Rickettsial Genes gltA Research Articles

Epidemiology of Rickettsia spp. in Atlantic rainforest areas of island and seashore mainland, southern Brazil.

Non-fatal cases of rickettsial infection with different clinical features than the classic BSF (Brazilian Spotted Fever) have been reported in seashore areas of Paraná state, southern Brazil. In addition, Amblyomma ovale tick infected by Rickettsia parkeri strain Atlantic rainforest has been also described in this area. Accordingly, the aim of this study was to investigate the occurrence of anti-Rickettsia spp. antibodies in human and dog populations, and Rickettsia spp. infection in ticks from oceanic islands and seashore mainland cities of southern Brazil. Serum samples were collected from 328 persons and their 282 dogs from three islands and two seashore mainland cities. A total of 211 ticks were collected from dogs, identified as A. ovale and R. sanguineus. In overall, 40 of 328 (12.2%) human samples were seropositive for Rickettsia spp., including 21 of 190 (11.1%) on islands and 19 of 138 (13.7%) on seashore mainland, and 62 of 282 (22.0%) dog samples, including 31 of 153 (20.3%) on islands and 31 of 129 (24.0%) in seashore mainland areas. In overall, nine of 82 (11.0%) ticks were positive to real-time PCR assay targeting a fragment of the rickettsial gltA gene, including two of 64 (3.1%) Rickettsia sanguineus and seven of 18 (38.9%) A. ovale, of which four were infected with the R. parkeri strain Atlantic rainforest. Despite no association between risk factors and Rickettsia spp. seropositivity was found in human beings, access to natural areas (p=.011) and tick infestation (p=.004) was significantly associated to dog seropositivity. The serological and molecular findings herein have confirmed previous tick and clinical case reports and enlarged the geographical occurrence of A. ovale infected by R. parkeri strain Atlantic rainforest in oceanic islands and seashore mainland cities of Paraná State, indicating a new likely transmission area of this new rickettsial infection in human beings and dogs of southern Brazil.

Amblyomma ticks in animal carcasses hunted in Mapinguari National Park, Western Amazon, Brazil: New records on species and host-parasite relationships

Ticks are obligatory parasites and transmit several pathogens to animals and humans. This study aimed to report the parasitism of ticks on carcasses of animals hunted by hunters from communities near Mapinguari National Park, at the shared border of Amazonas and Rondonia states, northern Brazil. The ticks were collected from heads of carcasses of the following animals: South American tapir (Tapirus terrestris), collared peccary (Pecari tajacu) and long-nosed armadillo (Dasypus beniensis). Six Amblyomma tick species were identified: Amblyomma coelebs, Amblyomma naponense, Amblyomma latepunctatum, Amblyomma oblongoguttatum, Amblyomma scalpturatum, Amblyomma triste and Amblyomma spp. The most abundant tick species were A. oblongoguttatum and A. scalpturatum. DNA extraction and polymerase chain reaction (PCR) were performed on all ticks to test for the presence of rickettsial gltA gene fragments, but no amplification was observed. This study reports, for the first time, the parasitism of A. coelebs in the armadillo D. beniensis and the presence of A. triste in the states of Amazonas and Rondonia, updating the tick fauna to 24 and 39 species for these states, respectively.

Molecular Survey and Spatial Distribution of Rickettsia spp. in Ticks Infesting Free-Ranging Wild Animals in Pakistan (2017-2021).

