Survival of Rickettsia conorii in artificially contaminated whole and leukoreduced canine blood units during the storage period.

BACKGROUND: The ability of tick-borne agents to survive in stored blood bags is a key factor for their transmissibility by blood transfusion. The aim of this study was to evaluate the survival and potential infectivity of Rickettsia conorii (RC) in artificially contaminated canine whole blood (WB) and in leukoreduced whole blood (LR-WB) during the storage period. METHODS: RC was cultured on L929 cells. We used a one-week 25-cm2 flask with 70-80% of L929 infected cells to prepare the bacterial inoculum by pelleting cells and suspending the pellet in the donors' serum. We infected five 100 ml WB units with RC within 2 h from the collection and maintained it at room temperature for 4 h prior to refrigeration. We filtered 50 ml of each WB bag to obtain leukoreduced WB (LR-WB) at day 1 post-infection (dpi). We checked WB and LR-WB bags at 1, 4, 7, 14, 21, 28, 35 dpi for RC presence and viability through real-time PCR (rPCR) for DNA and mRNA, respectively, and by isolation. Identification of isolates was confirmed by indirect immunofluorescence and rPCRs. RESULTS: RC survived for the entire storage period in both whole and leukoreduced blood. All bags contained viable bacteria until 7 dpi; RC viability generally decreased over time, particularly in LR-WB bags where the isolation time was longer than in WB. Viable bacteria were still isolated at 35 dpi in 3 WB and 3 LR-WB. CONCLUSIONS: Leukoreduction reduced but did not eliminate RC in infected units. The survival and infectivity of RC in canine blood during the storage period may represent a threat for recipients.

First detection of Rickettsia conorii ssp. caspia in Rhipicephalus sanguineus in Zambia.

Ticks are important vectors for Rickettsia spp. of the spotted fever group all around the world. Rickettsia conorii is the etiological agent of boutonneuse fever in the Mediterranean region and Africa. Tick identification was based on morphological features and further characterized using the 16S rRNA gene. The ticks were individually tested using pan-Rickettsia real-time-PCR for screening, and 23S-5S intergenic spacer region, 16S rDNA, gltA, sca4, ompB, and ompA genes were used to analyze the Rickettsia positive samples. Rickettsia conorii ssp. caspia was detected in tick collected in Zambia for the first time, thus demonstrating the possibility of the occurrence of human disease, namely Astrakhan fever, due to this Rickettsia ssp. in this region of Africa. The prevalence of R. conorii ssp. caspia was 0.06% (one positive tick out of 1465 tested ticks) and 0.07% (one positive tick out of 1254 tested Rh. sanguineus).

The role of Rhipicephalus sanguineus sensu lato saliva in the dissemination of Rickettsia conorii in C3H/HeJ mice.

Animal models have been developed for the study of rickettsial pathogenesis. However, to understand what occurs during the natural route of rickettsial transmission via the tick bite, the role of tick saliva should be considered in these models. To address this, we analysed the role of tick saliva in the transmission of Rickettsia conorii (Rickettsiales: Rickettsiaceae) in a murine host by intradermally (i.d.) inoculating two groups of susceptible C3H/HeJ mice with this Rickettsia, and infesting one group with nymphal Rhipicephalus sanguineus sensu lato (Ixodida: Ixodidae) ticks. Quantification of bacterial loads and mRNA levels of interleukin-1ß (IL-1ß), IL-10 and NF-κB was performed in C3H/HeJ lung samples by real-time quantitative polymerase chain reaction (PCR) and real-time reverse transcriptase PCR, respectively. Lung histology was examined to evaluate the pathological manifestations of infection. No statistically significant difference in bacterial load in the lungs of mice was observed between these two groups; however, a statistically significant difference was observed in levels of IL-1ß and NF-κB, both of which were higher in the group inoculated with rickettsiae but not infected with ticks. Lung histology in both groups of animals revealed infiltration of inflammatory cells. Overall, this study showed that i.d. inoculation of R. conorii caused infection in the lungs of C3H/HeJ mice and tick saliva inhibited proinflammatory effects.

