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.     

Rickettsiae in arthropods collected from the North African Hedgehog (Atelerix algirus) and the desert hedgehog (Paraechinus aethiopicus) in Algeria

Hedgehogs have become a popular pet despite their potential role in zoonotic disease transmission. We conducted an entomological study in a mountainous region of northeast Algeria in which we collected 387 fleas (Archeopsylla erinacei) and 342 ticks (Rhipicephalus sanguineus and Haemaphysalis erinacei) from Paraechinus aethiopicus and Atelerix algirus hedgehogs. Of the hedgehogs sampled, 77.7% and 91% were infested with fleas and ticks, respectively. Significantly more ticks and fleas were collected from A. algirus than from P. aethiopicus. Rickettsia felis was detected in 95.5% of fleas and R. massiliae was detected in 6.25% of Rh. sanguineus ticks by molecular tools. A new Rickettsia species of the spotted fever group was detected in 11.25% of Rh. sanguineus and in 77% of H. erinacei ticks. Overall, we show that hedgehogs can act as hosts for ectoparasites infected with several rickettsial agents. These data justify a more detailed investigation of animal reservoirs for Rickettsiae.     

High incidence of rickettsiosis correlated to prevalence of Rickettsia japonica among Haemaphysalis longicornis tick

Endemic spotted fever group rickettsiosis was reported in Shimane Prefecture, Japan. From an analysis of 14 clinical cases found in the endemic area, the infectious agent of spotted fever group rickettsiosis was identified as Rickettsia japonica. In this study, we also found that Rickettsia japonica was highly infected with the vector tick, Haemaphysalis longicornis, in the endemic area. These findings suggest that the high incidence of rickettsiosis in Shimane Prefecture can be explained by the high prevalence of Rickettsia japonica among Haemaphysalis longicornis ticks.     

Infection by spotted fever rickettsiae in people, dogs, horses and ticks in Londrina, Parana State, Brazil

Spotted fever is a disease caused by bacteria from the genus Rickettsia of the spotted fever group (SFG). Rickettsia rickettsii is likely the main agent of Brazilian spotted fever (BSF). With the objective of gathering information on the circulation of SFG rickettsiae in Londrina, Parana state, ticks from dogs and horses and also blood from dogs, horses and humans were collected in a neighbourhood of the city which presented potential for circulation of rickettsiae between hosts and vectors. Amblyomma cajennense, Dermacentor nitens, and Rhipicephalus sanguineus ticks were subjected to Polymerase Chain Reaction targeting a fragment of the Rickettsia gltA gene. This specific gene encodes the enzyme citrate synthase of Rickettsia spp., and results on all ticks were negative. Human and animal sera were tested by Indirect Immunofluorescence Assay in which R. rickettsii and R. parkeri were used as antigens. Sera from 4.7% human, 2.7% canine and 38.5% equine were positive for R. rickettsii. For R. parkeri, 0.9% human, 2.7% canine and 11.5% equine samples were positive. All samples reactive to R. parkeri also reacted to R. rickettsii. An epidemiological questionnaire was applied, but there were no statistically significant results. Comparison of our serological results with previous studies in Brazil, among BSF endemic and non-endemic areas, indicates that there is no established rickettsial infection in the study area, a statement corroborated with our molecular analysis. Nonetheless, as humans of the present study are highly exposed to tick infestations, health education within the population is needed to obtain efficient tick control.     

Tick infestation and spotted-fever group Rickettsia in shelter dogs, California, 2009

In response to an outbreak of Rocky Mountain spotted fever (RMSF) in Baja California in early 2009, dogs at two shelters in neighbouring Imperial County, California, were evaluated for ectoparasites. Brown dog ticks (Rhipicephalus sanguineus), a recognized vector for RMSF, were found on 35 (30%) of 116 dogs but all ticks tested negative for Rickettsia rickettsii by PCR.     

