Report of <i>Amblyomma sculptum</i> in a House in a <i>Rickettsia rickettsii</i> Circulation Area

Alkmim, Matheus Araújo de; Ferreira, Lorena Lopes; Bastianetto, Eduardo; Bastos, Camila de Valgas e; Silveira, Júlia A.G.

doi:10.1089/vbz.2020.2735

Cited by 3 publications

(4 citation statements)

References 12 publications

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“…The shores of Lake Paranoa ´are occupied by a variety of species, ranging from residential and protected areas to clubs and parks, which are visited daily by humans and domestic animals. These animals may have occasional contact with A. sculptum and carry ticks into residences, highlighting the role of pets as possible carriers of BSF vectors into human settlements [61]. We emphasized that the number of A. sculptum ticks may be influenced by the number of domestic animals, especially dogs and cats [62,63], and therefore we recommend that further studies in the Lake Paranoa ´consider the frequency of domestic animals in addition to capybaras presence.…”

Section: Plos Onementioning

confidence: 89%

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Effect of environmental variables on the abundance of Amblyomma ticks, potential vectors of Rickettsia parkeri in central Brazil

Gomes,

Gurgel-Gonçalves,

Gazeta

et al. 2024

PLoS ONE

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Amblyomma ticks are vectors of both Rickettsia rickettsii and R. parkeri in the Americas, where capybaras (Hydrochoerus hydrochaeris) are the main hosts in urban areas, thus contributing to the transmission of spotted fever. Herein, we studied: (i) the seasonal dynamics and abundance of ticks in areas where capybaras live, (ii) the effect of environmental variables on tick abundance, and (iii) the presence of Rickettsia-infected ticks. Between September 2021 and September 2022, we sampled ticks using cloth-dragging at 194 sites on the shore of Lake Paranoá in Brasília, Brazil. We measured environmental data (season, vegetation type, canopy density, temperature, humidity, and presence or vestige of capybara) at each site. Nymphs and adults were morphologically identified to the species level, and a selected tick sample including larvae was subjected to genotypic identification. We investigated Rickettsia-infected ticks by PCR (gltA, htrA, ompB, and ompA genes) and associations between tick abundance and environmental variables using Generalized Linear Models. A total of 30,334 ticks (96% larvae) were captured. Ticks were identified as Amblyomma, with A. sculptum comprising 97% of the adult/nymphs. Genotype identification of a larval sample confirmed that 95% belonged to A. dubitatum. Seasonal variables showed significant effects on tick abundance. Most larvae and nymphs were captured during the early dry season, while the adults were more abundant during the wet season. Vegetation variables and the presence of capybaras showed no association with tick abundance. Rickettsia parkeri group and R. bellii were identified in A. dubitatum, while A. sculptum presented R. bellii. We conclude that: (i) Amblyomma ticks are widely distributed in Lake Paranoá throughout the year, especially larvae at the dry season, (ii) the abundance of Amblyomma ticks is explained more by climatic factors than by vegetation or presence of capybaras, and (iii) A. dubitatum ticks are potential vectors of R. parkeri in Brasília.

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Section: Plos Onementioning

confidence: 89%

“…These animals may have occasional contact with A . sculptum and carry ticks into residences, highlighting the role of pets as possible carriers of BSF vectors into human settlements [ 61 ]. We emphasized that the number of A .…”

Section: Discussionmentioning

confidence: 99%

Effect of environmental variables on the abundance of Amblyomma ticks, potential vectors of Rickettsia parkeri in central Brazil

Gomes,

Gurgel-Gonçalves,

Gazeta

et al. 2024

PLoS ONE

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“…Capybaras have encroached on suburban habitats, putting them in close contact with human populations [ 48 ]. When dogs cross the environment in which capybaras live, they can serve as bridge hosts to facilitate human contact with infected ticks [ 50 ]. Indeed, dogs have been documented to have a relatively high seroprevalence to spotted fever group rickettsiae in Brazil (up to 70%) [ 51 , 52 , 53 ], and as many as 13% of Rh.…”

