scholarly journals Amblyomma aureolatum Genetic Diversity and Population Dynamics Are Not Related to Spotted Fever Epidemiological Scenarios in Brazil

Pathogens ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1146
Author(s):  
Karla Bitencourth ◽  
Marinete Amorim ◽  
Stefan Vilges de Oliveira ◽  
Gilberto Salles Gazêta
Keyword(s):  
Genetic Diversity ◽  
Population Dynamics ◽  
Spotted Fever ◽  
Tick Population ◽  
Rickettsia Felis ◽  
Disease Epidemiology ◽  
Rickettsia Rickettsii ◽  
D Loop ◽  
Tick Borne Disease ◽  
Rickettsia Bellii

Regional differences in tick-borne disease epidemiology may be related to biological variations between vector populations. Amblyomma aureolatum (Ixodida: Ixodidae), a neotropical tick, is known from several regions in Brazil. However, only in the metropolitan area of São Paulo (SP) state are there studies that establish its role as a vector of a pathogenic rickettsia (Rickettsia rickettsii). The aim of the study was to analyze the genetic diversity, population dynamics, and rickettsia infection in A. aureolatum populations from different spotted fever scenarios in Brazil. Samples were subjected to DNA extraction, amplification and sequencing of 12S rDNA, cytochrome oxidase subunit II and D-loop mitochondrial markers for tick population analyses, and gltA, htrA, ompA, and ompB genes for rickettsia researches. Of the 7–17 tick haplotypes identified, 5–13 were exclusive to each population and 2–12 for each epidemiological scenario, as well as three haplotypes shared by all populations. Amblyomma aureolatum populations are expanding, and do not appear to be genetically structured vis-a-vis the different epidemiological scenarios studied. Rickettsia bellii (in SP) and Rickettsia felis (in Santa Catarina) were identified as infecting A. aureolatum. No relationship between tick haplotypes and rickettsia types were observed.

Características clínicas y para clínicas de los pacientes con fiebre manchada por Rickettsia rickettsii en Panamá (1950-1951; 2004-2018)

2019 ◽  
Vol 39 (3) ◽  
Author(s):  
Carlos Daza ◽  
Sergio Eduardo Bermúdez Castillero
Keyword(s):  
Latin America ◽  
Mortality Rate ◽  
Clinical Characteristics ◽  
Spotted Fever ◽  
Clinical Suspicion ◽  
Neglected Diseases ◽  
Rickettsia Rickettsii ◽  
Tick Borne Disease ◽  
America Latina ◽  
Low Prevalence

<p>[Clinical and para clinical characteristics of patients with fever spotted by Rickettsia 
rickettsii in Panama (1950-1951; 2004-2017)]</p><p> </p><p>Resumen<br />La fiebre manchada causada por Rickettsia rickettsii es por mucho la enfermedad transmitida por garrapatas más importante en América Latina y una de las zoonosis más relevante del continente. En Panamá esto es notorio si se considera que los casos confirmados de la misma se han registrado en dos series: 1950-1951, donde se presentaron cinco casos, donde los dos primeros fueron resultaron fatales, y de 2004-2017, donde se confirmaron 10 casos, con nueve fallecimientos. A pesar de lo anterior, la fiebre manchada causada por R. rickettsii es una enfermedad de baja prevalencia y está dentro de las enfermedades desatendidas. El diagnóstico oportuno de R. rickettsii en personas afectadas por la misma, incrementa la posibilidad de sobrevivencia del paciente; sin embargo, a pesar de su alto porcentaje de mortalidad, esta enfermedad es poco reconocida y no se cuenta con sospecha clínica. Con el objetivo de presentar sus características clínicas en Panamá, se analizan individualmente cada reportes de caso, incluyendo datos etarios, de localidad, síntomas descritos, análisis aplicados y tratamiento.   <br /><br />Abstract<br />The spotted fever caused by Rickettsia rickettsii is by far the most important tick-borne disease in Latin America and one of the most important zoonoses in the continent. In Panama this is notorious if it is considers that the confirmed cases have been registered in two series: 1950-1951, with five cases and two fatal; and 2004-2017, with 10 cases and nine deaths. Despite the above, spotted fever caused by R. rickettsii is a disease of low prevalence and is among the neglected diseases. The timely diagnosis of R. rickettsii in people affected by it, increases the possibility of survival of the patient; however, despite its high mortality rate, this disease is poorly recognized and there is no clinical suspicion. In order to present their clinical characteristics in Panama, each reports of case is analyzed individually, including age, location, symptoms described, applied analysis and treatment.<br /><br /></p>

scholarly journals Serosurvey on rickettsiae of the spotted fever group and Rickettsia bellii among dogs in the state of Goiás, Brazil