Rickettsia spp. associated with ticks infesting wild animals have been mostly neglected in several countries, including Pakistan. To address this knowledge gap, ticks were collected during 2017 to 2021 from wild animals including cats (Felis chaus), Indian hedgehogs (Paraechinus micropus), and wild boars (Sus scrofa). The collected ticks were morpho-molecularly identified and screened for the detection of Rickettsia spp. Morphologically identified ticks were categorized into four species of the genus Rhipicephalus: Rhipicephalus haemaphysaloides, Rh. turanicus, Rh. sanguineus sensu lato (s.l), and Rh. microplus. Among 53 wild animals examined, 31 were infested by 531 ticks, an overall prevalence of 58.4%. Adult female ticks were predominant (242 out of 513 ticks collected, corresponding to 46%) in comparison with males (172, 32%), nymphs (80, 15%) and larvae (37, 7%). The most prevalent tick species was Rh. turanicus (266, 50%), followed by Rh. microplus (123, 23%), Rh. sanguineus (106, 20%), and Rh. haemaphysaloides (36, 7%). Among the screened wild animals, wild boars were the most highly infested, with 268 ticks being collected from these animals (50.4%), followed by cats (145, 27.3%) and hedgehogs (118, 22.3%). Tick species Rh. haemaphysaloides, Rh. turanicus, and Rh. sanguineus were found on wild boars, Rh. haemaphysaloides, and Rh. microplus on cats, and Rh. turanicus on hedgehogs. In a phylogenetic analysis, mitochondrial cytochrome C oxidase 1 (cox1) sequences obtained from a subsample (120) of the collected ticks clustered with sequences from Bangladesh, China, India, Iran, Myanmar, and Pakistan, while 16S ribosomal DNA (16S rDNA) sequences clustered with sequences reported from Afghanistan, Egypt, India, Pakistan, Romania, Serbia, and Taiwan. Among Rickettsia infected ticks (10/120, 8.3%), Rh. turanicus (7/10, 70%), and Rh. haemaphysaloides (3/10, 30%) were found infesting wild boars in the districts Mardan and Charsadda. The obtained rickettsial gltA gene sequences showed 99% and ompA gene sequences showed 100% identity with Rickettsia massiliae, and the phylogenetic tree shows ompA clustered with the same species reported from France, Greece, Spain, and USA. This study emphasizes the need for effective surveillance and control programs in the region to prevent health risks due to tick-borne pathogens, and that healthy infested wild animals may play a role in the spread of these parasites.

Rickettsial infection in free-ranging capybaras (Hydrochoerus hydrochaeris) and their ticks (Acari, Ixodidae) in the Caatinga and Atlantic forest biomes, Northeastern Brazil.

Caatinga and Atlantic Forest are Brazilian biomes threatened by anthropogenic disturbances, which are a serious threat to biodiversity and favor the emergence of zoonotic pathogens. Capybara populations are increasingly present in urban and rural areas due to the loss of their natural habitats. There are no studies on the rickettsial infection in these rodents in Northeastern Brazil, although there are case records of Brazilian Spotted Fever (BSF) in this region. In this context, we evaluated rickettsial infection in capybaras and their ticks in four areas of the Atlantic Forest and Caatinga biomes in Northeastern Brazil. Blood sera from 21 capybaras were tested by indirect immunofluorescence assay (IFA) using Rickettsia rickettsii, R. parkeri, and R. amblyommatis antigens. Blood samples and ticks (Amblyomma sp., Amblyomma dubitatum and Amblyomma sculptum) were tested by PCR, targeting a fragment of the rickettsial gltA gene and R. bellii primers. Overall, 15 out of 21 capybaras (71.4%) reacted positively (titer ≥64) to at least one of the three Rickettsia antigens tested, with final titers ranging from 64 to 1024. No rickettsial DNA was found in capybara blood samples. Rickettsial DNA was detected in 22 of 31 adult tick pools using gltA gene, being all nine pools of A. sculptum and 16 of the 19 of A. dubitatum, but all samples were negative to R. bellii specific primers. All attempts to sequence the amplicon were unsuccessful, indicating a possible low rickettsial load in the tick samples. The present study reports for the first time the serological evidence of Rickettsia spp. infection in free-ranging capybaras and suggest the rickettsial infection in A. sculptum and A. dubitatum in the Caatinga and Atlantic Forest biomes in Northeastern Brazil.