Section: Clinical and Epidemiological Significance Of Rocky Mountain ...mentioning

confidence: 99%

A Vaccine for Canine Rocky Mountain Spotted Fever: An Unmet One Health Need

et al. 2022

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Outbreaks of life-threatening Rocky Mountain spotted fever in humans and dogs associated with a canine-tick maintenance cycle constitute an important One Health opportunity. The reality of the problem has been observed strikingly in Mexico, Brazil, Colombia, and Native American tribal lands in Arizona. The brown dog tick, Rhipicephalus sanguineus sensu lato, acquires the rickettsia from bacteremic dogs and can maintain the bacterium transtadially to the next tick stage. The subsequent adult tick can then transmit infection to a new host, as shown by guinea pig models. These brown dog ticks maintain spotted fever group rickettsiae transovarially through many generations, thus serving as both vector and reservoir. Vaccine containing whole-killed R. rickettsii does not stimulate sufficient immunity. Studies of Rickettsia subunit antigens have demonstrated that conformationally preserved outer-membrane autotransporter proteins A and B are the leading vaccine candidates. The possibility of a potentially safe and effective live attenuated vaccine has only begun to be explored as gene knockout methods are applied to these obligately intracellular pathogens.

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“…Of great importance is its ability to transmit pathogens during the blood-feeding process on vertebrate hosts. In the scientific field, it is well-established that A. sculptum serves as a vector for the bacterium Rickettsia rickettsii Lima, 1916, which can be transmitted to humans when an infected tick feeds on human blood, leading to Brazilian Spotted Fever (BSF) [5][6][7][8]. Recent years have seen reported cases of BSF in Brazil, highlighting the urgent need for alternative tick control methods [9,10].…”

Section: Introductionmentioning

confidence: 99%

Effects of Piper aduncum (Piperales: Piperaceae) Essential Oil and Its Main Component Dillapiole on Detoxifying Enzymes and Acetylcholinesterase Activity of Amblyomma sculptum (Acari: Ixodidae)

Pereira Filho,

do Vale,

de Oliveira Monteiro

et al. 2024

IJMS

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Amblyomma sculptum is a species of tick in the family Ixodidae, with equids and capybaras among its preferred hosts. In this study, the acaricidal activity of the essential oil (EO) from Piper aduncum and its main component, Dillapiole, were evaluated against larvae of A. sculptum to establish lethal concentration values and assess the effects of these compounds on tick enzymes. Dillapiole exhibited slightly greater activity (LC50 = 3.38 mg/mL; 95% CI = 3.24 to 3.54) than P. aduncum EO (LC50 = 3.49 mg/mL; 95% CI = 3.36 to 3.62) against ticks. The activities of α-esterase (α-EST), β-esterase (β-EST), and glutathione-S-transferase (GST) enzymes in A. sculptum larvae treated with Dillapiole showed a significant increase compared to the control at all concentrations (LC5, LC25, LC50 and LC75), similar results were obtained with P. aduncum EO, except for α-EST, which did not differ from the control at the highest concentration (LC75). The results of the acetylcholinesterase (AChE) activity show an increase in enzyme activity at the two lower concentrations (LC5 and LC25) and a reduction in activity at the two higher, lethal concentrations (LC50 and LC75) compared to the control. These results suggest potential mechanisms of action for these natural acaricides and can provide guidance for the future development of potential plant-derived formulations.

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Report of Amblyomma sculptum in a House in a Rickettsia rickettsii Circulation Area

Cited by 3 publications

References 12 publications

Effect of environmental variables on the abundance of Amblyomma ticks, potential vectors of Rickettsia parkeri in central Brazil

Effect of environmental variables on the abundance of Amblyomma ticks, potential vectors of Rickettsia parkeri in central Brazil

A Vaccine for Canine Rocky Mountain Spotted Fever: An Unmet One Health Need

Effects of Piper aduncum (Piperales: Piperaceae) Essential Oil and Its Main Component Dillapiole on Detoxifying Enzymes and Acetylcholinesterase Activity of Amblyomma sculptum (Acari: Ixodidae)

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