Rickettsial infection in domestic mammals and their ectoparasites in El Valle de Antón, Coclé, Panamá

The present research evaluated the presence of Rickettsia spp. on ectoparasites of horses and dogs (using PCR techniques), and their sera (using immunofluorescence assay) in El Valle de Antón town in Panama. A total of 20 horses and 20 dogs were sampled, finding four species of ectoparasites on dogs (the ticks Rhipicephalus sanguineus, Amblyomma ovale, Amblyomma oblongoguttatum, and the flea Ctenocephalides felis), and two tick species on horses (Amblyomma cajennense and Dermacentor nitens). DNA of Rickettsia amblyommii was found in pools of A. cajennense, D. nitens, and R. sanguineus, while Rickettsia felis was detected in C. felis pools. Overall, 70% (14/20) and 65% (13/20) of the horses and dogs, respectively, were seroreactive (titer ≥ 64) to spotted fever group rickettsiae. Sera from six dogs and five horses reacted to R. amblyommii antigens with titers at least four-fold higher than those for the other antigens tested (Rickettsia bellii, Rickettsia parkeri, Rickettsia rhipicephali, R. felis, and R. rickettsii). These serological results, coupled with our molecular findings, suggest that these dogs and horses were infected by Rickettsia amblyommii. More studies need to be realized afford to identify the Rickettsia species responsible for other serological and molecular positive results, and their ecological importance.     

Bartonella and Rickettsia in arthropods from the Lao PDR and from Borneo, Malaysia

Rickettsioses and bartonelloses are arthropod-borne diseases of mammals with widespread geographical distributions. Yet their occurrence in specific regions, their association with different vectors and hosts and the infection rate of arthropod-vectors with these agents remain poorly studied in South-east Asia. We conducted entomological field surveys in the Lao PDR (Laos) and Borneo, Malaysia by surveying fleas, ticks, and lice from domestic dogs and collected additional samples from domestic cows and pigs in Laos. Rickettsia felis was detected by real-time PCR with similar overall flea infection rate in Laos (76.6%, 69/90) and Borneo (74.4%, 268/360). Both of the encountered flea vectors Ctenocephalides orientis and Ctenocephalides felis felis were infected with R. felis. The degrees of similarity of partial gltA and ompA genes with recognized species indicate the rickettsia detected in two Boophilus spp. ticks collected from a cow in Laos may be a new species. Isolation and further characterization will be necessary to specify it as a new species. Bartonella clarridgeiae was detected in 3/90 (3.3%) and 2/360 (0.6%) of examined fleas from Laos and Borneo, respectively. Two fleas collected in Laos and one flea collected in Borneo were co-infected with both R. felis and B. clarridgeiae. Further investigations are needed in order to isolate these agents and to determine their epidemiology and aetiological role in unknown fever in patients from these areas.     

Tick-borne rickettsial diseases: emerging risks in Europe

Ticks are currently considered the main vectors of human infectious diseases in Europe, particularly since their role in the transmission of the agent of Lyme borreliosis was demonstrated in the 1980s. In the recent years, ticks have also been shown to be the vectors of numerous emerging rickettsial diseases. Although Mediterranean spotted fever (MSF) due to Rickettsia conorii was thought for a long time to be the only tick-borne rickettsial disease prevalent in Europe, five more spotted fever rickettsiae have been described as emerging pathogens in the last decade. Further, cases of infection due to Anaplasma phagocytophilum, the agent of human anaplasmosis (previously known as human granulocytic ehrlichiosis), have been reported throughout Europe. We present here these emerging diseases and discuss other potential threat for the future.     

Tick- and flea-borne rickettsial emerging zoonoses

Between 1984 and 2004, nine more species or subspecies of spotted fever rickettsiae were identified as emerging agents of tick-borne rickettsioses throughout the world. Six of these species had first been isolated from ticks and later found to be pathogenic to humans. The most recent example is Rickettsia parkeri, recognized as a human pathogen more than 60 years after its initial isolation from ticks. A new spotted fever rickettsia, R. felis was also found to be associated with fleas and to be a human pathogen. Similarly, bacteria within the family Anaplasmataceae have been considered to be of veterinary importance only, yet three species have been implicated in human diseases in recent years, including Ehrlichia chaffeensis, the agent of human monocytic ehrlichiosis, Anaplasma phagocytophilum, the agent of human anaplasmosis (formerly known as "human granulocytic ehrlichiosis agent", E. equi and E. phagocytophila), and finally Ehrlichia ewingii, which causes granulocytic ehrlichiosis in humans. We present here an overview of the various tick- and flea-borne rickettsial zoonoses described in the last 20 years, focusing on the ecological, epidemiological and clinical aspects.     