Ticks (Acari: Ixodidae) on marsh deer (Blastocerus dichotomus) at a conservation center: infestation and Rickettsia parkeri infection dynamics along nine years

The objective of this work was to evaluate the relationship between the populations of the ticks Amblyomma triste Koch, 1844, Rhipicephalus microplus (Canestrini, 1888), Amblyomma sculptum Berlese, 1888, the pathogenic bacteria Rickettsia parkeri and a marsh deer (Blastocerus dichotomus) population after its removal from a pristine environment. For this purpose, ticks were collected from the cervical region of deer at the Marsh Deer Conservation Center in Promissão, São Paulo State, Brazil for nine consecutive years (2000 - 2008). Deer in captivity at the Center were kept in 2,000 m² paddocks surrounded by two-meter-high fences in the Tiete-river marsh. In total, 1,012 ticks of 26 deer were collected. Prevalence of the species A. triste among tick-infested hosts was the highest in the first triennium but decreased to the second and further to the third triennium. In contrast, the R. microplus prevalence amidst infested host population, increased from the first to the third triennium and was the species that attained the highest infestation intensity. Amblyomma sculptum was the tick with the lowest infestation prevalence and intensity throughout the period. The change in the proportion between the two most prevalent species was attributed to the new environment, specifically its restricted size and within it a dry area more suitable for R. microplus. DNA of 424 ticks processed in 276 pools was tested for Rickettsia genetic material by polymerase chain reactions (PCR). Twenty samples of the study were positive for the rickettsial gltA gene. Of these, 18 were from A. triste ticks and revealed the presence of the ompA spotted fever group gene as well. Eleven samples were sequenced and showed 100% identity with R. parkeri sensu stricto. Two samples from R. microplus did not amplify ompA gene neither yielded product in a PCR specific for Rickettsia bellii. Sequencing of the gltA gene in the DNA of these two ticks was also 100% identical with R. parkeri s.s. In conclusion, the changes in the deer environment modified the tick populations but maintained, at least temporary, R. parkeri bacteria in A. triste ticks. Rhipicephalus microplus was refractory to the R. parkeri infection and bacterial DNA in this tick species indicated DNA spill over from other tick species. It was demonstrated that captive marsh deer may sustain cattle tick populations on its own. This would hardly occur under pristine conditions because of the inadequacy the marsh deer´s naturally humid habitat for the cattle tick. However, deer transportations of R. microplus ticks from one farm to another may occur whenever habitat loss pushes this wild animal towards farms.

Evaluation of rickettsial infection in free-range capybaras (Hydrochoerus hydrochaeris Linnaeus, 1766) (Rodentia: Caviidae) and ticks (Acari: Ixodidae) in the Western Amazon, Brazil

Capybaras (Hydrochoerus hydrochaeris Linnaeus, 1766) (Rodentia: Caviidae) are important hosts of Amblyomma ticks (Acari: Ixodidae), which in turn can transmit rickettsiae to humans and animals. However, there is a scarcity of studies about the tick fauna and rickettsial infection in the Amazon region. The present study evaluated rickettsial infection in capybaras and ticks in different areas of the municipality of Rio Branco, state of Acre, in the Western Brazilian Amazon, where rickettsiosis has never been reported. Blood sera from 43 capybaras from four localities in Rio Branco were tested by indirect immunofluorescence assay using Rickettsia rickettsii antigens. Ticks were collected from capybaras and from vegetation as well. Ticks were taxonomically identified to the species level and some of them were tested by PCR, targeting a fragment of the rickettsial gltA gene. Additionally, ticks were tested for bacteria from the genus Borrelia and family Anaplasmatacae. All capybaras submitted to the serological examination were considered non-reactive to R. rickettsii. A total of 410 ticks were collected directly from the capybaras. Amblyomma dubitatum Neumann, 1899 was the most abundant species (82.4%), followed by Amblyomma naponense (Packard, 1869) (14.3%), Amblyomma humerale Koch, 1844 (0.7%), Amblyomma pacae Aragão, 1911 (0.4%), Amblyomma rotundatum Koch 1844 (0.2%) and Amblyomma sp. (1.7%). From the environment 262 ticks were collected: Rhipicephalus microplus (Canestrini, 1888) (88.9%), Dermacentor nitens Neumann, 1897 (9.9%), Amblyomma varium Koch, 1844 (0.7%) and A. rotundatum (0.3%). With the exception of A. humerale, A. rotundatum and R. microplus, all other species are reported here for the first time in the state. Some of the ticks sampled (N = 317) were tested by molecular methods for infection by Rickettsia spp. Rickettsia bellii was identified infecting A. dubitatum and A. rotundatum, while Rickettsia amblyommatis only was found infecting A. humerale and Rickettsia sp. strain Tapirapé was found in A. naponense. This is the first detection of R. bellii and Rickettsia sp. strain Tapirapé in Acre. No Borrelia or Anaplasmataceae were found in the tested ticks. These results add relevant knowledge about the Rickettsia spp. and the acarological fauna in the region of the Western Amazon, and are essential for the maintenance of vigilance about possible pathogens that occur in the state and determination of the risks that they pose to humans and animals that inhabit the region.

