Febrile illness associated with Rickettsia conorii infection in dogs from Sicily.
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SUBMITTER: Solano-Gallego L
PROVIDER: S-EPMC3291343 | biostudies-literature | 2006 Dec
REPOSITORIES: biostudies-literature
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Febrile illness associated with Rickettsia conorii infection in dogs from Sicily.
Solano-Gallego Laia L Kidd Linda L Trotta Michele M Di Marco Marco M Caldin Marco M Furlanello Tommaso T Breitschwerdt Edward E
Emerging infectious diseases 20061201 12
We report serologic and molecular evidence of acute, febrile illness associated with Rickettsia conorii in 3 male Yorkshire terriers from Sicily (Italy). ...[more]
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Project description:BackgroundRickettsia 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.MethodsDogs 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.ResultsThe 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.ConclusionsThis 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.
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Project description: Not available
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Project description:Underdiagnosis of fatal spotted fever may be attributed to nonspecific clinical features and insensitive acute-phase serologic studies. We describe the importance of molecular and immunohistochemical methods in establishing the postmortem diagnosis of locally acquired Israeli spotted fever due to Rickettsia conorii subsp. israelensis in a traveler returning to Israel from India.
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Project description:Scientific analysis of the genus Rickettsia is undergoing a rapid period of change with the emergence of viable genetic tools. The development of these tools for the mutagenesis of pathogenic bacteria will permit forward genetic analysis of Rickettsia pathogenesis. Despite these advances, uncertainty still remains regarding the use of plasmids to study these bacteria in in vivo mammalian models of infection, namely, the potential for virulence changes associated with the presence of extrachromosomal DNA and nonselective persistence of plasmids in mammalian models of infection. Here, we describe the transformation of Rickettsia conorii Malish 7 with the plasmid pRam18dRGA[AmTrCh]. Transformed R. conorii stably maintains this plasmid in infected cell cultures, expresses the encoded fluorescent proteins, and exhibits growth kinetics in cell culture similar to those of nontransformed R. conorii. Using a well-established murine model of fatal Mediterranean spotted fever, we demonstrate that R. conorii(pRam18dRGA[AmTrCh]) elicits the same fatal outcomes in animals as its untransformed counterpart and, importantly, maintains the plasmid throughout infection in the absence of selective antibiotic pressure. Interestingly, plasmid-transformed R. conorii was readily observed both in endothelial cells and within circulating leukocytes. Together, our data demonstrate that the presence of an extrachromosomal DNA element in a pathogenic rickettsial species does not affect either in vitro proliferation or in vivo infectivity in models of disease and that plasmids such as pRam18dRGA[AmTrCh] are valuable tools for the further genetic manipulation of pathogenic rickettsiae.
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Project description:BackgroundMediterranean spotted fever (MSF) is a zoonotic and vector-borne disease caused by Rickettsia conorii. We report a case (36 year-old-woman) of MSF caused by Rickettsia conorii from Iran.Case presentationIn September 2019, the patient was admitted to the hospital in Kerman province with flu-like symptoms and maculopapular lesions. According to the laboratory results, thrombocytopenia, elevated liver enzymes, and cardiac enzymes were observed. Skin biopsy was examined for Crimean-Congo Hemorrhagic Fever (CCHF) and MSF using the Real-Time-PCR and ELISA method. Finally, the sample was positive for Rickettsia conorii subsp. israelensis and treated with doxycycline and completely recovered.ConclusionsThis study showed that MSF could be present in Iran. Therefore, identifying endemic areas in Iran for this disease should be on the agenda.
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Project description:China is not considered as an endemic area of Rickettsia conorii, so there is no routine clinical way to diagnose this infection. This study aims to determine whether 2 febrile patients who had a tick bite in East China were indeed infected with R. conorii. The citrate synthase gene (gltA) was amplified with universal rickettsial primers by real-time fluorescent PCR from the patients' blood samples. Nested PCR was used to amplify the outer membrane protein A gene (ompA) for positive specimens. PCR products were further identified and analyzed through nucleic acid sequencing. Positive amplification of the gltA and ompA genes was found in both patients. The nucleotide sequences (303 bp) of the ompA gene of the 2 patients had high homology (99%) with the R. conorii Indian tick typhus strain in GenBank. A more than 4-fold increase in IgG against R. conorii provided supportive evidence of SFG Rickettsia infection. And the rapid recovery after doxycycline treatment also supported a rickettsial cause for the disease. Physicians in East China should be aware of human infections with R. conorii. PCR-based diagnostic methods offer a rapid and precise way to diagnose rickettsiosis, improving patient identification and management.
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2015-11-17 | PXD002650 | Pride