Ultrastructural Morphology and Molecular Analyses of Tropical and Temperate "Species" of Rhipicephalus sanguineus sensu lato (Acari: Ixodidae) in Brazil.
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SUBMITTER: Caetano RL
PROVIDER: S-EPMC5850649 | biostudies-literature | 2017 Sep
REPOSITORIES: biostudies-literature
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Ultrastructural Morphology and Molecular Analyses of Tropical and Temperate "Species" of Rhipicephalus sanguineus sensu lato (Acari: Ixodidae) in Brazil.
Caetano Rebecca Leal RL Vizzoni Vinicius Figueiredo VF Bitencourth Karla K Carriço Cesar C Sato Tayra Pereira TP Pinto Zeneida Teixeira ZT De Oliveira Stefan Vilges SV Amorim Marinete M Voloch Carolina Moreira CM Gazeta Gilberto Salles GS
Journal of medical entomology 20170901 5
The Rhipicephalus sanguineus (Latreille) complex (Acari:Ixodidae) is composed of species with intra- and interspecific morphological variation that make their diagnosis difficult. In the present study, male specimens of the R. sanguineus complex were collected from dogs in six districts of three regions of Brazil and submitted to molecular and scanning electron microscopy (SEM) analyses. Analysis of COX1 gene, 12S rDNA, and D-loop rDNA shows that ticks classified as R. sanguineus form two differ ...[more]
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Project description:The tick vector Rhipicephalus sanguineus is established as a complex of closely related species with high veterinary-medical significance, in which the presence of different genetic, morphological, and biological traits has resulted in the recognition of different lineages within taxa. One of the most striking differences in the "temperate" and "tropical" lineages of R. sanguineus (s.l.) is the vector competence to Ehrlichia canis, suggesting that these ticks tolerate and react differently to pathogen infection. The present study addresses the SG and MG proteome of the R. sanguineus tropical and temperate lineages and compares their proteomic profile during E. canis infection. Batches of nymphs from the two lineages were allowed to feed on naïve and experimentally E. canis infected dogs and after molting, adults were dissected, and salivary glands and midgut tissues separated. Samples were screened for the presence of E. canis before proteomic analyses. The representation of the proteins identified in infected and non-infected tissues of each lineage was compared and gene ontology used for protein classification. Results highlight important differences in those proteomic profiles that added to previous reported genetic, biological, behavioral, and morphological differences, strengthening the hypothesis of the existence of two different species. Comparing infected and non-infected tissues, the results show that, while in midgut tissues the response to E. canis infection is similar in the salivary glands, the two lineages show a different pattern of protein representation. Focusing on the proteins found only in the infected condition, the data suggests that the cement cone produced during tick feeding may be implicated in pathogen infection. This study adds useful information to the debate on the controversial R. sanguineus systematic status, to the discussion related with the different vectorial competence occurring between the two lineages and identifies potential targets for efficient tick and tick-borne disease control.
| S-EPMC7879575 | biostudies-literature
Project description:BackgroundThe main transmission route of Leishmania infantum is through the bites of sand flies. However, alternative mechanisms are being investigated, such as through the bites of ticks, which could have epidemiological relevance. The objective of this work was to verify the presence of Leishmania spp. in Rhipicephalus sanguineus sensu lato collected from naturally infected dogs in the Federal District of Brazil.MethodsTicks were dissected to remove their intestines and salivary glands for DNA extraction and the subsequent amplification of the conserved region of 120 bp of kDNA and 234 bp of the hsp70 gene of Leishmania spp. The amplified kDNA products were digested with endonucleases HaeIII and BstUI and were submitted to DNA sequencing. Isolated Leishmania parasites from these ticks were analyzed by multilocus enzyme electrophoresis, and the DNA obtained from this culture was subjected to microsatellite analyses.ResultsOverall, 130 specimens of R. sanguineus were collected from 27 dogs. Leishmania spp. were successfully isolated in culture from five pools of salivary glands and the intestines of ticks collected from four dogs. The amplified kDNA products from the dog blood samples and from the tick cultures, when digested by HaeIII and BstUI, revealed the presence of L. braziliensis and L. infantum. One strain was cultivated and characterized as L. infantum by enzyme electrophoresis. The amplified kDNA products from the blood of one dog showed a sequence homology with L. braziliensis; however, the amplified kDNA from the ticks collected from this dog showed a sequence homology to L. infantum.ConclusionThe results confirm that the specimens of R. sanguineus that feed on dogs naturally infected by L. infantum contain the parasite DNA in their intestines and salivary glands, and viable L. infantum can be successfully isolated from these ectoparasites.