Detection of Candidatus Rickettsia tarasevichiae from tick collected from human patient, South Korea

Here we report the detection of Candidatus Rickettsia tarasevichiae from tick collected from human patient through DNA amplification. The tick was identified to be Haemaphysalis longicornis. We amplified and sequenced rickettsial citrate synthase gene (gltA), 190_kDa outer protein gene (ompA), and 120_ kDa outer protein gene (ompB). Sequencing results showed that gltA gene and ompA (GenBank accession No. KT899085, KT899079, respectively) shared 100% nucleotide sequence similarities with Candidatus R. tarasevichiae. In addition, ompB gene shared 96% nucleotide sequence similarity with R. canadensis. However, DNA extracted from patient serum showed 98% sequence similarity with R. japonica (AF123713.1). This result implies that H. longicornis ticks harbor both Candidatus R. tarasevichiae and R. japonica.

Identification of Rickettsial Infections (Rickettsia sp. TH2014) in Ctenocephalides orientis Fleas (Siphonaptera: Pulicidae)

Rickettsia felis (Rickettsiales: Rickettsiaceae) is an emergent human pathogen that causes febrile illnesses in various parts of the world. This study describes the identification and growth characteristics of a R. felis-like organism (designated as Rickettsia sp. TH2014) cultured from Ctenocephalides orientis fleas in rural Malaysia. In this study, culturing of rickettsiae from filtered triturated flea lysates was performed in Aedes albopictus C6/36 cells. Cytopathic effects were observed from one of the samples 4 d post-inoculation. Electron microscopy revealed actively replicating intracytosolic coccobacillary organisms in the rickettsia-infected cells. Sequence analysis of amplified citrate synthase (gltA) gene fragment shows complete match of the rickettsia with Rickettsia sp. Rf31 in Southeast Asia, and 'Candidatus Rickettsia senegalensis' strain PU01-02 in Africa. The whole-genome sequence of Rickettsia sp. TH2014 was determined and assembled. The estimated genome size and guanine + cytosine content of the rickettsia are 1.37 Mb and 32.9%, respectively. The high values of average nucleotide identity and tetra-nucleotide signature correlation index obtained from pairwise genome comparison study suggest the identification of the rickettsia as R. felis. The whole-genome single-nucleotide polymorphism analysis demonstrates close genetic relatedness of the rickettsia with R. felis and Rickettsia asemboensis. However, based on sequence analyses of rickettsial genes (16S rDNA, gltA, ompB, and sca4), Rickettsia sp. TH2014 is found to be distinct from R. felis and R. asemboensis. The sequence analyses reveal that Rickettsia sp. TH2014 is highly similar to 'Ca. Rickettsia senegalensis' detected in fleas from Africa, Asia, and North America. Further investigation to provide insights on pathogenic potential and transmission dynamics of the rickettsia is warranted.

