Molecular detection of Rickettsia rickettsii, Ehrlichia canis and Rangelia vitalli in Rhipicephalus sanguineus senso latu collected from dogs in Brazil / [Detecção molecular de Rickettsia rickettsii, Ehrlichia canis e Rangelia vitalli em Rhipicephalus sanguineus sensu lato coletados de cães no Brasil]

ABSTRACT This study evaluated by molecular methods the presence of major canine tick-borne agents in ticks infesting domestic dogs of a hospital population in a neglected area of the southern zone of the São Paulo Metropolitan region, which is characterized by an extensive urban area surrounded and interspersed by forest remnants of the original Atlantic rainforest. During 2017, 106 tick specimens - 71 adults and 33 nymphs of Rhipicephalus sanguineus sensu lato (s.l.), and two adults of Amblyomma aureolatum - were collected from 41 dogs that were attended in a Veterinary Teaching Hospital in São Paulo City, Brazil. By molecular analyses, 4.2% (3/71) of the R. sanguineus s.l. adult ticks contained the bacterium Rickettsia rickettsii, 2.8% (2/71) contained the bacterium Ehrlichia canis, and 4.2% (3/71) contained the protozoan Rangelia vitalii. These results indicate that domestic dogs of the southern zone of the São Paulo metropolitan region might be exposed to three of the major tick-borne agents affecting dogs in Brazil, R. rickettsii, E. canis and R. vitalii. In addition, the findings reinforce the circulation of the human pathogen R. rickettsii in the study area in a likely enzootic cycle involving dogs and R. sanguineus ticks.

RESUMO Este estudo avaliou, por métodos moleculares, a presença dos principais agentes etiológicos de doenças caninas transmitidas por carrapatos que infestam cães domésticos de uma população hospitalar, em uma área negligenciada da zona sul da região metropolitana de São Paulo, caracterizada por uma extensa área urbana circundada e intercalada por remanescentes florestais de Mata Atlântica. Durante o ano de 2017, 106 espécimes de carrapatos - 71 adultos e 33 ninfas de Rhipicephalus sanguineus sensu lato (s.l.), e dois adultos de Amblyomma aureolatum - foram coletados de 41 cães atendidos em um Hospital Veterinário Universitário da cidade de São Paulo, Brasil. Por análises moleculares, 4,2% (3/71) de R. sanguineus s.l. adultos continham a bactéria Rickettsia rickettsii, 2,8% (2/71) continham a bactéria Ehrlichia canis e 4,2% (3/71) continham o protozoário Rangelia vitalii. Esses resultados indicam que cães domésticos da zona sul da região metropolitana de São Paulo podem estar expostos a três dos principais agentes carrapatos que afetam cães no Brasil, R. rickettsii, E. canis e R. vitalii. Além disso, os achados reforçam a circulação do patógeno humano R. rickettsii na área de estudo, em um provável ciclo enzoótico envolvendo cães e carrapatos R. sanguineus.

'Candidatus Rickettsia andeanae' and Probable Exclusion of Rickettsia parkeri in Ticks from Dogs in a Natural Area of the Pampa Biome in Brazil.

Spotted fever illness caused by the tick-borne pathogen Rickettsia parkeri has emerged in the Pampa biome in southern Brazil, where the tick Amblyomma tigrinum is implicated as the main vector. Because domestic dogs are commonly parasitized by A. tigrinum, this canid is also a suitable sentinel for R. parkeri-associated spotted fever. Herein, we investigate rickettsial infection in ticks, domestic dogs and small mammals in a natural reserve of the Pampa biome in southern Brazil. The ticks A. tigrinum, Amblyomma aureolatum and Rhipicephalus sanguineus were collected from dogs. Molecular analyses of ticks did not detect R. parkeri; however, at least 34% (21/61) of the A. tigrinum ticks were infected by the non-pathogenic agent 'Candidatus Rickettsia andeanae'. Serological analyses revealed that only 14% and 3% of 36 dogs and 34 small mammals, respectively, were exposed to rickettsial antigens. These results indicate that the study area is not endemic for R. parkeri rickettsiosis. We tabulated 10 studies that reported rickettsial infection in A. tigrinum populations from South America. There was a strong negative correlation between the infection rates by R. parkeri and 'Candidatus R. andeanae' in A. tigrinum populations. We propose that high infection rates by 'Candidatus R. andeanae' might promote the exclusion of R. parkeri from A. tigrinum populations. The mechanisms for such exclusion are yet to be elucidated.

Records and altitudinal assessment of Amblyomma aureolatum and Amblyomma ovale (Acari: Ixodidae) in the State of Rio de Janeiro, southeast Brazil.