| S-EPMC4600268 | biostudies-literature
Project description:BackgroundThe brown dog tick Rhipicephalus sanguineus (sensu stricto) is reputed to be the most widespread tick of domestic dogs worldwide and has also been implicated in the transmission of many pathogens to dogs and humans. For more than two centuries, Rh. sanguineus (s.s.) was regarded as a single taxon, even considering its poor original description and the inexistence of a type specimen. However, genetic and crossbreeding experiments have indicated the existence of at least two distinct taxa within this name: the so-called "temperate" and "tropical" lineages of Rh. sanguineus (sensu lato). Recent genetic studies have also demonstrated the existence of additional lineages of Rh. sanguineus (s.l.) in Europe and Asia. Herein, we assessed the biological compatibility between two lineages of Rh. sanguineus (s.l.) found in southern Europe, namely Rhipicephalus sp. I (from Italy) and Rhipicephalus sp. II (from Portugal).MethodsTicks morphologically identified as Rh. sanguineus (s.l.) were collected in southern Portugal and southern Italy. Tick colonies were established and crossbreeding experiments conducted. Morphological, biological and genetic analyses were conducted.ResultsCrossbreeding experiments confirmed that ticks from the two studied lineages were able to mate and generate fertile hybrids. Hybrid adult ticks always presented the same genotype of the mother, confirming maternal inheritance of mtDNA. However, larvae and nymphs originated from Rhipicephalus sp. I females presented mtDNA genotype of either Rhipicephalus sp. I or Rhipicephalus sp. II, suggesting the occurrence of paternal inheritance or mitochondrial heteroplasmy. While biologically compatible, these lineages are distinct genetically and phenotypically.ConclusionsThe temperate lineages of Rh. sanguineus (s.l.) studied herein are biologically compatible and genetic data obtained from both pure and hybrid lines indicate the occurrence of paternal inheritance or mitochondrial heteroplasmy. This study opens new research avenues and raises question regarding the usefulness of genetic data and crossbreeding experiments as criteria for the definition of cryptic species in ticks.
| S-EPMC6038233 | biostudies-literature
Project description:Brown dog ticks morphologically identifiable as Rhipicephalus sanguineus sensu lato, are distributed world-wide and their systematics is controversial. Results of genetic and reproductive compatibility studies of geographically distinct populations of R. sanguineus s.l. indicate that the R. sanguineus complex is paraphyletic. To further elucidate systematic relationships within R. sanguineus s.l. and geographic boundaries of its lineages, we conducted a phylogeographical study of 136 tick specimens from 23 countries. Voucher specimens were morphologically identified. A phylogenetic tree was constructed using concatenated partial mitochondrial 12S and 16S rDNA gene sequences and analyzed by the Neighbor-Joining method. A set of 19 bioclimatic variables within the WorldClim dataset were extracted and analyzed to assess correlations between distribution of R. sanguineus s.l. lineages and climatic variables. The following four branches are clearly recognized on the phylogenetic tree: R. sanguineus s.l.-tropical and temperate clades, R. leporis, and R. turanicus. DNA sequences of Rhipicephalus ticks from Israel differ from those of other groups. Strong association between geographical locations of major clades of R. sanguineus s.l. and temperature was identified. The tropical clade of R. sanguineus s.l. occupies areas with the annual mean temperature >20 °C, whereas the temperate clade is present in areas with the annual mean temperature <20 °C. Our results indicate that ticks in two closely related phylogenetic clades are adapted to different environmental conditions and support proposals for re-classification of R. sanguineus complex. Differences in R. sanguineus s.l. ecology and human/animal pathogens transmitted by different taxa of brown dog tick need to be studied.