2020 ◽  
Vol 29 (2) ◽  
Author(s):  
Lucianne Cardoso Neves ◽  
Ana Laura Gonçalves Barreto ◽  
Mariana Xavier de Souza ◽  
Danieli Brolo Martins ◽  
Amália Regina Mar Barbieri ◽  
...  
Keyword(s):  
Spotted Fever ◽  
First Record ◽  
Immunofluorescence Assay ◽  
The State ◽  
Spotted Fever Group ◽  
Serum Samples ◽  
Rickettsia Parkeri ◽  
Serological Tests ◽  
Rickettsia Rickettsii ◽  
Rickettsia Bellii

Abstract The purpose of this study was to do a serological survey on three rickettsial species: Rickettsia rickettsii and Rickettsia parkeri, two species of the spotted fever group (SFG) that are considered to be great importance for public health; and Rickettsia bellii, a species of unknown pathogenicity that infects a variety of human-biting ticks. Serum samples from 273 dogs were tested using the indirect immunofluorescence assay (IFA). A total of 52 samples (19.04%) were seropositive for at least one of the three Rickettsia spp. antigens. Thirty-eight (73.07%), twelve (23.07%) and one (1.92%) of these dogs showed homologous reactions to R. bellii, R. rickettsii and R. parkeri, respectively. Our results showed that the seroprevalence of Rickettsia spp. was relatively low. However, the positive serological tests indicated that these dogs had become infected by these agents at some point in their lives. Lastly, our study adds to the previous knowledge on the epidemiology of rickettsiosis in the state of Goiás by doing the first record of detection of anti-R. rickettsii, R. parkeri and R. bellii antibodies by IFA among dogs, thus indicating that these agents may be circulating in the dog population analyzed.

scholarly journals Mechanistic movement models reveal ecological drivers of tick-borne pathogen spread

2021 ◽  
Vol 18 (181) ◽  
pp. 20210134
Author(s):  
Olivia Tardy ◽  
Catherine Bouchard ◽  
Eric Chamberland ◽  
André Fortin ◽  
Patricia Lamirande ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Tick Population ◽  
Infection Prevalence ◽  
Spread Rate ◽  
Infected Tick ◽  
Tick Density ◽  
Heterogeneous Landscapes ◽  
Tick Infection ◽  
Tick Borne Disease ◽  
Host Movement

Identifying ecological drivers of tick-borne pathogen spread has great value for tick-borne disease management. However, theoretical investigations into the consequences of host movement behaviour on pathogen spread dynamics in heterogeneous landscapes remain limited because spatially explicit epidemiological models that incorporate more realistic mechanisms governing host movement are rare. We built a mechanistic movement model to investigate how the interplay between multiple ecological drivers affects the risk of tick-borne pathogen spread across heterogeneous landscapes. We used the model to generate simulations of tick dispersal by migratory birds and terrestrial hosts across theoretical landscapes varying in resource aggregation, and we performed a sensitivity analysis to explore the impacts of different parameters on the infected tick spread rate, tick infection prevalence and infected tick density. Our findings highlight the importance of host movement and tick population dynamics in explaining the infected tick spread rate into new regions. Tick infection prevalence and infected tick density were driven by predictors related to the infection process and tick population dynamics, respectively. Our results suggest that control strategies aiming to reduce tick burden on tick reproduction hosts and encounter rate between immature ticks and pathogen amplification hosts will be most effective at reducing tick-borne disease risk.

scholarly journals Seroprevalence of Rickettsia bellii and Rickettsia felis in dogs, São José dos Pinhais, State of Paraná, Brazil

2010 ◽  
Vol 19 (4) ◽  
pp. 222-227 ◽  
Author(s):  
Fernanda Silva Fortes ◽  
Iara Silveira ◽  
Jonas Moraes-Filho ◽  
Ronaldo Viana Leite ◽  
José Edivaldo Bonacim ◽  
...  
Keyword(s):  
Spotted Fever ◽  
Human Case ◽  
Immunofluorescence Assay ◽  
Human Infection ◽  
Southern Brazil ◽  
Serum Samples ◽  
Rickettsia Felis ◽  
Rickettsia Species ◽  
Rickettsia Rickettsii ◽  
Low Prevalence