Rickettsial Infection in Animals,Humans and Ticks in Paulicéia,Brazil

A previous study in Paulicéia Municipality, south‐eastern Brazil, reported 9.7% of the Amblyomma triste ticks to be infected by Rickettsia parkeri, a bacterial pathogen that causes spotted fever in humans. These A. triste ticks were shown to be associated with marsh areas, where the marsh deer Blastocerus dichotomus is a primary host for this tick species. During 2008–2009, blood serum samples were collected from 140 horses, 41 dogs, 5 opossums (Didelphis albiventris) and 26 humans in farms from Pauliceia Municipality. Ticks were collected from these animals, from vegetation and from additional wildlife in these farms. Overall, 25% (35/140) of the horses, 7.3% (3/41) of the dogs, 3.8% (1/26) of the humans and 100% (5/5) of the opossums were seroreactive (titre ≥64) to spotted fever group (SFG) Rickettsia spp. Multivariate statistical analysis indicated that horses that were allowed to forage in the marsh were 4.8 times more likely to be seroreactive to spotted fever group (SFG) Rickettsia spp than horses that did not forage in the marsh. In addition, horses that had been living in the farm for more than 8.5 years were 2.8 times more likely to be seroreactive to SFG Rickettsia spp than horses that were living for ≤8.5 years. Ticks collected from domestic animals or from vegetation included Amblyomma cajennense, Amblyomma coelebs, Amblyomma dubitatum, Dermacentor nitens and Rhipicephalus microplus. By PCR analyses, only one pool of A. coelebs ticks from the vegetation was shown to be infected by rickettsiae, for which DNA sequencing revealed to be Rickettsia amblyommii. Ticks (not tested by PCR) collected from wildlife encompassed A. cajennense and Amblyomma rotundatum on lizards (Tupinambis sp), and A. cajennense and A. triste on the bird Laterallus viridis. Our results indicate that the marsh area of Paulicéia offers risks of infection by SFG rickettsiae.     

唐山地区蜱传斑点热群立克次体分子流行病学

根据已发表的长角血蜱16SrRNA序列及斑点热群立克次体外膜蛋白A（OmpA）基因序列设计2对特异性引物,对唐山地区采集的长角血蜱进行PCR检测,并对阳性样本进行测序和序列分析,抽检样本建立分子系统进化树。结果表明,在315份蜱DNA样本中检测出25份阳性样本,阳性率为7.94%;序列分析结果显示唐山地区长角血蜱携带立克次体同处于一个分支,与日本株立克次体同源性最高（93.30%）,其次是福建株立克次体（92.11%）,黑龙江立克次体绥芬株（90.45%）、虎林株（90.42%）。结论得出唐山地区蜱传斑点热感染较严重,分子进化分析结果显示唐山地区蜱传斑点热群立克次体可能为一新种。     

Seroprevalence of spotted fever group rickettsiae in canines along the United States–Mexico border

Portions of northern Mexico are experiencing a re‐emergence of Rocky Mountain spotted fever (RMSF), a tickborne disease caused by Rickettsia rickettsii, a member of the spotted fever group of rickettsiae (SFGR). Infection with R. rickettsii can result in serious and life‐threatening illness in people and dogs. Canine seroprevalence has been used as a sentinel for human RMSF in previous studies. This study aims to quantify SFGR seroprevalence in canines in three northern Mexican states and identify risk factors associated with seropositivity. A total of 1,136 serum samples and 942 ticks were obtained from dogs participating in government sterilization campaigns and from animal control facilities in 14 Mexican cities in three states. SFGR antibodies were detected using indirect immunofluorescence antibody assays at titre values ≥1/64. Six per cent (69 dogs) showed antibodies to SFGR, with the highest seroprevalence reported in Baja California (12%), Coahuila (4%) and Sonora (4%). Dogs from Baja California had three times higher odds of having SFGR antibodies compared to dogs from Sonora (OR = 3.38, 95% CI, 1.81–6.37). Roughly one quarter (25%) of surveyed dogs were parasitized by ticks (Rhipicephalus sanguineus sensu lato) at the time of sample collection. A portion of collected ticks were tested for rickettsial DNA using polymerase chain reaction. Positive samples were then sequenced, showing evidence of SFGR including R. massiliae, R. parkeri and R. rickettsii. Dogs that spent the majority of time on the street, such as free‐roaming or community‐owned dogs, showed a greater risk of tick infestation, seropositivity, bearing seropositive ticks, and may play a pivotal role in the spread of SFGR among communities. Estimating the seroprevalence of SFGR in the canine population can help public health campaigns target high‐risk communities for interventions to reduce human RMSF cases.     