[ON THE ROLE OF RICKETTSIA RAOULTII IN THE EPIDEMIOLOGY OF RICKETTSIOSES IN RUSSIA].

The paper analyzes data on the prevalence and possible epidemiological importance of Rickettsia raoultii. The possible risk of infection in the population was assessed from the results of a serological study of patients after tick suction and from those of molecular biological determination of contamination of removed carriers. The place of Rickettsia raoultii among other rickettsia causing rickettsioses of a tick-borne spotted fever group is assessed in Russia.

Characterization of spotted fever group Rickettsiae in ticks from a city park of Rome, Italy.

BACKGROUND: Ticks are vectors and important reservoirs for microbial agents that cause disease in humans and animals. Among these pathogens, the members of Rickettsia species play an important role in public health. AIM AND METHODS: One hundred twenty-nine ticks belonging to four tick species (Ixodes ricinus, Rhipicephalus turanicus, Dermacentor marginatus, and Haemaphysalis punctata) were collected at different sites of the Insugherata Natural Reserve, localized in the urban area of Rome, Italy. Questing ticks were tested by PCR for Rickettsia spp., amplifying partial gene of ompA. RESULTS: Forty-six ticks were found to be infected with Rickettsia species. Five SFG rickettsiae were identified: three human pathogens Rickettsia conorii, Rickettsia massiliae and Rickettsia aeschlimannii, and two putative new strains Rickettsia sp. strain RM1 and Rickettsia sp. strain RM2. The phylogenetic analysis of partial gene sequences of ompA, gltA, and 17-kd antigen showed that they clustered with several rickettsiae with unidentified pathogenicity. However, Rickettsia sp. strain RM1 and Rickettsia sp. strain RM2 clustered in a statistically supported clade with R. massiliae, and R. monacensis, respectively. CONCLUSION: Our findings suggest that Rickettsia species other than R. conorii are implicated in human disease in Italy.

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.

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.

Molecular characterization of mediterranean spotted fever rickettsia isolated from a European traveler in the state of São Paulo, Brazil.

Rickettsial spotted fever is common in southeastern Brazil. Differential diagnosis of pathogens can be performed with proper laboratory methods. A traveler arriving from Portugal developed a fatal febrile hemorrhagic syndrome diagnosed as spotted fever rickettsiosis. We isolated the agent, which was identified as Rickettsia conorii conorii by sequencing rickettsial genes.

Urban family cluster of spotted fever rickettsiosis linked to Rhipicephalus sanguineus infected with Rickettsia conorii subsp. caspia and Rickettsia massiliae.

Here, we report an epidemiological and entomological investigation of a cluster of cases of spotted fever group (SFG) rickettsiosis occurring in southern France. A family of 3 (husband, wife, and their son) presented with symptoms compatible with SFG rickettsiosis. For 2 patients, serum samples presented increased levels of IgM and IgG for SFG Rickettsia. The patients' home was investigated, and Rhipicephalus sanguineus ticks were collected from the floor from behind the furniture. Of 22 ticks collected, 20 tested positive for Rickettsia. As Rh. sanguineus serves as a vector for both Rickettsia conorii and Ri. massiliae in southern France, all Rh. sanguineus isolates were tested by real-time PCR and conventional PCR to detect the 2 species. Nine ticks tested positive for Ri. conorii subsp. caspia (marking the first documentation of this subspecies in France), 7 tested positive for Ri. massiliae, and 4 tested positive for both rickettsiae. This study is the first report of coinfection of Rh. sanguineus ticks with Ri. conorii and Ri. massiliae in southern France.

Domestic dogs (Canis familiaris) as reservoir hosts for Rickettsia conorii.