Information on the altitudinal distribution of the hard ticks Amblyomma aureolatum and Amblyomma ovale in Brazil is scarce and mainly limited to occasional records. In this study we report our evaluation of records on the altitudinal distribution of A. aureolatum and A. ovale collected from dogs and humans and directly from the environment (host-questing ticks), based on active or passive procedures. The collections were conducted in rural areas of municipalities in the state of Rio de Janeiro, Brazil between 2013 and 2017. Active procedures consisted of dragging or flagging, visual examination of vegetation and removal of ticks present on the authors' clothing or on infested dogs. Overall, 222 ticks were collected. The altitudes at the collection sites ranged from 98 to 1220 m a.s.l. We noted a significant difference in the altitudinal distribution of A. aureolatum and A. ovale (Mann-Whitney U-test, U = 518.5, P < 0.001). The overlap of these two species occurred at altitudes of between 650 and 900 m a.s.l. The results indicated that the higher the altitude, the greater the probability for the occurrence of A. aureolatum and, conversely, the lower the likelihood for the occurrence of A. ovale. The findings of this study improve currrent knowledge on the bioecology of these tick species and have implications for studies on the epidemiology of spotted fever in Brazil.

Detecção de anticorpos anti-Rickettsia rickettsii em cães residentes em área negligenciada no município de São Paulo, SP, Brasil / [Detection of anti-Rickettsia rickettsii antibodies in dogs living in a neglected area in São Paulo, SP, Brazil]

A febre maculosa brasileira (FMB), descrita inicialmente nos Estados Unidos como febre maculosa das Montanhas Rochosas, é uma antropozoonose relatada apenas no continente americano e causada pela bactéria Rickettsia rickettsii. No Brasil a transmissão ocorre sobretudo pela picada de carrapatos do gênero Amblyomma spp. A doença foi inicialmente descrita como de transmissão em áreas rurais e silvestres, no entanto áreas periurbanas e urbanas vêm apresentando casos, principalmente relacionados com a presença de humanos residindo em pequenos fragmentos de mata ciliar. O presente estudo teve por objetivo elucidar a dispersão da FMB nas proximidades dos reservatórios Guarapiranga e Billings, na cidade de São Paulo, SP. Para tanto, a presença de anticorpos anti-R. rickettsii, Rickettsia parkeri e Rickettsia bellii foi avaliada em cães atendidos nas campanhas de esterilização cirúrgica e residentes ao redor dos reservatórios. Foram coletadas amostras de 393 cães, e as amostras de soro foram analisadas pela reação de imunofluorescência indireta (RIFI), com ponto de corte de 1:64. Os títulos para R. rickettsii variaram de 256 a 4096, com positividade de 3,3% (13/393); para R. bellii, de 128 a 1024 e 4,1% (16/393) de positivos, e um único animal (0,25%) foi soropositivo para R. parkeri, com título de 128. Os achados permitem concluir que a região de estudo apresenta condições de se tornar uma possível área com casos de FMB, pois comporta fragmentação de Mata Atlântica, condições essas ideais para a manutenção do vetor do gênero Amblyomma já descrito na região, bem como para a presença da Rickettsia rickettsii circulante entre os cães, confirmada pela existência de anticorpos. Condutas referentes à conscientização da população por meio de trabalhos educacionais devem ser implantadas para a prevenção da doença na população da área.(AU)

Brazilian Spotted Fever (BSF), initially described in the United States as Rocky Mountain Spotted Fever, is an anthropozoonosis reported only in the Americas and caused by the bacterium Rickettsia rickettsii. In Brazil, transmission occurs mainly through tick bites of the genus Amblyomma spp. The disease was initially described as transmission of rural and wild areas; however, peri-urban and urban areas have been presenting cases, mainly related to the presence of humans residing in small fragments of riparian forest. The present study aimed to elucidate the dispersal of BSF near the Guarapiranga and Billings Reservoirs, in the city of São Paulo, SP. The presence of anti-R. rickettsii, Rickettsia parkeri and Rickettsia bellii antibodies were evaluated in dogs treated in surgical sterilization campaigns and residents around the Reservoirs. Samples were collected from 393 dogs and serum samples were analyzed by indirect immunofluorescence reaction (RIFI) with a cutoff of 1:64. The titles for R. rickettsii varied from 256 to 4096 with a positivity of 3.3% (13/393); for R. bellii from 128 to 1024 and 4.1% (16/393) of positive and a single animal (0.25%) was seropositive for R. parkeri with a titre of 128. The findings allow us to conclude that the study region has conditions to become a possible area with BSF cases, as it involves Atlantic Forest, ideal conditions for the maintenance of the vector of the genus Amblyomma already described in the region and the presence of circulating Rickettsia rickettsii among dogs, confirmed by the presence of antibodies. Conducts regarding the awareness of the population through educational work should be implemented to prevent the disease in the population of the area.(AU)

Fatal Brazilian Spotted Fever Associated with Dogs and Amblyomma aureolatum Ticks, Brazil, 2013.

In São Paulo metropolitan area, Brazil, Amblyomma aureolatum ticks are the main vector of Rickettsia rickettsii, which causes Brazilian spotted fever. In 2013, a boy in São Paulo died of Brazilian spotted fever associated with household dogs and A. aureolatum ticks. Prompt recognition and treatment of this illness might prevent deaths.

Rickettsia rickettsii Co-feeding Transmission among Amblyomma aureolatum Ticks.

