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The Pacific Coast tick (Dermacentor occidentalis Marx, 1892) is a frequently encountered and commonly reported human-biting tick species that has been recorded from most of California and parts of southwestern Oregon, southcentral Washington, and northwestern Mexico. Although previous investigators have surveyed populations of D. occidentalis for the presence of Rickettsia species across several regions of California, populations of this tick have not been surveyed heretofore for rickettsiae from Baja California, Oregon, or Washington. We evaluated 1,367 host-seeking, D. occidentalis adults collected from 2015 to 2022 by flagging vegetation at multiple sites in Baja California, Mexico, and Oregon and Washington, United States, using genus- and species-specific assays for spotted fever group rickettsiae. DNA of Rickettsia 364D, R. bellii, and R. tillamookensis was not detected in specimens from these regions. DNA of R. rhipicephali was detected in D. occidentalis specimens obtained from Ensenada Municipality in Baja California and southwestern Oregon, but not from Washington. All ompA sequences of R. rhipichephali that were amplified from individual ticks in southwestern Oregon were represented by a single genotype. DNA of the Ixodes pacificus rickettsial endosymbiont was amplified from specimens collected in southwestern Oregon and Klickitat County, Washington; to the best of our knowledge, this Rickettsia species has never been identified in D. occidentalis. Collectively, these data are consistent with a relatively recent introduction of Pacific Coast ticks in the northernmost extension of its recognized range.

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Spotted fever group (SFG) rickettsiae are obligatory intracellular bacteria that cause disease in humans and other animals. Ixodid ticks are the principal vectors of SFG rickettsiae. The present study aimed to determine the prevalence and species identity of SFG rickettsiae in ticks and horses from urban and rural areas of western Cuba using PCR assays. Tick samples, collected from 79 horses, consisted of 14 Amblyomma mixtum adults, 111 Dermacentor nitens adults and 19 pools of D. nitens nymphs (2-5 individuals/pool). The PCR results revealed the presence of Rickettsia spp. in 64% of the A. mixtum adults, 16% of the D. nitens adults, and 11% of the pooled samples of D. nitens nymphs. In contrast, Rickettsia spp. was not detected in any of the 200 horse blood samples included in this study. DNA sequence data of the rickettsial 17 kDa antigen gene showed that Rickettsia amblyommatis was present in A. mixtum; and Rickettsia felis in D. nitens. This is the first report of R. felis in D. nitens in Cuba. The present study extends our knowledge of the potential vector spectrum and distribution of SFG rickettsiae pathogens in western Cuba.

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The entity called tick-borne lymphadenopathy, also known as dermacentor-borne necrosis eritema lymphadenopathy, is included in the differential diagnosis of diseases transmitted by ticks, which have increased considerably in recent years due to greater clinical-epidemiological observation and diagnostic improvement. It is a zoonosis caused by Rickettsia slovaca and transmitted by the bite of the Dermacentor marginatus tick. Affected patients have a necrotic eschar surrounded by an erythematous halo in the scalp, as well as painful regional lymphadenopathy. We present a seven-year-old male who shows, after the extraction of a tick, a necrotic eschar on the scalp, accompanied by lymphadenopathy and low-grade fever. The study of polymerase chain reaction and culture of the lesion confirm the presence of Rickettsia slovaca. The patient received oral azithromycin with a good response. In Primary Care, it is important to monitor the tick bites, to detect possible diseases transmitted by them.

La entidad llamada tick-borne lymphadenopathy, también conocida como dermacentor-borne necrosis eritema lymphadenopathy, se incluye dentro del diagnóstico diferencial de enfermedades transmitidas por garrapatas, que han aumentado considerablemente en los últimos años debido a una mayor observación clínica-epidemiológica y mejoría diagnóstica. Es una zoonosis causada por Rickettsia slovaca y transmitida por la picadura de la garrapata Dermacentor marginatus. Los pacientes afectados tienen una escara necrótica rodeada de un halo eritematoso en el cuero cabelludo y adenopatías regionales dolorosas. Se presenta a un varón de siete años que mostró, tras la extracción de una garrapata, una escara necrótica en el cuero cabelludo, con adenopatías y febrícula. La reacción en cadena de la polimerasa y el cultivo de la lesión confirmaron la presencia de Rickettsia slovaca. El paciente recibió azitromicina oral con buena respuesta. En Atención Primaria, es importante el seguimiento de las picaduras de garrapatas para detectar posibles enfermedades transmitidas por estas.

