Phylogeographic analysis reveals association of tick-borne pathogen, Anaplasma marginale, MSP1a sequences with ecological traits affecting tick vector performance

<p>Abstract</p> <p>Background</p> <p>The tick-borne pathogen <it>Anaplasma marginale</it>, which is endemic worldwide, is the type species of the genus <it>Anaplasma </it>(Rickettsiales: Anaplasmataceae). <it>Rhipicephalus </it>(<it>Boophilus</it>) <it>microplus </it>is the most important tick vector of <it>A. marginale </it>in tropical and subtropical regions of the world. Despite extensive characterization of the genetic diversity in <it>A. marginale </it>geographic strains using major surface protein sequences, little is known about the biogeography and evolution of <it>A. marginale </it>and other <it>Anaplasma </it>species. For <it>A. marginale</it>, MSP1a was shown to be involved in vector-pathogen and host-pathogen interactions and to have evolved under positive selection pressure. The MSP1a of <it>A. marginale </it>strains differs in molecular weight because of a variable number of tandem 23-31 amino acid repeats and has proven to be a stable marker of strain identity. While phylogenetic studies of MSP1a repeat sequences have shown evidence of <it>A. marginale</it>-tick co-evolution, these studies have not provided phylogeographic information on a global scale because of the high level of MSP1a genetic diversity among geographic strains.</p> <p>Results</p> <p>In this study we showed that the phylogeography of <it>A. marginale </it>MSP1a sequences is associated with world ecological regions (ecoregions) resulting in different evolutionary pressures and thence MSP1a sequences. The results demonstrated that the MSP1a first (R1) and last (RL) repeats and microsatellite sequences were associated with world ecoregion clusters with specific and different environmental envelopes. The evolution of R1 repeat sequences was found to be under positive selection. It is hypothesized that the driving environmental factors regulating tick populations could act on the selection of different <it>A. marginale </it>MSP1a sequence lineages, associated to each ecoregion.</p> <p>Conclusion</p> <p>The results reported herein provided the first evidence that the evolution of <it>A. marginale </it>was linked to ecological traits affecting tick vector performance. These results suggested that some <it>A. marginale </it>strains have evolved under conditions that support pathogen biological transmission by <it>R. microplus</it>, under different ecological traits which affect performance of <it>R. microplus </it>populations. The evolution of other <it>A. marginale </it>strains may be linked to transmission by other tick species or to mechanical transmission in regions where <it>R. microplus </it>is currently eradicated. The information derived from this study is fundamental toward understanding the evolution of other vector-borne pathogens.</p

Usutu virus in migratory song thrushes, Spain

Letter to the Editor.This research was supported by European Union grants 278976 from the following programs of the EMIDA ERANET (Coordination of European Research on Emerging and Major Infectious Diseases of Livestock; www.emida-era. net): ANTIGONE (Anticipating the Global Onset of Novel Epidemics) and APHAEA (Harmonised Approaches in Monitoring Wildlife Population Health).Peer Reviewe

Divergent environmental preferences and areas of sympatry of tick species in the Amblyomma cajennense complex (Ixodidae)

Four species of Neotropical ticks, Amblyomma mixtum, Amblyomma cajennense, Amblyomma tonelliae and Amblyomma sculptum (formerly included in the catch-all name A. cajennense), have an allopatric distribution in much of their range, with areas of parapatry for at least two of them. We inferred the abiotic niches of these organisms using coefficients of a harmonic regression of the temperature and the Normalized Difference Vegetation Index (NDVI, reflecting plant stress) from remotely sensed data from MODIS satellites with 0.05° spatial resolution. Combinations of coefficients describing the phenology of these two variables pointed to divergent niche preferences, compatible with previous events of vicariance among the species. Amblyomma cajennense has been recorded in areas with small variations in temperature and NDVI. The remaining species were recorded in areas with large variations. The maximum environmental niche overlap was ∼73.6% between A. mixtum and A. cajennense and 73.5% between A. tonelliae and A. sculptum. Projecting these inferences on the geographical space revealed probable areas of sympatry or parapatry between A. mixtum and A. cajennense or between A. tonelliae and A. sculptum, the latter of which was confirmed with field collections. The A. sculptum distribution overlaps with that of A. tonelliae in northern Argentina and Paraguay; parapatry occurs at one extreme of the conditions occupied by both species. Compared with areas of allopatry, sites with both species had consistently lower temperatures, except for 10–12 weeks during the summer, and higher NDVI values throughout the year. We hypothesise that the overlap between A. tonelliae and A. sculptum resulted from secondary contact between populations, with A. sculptum adapting to sites with high water availability to balance high summer temperatures. Additional surveys of the areas of spatial overlap among these species are necessary to elucidate the forces driving their evolution and their adaptation to the environment.Fil: Estrada Peña, Agustín. Universidad de Zaragoza; EspañaFil: Tarragona, Evelina Luisa. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Vesco, Umberto. Università di Torino; ItaliaFil: De Meneghi, Daniele. Università di Torino; ItaliaFil: Mastropaolo, Mariano. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Mangold, Atilio Jose. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Guglielmone, Alberto Alejandro. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Nava, Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentin

Ticks from Catamarca and Tucumán provinces: study of a collection from wild and domestic hosts

Durante 2003-2004 se obtuvieron garrapatas de caballos (Amblyomma neumanni) y de corzuela, Mazama gouazoupira (A. neumanni y Haemaphysalis juxtakochi) en Catamarca y de perros (A. tigrinum, Rhipicephalus sanguineus), mara, Dolichotis patagonum (R. sanguineus), lampalagua, Boa constrictor (Amblyomma argentinae) y tapir, Tapirus terrestris (Amblyomma dubitatum) en Tucumán. Aunque R. sanguineus se presume que se encuentra establecida en la mayor parte de los centros urbanos argentinos, éstos son los primeros registros para Tucumán. El hallazgo sobre mara es el primero para este tipo de hospedador. También los registros de A. dubitatum y de H. juxtakochi en Tucumán y Catamarca, respectivamente, son los primeros para ambas provincias.During 2003-2004 samples of ticks were obtained from horses (Amblyomma neumanni) and a gray brocket deer, Mazama gouazoupira (A. neumanni and Haemaphysalis juxtakochi) in Catamarca, and from dogs (A. tigrinum, Rhipicephalus sanguineus), mara, Dolichotis patagonum (R. sanguineus), boa, Boa constrictor (Amblyomma argentinae) and tapir, Tapirus terrestris (Amblyomma dubitatum) in Tucumán. Although R. sanguineus is presumably established in most Argentinean localities, these are the first records for Tucumàn. Its finding on a mara is a new host record. As well, the findings of A. dubitatum and H. juxtakochi in Tucumán and Catamarca, respectively, are also the firsts for these provinces.Fil: Zerpa, C.. Universidad Juan Agustín Maza; ArgentinaFil: Venzal, J. M.. Universidad de la República; UruguayFil: López, N.. Sin filiacion; ArgentinaFil: Mangold, Atilio Jose. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Santa Fe. Estacion Experimental Agropecuaria Rafaela. Agencia de Extension Rural Rafaela.; ArgentinaFil: Guglielmone, Alberto Alejandro. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Santa Fe. Estacion Experimental Agropecuaria Rafaela. Agencia de Extension Rural Rafaela.; Argentin

Allopatric speciation in ticks: genetic and reproductive divergence between geographic strains of Rhipicephalus (Boophilus) microplus