Amblyomma aureolatum ticks are vectors of Rickettsia rickettsii, the etiologic agent of Rocky Mountain spotted fever in Brazil. Maintenance of R. rickettsii in nature depends on horizontal transmission along tick generations. Although such transmission is known to occur when uninfected and infected ticks feed simultaneously on susceptible animals (co-feeding systemic transmission), we investigated co-feeding nonsystemic transmission, which was based on R. rickettsii-infected and -uninfected A. aureolatum ticks feeding simultaneously on guinea pigs immune to R. rickettsii. Our acquisition and transmission infestations demonstrated that horizontal transmission of R. rickettsii by co-feeding ticks on immune hosts with no systemic infection did not occur when uninfected larvae fed distantly from infected nymphs but did occur in a few cases when uninfected larvae fed side-by-side with infected nymphs, suggesting that they shared the same feeding site. The co-feeding nonsystemic transmission type might have no epidemiologic importance for Rocky Mountain spotted fever.

Evaluation of the vector competence of six ixodid tick species for Rangelia vitalii (Apicomplexa, Piroplasmorida), the agent of canine rangeliosis.

Rangelia vitalii is the etiologic agent of canine rangeliosis, a severe piroplasmosis that affects domestic dogs in Brazil, Uruguay and Argentina. While R. vitalii is one of the most pathogenic tick-borne pathogens for dogs in the world, its tick vector has remained unknown. The present study evaluated the vector competence of Rhipicephalus sanguineus sensu lato (both tropical and temperate species), Amblyomma aureolatum, Amblyomma ovale, Amblyomma tigrinum, and Amblyomma sculptum for R. vitalii. These six tick species were selected for the study because they comprise the main tick species infesting dogs within the distribution area of canine rangeliosis in South America. Acquisition feeding of the above six tick species was performed on domestic dogs showing clinical signs of canine rangeliosis, after being experimentally infected through intravenous inoculation or infestation with R. vitalii-infected ticks. Thereafter, engorged ticks were evaluated for transstadial and transovarial passages of R. vitalii through molecular analysis after molting or oviposition and egg hatching. The resultant ticks were evaluated for their competence to transmit R. vitalii to susceptible dogs. Among the six tick species, only A. aureolatum was able to acquire and perpetuate R. vitalii by transstadial and transovarial passages, as demonstrated by >5% infection rates of ticks after hatching or molting. When exposed to transmission feeding, only A. aureolatum ticks were competent to transmit R. vitalii to dogs, which became severely ill, and the results confirmed by molecular methods and blood smear examination to have acquired rangeliosis. Results of the present study, coupled with epidemiological data, indicate that A. aureolatum is a natural vector of R. vitalii. Our results also indicate that R. vitalii is the first Piroplasmorida agent to be transovarially transmitted in Amblyomma ticks.

Molecular evidence of Babesia species in Procyon cancrivorus (Carnivora, Procyonidae) in Uruguay.

The crab-eating raccoon (Procyon cancrivorus) is a carnivore widely distributed from southern Central America to all South American countries except Chile. In the Southern cone of America, P. cancrivorus has been found parasitized by several Amblyomma spp. Particularly, in Uruguay, A. aureolatum is the only tick found in this wild carnivore. Piroplasmid hemoparasites were found in Procyon lotor from North America and Japan. In this work, molecular evidence Babesia sp. DNA was found in blood and tissues from road-killed P. cancrivorus from different locations in Uruguay. PCRs targeting 18S rRNA gene were carried out. Subsequently, the obtained amplicons were sequenced and full-length sequences was assembled. A phylogenetic tree was constructed and revealed that the Babesia sp. found in this work clustered with other 18sRNA sequences of Babesia spp. obtained from P. lotor from Japan and USA, along with Babesia spp. of maned wolf and I. ovatus. This is the first report of molecular evidence of Babesia sp. parasitizing P. cancrivorus.

Ixodidae fauna of domestic dogs in Parana, southern Brazil / Fauna ixodídica em cães domésticos no Paraná, Sul do Brasil

Abstract The present study aimed to contribute towards identification and registration of tick species that parasitize dogs in rural and urban areas of three mesoregions of Paraná, southern Brazil, and to estimate the rate of occurrence of each species. Fifty-six dogs with ticks living in three mesoregions: Metropolitana de Curitiba (MC), Centro Oriental (COP) and Centro Sul Paranaense (CSP), were used in the study. From these 56 dogs, 253 ticks were collected and were identified and morphologically characterized according to the species. Among all the ticks, 69.6% were identified as belonging to the species Rhipicephalus sanguineus sensu lato (s. l.); 28.1% as Amblyomma aureolatum and 2.4% as Amblyomma ovale. Among the dogs in MC that were evaluated, 57.7% were parasitized by R. sanguineus s. l., 38.5% by A. aureolatum and 3.8% by A. ovale; while in COP, 72.4% of the dogs were parasitized by A. aureolatum and 27.6% by R. sanguineus s. l.. In CSP, one tick was obtained, which was identified as A. aureolatum.

