Understanding host-pathogen-tick interactions remains a vitally important issue that might be better understood by basic research focused on each of the dyad interplays. Pathogens gain access to ...either the vector or host during tick feeding when ticks are confronted with strong hemostatic, inflammatory and immune responses. A prominent example of this is the
spp.-tick-vertebrate host relationship.
spp. are intraerythrocytic apicomplexan organisms spread worldwide, with a complex life cycle. The presence of transovarial transmission in almost all the
species is the main difference between their life cycle and that of other piroplasmida. With more than 100 species described so far,
are the second most commonly found blood parasite of mammals after trypanosomes. The prevalence of
spp. infection is increasing worldwide and is currently classified as an emerging zoonosis.
and
are the most frequent etiological agents associated with human babesiosis in North America and Europe, respectively. Although the
-tick system has been extensively researched, the currently available prophylactic and control methods are not efficient, and chemotherapeutic treatment is limited. Studying the molecular changes induced by the presence of
in the vector will not only elucidate the strategies used by the protozoa to overcome mechanical and immune barriers, but will also contribute toward the discovery of important tick molecules that have a role in vector capacity. This review provides an overview of the identified molecules involved in
-tick interactions, with an emphasis on the fundamentally important ones for pathogen acquisition and transmission.
A system biology approach was used to gain insight into tick biology and interactions between vector and pathogen.
is one of the main vectors of
which has a massive impact on animal health. It is ...vital to obtain more information about this relationship, to better understand tick and pathogen biology, pathogen transmission dynamics, and new potential control approaches. In ticks, salivary glands (SGs) play a key role during pathogen infection and transmission. RNA sequencing obtained from uninfected and
infected SGs obtained from fed female ticks resulted in 6823 and 6475 unigenes, respectively. From these, 360 unigenes were found to be differentially expressed (
< 0.05). Reversed phase liquid chromatography-mass spectrometry identified a total of 3679 tick proteins. Among them 406 were differently represented in response to
infection. The omics data obtained suggested that
infection lead to a reduction in the levels of mRNA and proteins (
= 237 transcripts,
= 212 proteins) when compared to uninfected controls. Integrated transcriptomics and proteomics datasets suggested a key role for stress response and apoptosis pathways in response to infection. Thus, six genes coding for GP80, death-associated protein kinase (DAPK-1), bax inhibitor-1 related (BI-1), heat shock protein (HSP), heat shock transcription factor (PHSTF), and queuine trna-ribosyltransferase (QtRibosyl) were selected and RNA interference (RNAi) performed. Gene silencing was obtained for all genes except
Knockdown of
,
, and
led to a significant increase in
infection levels while
and
knockdown resulted in a non-significant decrease of infection levels when compared to the respective controls. Gene knockdown did not affect tick survival, but engorged female weight and egg production were affected in the
,
, and
-silenced groups in comparison to controls. These results advanced our understanding of tick-
molecular interactions, and suggested new tick antigens as putative targets for vaccination to control tick infestations and pathogen infection/transmission.
Ticks are among the most prevalent blood-feeding arthropods, and they act as vectors and reservoirs for numerous pathogens. Sialotranscriptomic characterizations of tick responses to blood feeding ...and pathogen infections can offer new insights into the molecular interplay occurring at the tick-host-pathogen interface. In the present study, we aimed to identify and characterize
salivary gland (SG) genes that were differentially expressed in response to blood feeding and
infection. Our experimental approach consisted of RNA sequencing of SG from three different tick samples, fed-infected, fed-uninfected, and unfed-uninfected, for characterization and inter-comparison. Overall, 7,272 expressed sequence tags (ESTs) were constructed from unfed-uninfected, 13,819 ESTs from fed-uninfected, and 15,292 ESTs from fed-infected ticks. Two catalogs of transcripts that were differentially expressed in response to blood feeding and
infection were produced. Four genes coding for a putative vitellogenin-3, lachesin, a glycine rich protein, and a secreted cement protein were selected for RNA interference functional studies. A reduction of 92, 65, and 51% was observed in
, and
mRNA levels in SG, respectively. The
knockdown led to increased tick mortality, with 77% of ticks dying post-infestation. The reduction of the secreted cement protein-mRNA levels resulted in 46% of ticks being incapable of correctly attaching to the host and significantly lower female weights post-feeding in comparison to the control group. The
knockdown resulted in a 70% reduction of the levels associated with
infection in
SG and 70% mortality. These results improved our understanding of the role of tick SG genes in
infection/proliferation and tick feeding. Moreover, lachesin, vitellogenin-3, and secreted cement proteins were validated as candidate protective antigens for the development of novel tick and tick-borne disease control measures.
The tick vector
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
(s.l.) is the vector competence to
, suggesting that these ticks tolerate and react differently to pathogen infection. The present study addresses the SG and MG proteome of the
tropical and temperate lineages and compares their proteomic profile during
infection. Batches of nymphs from the two lineages were allowed to feed on naïve and experimentally
infected dogs and after molting, adults were dissected, and salivary glands and midgut tissues separated. Samples were screened for the presence of
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
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
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.