Rickettsia conorii is the causative agent of Mediterranean spotted fever (MSF) and Israeli spotted fever (ISF) transmitted by the brown dog tick Rhipicephalus sanguineus. In areas where MSF or ISF are prevalent, dogs have high prevalence of R. conorii -neutralizing antibodies. However, the true role of dogs in the persistence of the R. conorii transmission cycle is unknown, and their reservoir competence for this pathogen has remained untested. We assessed the ability of dogs infected with R. conorii to transmit the pathogen to previously uninfected Rh. sanguineus ticks. Dogs were infected either via needle-inoculation of cultured rickettsiae or naturally via infected tick bite. Dogs were monitored for clinical signs of infection, for rickettsemia by PCR, and for seroconversion and were subjected to infestation with uninfected ticks at different time points. Rh. sanguineus larvae and nymphs successfully acquired the agent from both needle-inoculated and tick-infected dogs and transmitted it transtadially. Tick-infected dogs remained infectious to ticks for at least a month postinfection. The molted ticks were, in turn, infectious to naïve dogs. These results demonstrate that dogs are capable of acquiring R. conorii from infected Rh. sanguineus ticks and transmitting infection to cohorts of uninfected ticks, thus confirming for the first time that dogs are indeed competent reservoirs for R. conorii. In addition, dogs with different genetic backgrounds appear to differ in their susceptibility to R. conorii infection.

Ticks parasitizing humans in Greece.

In summer 2008, two fatal cases were observed in Northeastern Greece: a Crimean-Congo hemorrhagic fever (CCHF) case (first report in Greece) and a Mediterranean spotted fever case. In total, 537 ticks removed from humans who referred for this reason to the two hospitals of the region during June-September 2008 were identified. The vast majority of them (81.5%) were Rhipicephalus sanguineus, which is the main vector of Rickettsia conorii, while Hyalomma marginatum, the main vector of CCHF virus, accounted for 5.2%. The increased aggressiveness of R. sanguineus might be related to the weather conditions occurred during 2007-2008, while a variety of factors, including climate, might play a role in CCHF emergence.

[Mediterranean spotted fever in paediatric and adult patients: two clinical aspects of the same disease]. / La febbre bottonosa del Mediterraneo in età pediatricae in età adulta: due realtà cliniche differenti nella stessamalattia.

Mediterranean Spotted Fever is an acute febrile disease caused by Rickettsia conorii and transmitted to humans by the brown dog tick Rhipicephalus sanguineus. Nearly 400 cases are reported every year in Sicily, mainly from June to September. The aim of this study is to compare the clinical and laboratory features of two different groups of patients , one of adults and one of children. The analysis included all adult patients with MSF diagnosed at the Institute of Infectious Diseases, Paolo Giaccone University Polyclinic in Palermo, during the period January 2007- August 2010 and all the children diagnosed with MSF at the G. Di Cristina Children Hospital in Palermo during the period January 1997- December 2004. On admission, a complete physical and laboratory examination was carried out on every patient. An indirect immunofluorescence assay for Rickettsia conorii was performed in every case, a PCR assay was performed with blood samples from some adult patients. Analysis of the results confirms that MSF is a benign, and self-limiting disease in children, while severe complications can often arise in adults.

[Pediatric Mediterranean spotted fever]. / La fièvre boutonneuse méditerranéenne chez l'enfant.

In France, Mediterranean spotted fever due to Rickettsia conorii is mainly observed in the South-east. Rhipicephalus sanguineus, the brown dog tick, is the vector and the reservoir of the disease. Clinical diagnosis relies on the association of fever, rash and inoculation's scar during summertime. Pathological lesion is a diffuse vasculitis. Severity is often explained by a delay in diagnosis, but prognosis is good in pediatrics. Treatment relies on doxycycline and on macrolids in children under eight.

Deciphering the relationships between Rickettsia conorii conorii and Rhipicephalus sanguineus in the ecology and epidemiology of Mediterranean spotted fever.