Resumo O presente estudo objetivou contribuir com a identificação e o registro das espécies de carrapatos que parasitam cães de áreas rurais e urbanas de três mesorregiões do Paraná, Sul do Brasil, e estimar a taxa de ocorrência de cada espécie. Cinquenta e seis cães com carrapatos, provenientes das mesorregiões: Metropolitana de Curitiba (MC), Centro Oriental (COP) e Centro Sul Paranaense (CSP) foram utilizados no estudo. Dos 56 cães, foram coletados 253 carrapatos que foram identificados e caracterizados morfologicamente de acordo com a espécie. Do total de carrapatos, 69,6% foram identificadas como pertencentes à espécie Rhipicephalus sanguineus s. l.; 28,1% como Amblyomma aureolatum e 2,4% como Amblyomma ovale. Dentre os animais avaliados, provenientes da MC, 57,7% estavam parasitados por R. sanguineus s. l., 38,5% por A. aureolatum e 3,8% por A. ovale; enquanto na COP 72,4% dos cães foram parasitados por A. aureolatum e 27,6% por R. sanguineus s. l.. Na CSP foi obtido um carrapato, identificado como A. aureolatum.

Association of the occurrence of Brazilian spotted fever and Atlantic rain forest fragmentation in the São Paulo metropolitan region, Brazil

Brazilian Spotted Fever (BSF) is a zoonotic disease caused by the bacterium Rickettsia rickettsii. In the São Paulo Metropolitan Region (SPMR) it is transmitted by Amblyomma aureolatum ticks. In this region, annual lethality of the disease can reach 80% and spatial occurrence depends on environmental factors and more particularly on the presence and interaction of domestic and wild carnivores as well as the presence and characteristics of the remnant Atlantic Rain Forest patches. This study analyzed the association between forest fragmentation and its influence on the risk of occurrence of the disease in the human population. Domestic dogs tested for R. rickettsii antibodies in nine different areas under the influence of different patterns of Rain Forest fragmented landscapes and human occupancy. Landscape metrics were obtained by analyzing satellite images and high-resolution orthophotos. Principal component analysis (PCA) was used to determine among the different landscape variables the one that could best explain the data variance, and the results were tested against canine seroprevalence in order to address disease occurrence risk levels. From 270 canine samples, the seroprevalence ranged from 0 to 37%...

Association of the occurrence of Brazilian spotted fever and Atlantic rain forest fragmentation in the São Paulo metropolitan region, Brazil.

Brazilian Spotted Fever (BSF) is a zoonotic disease caused by the bacterium Rickettsia rickettsii. In the São Paulo Metropolitan Region (SPMR) it is transmitted by Amblyomma aureolatum ticks. In this region, annual lethality of the disease can reach 80% and spatial occurrence depends on environmental factors and more particularly on the presence and interaction of domestic and wild carnivores as well as the presence and characteristics of the remnant Atlantic Rain Forest patches. This study analyzed the association between forest fragmentation and its influence on the risk of occurrence of the disease in the human population. Domestic dogs tested for R. rickettsii antibodies in nine different areas under the influence of different patterns of Rain Forest fragmented landscapes and human occupancy. Landscape metrics were obtained by analyzing satellite images and high-resolution orthophotos. Principal component analysis (PCA) was used to determine among the different landscape variables the one that could best explain the data variance, and the results were tested against canine seroprevalence in order to address disease occurrence risk levels. From 270 canine samples, the seroprevalence ranged from 0 to 37%. PCA showed an inverse correlation between functionally connected large forest patches and the canine seroprevalence for R. rickettsii (p=0.030; Spearman's R=-0.683), while there was a positive correlation between forest border effect and canine seroprevalence (p=0.037; Spearman's R=- 0.909). The further attributed disease occurrence risk level supported the real spatial prevalence of the disease reported for the last eight years (p=0.023; Spearman's R=0.63). The results suggest an important relation of deforestation and fragmentation with the occurrence of BSF in the SPMR.

Febre maculosa brasileira / Brazilian spotted fever

A febre maculosa brasileira (FMB) é uma doença infecciosa transmitida por carrapatos do gênero Amblyomma, tendo como principal agente etiológico a bactéria Rickettsia rickettsii, manifestando-se por um quadro febril agudo. O primeiro relato de riquetsiose no Brasil foi em 1900, no Instituto Bacteriológico de São Paulo, pelo Dr. Adolfo Lutz. A doença reemergiu e se tornou um importante problema de saúde pública no Brasil a partir da década de 1980. Desde então, observou-se aumento no número de casos, expansão das áreas de transmissão, transmissão em áreas urbanas e, em especial, elevadas taxas de letalidade. As rickettsias são bactérias intracelulares obrigatórias, com predisposição ao parasitismo de células endoteliais, que estão classicamente divididas em três grupos: o grupo tifo, composto por Rickettsia prowazekii e Rickettsia typhi; o grupo da febre maculosa, que inclui mais de 20 espécies válidas, principalmente associadas aos carrapatos (por exemplo, R. rickettsii e R. parkeri); e um grupo mais basal, em que estão incluídas R. bellii, R. monteiroi e R. canadensis. No Brasil, a transmissão da FMB está associada aos carrapatos do gênero Amblyomma, e as espécies de maior importância na transmissão da doença são A. sculptum (antigo A. cajennense) e A. aureolatum. A doença se caracteriza por febre, mialgia e cefaleia intensa, exantema, edema nas mãos e nos pés, sendo que em alguns casos apresenta-se de maneira generalizada. A doença causa sepse com comprometimento pulmonar, podendo ocasionar insuficiência respiratória aguda, problemas renais, como insuficiência renal aguda, diátese hemorrágica, lesões neurológicas com meningite, encefalite e icterícia. Os casos clínicos que evoluem para óbito, devido a diagnóstico e tratamento tardios, normalmente ocorrem entre o 5° e o 15° dias após o início dos sintomas.[...]