Molecular detection of Rickettsia rhipicephali and other spotted fever group Rickettsia species in Amblyomma ticks infesting wild birds in the state of Minas Gerais, Brazil

The current study evaluated parasitism of wild birds by ticks in a fragment of Atlantic Forest in the state of Minas Gerais, Brazil, and examined the ticks for rickettsial agents. Birds were captured during 2014 and 2015 and ticks were identified by sequencing fragments of the 16S and 12S ribosomal DNA. Among 260 birds representing 19 families and 52 species, a total of 69 (26.5%) were found to be infested by larvae (LL) and/or nymphs (NN) of Amblyomma longirostre (Koch, 1844) (45 LL, 4 NN), Amblyomma calcaratum Neumann, 1899 (9 LL, 15 NN), Amblyomma nodosum Neumann, 1899 (2 NN), Amblyomma parkeri Fonseca and Aragão, 1952 (21 LL), Amblyomma sp. haplotype Nazaré (77 LL), and Haemaphysalis leporispalustris (Packard, 1869) (17 LL, 1 NN). The use of PCR and sequencing of the rickettsial genes gltA, htrA, ompA and ompB, revealed the presence of “Candidatus Rickettsia amblyommii” in A. longirostre (13/49; 26%) and Rickettsia parkeri (strain ApPR) in both A. parkeri (1/21; 5%) and haplotype Nazaré (42/77; 55%) ticks. In addition, we detected Rickettsia rhipicephali in 31 (40%) of the 77 haplotype Nazaré ticks. This is the first record of this rickettsial agent in a species of the genus Amblyomma. The pathogenic potential of this bacterium is undetermined, but the unprecedented association with Amblyomma ticks may represent a cause for concern for public and/or animal health.

Rickettsia lusitaniae associated with Ornithodoros yumatensis (Acari: Argasidae) from two caves in Yucatan, Mexico

The genus Rickettsia includes obligate intracellular bacteria transmitted by several hematophagous arthropods such as ticks, fleas and sucking lice. In particular hard ticks (Ixodidae) have been cited as the main vectors of pathogenic rickettsiae in Mexico. However, there have been only two records of a single Rickettsia species associated with Mexican soft ticks (Argasidae). In this study, we searched for rickettsial DNA in argasid ticks (13 adults and eight nymphs of Ornithodoros yumatensis) from two bat caves in the state of Yucatan, Mexico. Additionally one larva collected in a cave from Chiapas, Mexico, and associated with Desmodus rotundus was used to corroborate the tick taxonomic determination. Of these, nine ticks (43%) yielded expected PCR products for the rickettsial gltA gene. These PCR-positive ticks were tested with additional PCR protocols targeting the rickettsial genes gltA, ompA and ompB. DNA partial sequences from these genes showed 99–100% identities with Rickettsia lusitaniae, an agent isolated from O. erraticus in Portugal, and closely related to R. felis and R. hoogstraalii. Based on the results from this study, the inventory of rickettsiae distributed in Mexico increases from six to seven species.

Rickettsia vini n. sp. (Rickettsiaceae) infecting the tick Ixodes arboricola (Acari: Ixodidae).

BackgroundRecently, a new rickettsia named ‘Candidatus Rickettsia vini’ belonging to the spotted fever group has been molecularly detected in Ixodes arboricola ticks in Spain, the Czech Republic, Slovakia and Turkey, with prevalence reaching up to 100 %. The aim of this study was to isolate this rickettsia in pure culture, and to describe it as a new Rickettsia species.MethodsA total of 148 ornitophilic nidicolous ticks Ixodes arboricola were collected in a forest near Breclav (Czech Republic) and examined for rickettsiae. Shell vial technique was applied to isolate rickettsiae in Vero cells. Rickettsial isolation was confirmed by optical microscopy and sequencing of partial sequences of the rickettsial genes gltA, ompA, ompB, and htrA. Laboratory guinea pigs and chickens were used for experimental infestations and infections. Animal blood sera were tested by immunofluorescence assay employing crude antigens of various rickettsiae.ResultsRickettsia vini n. sp. was successfully isolated from three males of I. arboricola. Phylogenetic analysis of fragments of 1092, 590, 800, and 497 nucleotides of the gltA, ompA, ompB, and htrA genes, respectively, showed closest proximity of R. vini n. sp. to Rickettsia japonica and Rickettsia heilongjiangensis belonging to the spotted fever group. Experimental infection of guinea pigs and chickens with R. vini led to various levels of cross-reactions of R. vini-homologous antibodies with Rickettsia rickettsii, Rickettsia parkeri, ‘Candidatus Rickettsia amblyommii’, Rickettsia rhipicephali, Rickettsia bellii, and Rickettsia felis. Laboratory infestations by R. vini-infected I. arboricola larvae on chickens led to no seroconversion to R. vini n. sp., nor cross-reactions with R. rickettsii, R. parkeri, ‘Ca. R. amblyommii’, R. rhipicephali, R. bellii or R. felis.ConclusionsOur results suggest that R. vini n. sp. is possibly a tick endosymbiont, not pathogenic for guinea pigs and chickens. Regarding specific phenotypic characters and significant differences of DNA sequences in comparison to the most closely related species (R. japonica and R. heilongjiangensis), we propose to classify the isolate as a new species, Rickettsia vini.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1742-8) contains supplementary material, which is available to authorized users.

