Browsing by Author "Santos-Silva, M.M."
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- An insight into the transcriptome of Rhipicephalus bursa: differential gene expression upon feeding and in response to salivary glands infection with Babesia ovisPublication . Couto, J.; Antunes, S.; Ferrolho, J.; Santos, A.S.; Santos-Silva, M.M.; de la Fuente, J.; Domingos, A.Understanding the paradigm of the pathogen-tick-host triad remains an intricate issue. Basic research focusing on each one of these interplays is necessary to better comprehend this dynamic system. One of such complex association is the Babesia ovis, transmitted by the Rhipicephalus bursa ticks. B. ovis is an intra-erythrocytic protozoan parasite highly pathogenic parasite, causing severe infection in sheep. Pathogen and vector co-evolved and during infection a substantial molecular dialogue/interchanges takes place. The pathogen is adapted to both its hosts, and remarkably transovarial and transstadial transmissions are present in the vector. In ticks, the salivary glands (SG) play important role in both, feeding and pathogen interaction, being a vehicle for pathogen transmission and a barrier that they need to surpass.
- Anaplasma marginale and Theileria annulata in questing ticks from PortugalPublication . Antunes, S.; Ferrolho, J.; Domingues, N.; Santos, A.S.; Santos-Silva, M.M.; Domingos, A.Ticks are ubiquitous arthropods and vectors of several pathogenic agents in animals and humans. Monitoring questing ticks is of great importance to ascertain the occurrence of pathogens and the potential vector species, offering an insight into the risk of disease transmission in a given area. In this study 428 host-seeking ticks, belonging to nine species of Ixodidae and collected from 17 of the 23 Portuguese mainland subregions, were screened for several tick-borne agents with veterinary relevance: Anaplasma marginale, Anaplasma ovis, Anaplasma centrale, Babesia spp., Coxiella burnetii and Theileria spp. Prevalence was assessed by PCR and amplified amplicons sequenced for validation of results. Twenty ticks, in a total of 428, were found positive: one Ixodes ventalloi for Theileria annulata and four Dermacentor marginatus, one Haemaphysalis punctata, five Ixodes ricinus, five I. ventalloi, and four Rhipicephalus sanguineus sensu lato for A. marginale. According to the reviewed literature, this is the first report of A. marginale and T. annulata detection in I. ventalloi. Furthermore, the amplification of A. marginale DNA in several tick species suggests a broad range for this agent in Portugal that might include other uncommon species as R. sanguineus s.l. This work provides new data towards a better understanding of tick-pathogen associations and also contributes to the surveillance of tick-borne agents in geographic areas with limited information.
- A comparative test of ixodid tick identification by a network of European researchersPublication . Estrada-Peña, A.; D'Amico, G.; Palomar, A.M.; Dupraz, M.; Fonville, M.; Heylen, D.; Habela, M.A.; Hornok, S.; Lempereur, L.; Madder, M.; Núncio, M.S.; Otranto, D.; Pfaffle, M.; Plantard, O.; Santos-Silva, M.M.; Sprong, H.; Vatansever, Z.; Vial, L.; Mihalca, A.D.This study reports the results of a comparative test of identification of ticks occurring in Western Europe and Northern Africa. A total of 14 laboratories were voluntarily enrolled in the test. Each participant received between 22 and 25 specimens of adult and nymphal ticks of 11 species: Dermacentor marginatus, D. reticulatus, Haemaphysalis punctata, Hyalomma lusitanicum, Hy. marginatum, Ixodes ricinus, I. hexagonus, Rhipicephalus annulatus, R. bursa, R. rossicus, and/or R. sanguineus s.l. Ticks were morphologically identified by three of the co-authors and the identification confirmed by a fourth co-author who used molecular methods based on several genes. Then ticks were randomly selected and blindly distributed among participants, together with a questionnaire. Only specimens collected while questing and, if possible, in the same survey, were circulated. Because of the random nature of the test, a participant could receive several specimens of the same species. Species in the different genera had variable misidentification rates (MR) of 7% (Dermacentor), 14% (Ixodes), 19% (Haemaphysalis), 36% (Hyalomma), and 54% (Rhipicephalus). Within genera, the MR was also variable ranging from 5.4% for I. ricinus or 7.4% for D. marginatus or D. reticulatus to 100% for R. rossicus. The test provided a total misidentification rate of 29.6% of the species of ticks. There are no significant differences in MR according to the sex of the tick. Participants were requested to perform a second round of identifications on the same set of ticks, using only purposely prepared keys (without illustrations), circulated to the enrolled participants, including 2 species of the genus Dermacentor, 8 of Haemaphysalis, 10 of Hyalomma, 23 of Ixodes, and 6 of Rhipicephalus. The average MR in the second round was 28%: 0% (Dermacentor), 33% (Haemaphysalis), 30% (Hyalomma) 18% (Ixodes), and 50% (Rhipicephalus). Species which are not reported in the countries of a participating laboratory had always highest MR, i.e. purely Mediterranean species had highest MR by laboratories in Central and Northern Europe. Participants expressed their concerns about a correct identification for almost 50% of the ticks of the genera Hyalomma and Rhipicephalus. The results revealed less than total confidence in identifying the most prominent species of ticks in the Western Palearctic, and underpin the need for reference libraries for specialists involved in this task. Results also showed that a combination of certain genes may adequately identify the target species of ticks.