Mediterranean spotted fever is the most important tick-borne disease occurring in Southern Europe and North Africa. The first case of this life-threatening zoonosis was reported in 1910. In the 1930s, the role of the brown dog tick, Rhipicephalus sanguineus, and the causative agent, Rickettsia conorii were described. However, basic questions regarding the relationships between the rickettsia and its tick vector are still unresolved, and the life cycle of R. conorii is incompletely known. There is a lack of knowledge associated with the role of Rh. sanguineus in the maintenance and transmission of R. conorii. The infectious rate of Rh. sanguineus ticks with R. conorii has been found low every time it has been tested; usually lower that 1%. The deleterious impact of R. conorii on ticks has been suggested in experimental models as a potential reason to explain a low prevalence in nature. The long-recognized phenomenon known as reactivation has been suggested as a cause of negative effects--that is, the change in temperature and physiology of the tick host induces the agent to emerge from dormancy and attain infectivity with bad effects on ticks. However, naturally infected colonies of ticks have been maintained in laboratory conditions over several generations. We discuss here several aspects that have been recently studied to better understand Rh. sanguineus-R. conorii relationships, including comparison between the fitness of infected and non-infected ticks in laboratory conditions and the role of external factors such as temperature and starvation.

Incongruent effects of two isolates of Rickettsia conorii on the survival of Rhipicephalus sanguineus ticks.

Rickettsia conorii, the etiologic agent of Mediterranean spotted fever is widely distributed in Southern Europe, the Middle East, Africa, India and the Caspian region. In the Mediterranean region, the brown dog tick, Rhipicephalus sanguineus, is the recognized vector of R. conorii. To study tick-pathogen relationships and pathogenesis of infection caused in model animals by the bite of an infected tick, we attempted to establish a laboratory colony of Rh. sanguineus persistently infected with R. conorii. Rhipicephalus sanguineus ticks of North American and Mediterranean origin were exposed to R. conorii isolates of African (R. conorii conorii strain Malish) and Mediterranean (R. conorii israelensis strain ISTT) origin. Feeding of ticks upon infected mice and dogs, intra-hemocoel inoculation, and submersion in suspensions of purified rickettsiae were used to introduce the pathogen into uninfected ticks. Feeding success, molting success and the longevity of molted ticks were measured to assess the effects of R. conorii on the survival of Rh. sanguineus. In concordance with previously published results, Rh. sanguineus larvae and nymphs from both North American and Mediterranean colonies exposed to R. conorii conorii Malish experienced high mortality during feeding and molting or immediately after. The prevalence of infection in surviving ticks did not exceed 5%. On the other hand, exposure to ISTT strain had lesser effect on tick survival and resulted in 35-66% prevalence of infection. Rh. sanguineus of Mediterranean origin were more susceptible to infection with either strain of R. conorii than those from North America. Previous experimental studies had demonstrated transovarial and transstadial transmission of R. conorii in Rh. sanguineus; however, our data suggest that different strains of R. conorii may employ different means of maintenance in nature. The vertebrate host may be a more important reservoir than previously thought, or co-feeding transmission between different generations of ticks may obviate or lessen the requirement for transovarial maintenance of R. conorii.

[Rickettsia conorii infection in Romania, 2000-2008]. / Evolutia febrei butonoase în România 2000-2008.