Brazilian spotted fever is an infectious disease transmitted by ticks of the genus Amblyomma, having as its main etiological agent the bacterium Rickettsia rickettsii, manifesting through acute febrile condition. The first report about rickettsial disease in Brazil was in 1900, at the Bacteriological Institute of São Paulo, by Dr. Adolfo Lutz. The disease has reemerged and became an important public health problem in Brazil since the 1980s. The number of cases has increased, as well as the expansion of transmission areas, transmission in urban areas, and, in particular, high lethality rates. Rickettsiae are obligate intracellular bacteria predisposed that act as parasites in endothelial cells, which are classically divided in three groups: the typhus group, composed of Rickettsia prowazekii and Rickettsia typhi; The spotted fever group, composed of more than 20 valid species, mainly associated with ticks (e.g., R. rickettsii and R. parkeri); and a more basal group that includes R. bellii, R. monteiroi and R. canadensis. The transmission of Brazilian spotted fever is associated mainly with the ticks Amblyomma sculptum (formerly A. cajennense) and Amblyomma aureolatum. The disease is characterized by fever, myalgia and severe headache, rash, edema in hands and feet, and in some cases shows general symptoms. The disease causes sepsis with pulmonary involvement, which can cause acute respiratory failure, renal problems, such as acute renal failure, haemorrhagic diathesis, neurological lesions with meningitis, encephalitis and jaundice. The cases of death by late diagnosis and treatment usually occur between 5 and 15 days after the onset of symptoms. Diagnosis of the disease is made through the indirect immunofluorescence reaction (IFI), polymerase chain reaction (PCR) and isolation in cell culture. Treatment should initiate at the beginning of clinical signs and stop only two or three days after fever disappearance.[...]

Ixodidae fauna of domestic dogs in Parana, southern Brazil / Fauna ixodídica em cães domésticos no Paraná, Sul do Brasil

The present study aimed to contribute towards identification and registration of tick species that parasitize dogs in rural and urban areas of three mesoregions of Paraná, southern Brazil, and to estimate the rate of occurrence of each species. Fifty-six dogs with ticks living in three mesoregions: Metropolitana de Curitiba (MC), Centro Oriental (COP) and Centro Sul Paranaense (CSP), were used in the study. From these 56 dogs, 253 ticks were collected and were identified and morphologically characterized according to the species. Among all the ticks, 69.6% were identified as belonging to the species Rhipicephalus sanguineus sensu lato (s. l.); 28.1% as Amblyomma aureolatum and 2.4% as Amblyomma ovale. Among the dogs in MC that were evaluated, 57.7% were parasitized by R. sanguineus s. l., 38.5% by A. aureolatum and 3.8% by A. ovale; while in COP, 72.4% of the dogs were parasitized by A. aureolatum and 27.6% by R. sanguineus s. l.. In CSP, one tick was obtained, which was identified as A. aureolatum.(AU)

O presente estudo objetivou contribuir com a identificação e o registro das espécies de carrapatos que parasitam cães de áreas rurais e urbanas de três mesorregiões do Paraná, Sul do Brasil, e estimar a taxa de ocorrência de cada espécie. Cinquenta e seis cães com carrapatos, provenientes das mesorregiões: Metropolitana de Curitiba (MC), Centro Oriental (COP) e Centro Sul Paranaense (CSP) foram utilizados no estudo. Dos 56 cães, foram coletados 253 carrapatos que foram identificados e caracterizados morfologicamente de acordo com a espécie. Do total de carrapatos, 69,6% foram identificadas como pertencentes à espécie Rhipicephalus sanguineus s. l.; 28,1% como Amblyomma aureolatum e 2,4% como Amblyomma ovale. Dentre os animais avaliados, provenientes da MC, 57,7% estavam parasitados por R. sanguineus s. l., 38,5% por A. aureolatum e 3,8% por A. ovale; enquanto na COP 72,4% dos cães foram parasitados por A. aureolatum e 27,6% por R. sanguineus s. l.. Na CSP foi obtido um carrapato, identificado como A. aureolatum.(AU)

