Phylogenetic Evidence for the Existence of Multiple Strains of Rickettsia parkeri in the New World

Free PMC Article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5881050/The bacterium Rickettsia parkeri has been reported to infect ticks of the "Amblyomma maculatum species complex" in the New World, where it causes spotted fever illness in humans. In South America, three additional rickettsial strains, namely, Atlantic rainforest, NOD, and Parvitarsum, have been isolated from the ticks Amblyomma ovale, Amblyomma nodosum, and Amblyomma parvitarsum, respectively. These three strains are phylogenetically closely related to R. parkeri, Rickettsia africae, and Rickettsia sibirica Herein, we performed a robust phylogenetic analysis encompassing 5 genes (gltA, ompA, virB4, dnaA, and dnaK) and 3 intergenic spacers (mppE-pur, rrl-rrf-ITS, and rpmE-tRNAfMet) from 41 rickettsial isolates, including different isolates of R. parkeri, R. africae, R. sibirica, Rickettsia conorii, and strains Atlantic rainforest, NOD, and Parvitarsum. In our phylogenetic analyses, all New World isolates grouped in a major clade distinct from the Old World Rickettsia species (R. conorii, R. sibirica, and R. africae). This New World clade was subdivided into the following 4 clades: the R. parkerisensu stricto clade, comprising the type strain Maculatum 20 and all other isolates of R. parkeri from North and South America, associated with ticks of the A. maculatum species complex; the strain NOD clade, comprising two South American isolates from A. nodosum ticks; the Parvitarsum clade, comprising two South American isolates from A. parvitarsum ticks; and the strain Atlantic rainforest clade, comprising six South American isolates from the A. ovale species complex (A. ovale or Amblyomma aureolatum). Under such evidences, we propose that strains Atlantic rainforest, NOD, and Parvitarsum are South American strains of R. parkeriIMPORTANCE Since the description of Rickettsia parkeri infecting ticks of the "Amblyomma maculatum species complex" and humans in the New World, three novel phylogenetic close-related rickettsial isolates were reported in South America. Herein, we provide genetic evidence that these novel isolates, namely, strains Atlantic rainforest, NOD, and Parvitarsum, are South American strains of R. parkeri. Interestingly, each of these R. parkeri strains seems to be primarily associated with a tick species group, namely, R. parkerisensu stricto with the "Amblyomma maculatum species group," R. parkeri strain NOD with Amblyomma nodosum, R. parkeri strain Parvitarsum with Amblyomma parvitarsum, and R. parkeri strain Atlantic rainforest with the "Amblyomma ovale species group." Such rickettsial strain-tick species specificity suggests a coevolution of each tick-strain association. Finally, because R. parkerisensu stricto and R. parkeri strain Atlantic rainforest are human pathogens, the potential of R. parkeri strains NOD and Parvitarsum to be human pathogens cannot be discarded.This work was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (grant 2011/51979-1 to F.A.N.-B.) and by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior CAPES/PROEX 1841/2016.info:eu-repo/semantics/publishedVersio

Primer registro de ácaros (Gamasida: Laelapidae) parásitos de roedores silvestres en Uruguay, con nuevos registros de hospedadores

Information is presented for the first time on laelapid mites associated with wild rodents in Uruguay. Specimens of the following species were identified: Laelapinae: Androlaelaps fahrenholzi (Berlese), Androlaelaps rotundus (Fonseca), Gigantolaelaps wolffsohni (Oudemans), Laelaps paulistanensis (Fonseca), Laelaps manguinhosi (Fonseca) and Mysolaelaps microspinosus Fonseca; Haemogamasinae: Eulaelaps stabularis (Koch). Most of the ectoparasite-host associations are reported for the first time. New host and locality records presented in this study are in accordance with previous findings on the same and/or related host species in nearby South American localities.Se presenta por primera vez infonnación sobre ácaros lelápidos asociados a roedores silvestres en Uruguay. Se identificaronespecímenes de las siguientes especies: Laelapinae:Androlaelaps fahrenholzi (Berlese). Androlaelaps rotundus (Fonseca). Gigantolaelaps wolffsohni (Oudemans). Laelapspaulistanensis Fonseca. Laelaps manguinhosi Fonseca y Mysolaelaps microspinosus Fonseca; Haemogamasinae: Eulaelaps stabularis (Koch). La mayoría de las asociaciones ectoparásitohospedador se registran por primera vez. Los nuevos registros de hospedador y localidad que se presentanen este estudio coinciden con hallazgos previos en las mismas, o estrechamente relacionadas, especies hospedadoras en localidades cercanas de Sud América.Centro de Estudios Parasitológicos y de Vectore