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The study of rickettsial agents associated with ticks from wild felines is scarce. In Europe, three species of Rickettsia have been detected (Rickettsia helvetica, Rickettsia massiliae, and Rickettsia monacensis) in ticks collected from the Iberian lynx (Lynx pardinus). However, no studies have been conducted on another lynx species. For this reason, the aim of this study was to identify the diversity of Rickettsia species in ticks associated with bobcats (Lynx rufus) collected in the State of Tamaulipas, Mexico. During 1999 and 2004, nine bobcats from two municipalities of the state were trapped and visually inspected for the presence of ticks. A total of 95 ticks were collected from these lynxes. Ticks were preserved in 96% ethanol. Subsequently we identified the presence of Rickettsia DNA by the amplification of several fragments of genes 17 kDa, ompA and ompB. Recovered sequences were concatenated, aligned, and compared with those of reference deposited in GenBank. Additionally, a phylogenetic analysis was performed using the Maximum Likelihood method. The ticks were morphologically identified as belonging to the species Dermacentor variabilis. We selected a subset of 60 ticks which were examined, and 5% (3/60) were positive with an identity of 99% to sequences of R. rickettsii deposited in GenBank. The results obtained represent the first record of R. rickettsii in ticks associated with wild carnivores, and in particular with bobcats distributed in northeast of Mexico.

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Horses are among the domestic animals that closely interact with humans and are highly parasitized by ticks, which are the primary vectors of zoonoses. As horses in Tayrona National Natural Park (PNNT) are used as a means of transporting goods, luggage and people, they are in constant contact with wild animals, workers and tourists from different countries. These factors increase the transmission risk of hemoparasites. The purpose of this study was to determine the presence of Rickettsia sp., Anaplasma sp., and Theileria sp., in horse ticks in this protected area using conventional PCR. We collected 343 ticks of genera Amblyomma, Rhipicephalus and Dermacentor. Of the 61 samples analyzed by PCR, 18 (29.5%) individuals were positive for Rickettsia sp., 15 (24.5%) for Anaplasma sp. and 4 (6.6%) for Theileria sp. This is the first report of these hemoparasite genera in ticks associated with horses in this preserved natural area, demonstrating the importance of additional studies on the presence and epidemiology of hemoparasites and their vectors in domestic and wild animals in conserved areas with a high flow of tourists.

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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 were A. 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(AU)

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.(AU)

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RESUMO

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 were A. 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(AU)

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.(AU)

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During a study to identify zoonotic pathogens in northwestern Mexico, we detected the presence of a rickettsial agent in Dermacentor parumapertus ticks from black-tailed jackrabbits (Lepus californicus). Comparison of 4 gene sequences (gltA, htrA, ompA, and ompB) of this agent showed 99%-100% identity with sequences of Rickettsia parkeri.

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The aim of this study was to investigate the presence of DNA of Borrelia burgdorferi sensu lato (s.l.) in ticks that feed on horses used for animal traction in rural Jataizinho, Parana, Brazil. Between February and June 2008, a total of 224 ticks was collected of which 75% were identified as Dermacentor nitens and 25% as Amblyomma cajenense. To amplify B. burgdorferi s.l. DNA, the intergenic space region (ISR) between the 5S (rrf) 23S (rrl) rRNA genes was used as targets for nested-PCR. Two ticks of the D. nitens species were positive for B. burgdorferi s.l. Both species showed a fragment of 184 bp, but the sequencing revealed 99.9% homology with the B. burgdorferi sensu stricto (s.s.) strain B31. These results showed, for the first time, the presence of spirochete DNA infecting ticks that parasitize horses used for animal traction, in the rural municipality mentioned. In conclusion, this study opens up promising prospects for determining the infection rate of B. burgdorferi s.s. genospecies or other species in the equine population, as well as the impact of the infection rate on Lyme disease in the state of Parana.

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RESUMO

The aim of this study was to investigate the presence of DNA of Borrelia burgdorferi sensu lato (s.l.) in ticks that feed on horses used for animal traction in rural Jataizinho, Parana, Brazil. Between February and June 2008, a total of 224 ticks was collected of which 75% were identified as Dermacentor nitens and 25% as Amblyomma cajenense. To amplify B. burgdorferi s.l. DNA, the intergenic space region (ISR) between the 5S (rrf) 23S (rrl) rRNA genes was used as targets for nested-PCR. Two ticks of the D. nitens species were positive for B. burgdorferi s.l. Both species showed a fragment of 184 bp, but the sequencing revealed 99.9% homology with the B. burgdorferi sensu stricto (s.s.) strain B31. These results showed, for the first time, the presence of spirochete DNA infecting ticks that parasitize horses used for animal traction, in the rural municipality mentioned. In conclusion, this study opens up promising prospects for determining the infection rate of B. burgdorferi s.s. genospecies or other species in the equine population, as well as the impact of the infection rate on Lyme disease in the state of Parana.

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