Rickettsia lusitaniae sp. nov. isolated from the soft tick Ornithodoros erraticus (Acarina: Argasidae)

In this study a novel Rickettsia from the spotted fever group, isolated from Ornithodoros erraticus soft ticks collected from pigpens in the south of Portugal, is described. After initial screening revealed Rickettsia-positive ticks, isolation attempts were then performed. Successful isolates were achieved by shell-vial technique using Vero E6 cells at 28 °C. Molecular characterization of the isolate was performed based on analysis of five rickettsial genes gltA, ompA, ompB, sca1 and htr with their subsequent concatenation along with other rickettsial species resulting in a clustering of the new isolate with Rickettsia felis and Rickettsia hoogstraalii. The degree of nucleotide sequence similarity with other rickettsiae fulfills the criteria for classification of our isolate as a novel species. The name Rickettsia lusitaniae sp. nov. (= CEVDI PoTiRo) is proposed for this new species found in O. erraticus.     

Borrelia burgdorferi sensu lato and Rickettsia spp. infections in hard ticks (Ixodes ricinus) in the region of Hanover (Germany)

In a total of 605 Ixodes (I.) ricinus ticks collected in the spring-months March, April and May 2005, quantitative real time PCR (qPCR) revealed 26.6% Borrelia (B.) burgdorferi sensu lato (sl)-positive ticks, i. e. divided by sex and stage into 31.9% positive adults (34.8% females and 29.0% males) and 18.5% positive nymphs. Mono-infections with genospecies from the B. burgdorferi sl-complex were found in over two thirds of the positive individuals, whereas almost one third showed double- or even triple-infections. Genospecies-specific conventional PCR determined B. afzelii as the most frequent genospecies followed by B. garinii, B. spielmanii, B. valaisiana and B. burgdorferi sensu stricto (ss). Rickettsia spp. were found in 34.2% of the collected ticks, divided into 37.6% adults (42.5% females and 32.8% males) and 29.0% nymphs. Co-infections of Rickettsia-positive ticks with B. burgdorferi sl spirochaetes were present in 10.1% of the ticks. Thereby, adult ticks exhibited a co-infection rate of 13.4% (15.5% females and 11.3% males) and nymphs of 5.0%. Independently of the above mentioned study, 3939 Ixodes ticks, sent in between 2006 and 2010 for B. burgdorferi sl-diagnostic, were examined by qPCR exclusively for B. burgdorferi sl. The resulting B. burgdorferi sl prevalence was 23.1% and 24.4% in 2006 and 2007, respectively, followed by a continuous decrease to 12.8% in 2010. To analyse whether this observed decrease in infection frequency is due to sampling bias, in a current study randomly sampled ticks collected from defined sites equally distributed over the city of Hanover are investigated in a statistically relevant sample size.     

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.     

Molecular evidence of vector-borne pathogens in dogs and cats and their ectoparasites in Algiers,Algeria

In Algeria, only limited information is currently available on the prevalence of emergent canine and feline vector-borne diseases. The aim of the present work was to detect by qPCR vector-associated bacteria in stray dogs and cats and their ectoparasites from Algiers.18/117 (15.38%) dogs and 2/107 (1.87%) cats were positive for at least one vector-borne agent. Coxiella burnetii and Bartonella henselae were identified in 1/117 (0.85%) dog individually. Ehrlichia canis DNA was detected in 17/117 (14.52%) dogs. 1/107 (0.93%) cat was positive to C. burnetii and another 1/107 (0.93%) to B. henselae.DNA of Rickettsia massiliae, Rickettsia conorii and E. canis was detected in Rhipicephalus sanguineus. Cat fleas were infected with Rickettsia felis, B. henselae and Bartonella clarridgeiae. B. vinsonii subsp. berkhoffii was identified in Xenopsylla cheopis collected from dogs.The findings of this study indicate that dogs and cats from Algeria are exposed to multiple tick and flea-borne pathogens.     

Implications of presumptive fatal Rocky Mountain spotted fever in two dogs and their owner

A dog was examined because of petechiation, an inability to stand, pale mucous membranes, a possible seizure, and thrombocytopenia. Tick-borne illness was suspected, but despite treatment, the dog died. Eight days later, a second dog owned by the same individual also died. The dog was not examined by a veterinarian, but Rocky Mountain spotted fever (RMSF) was suspected on the basis of clinical signs. Two weeks after the second dog died, the owner was examined because of severe headache, fever, nausea, vomiting, decreased appetite, lethargy, and a fine rash on the body, face, and trunk. Despite intensive treatment for possible RMSF, the owner died. Although results of an assay for antibodies to Rickettsia rickettsii were negative, results of polymerase chain reaction assays of liver, spleen, and kidney samples collected at autopsy were positive for spotted fever group Rickettsia spp. These cases illustrate how dogs may serve as sentinels for RMSF in humans and point out the need for better communication between physicians and veterinarians when cases of potentially zoonotic diseases are seen.     