Bacteria of the genus Rickettsia in ticks (Acari: Ixodidae) collected from birds in Costa Rica

The aim of this study was to document the presence of Rickettsia spp. in ticks parasitizing wild birds in Costa Rica. Birds were trapped at seven locations in Costa Rica during 2004, 2009, and 2010; then visually examined for the presence of ticks. Ticks were identified, and part of them was tested individually for the presence of Rickettsia spp. by polymerase chain reaction (PCR) using primers targeting fragments of the rickettsial genes gltA and ompA. PCR products were DNA-sequenced and analyzed in BLAST to determine similarities with previously reported rickettsial agents. A total of 1878 birds were examined, from which 163 birds (9%) were infested with 388 ticks of the genera Amblyomma and Ixodes. The following Amblyomma (in decreasing order of abundance) were found in immature stages (larvae and nymphs): Amblyomma longirostre, Amblyomma calcaratum, Amblyomma coelebs, Amblyomma sabanerae, Amblyomma varium, Amblyomma maculatum, and Amblyomma ovale. Ixodes ticks were represented by Ixodes minor and two unclassified species, designated here as Ixodes sp. genotype I, and Ixodes sp. genotype II. Twelve of 24 tested A. longirostre ticks were found to be infected with ‘Candidatus Rickettsia amblyommii’, and 2 of 4 A. sabanerae were found to be infected with Rickettsia bellii. Eight of 10 larval Ixodes minor were infected with an endosymbiont (a novel Rickettsia sp. agent) genetically related to the Ixodes scapularis endosymbiont. No rickettsial DNA was found in A. calcaratum, A. coelebs, A. maculatum, A. ovale, A. varium, Ixodes sp. I, and Ixodes sp. II. We report the occurrence of I. minor in Costa Rica for the first time and a number of new bird host–tick associations. Moreover, ‘Candidatus R. amblyommii’ and R. bellii were found in A. longirostre and A. sabanerae, respectively, in Costa Rica for the first time.

Molecular Detection of Rickettsia Species Within Ticks (Acari: Ixodidae) Collected from Arkansas United States.

Rocky Mountain spotted fever (RMSF), caused by the etiological agent Rickettsia rickettsii, is the most severe and frequently reported rickettsial illness in the United States, and is commonly diagnosed throughout the southeast. With the discoveries of Rickettsia parkeri and other spotted fever group rickettsiae (SFGR) in ticks, it remains inconclusive if the cases reported as RMSF are truly caused by R. rickettsii or other SFGR. Arkansas reports one of the highest incidence rates of RMSF in the country; consequently, to identify the rickettsiae in Arkansas, 1,731 ticks, 250 white-tailed deer, and 189 canines were screened by polymerase chain reaction (PCR) for the rickettsial genes gltA, rompB, and ompA. None of the white-tailed deer were positive, while two of the canines (1.1%) and 502 (29.0%) of the ticks were PCR positive. Five different tick species were PCR positive: 244 (37%) Amblyomma americanum L., 130 (38%) Ixodes scapularis Say, 65 (39%) Amblyomma maculatum (Koch), 30 (9%) Rhipicephalus sanguineus Latreille, 7 (4%) Dermacentor variabilis Say, and 26 (44%) unidentified Amblyomma ticks. None of the sequenced products were homologous to R. rickettsii. The most common Rickettsia via rompB amplification was Rickettsia montanensis and nonpathogenic Candidatus Rickettsia amblyommii, whereas with ompA amplification the most common Rickettsia was Ca. R. amblyommii. Many tick specimens collected in northwest Arkansas were PCR positive and these were commonly A. americanum harboring Ca. R. amblyommii, a currently nonpathogenic Rickettsia. Data reported here indicate that pathogenic R. rickettsii was absent from these ticks and suggest by extension that other SFGR are likely the causative agents for Arkansas diagnosed RMSF cases.