Brazilian spotted fever (BSF) is a vector-borne zoonosis caused by Rickettsia rickettsii bacteria. Dogs can be host sentinels for this bacterium. The aim of the study was to determine the presence of antibodies against Rickettsia spp. in dogs from the city of São José dos Pinhais, State of Paraná, Southern Brazil, where a human case of BSF was first reported in the state. Between February 2006 and July 2007, serum samples from 364 dogs were collected and tested at 1:64 dilutions by indirect immunofluorescence assay (IFA) against R. rickettsii and R. parkeri. All sera that reacted at least to one of Rickettsia species were tested against the six main Rickettsia species identified in Brazil: R. rickettsii, R. parkeri, R. bellii, R. rhipicephali, R. amblyommii and R. felis. Sixteen samples (4.4%) reacted to at least one Rickettsia species. Among positive animals, two dogs (15.5%) showed suggestive titers for R. bellii exposure. One sample had a homologous reaction to R. felis, a confirmed human pathogen. Although Rickettsia spp. circulation in dogs in the area studied may be considered at low prevalence, suggesting low risk of human infection, the present data demonstrate for the first time the exposure of dogs to R. bellii and R. felis in Southern Brazil.

scholarly journals Comparative Analysis of Infection by Rickettsia rickettsii Sheila Smith and Taiaçu Strains in a Murine Model

Pathogens ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 744
Author(s):  
Eliane Esteves ◽  
Chanida Fongsaran ◽  
Ingeborg M. Langohr ◽  
Sean P. Riley ◽  
Marcelo B. Labruna ◽  
...  
Keyword(s):  
United States ◽  
Spotted Fever ◽  
Case Fatality ◽  
Rocky Mountain ◽  
The United States ◽  
Rocky Mountain Spotted Fever ◽  
Rickettsia Rickettsii ◽  
Virulent Strains ◽  
Life Threatening ◽  
Tick Borne Disease

Rocky Mountain spotted fever (RMSF) is a life-threatening tick-borne disease caused by Rickettsia rickettsii, which is widely distributed throughout the Americas. Over 4000 cases of RMSF are recorded annually in the United States, while only around 100 cases are reported in Brazil. Conversely, while case fatality rates in the United States oscillate around 5%, in Brazil they can surpass 70%, suggesting that differences in tick vectoring capacity, population sensitivity, and/or variability in virulence of the rickettsial strains may exist. In this study, we compared the susceptibility of C3H/HeN mice to two highly virulent strains of R. rickettsii, one from the United States (Sheila Smith) and the other from Brazil (Taiaçu). Animals inoculated with the Taiaçu strain succumbed to infection earlier and exhibited severe histological lesions in both liver and spleen sooner than mice infected with the Sheila Smith strain. These differences in survival and signs of the disease are not related to a greater proliferation of the Taiaçu strain, as there were no significant differences in the rickettsial load in mice tissues inoculated with either strain. The present study is the first step to experimentally assess differences in fatality rates of RMSF in two different regions of the American continent.

scholarly journals Rickettsial spotted fever in capoeirão Village, Itabira, Minas Gerais, Brazil

2008 ◽  
Vol 50 (5) ◽  
pp. 297-301 ◽  
Author(s):  
Manoella Campostrini Barreto Vianna ◽  
Maurício Claudio Horta ◽  
Luis Antônio Sangioni ◽  
Adriana Cortez ◽  
Rodrigo Martins Soares ◽  
...  
Keyword(s):  
Spotted Fever ◽  
Minas Gerais ◽  
Immunofluorescence Assay ◽  
Tick Population ◽  
Rickettsial Infection ◽  
Rickettsia Rickettsii ◽  
Minas Gerais State ◽  
Brazilian Spotted Fever ◽  
Polymerase Chain ◽  
Sfg Rickettsia

The present study investigated the infection by spotted fever rickettsia in an endemic area for Brazilian spotted fever (BSF; caused by Rickettsia rickettsii) in Minas Gerais State, Brazil. Human, canine and equine sera samples, and Amblyomma cajennense adult ticks collected in a rural area of Itabira City, Minas Gerais State were tested for rickettsial infection. Through Immunofluorescence Assay (IFA) we demonstrated the presence of antibodies anti-R. rickettsii in 8.2%, 81.3% and 100% of the human, canine and equine sera, respectively. None of the 356 tick specimens analyzed were positive for Rickettsia by the hemolymph test or Polymerase Chain Reaction technique (PCR) for the htrA and the gltA genes. Our serological results on horses and dogs (sentinels for BSF) appoint for the circulation of a SFG Rickettsia in the study area, however in a very low infection rate among the A. cajennense tick population.

scholarly journals Integrated tick control on a farm with the presence of capybaras in a Brazilian spotted fever endemic region

2019 ◽  
Vol 28 (4) ◽  
pp. 671-676
Author(s):  
Shirley Batista de Araújo ◽  
Karina Araújo dos Anjos ◽  
Fernanda Calvo Duarte ◽  
Leonardo Costa Fiorini ◽  
Felipe Eduardo de Matos Godoi ◽  
...  
Keyword(s):  
Spotted Fever ◽  
Adult Tick ◽  
Tick Control ◽  
First Year ◽  
Tick Population ◽  
Single Individual ◽  
Endemic Region ◽  
Rickettsia Rickettsii ◽  
Tietê River ◽  
Brazilian Spotted Fever