Molecular identification of tick-borne bacteria in wild animals and their ticks in Central Anatolia,Turkey

Wild animals fulfill an important mission in the ecology of tick-borne diseases as both suitable hosts to tick vectors and reservoirs of the pathogens. However, current data regarding the role of wild animals in the ecology of tick-borne pathogens is insufficient and more investigations are required. In this study, we investigated tick-borne bacterial pathogens in wild boar, hare, and fox and their ticks in Turkey. A total of 102 tick pools comprised of 445 ticks and blood samples were analyzed for the presence of bacterial DNA by PCRs targeted rickettsial gltA and ompA genes, 5S-23S rDNA gene for Borrelia spp., and msp4 gene for Anaplasma spp. As a result of PCR and sequence analyses, three pathogenic spotted fever group (SFG) rickettsiae, two SFG rickettsiae with unknown pathogenicity and one pathogenic Borrelia burgdorferi sensu lato were detected in samples obtained from wild animals. Rickettsia slovaca was detected in ticks (13.7% of tick pools) collected from wild boars and blood of a wild boar. In addition, the presences of R. hoogstraalii (19.6% of tick pools), R. aeschlimannii (5.8% of tick pools), R. sibirica subsp. mongolitimonae (1.9% of tick pools) and Candidatus R. goldwasserii (0.9% of tick pools) were detected in ticks collected from wild animals. Furthermore, B. burgdorferi sensu stricto was detected in a tick pool collected from a wild boar. This is the first report on the presence of Candidatus R. goldwasserii in Turkey. Consequently, this study shows that pathogenic Rickettsia and Borrelia species are circulating in Turkish wildlife and these pathogens can pose a threat to human health. Also, it has been determined that the investigated wild animals play a role as maintenance host for vector ticks; therefore, these animals must also be considered in the ecology of the mentioned pathogens.     

Louse- and flea-borne rickettsioses: biological and genomic analyses

In contrast to 15 or more validated and/or proposed tick-borne spotted fever group species, only three named medically important rickettsial species are associated with insects. These insect-borne rickettsiae are comprised of two highly pathogenic species, Rickettsia prowazekii (the agent of epidemic typhus) and R. typhi (the agent of murine typhus), as well as R. felis, a species with unconfirmed pathogenicity. Rickettsial association with obligate hematophagous insects such as the human body louse (R. prowazekii transmitted by Pediculus h. humanus) and several flea species (R. typhi and R. felis, as well as R. prowazekii in sylvatic form) provides rickettsiae the potential for further multiplications, longer transmission cycles and rapid spread among susceptible human populations. Both human body lice and fleas are intermittent feeders capable of multiple blood meals per generation, facilitating the efficient transmission of rickettsiae to several disparate hosts within urban/rural ecosystems. While taking into consideration the existing knowledge of rickettsial biology and genomic attributes, we have analyzed and summarized the interacting features that are unique to both the rickettsiae and their vector fleas and lice. Furthermore, factors that underlie rickettsial changing ecology, where native mammalian populations are involved in the maintenance of rickettsial cycle and transmission, are discussed.     

Rocky Mountain spotted fever

Rocky Mountain spotted fever is an endemic tickborne disease found throughout the United States and other regions of the world. Exposure may result in a spectrum of disease from subclinical infection to severe or fatal multiorgan collapse. The disease is maintained in nature in Ixodid tick vectors and their hosts. The most important ticks in the United States are Dermacentor variabilis and Dermacentor andersoni. Small mammals are the natural reservoirs in the wild. Dogs become infected when a tick harboring Rickettsia rickettsii feeds on the dog. Dogs do not develop sufficient rickettsemia to act as a reservoir in the transmission of Rickettsia rickettsii. Thus, although dogs act as sentinels to the presence of the disease, they cannot directly transmit infection. Signs in early stages of disease often are nonspecific. The most characteristic laboratory abnormality is thrombocytopenia, but serologic testing is necessary for confirmation of infection. Tetracycline and chloramphenicol are effective antibiotics to treat infection. Treatment should continue for 14 to 21 days to allow host immune defenses to develop and eradicate the organism. Prevention requires avoidance of tick-infested areas and rapid removal of ticks should exposure occur.