OBJECTIVES: presenting the epidemiological aspects of Rickettsia conorii infection in Romania between 2000-2008. METHODS: A descriptive epidemiology study of Rickettsia conorii infection cases noticed in Romania between 2000-2008, which provide data regarding: time, place a4d person. The study also presents some risk factors. RESULTS: All cases were sporadic and were noticed in southern Romania. The highest incidence was registered in 2001 in Constanta district (44.2% per ten thousand inhabitants). The majority of cases were registred between April-November with a maximum of cases in August (38%) The patients were mainly from urban areas (80%); The more affected age group was 45-54 year (25%). The most predominant clinical expression was the medium one (58% of cases). In 99% of the cases, the release status from the hospital was cured and the evolution of the illness was favorable. In this period were just 2 deceased In 96% of the confirmed cases the tick exposure has appeared within the contact with parasited animals and took place in 60% of cases at home. 4% of the cases recognaised a professional contact with parasitated animals. In 93% of the cases the reservoir was represented by the parasitated dog. CONCLUSION: The sporadic evolution of the cases demonstrated that the natural focality of the disease in Romania persists, the distribution of cases matches with that of Rickettsia conorii and its tick vectors and also with the period of greatest activity of the vector (Rhipicephalus sanguineous, specific for dogs). The disease clearly represents a public health problem whose magnitude is not known.

Febre maculosa brasileira: avaliação dos dados da vigilância e descrição do perfil clínico e epidemiológico no Estado de São Paulo, 2003 a 2007 / Brazilian spotted fever: evaluation of surveillance data and description of clinical and epidemiological characteristics in São Paulo State, 2003 to 2007

Introdução: A febre maculosa brasileira (FMB) é uma doença infecciosa febril aguda, de elevada letalidade, causada pela bactéria Rickettsia rickettsii, transmitida por carrapato do gênero Amblyomma. Desde a implantação da notificação obrigatória da doença em 2001, não foi avaliada a qualidade dos dados da vigilância, nem o impacto da implantação do sistema Sinan/Net e digitação completa da ficha de investigação em 2007. Também são poucos os estudos sobre a sua epidemiologia. Objetivo: Avaliar a qualidade das informações e levantar alguns atributos do sistema de vigilância epidemiológica da FMB e descrever os casos confirmados/compatíveis notificados ao Centro de Vigilância Epidemiológica do Estado de São Paulo (CVE/SP), entre 2003 e 2007. Métodos: Estudo descritivo de série de casos, por meio da análise dos casos notificados em três bases de dados: Sinan/W, Casos/CVE e Sinan/Net. Foram analisados dois intervalos: 2003-2006, e 2007. Avaliados critérios de qualidade dos dados (duplicidade, completude e consistência), valor preditivo positivo e oportunidade do sistema de vigilância. Os casos confirmados/compatíveis foram descritos segundo as variáveis disponíveis em todo o período. Resultados: A duplicidade da notificação ocorreu nos dois períodos, o VPP diminuiu em todo o período, em decorrência do aumento das notificações, mas piora na confirmação/descarte dos casos (2007 apresentou 30 por cento com classificação final ignorada). A completude das variáveis foi melhor em 2007, especialmente dos casos confirmados/compatíveis, quando comparados com os casos descartados/ignorados. Os casos confirmados/compatíveis do Sina/Net (2007) apresentaram uma melhora global na completude quando comparados com os casos confirmados/compatíveis do Casos/CVE (2003-2006). As inconsistências foram pouco freqüentes, porém o sistema mantinha-se inoportuno no encerramento dos casos. Em 2007 observou-se uma melhora na cobertura de exames de sorologia, mas uma piora na realização de i...

Questions on Mediterranean spotted fever a century after its discovery.

Mediterranean spotted fever (MSF) was first described in 1910. Twenty years later, it was recognized as a rickettsial disease transmitted by the brown dog tick. In contrast to Rocky Mountain spotted fever (RMSF), MSF was thought to be a benign disease; however, the first severe case that resulted in death was reported in France in the 1980s. We have noted important changes in the epidemiology of MSF in the last 10 years, with emergence and reemergence of MSF in several countries. Advanced molecular tools have allowed Rickettsia conorii conorii to be classified as a subspecies of R. conorii. New clinical features, such as multiple eschars, have been recently reported. Moreover, MSF has become more severe than RMSF; the mortality rate was as high as 32% in Portugal in 1997. Whether Rhipicephalus sanguineus is the only vector and reservoir for R. conorii conorii is a question not yet answered.