Primer registro de ácaros (Gamasida: Laelapidae) parásitos de roedores silvestres en Uruguay, con nuevos registros de hospedadores

Information is presented for the first time on laelapid mites associated with wild rodents in Uruguay. Specimens of the following species were identified: Laelapinae: Androlaelaps fahrenholzi (Berlese), Androlaelaps rotundus (Fonseca), Gigantolaelaps wolffsohni (Oudemans), Laelaps paulistanensis (Fonseca), Laelaps manguinhosi (Fonseca) and Mysolaelaps microspinosus Fonseca; Haemogamasinae: Eulaelaps stabularis (Koch). Most of the ectoparasite-host associations are reported for the first time. New host and locality records presented in this study are in accordance with previous findings on the same and/or related host species in nearby South American localities.Se presenta por primera vez infonnación sobre ácaros lelápidos asociados a roedores silvestres en Uruguay. Se identificaronespecímenes de las siguientes especies: Laelapinae:Androlaelaps fahrenholzi (Berlese). Androlaelaps rotundus (Fonseca). Gigantolaelaps wolffsohni (Oudemans). Laelapspaulistanensis Fonseca. Laelaps manguinhosi Fonseca y Mysolaelaps microspinosus Fonseca; Haemogamasinae: Eulaelaps stabularis (Koch). La mayoría de las asociaciones ectoparásitohospedador se registran por primera vez. Los nuevos registros de hospedador y localidad que se presentanen este estudio coinciden con hallazgos previos en las mismas, o estrechamente relacionadas, especies hospedadoras en localidades cercanas de Sud América.Centro de Estudios Parasitológicos y de Vectore

Primer registro de ácaros (Gamasida: Laelapidae) parásitos de roedores silvestres en Uruguay, con nuevos registros de hospedadores

Information is presented for the first time on laelapid mites associated with wild rodents in Uruguay. Specimens of the following species were identified: Laelapinae: Androlaelaps fahrenholzi (Berlese), Androlaelaps rotundus (Fonseca), Gigantolaelaps wolffsohni (Oudemans), Laelaps paulistanensis (Fonseca), Laelaps manguinhosi (Fonseca) and Mysolaelaps microspinosus Fonseca; Haemogamasinae: Eulaelaps stabularis (Koch). Most of the ectoparasite-host associations are reported for the first time. New host and locality records presented in this study are in accordance with previous findings on the same and/or related host species in nearby South American localities.Se presenta por primera vez infonnación sobre ácaros lelápidos asociados a roedores silvestres en Uruguay. Se identificaronespecímenes de las siguientes especies: Laelapinae:Androlaelaps fahrenholzi (Berlese). Androlaelaps rotundus (Fonseca). Gigantolaelaps wolffsohni (Oudemans). Laelapspaulistanensis Fonseca. Laelaps manguinhosi Fonseca y Mysolaelaps microspinosus Fonseca; Haemogamasinae: Eulaelaps stabularis (Koch). La mayoría de las asociaciones ectoparásitohospedador se registran por primera vez. Los nuevos registros de hospedador y localidad que se presentanen este estudio coinciden con hallazgos previos en las mismas, o estrechamente relacionadas, especies hospedadoras en localidades cercanas de Sud América.Centro de Estudios Parasitológicos y de Vectore

Rickettsial infection in Amblyomma cajennense ticks and capybaras (Hydrochoerus hydrochaeris) in a Brazilian spotted fever-endemic area