Bovine anaplasmosis is caused by cattle infection with the tick-borne bacterium, Anaplasma marginale. The major surface protein 1a (MSP1a) has been used as a genetic marker for identifying A. ...marginale strains based on N-terminal tandem repeats and a 5'-UTR microsatellite located in the msp1a gene. The MSP1a tandem repeats contain immune relevant elements and functional domains that bind to bovine erythrocytes and tick cells, thus providing information about the evolution of host-pathogen and vector-pathogen interactions. Here we propose one nomenclature for A. marginale strain classification based on MSP1a. All tandem repeats among A. marginale strains were classified and the amino acid variability/frequency in each position was determined. The sequence variation at immunodominant B cell epitopes was determined and the secondary (2D) structure of the tandem repeats was modeled. A total of 224 different strains of A. marginale were classified, showing 11 genotypes based on the 5'-UTR microsatellite and 193 different tandem repeats with high amino acid variability per position. Our results showed phylogenetic correlation between MSP1a sequence, secondary structure, B-cell epitope composition and tick transmissibility of A. marginale strains. The analysis of MSP1a sequences provides relevant information about the biology of A. marginale to design vaccines with a cross-protective capacity based on MSP1a B-cell epitopes.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Ticks are obligatory blood-sucking arthropod (Acari:Ixodida) ectoparasites of domestic and wild animals as well as humans. The incidence of tick-borne diseases is rising worldwide, challenging our ...approach toward diagnosis, treatment and control options. Rhipicephalus bursa Canestrini and Fanzago, 1877, a two-host tick widely distributed in the Palearctic Mediterranean region, is considered a multi-host tick that can be commonly found on sheep, goats and cattle, and occasionally on horses, dogs, deer and humans. R. bursa is a species involved in the transmission of several tick-borne pathogens with a known impact on animal health and production. The aim of this study was to estimate R. bursa prevalence in Portugal Mainland and circulating pathogens in order to contribute to a better knowledge of the impact of this tick species. Anaplasma marginale and Theileria spp. were detected and classified using phylogenetic analysis. This is the first report of Theileria annulata and Theileria equi detection in R. bursa ticks feeding on cattle and horses, respectively, in Portugal. This study contributes toward the identification of currently circulating pathogens in this tick species as a prerequisite for developing future effective anti-tick control measures.
The negative impact of ticks and tick-borne diseases on animals and human health is driving research to discover novel targets affecting both vectors and pathogens. The salivary glands are involved ...in feeding and pathogen transmission, thus are considered as a compelling target to focus research. In this study, proteomics approach was used to characterize
sialoproteome in response to
infection and blood feeding. Two potential tick protective antigens were identified and its influence in tick biological parameters and pathogen infection was evaluated. Results demonstrate that the
sialoproteome is highly affected by feeding but infection is well tolerated by tick cells. The combination of both stimuli shifts the previous scenario and a more evident pathogen manipulation can be suggested. Knockdown of
led to a significative increase of infection in tick salivary glands but a brusque decrease in the progeny, revealing its importance in the cellular response to pathogen infection, which is worth pursuing in future studies. Additionally, an impact in the recovery rate of adults (62%), the egg production efficiency (45.75%), and the hatching rate (88.57 %) was detected. Building knowledge on vector and/or pathogen interplay bridges the identification of protective antigens and the development of novel control strategies.
Ticks and tick-borne diseases (TBDs) continue to pose an insidious and ever-present threat to livestock and livelihoods across the globe. Two of the most significant TBDs of cattle in Africa are ...heartwater and babesioisis, caused by
Ehrlichia ruminantium
and
Babesia bigemina
respectively. Both pathogens are endemic in Nigeria. However, to date, little data has been published regarding the number of cattle infected. In this study, blood samples were collected from cattle of the Kwara State, north-central Nigeria. Probe-based quantitative PCR (qPCR) and semi-nested PCR were used to investigate the presence of both pathogens, respectively. Our study found all samples (
n
= 157) to be surprisingly negative for both
B
.
bigemina
and
E
.
ruminantium
. These results contribute new information on the current burden of these two pathogens in Kwara State and may be helpful in informing more effective targeting of control strategies in Nigeria.
Tick-borne diseases (TBDs) are some of the most important animal health and management problems in Africa, including Nigeria. This study aims to determine the prevalence of an important TBD, ...anaplasmosis, in a North-central region of Nigeria. Blood samples were collected from cattle and stored on Whatman FTA
®
cards. Information on village, age and sex associated with each cattle was also recorded. The packed red blood cell volume (PCV) for each blood sample was determined. After DNA extraction, pathogen presence was evaluated by TaqMan
®
based qPCR of which 75.9 % of the cattle tested positive for
Anaplasma marginale
. Statistical analysis revealed that the presence of
A. marginale
infection differed significantly between cattle age groups. However, there was no significant difference in the prevalence of this pathogen between the sexes or among cattle grouped by PCV level. Finally, using a highly sensitive molecular method our pioneer study contributes to the improvement of the current knowledge regarding tick-borne pathogens that seriously affect animal health in specific areas of Nigeria.
Folate pathways components were demonstrated to be present in RNA‐sequencing data obtained from uninfected and pathogen‐infected Rhipicephalus ticks. Here, PCR and qPCR allowed the identification of ...folate‐related genes in Rhipicephalus spp. ticks and in the tick cell line IDE8. Genes coding for GTP cyclohydrolase I (gch‐I), thymidylate synthase (ts) and 6‐pyrovoyltetrahydropterin (ptps) were identified. Differential gene expression was evaluated by qPCR between uninfected and infected samples of four biological systems, showing significant upregulation and largest fold‐change for the gch‐I gene in the majority of the biological systems, supporting the selection for functional analysis by RNAi silencing. Efficient knockdown of the gch‐I gene in uninfected and Ehrlichia canis‐infected IDE8 cells showed no detectable impact on the capacity of the bacteria to invade or replicate in the tick cells. Overall, this work demonstrated an increase in the expression of some folate‐related genes, though not always statistically significantly, in the presence of infection, suggesting gene expression modulation of these pathways, either as a tick response to an invader or manipulation of the tick cell machinery by the pathogens to their advantage. This discovery points to folate pathways as interesting targets for further studies.
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