| S-EPMC5666566 | biostudies-literature
Project description:BackgroundThe taxonomic status of the brown dog tick Rhipicephalus sanguineus (sensu stricto) is a subject of on-going debate; there is a consensus that populations of this tick species should be referred to as R. sanguineus (sensu lato) until its taxonomic status is resolved. Recent genetic studies revealed the existence of more than one lineage of R. sanguineus (s.l.) in temperate countries. In this study, we assessed the genetic identity of ticks collected from rural dogs living in several areas located in all major geographical regions of Portugal.MethodsA total of 347 ticks were collected from rural dogs living in different regions of Portugal. These ticks were morphologically identified and partial mitochondrial 16S rRNA gene sequences (~300 bp) were obtained from representative specimens.ResultsThe ticks were morphologically identified as Ixodes ricinus (seven males and 27 females), Rhipicephalus bursa (one male), Rhipicephalus pusillus (one female) and R. sanguineus (s.l.) (two larvae, 101 nymphs, 108 males and 100 females). Partial mitochondrial 16S rRNA gene sequences were obtained from 58 R. sanguineus (s.l.) specimens, and all of them were genetically identified as belonging to the so-called temperate lineage of R. sanguineus (s.l.) CONCLUSIONS: These results strongly suggest that the temperate species of R. sanguineus (s.l.) is the only representative of this tick group found on dogs in Portugal. It also adds weight to the hypothesis that Rhipicephalus turanicus is not present in this country, although further investigations are necessary to confirm this.
| S-EPMC5346838 | biostudies-literature
Project description:Rhipicephalus sanguineus is the most widely reported tick in the world. Molecular characterisation is important to verify its taxonomic status in the different parts of the world. In this study, we provide information on the molecular characterisation of R. sanguineus tick of dogs collected from Nigeria. Ticks were collected from 62 of 93 sampled dogs. The collected ticks were subjected to morphological identification with the aid of appropriate entomological keys. Deoxyribonucleic acid (DNA) was extracted from the most prevalent tick species (R. sanguineus) and was subjected to further molecular characterisation protocols. The partial mitochondrial 16S rRNA gene sequences (∼300 bp) were obtained from representative specimens. Data were statistically analysed using the chi-square (χ2 ) test. Phylogenetic analysis was performed including different lineages of R. sanguineus (sl) from Africa, Asia, Europe and America, and other species belonging to the R. sanguineus 'tropical lineage' (R. linnaei) as well as Rhipicephalus turanicus and Ixodes ricinus. Results of this study showed that R. sanguineus was the most abundant ticks of dogs with a prevalence of 61.8% (68/110; 95% CI = 52.5-70.54), followed by Amblyomma variegatum (20.0%) and Haemaphysalis leachi (18.2%). The molecular analysis shows that they are genetically different from the temperate strains but closely related to those from other West African countries. There is a need to establish the vector competence of this common Nigerian dog tick.
| S-EPMC8959257 | biostudies-literature
Project description:BackgroundRhipicephalus sanguineus sensu lato ticks are widespread worldwide due to their adaptability to survive under different environmental conditions. They may act as vectors of a wide range of pathogens to humans and animals and their control is based on the use of chemical products on dogs and in the environment. Alternative control strategies, such as the use of entomopathogenic fungi as bio-control agents have also been investigated. The ability of native strains of Beauveria bassiana sensu lato in causing mortality in different tick species (e.g., Amblyomma cajennense and Rhipicephalus microplus) has been demonstrated. However, limited studies have assessed the use of B. bassiana for the control of R. sanguineus s.l. and none of them have employed native strains of this fungus. Here we investigated the pathogenicity of a native strain of B. bassiana (CD1123) against all developmental stages of R. sanguineus s.l..MethodsBatches of eggs, larvae, nymphs and adult ticks were immersed in a suspension of 10(7) conidia/ml of B. bassiana s.l., isolated from a R. sanguineus s.l. engorged female. All treatment and control groups were observed for 20 days, and the biological parameters (i.e., mortality, hatching, moulting percentage, pre-oviposition period, oviposition period and rate, eggs production efficiency, reproductive efficiency and fitness indexes) were assessed.ResultsThe effect of the B. bassiana strain tested herein on eggs, larvae, nymphs and adults showed a significantly higher mortality than those of the control groups (p < 0.05) at 5 days post-infection. No infected eggs hatched and no infected larvae moulted. Only 15% of infected nymphs moulted into adults. All biological parameters of treated groups differed significantly (p < 0.001) from those of control groups.ConclusionsThis study demonstrates that a suspension containing 10(7) conidia/ml of a native B. bassiana strain is highly virulent towards all life-cycle developmental stages of R. sanguineus s.l. and may be of potential interest as a biological control agent against these ticks.