Brazilian spotted fever (BSF), caused by the bacterium Rickettsia rickettsii, is the deadliest spotted fever of the world. In most of the BSF-endemic areas, capybaras (Hydrochoerus hydrochaeris) are the principal host for the tick Amblyomma cajennense, which is the main vector of BSF. In 2012, a BSF case was confirmed in a child that was bitten by ticks in a residential park area inhabited by A. cajennense-infested capybaras in Itú municipality, southeastern Brazil. Host questing A. cajennense adult ticks were collected in the residential park and brought alive to the laboratory, where they were macerated and intraperitoneally inoculated into guinea pigs. A tick-inoculated guinea pig that presented high fever was euthanized and its internal organs were macerated and inoculated into additional guinea pigs (guinea pig passage). Tissue samples from guinea pig passages were also used to inoculate Vero cells through the shell vial technique. Infected cells were used for molecular characterization of the rickettsial isolate through PCR and DNA sequencing of fragments of three rickettsial genes (gltA, ompA, and ompB). Blood serum samples were collected from 172 capybaras that inhabited the residential park. Sera were tested through the immunofluorescence assay using R. rickettsii antigen. A tick-inoculated guinea pig presented high fever accompanied by scrotal reactions (edema and marked redness). These signs were reproduced by consecutive guinea pig passages. Rickettsia was successfully isolated in Vero cells that were inoculated with brain homogenate derived from a 3rd passage-febrile guinea pig. Molecular characterization of this rickettsial isolate (designated as strain ITU) yielded DNA sequences that were all 100% identical to corresponding sequences of R. rickettsii in Genbank. A total of 83 (48.3%) out of 172 capybaras were seroreactive to R. rickettsii, with endpoint titers ranging from 64 to 8192. A viable isolate of R. rickettsii was obtained from the tick A. cajennense, comprising the first viable R. rickettsi isolate from this tick species during the last 60 years. Nearly half of the capybara population of the residential park was seroreactive to R. rickettsii, corroborating the findings that the local A. cajennense population was infected by R. rickettsii.We are grateful to the administrative staff of the residential park that provided logistic support for the present study, and to the “Superintendência de Controle de Endemias” of the state of São Paulo (SUCEN) for their valuable help in collecting ticks. This work was supported by the Brazilian funding agencies FAPESP, CNPq, and CAPES

Serological survey of Rickettsia in equids from Vale do Paraíba, São Paulo, Brazil, and their tick identification and molecular investigation of Rickettsia

A febre maculosa brasileira é uma doença grave e letal para seres humanos causada pela bactéria Rickettsia rickettsii. No estado de São Paulo, SP, Brasil, o agente etiológico desta enfermidade é transmitido pelo carrapato Amblyomma sculptum. Conforme descrito na literatura científica, os cavalos infectados com esta bactéria produzem uma forte resposta imune e podem ser importantes sentinelas para a detecção da doença. A presente investigação realizou um levantamento sorológico em cavalos de cinco fazendas do Vale do Paraíba, São Paulo, Brasil, à procura de anticorpos contra Rickettsia rickettsii, Rickettsia parkeri, Rickettsia amblyommatis, Rickettsia rhipicephali e Rickettsia bellii. Em cada fazenda, também foram coletados carrapatos identificados taxonomicamente e examinados por PCR em tempo real para o DNA de Rickettsia spp. Foram coletadas amostras de sangue de 206 cavalos e coletados 334 carrapatos desses animais entre os meses de janeiro e dezembro de 2017. Oitenta carrapatos foram identificados como A. sculptum e 254 Dermacentor nitens. Das amostras de sangue, 7,3% soroconverteram para Rickettsia spp., sendo que, 0,97% apresentaram soropositividade homóloga para R. bellii. Nenhum dos 80 carrapatos de A. sculptum foi positivo com o emprego de PCR em tempo real para Rickettsia spp. Embora não tenham sido detectados carrapatos infectados por Rickettsia spp em cinco fazendas do Vale do Paraíba, os animais apresentaram reações sorológicas positivas para este agente. Assim, outros estudos abrangentes deverão ser realizados na área investigando hospedeiros e vetores, gerando dados para medidas de controle da transmissão da febre maculosa brasileira.Brazilian spotted fever is a serious and lethal illness for humans and is caused by the Rickettsia rickettsii bacteria. In the state of São Paulo/SP (Brazil), the etiological agent of this disease is transmitted by the Amblyomma sculptum tick. It was already shown that horses infected with this bacteria produce a strong immune response and could be important sentinels for the detection of the disease in a proper region. The present investigation performed a serological survey in horses from five farms of Vale do Paraíba, São Paulo state, Brazil, searching for antibodies against, Rickettsia rickettsii, Rickettsia parkeri, Rickettsia amblyommatis, Rickettsia rhipicephali, and Rickettsia bellii. In each farm, ticks were also collected that were taxonomically identified and examined by real-time PCR for Rickettsia spp DNA. Blood samples were collected from 206 horses, and 334 ticks were picked up from these animals from January to December 2017. Eighty ticks wereA. sculptum and 254 Dermacentor nitens. Of the blood samples, 7.3% seroconverted to Rickettsia spp. Of these, 0.97% had a positive serological response to R. bellii. None of the 80 A. sculptum ticks were positive through real-time PCR for Rickettsia spp. Although there was no detection of ticks infected by Rickettsia spp in five farms of Paraíba Valley, the horses presented serological positive reactions against this agent. Thus, further large studies should be conducted in the area targeting hosts and vectors to generate data for control measures of the transmission of Brazilian spotted fever.&nbsp