Abstract Ticks of the Amblyomma cajennense complex present high infestation rates. These ticks transmit the bacterium Rickettsia rickettsii, which causes Brazilian Spotted Fever. For this reason, an integrated tick control system was adopted on a farm in the municipality of Itu, state of São Paulo. On this farm, which borders the Tietê river, domestic animals are in contact with populations of capybaras. Six locations were monitored and evaluated between the years of 2015 and 2017. During this work 1271 nymphs and adult ticks were caught, all of them from the Amblyomma sculptum species, except for a single individual from the Amblyomma dubitatum species. The integrated tick management reduced the overall infestation levels to zero. Adult tick population dropped in the first year of the study, while larvae population dropped in the second year. Nymph population dropped in both years, decreasing in higher numbers in the first year. The estimated mean infestation levels for all of the tick’s life cycle forms in the six monitored spots did not reach one individual in the end of the study. Estimated mean infestation levels for nymphs in these places equaled zero.

scholarly journals Serological evidence of Rickettsia in horses from a semi-arid Brazilian region

2021 ◽  
Vol 30 (2) ◽  
Author(s):  
Ila Ferreira Farias ◽  
Eline Almeida Rodrigues de Souza ◽  
Maria Carolina de Azevedo Serpa ◽  
Flávio Silva Palha ◽  
Glauber Meneses Barboza de Oliveira ◽  
...  
Keyword(s):  
Central Region ◽  
Endemic Area ◽  
Spotted Fever ◽  
Immunofluorescence Assay ◽  
North Central Region ◽  
North Central ◽  
Rickettsia Rickettsii ◽  
The North ◽  
Tick Borne Disease ◽  
Brazilian Spotted Fever

Abstract Brazilian spotted fever (BSF) is a common tick-borne disease caused by Rickettsia rickettsii. Horses are the primary hosts of the main vector, Amblyomma sculptum, and are considered efficient sentinels for circulation of Rickettsia. Therefore, the aim of this study was to detect antibodies reactive to R. rickettsii antigens in horses from a non-endemic area in the north-central region of Bahia state, Brazil. Blood samples and ticks were collected from 70 horses from the municipalities of Senhor do Bonfim, Antônio Gonçalves, Pindobaçu, and Campo Formoso. The sera obtained were tested by an indirect immunofluorescence assay to detect anti-Rickettsia antibodies. Overall, 5.7% (4/70) of the horses reacted to R. rickettsii antigens. Ticks were collected from 18.6% (13/70) of the horses and were identified as A. sculptum and Dermacentor nitens. Despite being a non-endemic area, seropositive animals were identified in our study, suggesting circulation of rickettsial agents in the region. This is the first serological survey of this agent in horses from the north-central region of Bahia, and further studies are needed to understand the epidemiology of BSF in these locations.

A cluster ofRickettsia rickettsiiinfection at an animal shelter in an urban area of Brazil

2014 ◽  
Vol 143 (11) ◽  
pp. 2446-2450 ◽  
Author(s):  
T. ROZENTAL ◽  
M. S. FERREIRA ◽  
R. GOMES ◽  
C. M. COSTA ◽  
P. R. A. BARBOSA ◽  
...  
Keyword(s):  
Urban Area ◽  
Spotted Fever ◽  
Fatal Case ◽  
Febrile Illness ◽  
Spotted Fever Group ◽  
Animal Shelter ◽  
Rickettsia Rickettsii ◽  
Occupationally Exposed ◽  
Tick Borne Disease ◽  
Brazilian Spotted Fever

SUMMARYRickettsia rickettsiiinfection is being increasingly recognized as an important cause of fatal acute illness in Brazil, where this tick-borne disease is designated Brazilian spotted fever (BSF). In this study we report five fatal cases of BSF in employees of an animal shelter in an urban area in the municipality of Rio de Janeiro in southeast Brazil after a natural disaster on 11 January 2011. Four of the cases occurred from 27 January to 11 April 2011, while the fifth fatal case was identified in April 2012. Three cases were confirmed by molecular analysis and two by epidemiological linkage. An investigation of BSF was performed in the animal shelter, and blood samples were collected from 115 employees and 117 randomly selected dogs. The presence of high levels (1024–4096) of antibodies against spotted fever group rickettsiae was found in three (2·6%) employees and 114 (97·5%) dogs. These findings emphasize the need to consider BSF as a possible cause of undifferentiated febrile illness, especially dengue and leptospirosis, in patients occupationally exposed to dogs heavily infested by ticks, mainly working at kennels and animal shelters that have inadequate space for the animals housed and frequently providing an environment conducive to exposure to pathogens such asR. rickettsii.

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