| S-EPMC4324834 | biostudies-literature
Project description:Brown dog ticks are distributed world-wide, and their systematics and phylogeny are the subject of an ongoing debate. The present study evaluates the reproductive compatibility between Rhipicephalus sanguineus ticks from North America, Israel, and Africa. Female ticks of the parent generation were mated with males from the same and alternate colonies. Every pure and hybrid cohort was maintained separately into the F2 generation with F1 females being allowed to mate only with males from the same cohort. The following survival parameters were measured and recorded for every developmental stage: feeding duration and success; engorgement weight, fertility, and fecundity of females; molting and hatching success. Ticks from North American and Mediterranean populations hybridized successfully. The survival parameters of all their hybrid lines were similar to those in pure lines throughout the F1 generation, and F1 adults were fully fertile. Parent adult ticks from the African population hybridized with either North American or Mediterranean ticks and produced viable progenies whose survival parameters were also similar to those in pure lines throughout the F1 generation. However, F1 adults in the four hybrid lines that included African ancestry were infertile. No parthenogenesis was observed in any pure or hybrid lines as proportion of males in F1 generation ranged from 40 to 60 %. Phylogenetic analysis of the 12S rDNA gene sequences placed African ticks into a separate clade from those of the North American or Mediterranean origins. Our results demonstrate that Rh. sanguineus ticks from North America and Israel represent the same species, whereas the African population used in this study is significantly distant and probably represents a different taxon.
| S-EPMC5659124 | biostudies-literature
Project description:Rhipicephalus sanguineus s.l. (Latreille, 1806) can establish populations in residences and may lead to severe domestic and peridomestic infestations. Detection in the early infestation stage is challenging because of their small body size and the lack of visibility when ticks stay in sheltered refugia. The residents may believe that the infestation has been eliminated when no ticks are observed until ticks reappear when seeking hosts. Thus, it is necessary to improve our understanding of tick phenology to achieve more effective infestation management. In this study, the relationships between environmental conditions and tick development were explored in laboratory and using linear and nonlinear models. Three R. sanguineus s.l. strains, from one colony of the temperate lineage and two of the tropical lineage, were evaluated for the development of all life stages and conversion efficiency index (CEI) under five temperatures and four relative humidities (RHs). The development times differed between the three tick strains across stages and were primarily dependent on temperature. The CEIs had little variance explained by temperature, RH, or strains. Compared with the linear and exponential models with temperature as the only variable, the Brière-1 model was the best approximating model for most of the developmental rates. The developmental temperature thresholds for R. sanguineus s.l. development estimated by the Brière-1 model varied inconsistently across strains and life stages. We developed a more predictive relationship between environmental factors and R. sanguineus s.l. development, which can be utilized to predict tick development using temperature and develop appropriate control strategies.
| S-EPMC9389420 | biostudies-literature
Project description:BackgroundThere has been a long-standing debate over the taxonomic status of Rhipicephalus sanguineus sensu lato. Different studies worldwide have reported the occurrence of different well-defined lineages, in addition to Rhipicephalus sanguineus sensu stricto. To date, there are very few studies examining the diverse aspects of this tick in Colombia. We assessed the population structure and genetic diversity of R. sanguineus s.l. in eight departmental regions across Colombia.MethodsA total of 170 ticks were collected from dogs in different departments of Colombia. All specimens were morphologically compatible with R. sanguineus s.l. and subjected to genetic analysis. DNA sequences were obtained for the 12S rDNA, cytochrome oxidase I (COI) and internal transcribed spacer 2 (ITS2) markers. A concatenated set of all mitochondrial markers was also constructed. Next, maximum likelihood phylogenetic trees were constructed using the sequences generated herein and sequences available in GenBank. Finally, we assessed different summary statistics and analysed population structure and divergence with Fst and Dxy and demographic changes with Tajima's D and Fu and Li's statistical tests.ResultsAnalysis of the 12S rDNA and COI revealed that all R. sanguineus s.l. specimens collected across different regions of Colombia clustered within the tropical lineage. Micro-geographical analyses showed that the tick population from Amazonas formed a distinct cluster separated from the other sequences, with moderate Fst and Dxy values. However, no signs of a robust population structure were found within the country. The results of Fu's FS tests, together with the haplotype networks and diversity values, signal a possible population expansion of this tick species in Colombia.ConclusionsEvidence provided herein supports the tropical lineage as the main circulating lineage in Colombia, exhibiting a general lack of genetic structure except for the Amazonas region.
| S-EPMC8383428 | biostudies-literature