrence of Rickettsia felis in dog and cat fleas (Ctenocephalides felis) from Italy

Rickettsia felis is an obligate intracellular bacterium belonging to the spotted fever group, suspected to cause a murine typhus-like illness in humans, with a cosmopolitan distribution. This study was designed to estimate presence and occurrence of this pathogen in fleas collected from dogs and cats in different areas of Italy. Two species of fleas were identified, Ctenocephalides felis (80.3%) and Ctenocephalides canis (19.7%).

Overall, 320 fleas (257 C. felis and 63 C. canis) collected from 117 animals (73 dogs and 44 cats) were tested. Thirty-eight (11.9%) C. felis fleas, 13 from cats (17.6%) and 25 from dogs (10.2%) were positive for R. felis. No C. canis was positive. Fleas from cats showed a tendency to be more positive than fleas from dogs. Prevalence of R. felis among areas and within provinces of the same area was extremely variable, ranging from 0 to 35.3%. Overall, prevalence in north-eastern Italy (23.2%) was significantly higher than in south-western Italy (7.1%). This study confirmed the occurrence of R. felis in cat and dog fleas (C. felis) from Italy, similar to other European countries. The results also suggest that R. felis should be considered in the human differential diagnosis of any spotted-like fever in Italy, especially if the patient is known to have been exposed to flea bites.

Molecular survey of Rickettsia spp. in sick dogs in Italy

The aim of this retrospective study was to investigate the prevalence of Rickettsia spp. DNA in the blood of sick dogs from Italy. Canine blood samples (n=650) submitted for molecular testing of Rickettsia spp. to a diagnostic laboratory from February 2003 to March 2006 were studied. The Rickettsia spp. DNA detection was performed by Light Cycler real-time PCR using hybridization probes separately conducted with specific primers and probes. The total percentage of Rickettsia spp.-positive dog samples was 1.5% (10 out of 650). The percentage of Rickettsia spp.-positive dog samples submitted from north, central and southern Italy were 0.4% (1/248), 1.4% (3/219) and 3.3% (6/183), respectively. Five out of 138 dogs (3.6%) from Sicily were positive on Rickettsia PCR testing. A statistical difference was found between the percentages of positive samples from the Yorkshire terrier group (10.7%) compared with the mixed breed group (0.7%). No statistical differences were found between seasonal period, region and gender. Based on molecular data, there is infrequent rickettsiemia in dogs.

Spotted fever group Rickettsia in ticks from southeastern Spain natural parks

During an 8-years study, we collected from vegetation or domestic and wild mammals 1246 ticks (624 males, 511 females and 111 nymphs) belonging to 13 species in Jaen province (Andalusia) and we analyzed these ticks by PCR and sequencing for the presence of rickettsiae. Specific rickettsiae DNA was detected in 243 (19.5%) of the ticks tested. Sequence analysis of amplicons of gltA, ompA and ompB genes revealed that Ixodes ricinus were infected with R. monacensis, including strain IRS3, and R. helvetica (prevalences of 27.0% and 2.7%, respectively), while in I. ventalloi we found only this last species (12.5%). Moreover, Dermacentor marginatus presents R. slovaca (24.7%) and R. raoultii (59.9%). In Rhipicephalus sanguineus group ticks (Rh. sanguineus, Rh. turanicus and Rh. pusillus) only R. massiliae (15.2%) was found. Haemaphysalis punctata and Ha. sulcata were infected with a Rickettsia sp. near R. hoogstraalii (prevalence of 3.1% and 16.1%, respectively). In addition, Ha. punctata appeared infected with R. monacensis-like Rickettsia (1.0%) and R. raoultii (9.3%). None of I. hexagonus, Hyalomma lusitanicum, Hyalomma sp., Ha. hispanica or Rh. bursa studied ticks contained rickettsiae.

Serologic and molecular characterization of tickborne pathogens in lions (Panthera leo) from the Fasano Safari Park, Italy

Lions (Panthera leo) are an endangered species threatened by illegal hunting, habitat loss, and infectious diseases. Little is known about the tick-borne pathogens that infect lions and could contribute to population declines. The objective of this study was to characterize Rickettsia spp., Anaplasma phagocytophilum, and Coxiella burnetii infections in 10 lions from the Fasano Safari Park in Italy by serology, polymerase chain reaction, and sequence analysis. Although animals did not show clinical signs of tick-borne diseases, evidence of infection with C. burnetii, spotted fever group Rickettsia sp., and A. phagocytophilum were found in 50%, 20%, and 10% of the lions, respectively. One of the lions tested positive for all three pathogens. This study is the first report of molecular evidence of infection with C. burnetii, Rickettsia sp., and A. phagocytophilum in lions and provides evidence that these felids become infected and serve as hosts for tick-transmitted bacteria.