Estudo de eficácia in vitro de doxiciclina frente à cultura de Rickettsia rickettsii/ Study of in vitro efficacy of doxycycline against the culture of Rickettsia rickettsii

A Febre Maculosa Brasileira é uma zoonose causada por Rickettsia rickettsii com manifestações clínicas iniciais gerais e inespecíficos com altas taxas de mortalidade quando não tratados. Apesar de clinicamente efetivo frente a R. rickettsii, são escassos os estudos que comprovem a eficácia in vitro da doxiciclina. Este estudo propõe avaliar a taxa de infecção em monocamadas de células Vero infectadas com R. rickettsii e tratadas com doxiciclina através da contagem bacteriana e Reação de cadeia da polimerase (PCR) em tempo real após tratamento com doses de 5, 10 e 15mg de antimicrobiano. O tratamento com doxiciclina foi efetivo com diminuição de 88,4% da infecção e diminuição de Cycle threshold (Ct) na técnica de PCR em tempo real

Ornithodoros brasiliensis Aragão (Acari: Argasidae): description of the larva, redescription of male and female, and neotype designation

Ornithodoros brasiliensis is an endemic tick from Brazil and is very aggressive to humans, resulting in pain, fever and intense inflammatory response. After more than 50 years without report, this species was recently found in rural areas of São Francisco de Paula municipality, State of Rio Grande do Sul, southern Brazil, from where it was originally described. Herein, we describe the larva and redescribe the adults of O. brasiliensis based on scanning electron microscopy. Since the type was lost we designate the neotype specimen under the number IBSP 10409. In addition, the relationship between O. brasiliensis and other species from the Neotropical region that share the morphological characteristics of Ornithodoros with dorsal humps on tarsi, and also live under the soil and feed on hosts other than bats, are discussed. Molecular analysis inferred from a portion of the 16S rRNA mitochondrial gene is also provided and it placed O. brasiliensis in a cluster supported by a maximal bootstrap value (100%) with Ornithodoros parkeri, Ornithodoros rostratus, and Ornithodoros turicata.Fil: Barros Battesti, Darci M.. Governo do Estado de Sao Paulo. Secretaria da Saude. Instituto Butantan; BrasilFil: Onofrio, Valeria C.. Governo do Estado de Sao Paulo. Secretaria da Saude. Instituto Butantan; BrasilFil: Nieri Bastos, Fernanda A.. Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia. Departamento de Medicina Veterinária Preventiva e Saúde Animal; BrasilFil: Soares, João Fábio. Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia. Departamento de Medicina Veterinária Preventiva e Saúde Animal; BrasilFil: Marcili, Arlei. Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia. Departamento de Medicina Veterinária Preventiva e Saúde Animal; BrasilFil: Famadas, Kátia M.. Universidad Federal Rural de Rio de Janeiro; BrasilFil: Faccini, Joao Luiz H.. Universidad Federal Rural de Rio de Janeiro; BrasilFil: Ramirez, Diego G.. Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia. Departamento de Medicina Veterinária Preventiva e Saúde Animal; BrasilFil: Doyle, Rovaina L.. Instituto de Pesquisas Veterinárias Desidério Finamor; BrasilFil: Martins, João Ricardo. Instituto de Pesquisas Veterinárias Desidério Finamor; BrasilFil: Junior, José R.. Universidade Federal do Rio Grande do Sul; BrasilFil: Guglielmone, Alberto Alejandro. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Labruna, Marcelo B.. Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia. Departamento de Medicina Veterinária Preventiva e Saúde Animal; Brasi