Molecular characterization of ‘Candidatus Rickettsia vini’ in Ixodes arboricola from the Czech Republic and Slovakia

The aim of this study was to analyze the prevalence of rickettsiae in the tree-hole tick Ixodes arboricola in the Czech Republic and Slovakia. During May to September of 2009 and 2013, bird boxes belonging to three different areas were screened for ticks. In total, 454 nestlings and 109 nests of 10 hole-breeding bird species were examined. Ticks were found on Ficedula albicollis, Parus major, Cyanistes caeruleus and Sitta europaea and/or in their nests. In total, 166 ticks (17 nymphs, 10 males and 139 females) were found at 3 areas (arithmetic mean±standard error: 55.3±45.9). All ticks were tested for the presence of Rickettsia species by polymerase chain reaction targeting the rickettsial genes gltA, ompA, ompB and htrA and amplicon sequencing. All individuals except 3 nymphs were infected with ‘Candidatus Rickettsia vini’. Multilocus sequence typing showed closest proximity to Rickettsia japonica and Rickettsia heilongjiangensis cluster. The presence of ‘Ca. R. vini’ is reported for the first time in Slovakia.

Rickettsia felis in Ctenocephalides felis felis from five geographic regions of Brazil.

This study evaluated rickettsial infection in 701 Ctenocephalides felis felis fleas that were collected from dogs and cats in 31 municipalities, encompassing all regions and major biomes of Brazil. A total of 268 (38.2%) fleas from 30 municipalities were polymerase chain reaction (PCR) positive for the rickettsial gltA gene. The PCR products from 44 fleas, consisting of at least 1 PCR-positive flea from each of 30 municipalities, generated DNA sequences identical to Rickettsia felis. Rickettsial prevalence was highly variable among 30 municipalities, with values ranging from 2.9% to 100%. Significantly higher infection rates by R. felis were associated with the Pampa biome (southern Brazil), and the temperate climate that prevails in southern Brazil. In contrast, lowest R. felis-infection rates were significantly associated with the Caatinga biome, and its semiarid climate. Further studies should evaluate the effect of temperature and moisture on the R. felis infection in Ctenocephalides fleas world widely.

Rickettsia lusitaniae sp. nov. isolated from the soft tick Ornithodoros erraticus (Acarina: Argasidae)

In this study a novel Rickettsia from the spotted fever group, isolated from Ornithodoros erraticus soft ticks collected from pigpens in the south of Portugal, is described. After initial screening revealed Rickettsia-positive ticks, isolation attempts were then performed. Successful isolates were achieved by shell-vial technique using Vero E6 cells at 28°C. Molecular characterization of the isolate was performed based on analysis of five rickettsial genes gltA, ompA, ompB, sca1 and htr with their subsequent concatenation along with other rickettsial species resulting in a clustering of the new isolate with Rickettsia felis and Rickettsia hoogstraalii. The degree of nucleotide sequence similarity with other rickettsiae fulfills the criteria for classification of our isolate as a novel species. The name Rickettsia lusitaniae sp. nov. (=CEVDI PoTiRo) is proposed for this new species found in O. erraticus.