- Detection and phylogenetic characterization of Theileria spp. and Anaplasma marginale in Rhipicephalus bursa in PortugalPublication . Ferrolho, A.; Antunes, S.; Santos, A.S.; Velez, R.; Padre, L.; Cabezas-Cruz, A.; Santos-Silva, M.M.; Domingos, A.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.
- Detection of Anaplasma phagocytophilum, Candidatus Neoehrlichia sp., Coxiella burnetii and Rickettsia spp. in questing ticks from a recreational park, PortugalPublication . Santos, A.S.; de Bruin, A.; Veloso, A.R.; Marques, C.; Pereira da Fonseca, I.; De Sousa, R.; Sprong, H.; Santos-Silva, M.M.Tick-borne agents with medical relevance have been recorded in Portugal but little is known about their oc-currence in urban outdoor leisure areas. This study aimed to investigate ticks and tick-borne agents in threepublic parks of Lisbon’s metropolitan area. A total of 234 questing ticks belonging to eight species were found inParque Florestal de Monsanto (PFM). Ixodes ventalloi represented 40% of collections. Mitochondrial genesconfirmed Ixodes morphological identification, evidencing the intraspecific variability of I. ricinus and particu-larly I. frontalis populations. Regarding tick-borne agents, Rickettsia massiliae DNA were found in 21 (9.0%) ticks,Coxiella burnetii in 15 (6.4%), Anaplasma phagocytophilum in five (2.1%), an agent closely related to CandidatusNeoehrlichia mikurensis in two (0.9%), Rickettsia sibirica mongolitimonae and Rickettsia monacensis each in one(0.4%). Active enzootic cycles were suggested for these agents by the detection of positives in different timeperiods. Five tick species were founded with C. burnetii, including I. ventalloi which seems to be a new associationrecord. This tick was also the only species found positive for A. phagocytophilum and the Candidatus Neoehrlichiamikurensis-like agent. Two A. phagocytophilum variants were detected in PFM, one of them representing a po-tentially new ecotype already found in I. ventalloi from another Portuguese area. To the authors´ knowledge, thisis also the first report of such a Candidatus Neoehrlichia mikurensis-like microorganism. These data show aninteresting diversity of ticks and tick-borne agents with potential public health relevance in PFM, an urbanrecreational area commonly frequented by humans and their pets.
- Distribution, abundance and ecology of ticks in Portugal mainland: data from five years of a surveillance program REVIVEPublication . Santos-Silva, M.M.; Santos, A.; Lopes de Carvalho, I.; Sousa, R.; Luz, T.; Parreira, L.; Chainho, L.; Gomes, M.S.; Milhano, N.; Osório, H.; Alves, M.J.; Núncio, M.S.; REVIVE WorkgroupREVIVE (National Network for Vector Surveillance) aims to: i) Monitor the activity of hematophagous arthropods; ii) Characterize the species and its seasonal occurrence; iii) Identify important pathogens in Public Health, depending on the density of the vectors, the level of infection or the introduction of exotic species to alert for control measures.
- Driving forces for changes in geographical distribution of Ixodes ricinus ticks in EuropePublication . Medlock, J.M.; Hansford, K.M.; Bormane, A.; Derdakova, M.; Estrada-Peña, A.; George, J-C; Golovljova, I.; Jaenson, T.G.; Jensen, J-K; Jensen, P.M.; Kazimirova, M.; Oteo, J.A.; Papa, A.; Pfister, K.; Plantard, O.; Randolph, S.E.; Rizzoli, A.; Santos-Silva, M.M.; Sprong, H.; Vial, L.; Hendrickx, G.; Zeller, H.; Van Bortel, W.Many factors are involved in determining the latitudinal and altitudinal spread of the important tick vector Ixodes ricinus (Acari: Ixodidae) in Europe, as well as in changes in the distribution within its prior endemic zones. This paper builds on published literature and unpublished expert opinion from the VBORNET network with the aim of reviewing the evidence for these changes in Europe and discusses the many climatic, ecological, landscape and anthropogenic drivers. These can be divided into those directly related to climatic change, contributing to an expansion in the tick's geographic range at extremes of altitude in central Europe, and at extremes of latitude in Scandinavia; those related to changes in the distribution of tick hosts, particularly roe deer and other cervids; other ecological changes such as habitat connectivity and changes in land management; and finally, anthropogenically induced changes. These factors are strongly interlinked and often not well quantified. Although a change in climate plays an important role in certain geographic regions, for much of Europe it is non-climatic factors that are becoming increasingly important. How we manage habitats on a landscape scale, and the changes in the distribution and abundance of tick hosts are important considerations during our assessment and management of the public health risks associated with ticks and tick-borne disease issues in 21st century Europe. Better understanding and mapping of the spread of I. ricinus (and changes in its abundance) is, however, essential to assess the risk of the spread of infections transmitted by this vector species. Enhanced tick surveillance with harmonized approaches for comparison of data enabling the follow-up of trends at EU level will improve the messages on risk related to tick-borne diseases to policy makers, other stake holders and to the general public.