12 pages, 5 figures.-- PMID: 19243585 [PubMed].-- PMCID: PMC2656471.-- Supporting information (Microsatellite genotypes of individual tick crosses, XLS file) available at: http://www.biomedcentral.com/content/supplementary/1471-2148-9-46-s1.xls.-- et al.[Background]: The cattle tick, Rhipicephalus (Boophilus) microplus, economically impact cattle industry in tropical and subtropical regions of the world. The morphological and genetic differences among R. microplus strains have been documented in the literature, suggesting that biogeographical and ecological separation may have resulted in boophilid ticks from America/Africa and those from Australia being different species. To test the hypothesis of the presence of different boophilid species, herein we performed a series of experiments to characterize the reproductive performance of crosses between R. microplus from Australia, Africa and America and the genetic diversity of strains from Australia, Asia, Africa and America.[Results]: The results showed that the crosses between Australian and Argentinean or Mozambican strains of boophilid ticks are infertile while crosses between Argentinean and Mozambican strains are fertile. These results showed that tick strains from Africa (Mozambique) and America (Argentina) are the same species, while ticks from Australia may actually represent a separate species. The genetic analysis of mitochondrial 12S and 16S rDNA and microsatellite loci were not conclusive when taken separately, but provided evidence that Australian tick strains were genetically different from Asian, African and American strains.[Conclusion]: The results reported herein support the hypothesis that at least two different species share the name R. microplus. These species could be redefined as R. microplus (Canestrini, 1887) (for American and African strains) and probably the old R. australis Fuller, 1899 (for Australian strains), which needs to be redescribed. However, experiments with a larger number of tick strains from different geographic locations are needed to corroborate these results.This work was supported by ICTTD-3, financed by the International Cooperation Program of the European Union, coordination action project No. 510561, the Consejería de Educación y Ciencia, JCCM, Spain (project PAI06-0046-5285) (to JF), the Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq (to MBL), the Consejo Nacional de Investigaciones Cientícas y Técnicas de Argentina (PIP 2058) and INTA Rafaela (TCP 426100) (to AJM, AAG and CT). V. Naranjo was funded by Junta de Comunidades de Castilla–La Mancha (JCCM), Spain.Peer reviewe

Genetic diversity of Anaplasma species major surface proteins and implications for anaplasmosis serodiagnosis and vaccine development

The genus Anaplasma (Rickettsiales: Anaplasmataceae) includes several pathogens of veterinary and human medical importance. An understanding of the diversity of Anaplasma major surface proteins (MSPs), including those MSPs that modulate infection, development of persistent infections, and transmission of pathogens by ticks, is derived in part, by characterization and phylogenetic analyses of geographic strains. Information concerning the genetic diversity of Anaplasma spp. MSPs will likely influence the development of serodiagnostic assays and vaccine strategies for the control of anaplasmosi

Comparative proteomics for the characterization of the most relevant Amblyomma tick species as vectors of zoonotic pathogens worldwide

Ticks transmit zoonotic pathogens worldwide. Nevertheless, very little information is available on their genome, transcriptome and proteome. Herein, we characterized the proteome of Amblyomma americanum adults and nymphs because of their role in pathogen transmission and compared the proteome of A. americanum, A. cajennense and A. variegatum adult ticks. We also used de novo sequencing proteomics data for the analysis of the phylogenetic relationships between the three Amblyomma spp. in a proof of concept for phyloproteomics. The results showed that host and tick proteins involved in blood digestion, heme detoxification, development and innate immunity were differentially represented between adults and nymphs. Although these ticks were unfed, over-represented host proteins may supply nutrients during off-host periods. Tick proteins involved in tick attachment, feeding, heat shock response, protease inhibition and heme detoxification were differentially represented between Amblyomma spp., suggesting adaptation processes to biotic and abiotic factors. These results suggested that phyloproteomics might be a useful tool for the phylogenetic analysis of tick species in which sequence data is a limiting factor and demonstrate the possibilities of proteomics studies for the characterization of relevant tick vector species and provide new relevant information to understand the physiology, development and evolution of these tick species. [Biological significance]: This is the first report on the proteome of the most important Amblyomma tick species for their relevance as vectors of zoonotic pathogens worldwide. Nevertheless, very little information is available on the genome, transcriptome and proteome of these vector ectoparasites. The results reported herein provide new relevant information to understand the physiology, development and evolution of these tick species. Phyloproteomics using de novo protein sequencing was assayed as a new approach for the phylogenetic analysis of tick species in which sequence data is a limiting factor. This article is part of a Special Issue entitled: Proteomics of non-model organisms.This research was supported by grants BFU2011-23896 and the EU FP7 ANTIGONE project number 278976. M. Popara is an Early Stage Researcher supported by the POSTICK ITN (Post-graduate training network for capacity building to control ticks and tick-borne diseases) within the FP7-PEOPLE-ITN programme (EU Grant No. 238511).Peer Reviewe