Febre maculosa brasileira / Brazilian spotted fever

A febre maculosa brasileira (FMB) é uma doença infecciosa transmitida por carrapatos do gênero Amblyomma, tendo como principal agente etiológico a bactéria Rickettsia rickettsii, manifestando-se por um quadro febril agudo. O primeiro relato de riquetsiose no Brasil foi em 1900, no Instituto Bacteriológico de São Paulo, pelo Dr. Adolfo Lutz. A doença reemergiu e se tornou um importante problema de saúde pública no Brasil a partir da década de 1980. Desde então, observou-se aumento no número de casos, expansão das áreas de transmissão, transmissão em áreas urbanas e, em especial, elevadas taxas de letalidade. As rickettsias são bactérias intracelulares obrigatórias, com predisposição ao parasitismo de células endoteliais, que estão classicamente divididas em três grupos: o grupo tifo, composto por Rickettsia prowazekii e Rickettsia typhi; o grupo da febre maculosa, que inclui mais de 20 espécies válidas, principalmente associadas aos carrapatos (por exemplo, R. rickettsii e R. parkeri); e um grupo mais basal, em que estão incluídas R. bellii, R. monteiroi e R. canadensis. No Brasil, a transmissão da FMB está associada aos carrapatos do gênero Amblyomma, e as espécies de maior importância na transmissão da doença são A. sculptum (antigo A. cajennense) e A. aureolatum. A doença se caracteriza por febre, mialgia e cefaleia intensa, exantema, edema nas mãos e nos pés, sendo que em alguns casos apresenta-se de maneira generalizada. A doença causa sepse com comprometimento pulmonar, podendo ocasionar insuficiência respiratória aguda, problemas renais, como insuficiência renal aguda, diátese hemorrágica, lesões neurológicas com meningite, encefalite e icterícia. Os casos clínicos que evoluem para óbito, devido a diagnóstico e tratamento tardios, normalmente ocorrem entre o 5° e o 15° dias após o início dos sintomas.[...](AU)

Brazilian spotted fever is an infectious disease transmitted by ticks of the genus Amblyomma, having as its main etiological agent the bacterium Rickettsia rickettsii, manifesting through acute febrile condition. The first report about rickettsial disease in Brazil was in 1900, at the Bacteriological Institute of São Paulo, by Dr. Adolfo Lutz. The disease has reemerged and became an important public health problem in Brazil since the 1980s. The number of cases has increased, as well as the expansion of transmission areas, transmission in urban areas, and, in particular, high lethality rates. Rickettsiae are obligate intracellular bacteria predisposed that act as parasites in endothelial cells, which are classically divided in three groups: the typhus group, composed of Rickettsia prowazekii and Rickettsia typhi; The spotted fever group, composed of more than 20 valid species, mainly associated with ticks (e.g., R. rickettsii and R. parkeri); and a more basal group that includes R. bellii, R. monteiroi and R. canadensis. The transmission of Brazilian spotted fever is associated mainly with the ticks Amblyomma sculptum (formerly A. cajennense) and Amblyomma aureolatum. The disease is characterized by fever, myalgia and severe headache, rash, edema in hands and feet, and in some cases shows general symptoms. The disease causes sepsis with pulmonary involvement, which can cause acute respiratory failure, renal problems, such as acute renal failure, haemorrhagic diathesis, neurological lesions with meningitis, encephalitis and jaundice. The cases of death by late diagnosis and treatment usually occur between 5 and 15 days after the onset of symptoms. Diagnosis of the disease is made through the indirect immunofluorescence reaction (IFI), polymerase chain reaction (PCR) and isolation in cell culture. Treatment should initiate at the beginning of clinical signs and stop only two or three days after fever disappearance.[...](AU)

Amblyomma aureolatum (Acari: Ixodidae): nuevos registros en las provincias de Buenos Aires y Santa Fe, Argentina

En los meses de julio de 2015 y enero de 2016 se colectaron garrapatas de un gato montés (Leopardus geoffroyi) localizado en la provincia de Buenos Aires y de un canino doméstico (Canis lupus familiaris) en la provincia de Santa Fe, respectivamente. El objetivo del presente trabajo es reportar el primer registro de Amblyomma aureolatum en la provincia de Buenos Aires y el primer hallazgo sobre caninos domésticos de la provincia de Santa Fe. Amblyomma aureolatum presenta importancia sanitaria ya que ha sido implicada como vector de Rickettsia rickettsii, uno de los agentes causales del grupo de las fiebres manchadas en humanos, y de Rangelia vitalii, agente causal de piroplasmosis en caninos domésticos, enfermedad vulgarmente conocida como "nambiuvú”. El presente reporte es un alerta para la comunidad sobre la presencia de A. aureolatum en nuevas localidades con el fin de implementar medidas profilácticas en caninos domésticos, para prevenir la infestación por este parásito y así evitar posibles patologías asociadas.