- Effects of tectonics and large scale climatic changes on the evolutionary history of Hyalomma ticksPublication . Sands, A.F.; Apanaskevich, D.A.; Matthee, S.; Horak, I.G.; Harrison, A.; Karim, S.; Mohammad, M.K.; Mumcuoglu, K.Y.; Rajakaruna, R.S.; Santos-Silva, M.M.; Matthee, C.A.Hyalomma Koch, 1844 are ixodid ticks that infest mammals, birds and reptiles, to which 27 recognized species occur across the Afrotropical, Palearctic and Oriental regions. Despite their medical and veterinary importance, the evolutionary history of the group is enigmatic. To investigate various taxonomic hypotheses based on morphology, and also some of the mechanisms involved in the diversification of the genus, we sequenced and analysed data derived from two mtDNA fragments, three nuclear DNA genes and 47 morphological characters. Bayesian and Parsimony analyses based on the combined data (2242 characters for 84 taxa) provided maximum resolution and strongly supported the monophyly of Hyalomma and the subgenus Euhyalomma Filippova, 1984 (including H. punt Hoogstraal, Kaiser and Pedersen, 1969). A predicted close evolutionary association was found between morphologically similar H. dromedarii Koch, 1844, H. somalicum Tonelli Rondelli, 1935, H. impeltatum Schulze and Schlottke, 1929 and H. punt, and together they form a sister lineage to H. asiaticum Schulze and Schlottke, 1929, H. schulzei Olenev, 1931 and H. scupense Schulze, 1919. Congruent with morphological suggestions, H. anatolicum Koch, 1844, H. excavatum Koch, 1844 and H. lusitanicum Koch, 1844 form a clade and so also H. glabrum Delpy, 1949, H. marginatum Koch, 1844, H. turanicum Pomerantzev, 1946 and H. rufipes Koch, 1844. Wide scale continental sampling revealed cryptic divergences within African H. truncatum Koch, 1844 and H. rufipes and suggested that the taxonomy of these lineages is in need of a revision. The most basal lineages in Hyalomma represent taxa currently confined to Eurasia and molecular clock estimates suggest that members of the genus started to diverge approximately 36.25 million years ago (Mya). The early diversification event coincides well with the collision of the Indian and Eurasian Plates, an event that was also characterized by large scale faunal turnover in the region. Using S-Diva, we also propose that the closure of the Tethyan seaway allowed for the genus to first enter Africa approximately 17.73 Mya. In concert, our data supports the notion that tectonic events and large scale global changes in the environment contributed significantly to produce the rich species diversity currently found in the genus Hyalomma.
- Francisella-like endosymbiont and Rickettsia aeschlimannii co-infection in a Hyalomma marginatum tickPublication . Carvalho, C.L.; Sousa, R.; Santos-Silva, M.M.; Santos, A.S.; Núncio, M.S.; Lopes de Carvalho, I.
- Importation of a Hyalomma lusitanicum tick into the UK on a dogPublication . Hansford, K.M.; Medlock, J.M.; Atkinson, B.; Santos-Silva, M.M.A SINGLE, fully engorged female Hyalomma lusitanicum tick was imported into the UK on a dog recently returned from Portugal during May 2016 and submitted to Public Health England's Tick Surveillance Scheme (TSS). H lusitanicum exists in a narrow geographical range from Portugal to Sicily (Estrada-Peña and others 2012), where its distribution is restricted due to its strict biotic niche (Estrada-Peña and Venzal 2007). Immature stages parasitise wildlife (Santos-Silva and others 2011) and adults are mostly associated with domestic and wild ungulates (Valcárcel and others 2015). However, records on dogs have been reported (Apanaskevich and others 2008), including in Portugal where biting of humans by this species has also been reported (Santos-Silva and others 2011)… (…)
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