Molecular detection of Rickettsia bellii and Rickettsia sp. strain Colombianensi in ticks from Cordoba, Colombia

The purpose of this study was to provide molecular evidence of Rickettsia spp. in ticks collected from 2 sites of Cordoba. From May to June 2009, 1069 Amblyomma cajennense ticks were removed from 40 capybaras (Hydrochoerus hydrochaeris) in a rural locality of Monteria. Furthermore, 458 Amblyomma sp. larvae and 20 Amblyomma sp. nymphs were collected in a rural locality of Los Cordobas (Cordoba) by drag sampling on vegetation (n=1547). Ticks were grouped into pools and tested for rickettsial infection by real-time PCR targeting the rickettsial gene gltA. Subsequently, PCR targeting for gltA, ompA, ompB, and 16S rRNA, sequencing, and phylogenetic analyses were undertaken. Rickettsial DNA was detected in 10 (4.6%) out of 214 pools of ticks by RT-PCR. Five (33%) of free-living Amblyomma sp. larval pools were positive, as well as 5 (2.6%) pools from A. cajennense. Only the gltA gene was amplified from 5 pools of free-living larvae. The nucleotide sequences were 100% identical to R. bellii by BLAST. Only one pool from A. cajennense was positive for gltA, ompA, ompB, and 16S rRNA. The partial nucleotide sequences of these genes were 100% identical to nucleotide sequences of the same genes of a new proposed species Candidatus Rickettsia sp. strain Colombianensi. This is the first report of R. bellii in ticks in Colombia and the second report of detection of Candidatus Rickettsia sp. strain Colombianensi. These Rickettsia species are still considered of unknown pathogenicity. Further studies are needed to characterize the ecological and potential pathogenic role of these 2 Rickettsia species found in Cordoba.

Rickettsial infections in ticks from wild birds in Paraguay

Ticks were collected from wild birds at 3 locations in Paraguay during the South American winter in August and September 2012. In total, 480 birds belonging to 106 species were examined. Overall, 31 (6.5%) birds representing 21 species were found parasitized by ticks which were identified as Amblyomma calcaratum Neumann (2 larvae, 20 nymphs), Amblyomma longirostre (Koch) (17 larvae, 3 nymphs), Amblyomma parvum Aragão (7 nymphs), Amblyomma aureolatum (Pallas) (1 nymph), Amblyomma ovale Koch (1 nymph), Amblyomma tigrinum Koch (1 larva), and Amblyomma spp. (4 larvae). Ticks collected accidentally on humans at the study locations during field work included 1 nymph of Amblyomma coelebs Neumann and 54 nymphs of Amblyomma cajennense (Fabricius). Most ticks were individually tested for the presence of Rickettsia species by polymerase chain reaction targeting rickettsial genes gltA and ompA and by amplicon sequencing. Two (12%) out of 17 A. longirostre larvae were found infected with Candidatus ‘Rickettsia amblyommii’, and 2 (33%) out of 6 A. parvum nymphs were infected with Candidatus ‘Rickettsia andeanae’. This study provides the first report of rickettsial infections in Paraguayan ticks.

A Rickettsia parkeri-like agent infecting Amblyomma calcaratum nymphs from wild birds in Mato Grosso do Sul, Brazil

In total, 142 birds, mostly passerines, belonging to 42 species were examined for the presence of ticks in 3 locations in Mato Grosso do Sul Brazil during 2006. Seven birds (5%) were infested with 4 nymphs of Amblyomma calcaratum (Ramphocelus carbo, 3 infested/12 examined) and 5 larvae of Amblyomma sp. (Furnarius rufus, 2/5; Turdus leucomelas, 1/6; and Paroaria capitata, 1/8). All 4 nymphs of A. calcaratum tested by polymerase chain reaction targeting rickettsial genes gltA and ompA and by amplicon sequencing were found to be infected with a Rickettsia sp. strain NOD, a Rickettsia parkeri-like agent. A. calcaratum infected with a rickettsial bacterium was found for the first time.

Rickettsia felisin Fleas, Southern Ethiopia, 2010

<i>Rickettsia felis</i>in Fleas, Southern Ethiopia, 2010