In July of 2015 and January of 2016, ticks were recovered from a Geoffroy’s cat (Leopardus geoffroyi) in Buenos Aires province and from a domestic dog (Canis lupus familiaris) in Santa Fe province, respectively. All ticks were identified as Amblyomma aureolatum. This report is the first record of A. aureolatum in Buenos Aires province and the first record in domestic dogs of Santa Fe province. Amblyomma aureolatum is a recognized vector of Rickettsia rickettsii, a spotted fever group agent in humans, and of Rangelia vitalii, a pathogenic piroplasmid of dogs, commonly referred to as "nambiuvú”. These findings allow local people to be aware of the presence of A. aureolatum to prevent infestations in dogs, and thus avoiding the occurrence of tick-borne diseases.

Isolation and characterization of microsatellite loci from the tick Amblyomma aureolatum (Acari: Ixodidae)

Amblyomma aureolatum (Pallas) is the main vector of the bacterium Rickettsia rickettsii, the etiological agent of Brazilian spotted fever. This disease is the most lethal human spotted fever rickettsiosis in the world. Microsatellite loci were isolated from a dinucleotide-enriched library produced from A. aureolatum sampled in Southeastern Brazil. Eight polymorphic microsatellites were further characterized among 38 individuals sampled from São Paulo metropolitan region. The number of observed alleles ranged from 2 to 9, observed heterozygosity was 0.184-0.647, and expected heterozygosity was 0.251-0.747. Cross-species amplifications suggested that these loci will be useful for other Amblyomma species...

Epidemiology of Rickettsia sp. strain Atlantic rainforest in a spotted fever-endemic area of southern Brazil.

The present study was performed in Vila Itoupava, an area of the state of Santa Catarina, southern Brazil, in which a tick-borne spotted fever illness has been endemic since 2003. Notably, both the etiological agent and the vector of these spotted fever cases remain unknown. During January 2011, humans, domestic dogs, and their ticks were sampled in households that are typically surrounded by highly preserved Atlantic rainforest fragments. Ticks collected from dogs were Amblyomma ovale (34% prevalence), Amblyomma aureolatum (18.9%), and Rhipicephalus sanguineus (3.8%). A total of 7.8% (6/77) A. ovale and 9.3% (4/43) A. aureolatum were infected by Rickettsia sp. strain Atlantic rainforest, a Rickettsia parkeri-like agent recently shown to cause spotted fever illness in southeastern Brazil. Overall, 67.3% (35/52) of the dogs were seroreactive to spotted fever group rickettsiae, mostly with highest endpoint titers to R. parkeri. Among humans, 46.7% (7/15) reacted serologically to rickettsiae at low to moderate endpoint titers. Because canine seroreactivity to R. parkeri was strongly associated with frequent contact with forests (the preferred habitat for A. ovale and A. aureolatum), it is concluded that sampled dogs have been infected by strain Atlantic rainforest through the parasitism of these tick species. The present study provides epidemiological evidence that the spotted fever in the study area has been caused by Rickettsia sp. strain Atlantic rainforest, transmitted to humans by either A. ovale or A. aureolatum. Further studies encompassing direct diagnostic methods on clinical specimens from patients are needed to confirm the above epidemiological evidence.

Situação epidemiológica da brucelose e tuberculose bovinas na região seis do Estado de São Paulo / Epidemiological situation of the bovine brucellosis and bovine tuberculosis in the sixth region of State of São Paulo

O objetivo do estudo foi caracterizar a situação epidemiológica da brucelose e tuberculose bovinas no Estado de São Paulo, o qual foi dividido em sete regiões. O presente estudo diz respeito à região seis, na qual 230 rebanhos com atividade reprodutiva foram aleatoriamente selecionados. Foram coletadas amostras de soro de 10 ou 15 fêmeas bovinas com idade igual ou superior a 24 meses (em rebanhos com <100 vacas e ≥100 vacas, respectivamente), para o diagnóstico da brucelose, totalizando 1.570 animais. Os soros foram submetidos a um protocolo de testes em série, tendo o teste do antígeno acidificado tamponado (rosa bengala) como método de triagem e o teste 2-mercaptoetanol como confirmatório. Para o diagnóstico da tuberculose foi utilizado o teste tuberculínico cervical comparativo em 20 ou 40 bovinos com idade igual ou superior a 24 meses, totalizando 2.319 animais. A escolha dos animais também foi feita de forma aleatória. A prevalência estimada de focos de brucelose foi de 7,82% [4,70%; 12,08%], e de tuberculose foi de 3,91% [1,80%; 7,29%], enquanto a prevalência estimada de animais foi de 2,6% [1,5%; 4,5%] para brucelose e 0,4% [0,2%; 0,8%] para tuberculose, na região. Em cada rebanho foi aplicado um questionário epidemiológico para avaliar o grau de associação de possíveis fatores de risco (odds ratio, OR) com a doença. As variáveis associadas à condição de foco foram, para brucelose, a presença de piquete de parição na propriedade, como fator protetor (OR = 0,35 [0,13; 0,97]) e para tuberculose, propriedades com 23 ou mais fêmeas bovinas com idade igual ou superior a 24 meses (OR = 6,11 [1,58; 23,67])

The objective of the study was to characterize the epidemiological situation of bovine brucellosis and tuberculosis in the State of São Paulo. The State was divided into seven regions and this paper was about the sixth region, were 230 herds with reproductive activity were randomly selected. Ten or 15 cows (age ≥ 24 months), randomly selected, were tested for brucellosis in each herd, through a serial testing procedure: Rose Bengal followed by 2 - Mercaptoethanol test. The cervical comparative tuberculin test was used for tuberculosis diagnosis in 20 or 40 cows (age ≥ 24 months), randomly selected, in each herd. A total of 1.570 animals were tested for brucellosis and 2.319 for tuberculosis. The prevalence of infected herds for brucellosis was 7,82% [4,70%; 12,08%] and 3,91% [1,80%; 7,29%] for tuberculosis, the prevalence of positive animals for brucellosis was 2,6% [1,5%; 4,5%] and 0,4% [0,2%; 0,8%] for tuberculosis. In order to investigate the risk factors for both diseases, an epidemiological questionnaire was applied in the selected farms. The presence of calving areas emerged as protective factor for brucellosis (OR = 0,35 [0,13; 0,97]) and herds with 23 or more cows (age 24 months) was pointed as risk factor for tuberculosis (OR= 6,11 [1,58; 23,67])

Tempo mínimo de parasitismo de carrapatos Amblyomma aureolatum infectados, para que ocorra a transmissão de Rickettsia rickettsii, agente etiológico da febre maculosa brasileira, para hospedeiros vertebrados / Minimum feeding period of Rickettsia rickettsii-infected Amblyomma aureolatum ticks to transmit the bacterium to vertebrate hosts

Rickettsia rickettsii é uma bactéria Gram-negativa, intra-celular obrigatória, causadora de uma grave riquetsiose em humanos, chamada no Brasil de Febre Maculosa Brasileira (FMB). Os carrapatos vetores de R. rickettsii para humanos, conhecidos até o momento no Brasil são Amblyomma cajennense e Amblyomma aureolatum. O presente estudo avaliou o tempo mínimo de parasitismo de A. aureolatum (ninfas não-alimentadas, machos adultos em jejum e pré-alimentados), infectadas por R. rickettsii, para que ocorra a transmissão da bactéria para o hospedeiro vertebrado. [...] De acordo com os resultados obtidos, ninfas não alimentadas de carrapatos A. aureolatum, infectados por R. rickettsii, necessitam realizar o repasto sanguíneo por um período mínimo de 12 horas, para que ocorra a transmissão da bactéria ao hospedeiro vertebrado; carrapatos adultos não alimentados, infectados por R. rickettsii, necessitam realizar o repasto sanguíneo por um período mínimo de 10 horas, para que ocorra a transmissão da bactéria ao hospedeiro vertebrado; e carrapatos adultos infectados por R. rickettsii e pré-alimentados em coelhos por 48 horas, necessitam realizar o repasto sanguíneo por um período mínimo de 10 minutos, para que ocorra a transmissão da bactéria ao hospedeiro vertebrado, utilizando-se cobaias como modelo experimental

Rickettsia rickettsii is the causative agent of the most severe rickettsiosis, known in Brazil as Brazilian Spotted Fever (BSF). Tick vectors of R. rickettsii to humans in Brazil are Amblyomma cajennense and Amblyomma aureolatum. The present study determined the minimum feeding period required for A. aureolatum-infected unfed nymphs, unfed adults, and fed adults to transmit infective forms of R. rickettsii to naïve guinea pigs. [...] According to the results, unfed nymphs of R. rickettsii-infected A. aureolatum ticks must feed for a minimum of 12 hours to transmit the bacterium to the vertebrate host; unfed R. rickettsii-infected adult ticks must feed for a minimum of 10 hours for transmission to occur, while previously fed adult ticks must feed for a minimum of 10 minutes to transmit R. rickettsii to vertebrate hosts, using guinea pigs as experimental model

Epidemiology of Brazilian spotted fever in the Atlantic Forest, state of São Paulo, Brazil

The tick-borne bacterium Rickettsia rickettsii is the a etiological agent of Brazilian spotted fever (BSF). The present study evaluated tick infestations on wild and domestic animals, and the rickettsial infection in these animals and their ticks in 7 forest areas adjacent to human communities in the São Paulo Metropolitan Area (SPMA). The results were compared to ecological traits of each sampled area. Two main tick species, Amblyomma aureolatum and Rhipicephalus sanguineus, were collected from dogs. The major ticks found on small mammals and birds were Ixodes loricatus and Amblyomma longirostre, respectively. Both anti-R. rickettsii antibodies and R. rickettsii-infected ticks were detected on dogs from only 2 areas in the southern part of the SPMA, which were considered to be endemic for BSF; the remaining 5 areas were considered to be non endemic. Ecologically, the BSF-endemic areas clearly differed from the non-endemic areas by the presence of significantly more degraded forest patches in the former. The present results corroborate historical observations that have indicated that all human cases of BSF in the SPMA were contracted in the southern part of this metropolitan area. However, not all forest patches in the southern part of the SPMA were shown to be associated with BSF endemism...