ESTRATEGIAS PARA LA REGULACIÓN DEL COMERCIO INTERNACIONAL DE FAUNA SILVESTRE EN MÉXICO

El objetivo de la investigación es proponer estrategias que abarquen los panoramas internacionales en relación al marco comercial y regulatorio tanto nacional como internacional , del comercio y la conservación de la fauna silvestre. Para lo cual se describen en cinco capítulos y finalizando con las propuestas de estrategias. El capítulo 1 aborda la importancia de la fauna silvestre, considerando las categorías económica, sociocultural y ambiental. En la importancia económica se retomara dos de las teorías del comercio internacional: la ventaja absoluta y la teoría de la localización, explicando cada una de estas y la relación que tiene con México, así como detallando los tres valores dado por la Organización de las Naciones Unidas, en 1994. En la importancia ambiental de la fauna silvestre las característica de su ubicación entre las regiones biogeográficas Neártica (templada) y Neotropical (tropical), su intrincado relieve y compleja historia geológica, que le confiere una geodiversidad de rasgos geológicos, físicos e históricos, las geoformas y de los diferentes tipos de suelo, cuya conjugación de factores hacen de México un país con una diversidad biológica. La importancia socio-cultural como la relación humano-animal ha sido una de las combinaciones más importantes para la fundación de las culturas, para los cuales la fauna silvestre ha sido objeto de culto, identidad y valores

Modeling the impact of climate and landscape on the efficacy of white tailed deer vaccination for cattle tick control in northeastern Mexico

Cattle ticks are distributed worldwide and affect animal health and livestock production. White tailed deer (WTD) sustain and spread cattle tick populations. The aim of this study was to model the efficacy of anti-tick vaccination of WTD to control tick infestations in the absence of cattle vaccination in a territory where both host species coexist and sustain cattle tick populations. Agent-based models that included land cover/landscape properties (patch size, distances to patches) and climatic conditions were built in a GIS environment to simulate WTD vaccine effectiveness under conditions where unvaccinated cattle shared the landscape. Published and validated information on tick life cycle was used to build models describing tick mortality and developmental rates. Data from simulations were applied to a large territory in northeastern Mexico where cattle ticks are endemic and WTD and cattle share substantial portions of the habitat. WTD movements were simulated together with tick population dynamics considering the actual landscape and climatic features. The size of the vegetation patches and the distance between patches were critical for the successful control of tick infestations after WTD vaccination. The presence of well-connected, large vegetation patches proved essential for tick control, since the tick could persist in areas of highly fragmented habitat. The continued application of one yearly vaccination on days 1-70 for three years reduced tick abundance/animal/patch by a factor of 40 and 60 for R. annulatus and R. microplus, respectively when compared to non-vaccinated controls. The study showed that vaccination of WTD alone during three consecutive years could result in the reduction of cattle tick populations in northeastern Mexico. Furthermore, the results of the simulations suggested the possibility of using vaccines to prevent the spread and thus the re-introduction of cattle ticks into tick-free areas.This research was supported by the EU FP7 ANTIGONE project number 278976.Peer Reviewe

Vaccination with recombinant Boophilus annulatus Bm86 ortholog protein, Ba86, protects cattle against B. annulatus and B. microplus infestations

<p>Abstract</p> <p>Background</p> <p>The cattle ticks, <it>Boophilus </it>spp., affect cattle production in tropical and subtropical regions of the world. Tick vaccines constitute a cost-effective and environmentally friendly alternative to tick control. The recombinant <it>B. microplus </it>Bm86 protective antigen has been shown to protect cattle against tick infestations. Recently, the gene coding for <it>B. annulatus </it>Bm86 ortholog, Ba86, was cloned and the recombinant protein was secreted and purified from the yeast <it>Pichia pastoris</it>.</p> <p>Results</p> <p>Recombinant Ba86 (Israel strain) was used to immunize cattle to test its efficacy for the control of <it>B. annulatus </it>(Mercedes, Texas, USA strain) and <it>B. microplus </it>(Susceptible, Mexico strain) infestations. Bm86 (Gavac and Mozambique strain) and adjuvant/saline were used as positive and negative controls, respectively. Vaccination with Ba86 reduced tick infestations (71% and 40%), weight (8% and 15%), oviposition (22% and 5%) and egg fertility (25% and 50%) for <it>B. annulatus </it>and <it>B. microplus</it>, respectively. The efficacy of both Ba86 and Bm86 was higher for <it>B. annulatus </it>than for <it>B. microplus</it>. The efficacy of Ba86 was higher for <it>B. annulatus </it>(83.0%) than for <it>B. microplus </it>(71.5%). The efficacy of Bm86 (Gavac; 85.2%) but not Bm86 (Mozambique strain; 70.4%) was higher than that of Ba86 (71.5%) on <it>B. microplus</it>. However, the efficacy of Bm86 (both Gavac and Mozambique strain; 99.6%) was higher than that of Ba86 (83.0%) on <it>B. annulatus</it>.</p> <p>Conclusion</p> <p>These experiments showed the efficacy of recombinant Ba86 for the control of <it>B. annulatus </it>and <it>B. microplus </it>infestations in cattle and suggested that physiological differences between <it>B. microplus </it>and <it>B. annulatus </it>and those encoded in the sequence of Bm86 orthologs may be responsible for the differences in susceptibility of these tick species to Bm86 vaccines.</p

Boophilus microplus: biological and molecular aspects of acaricide resistance and their impact on animal health

[ES]: La aplicación de ixodicidas durante mucho tiempo ha sido la alternativa de elección para el control de la garrapata Boophilus microplus, sin embargo, actualmente el uso de los ixodicidas tiene una eficacia limitada en la reducción de las infestaciones debido al desarrollo de poblaciones de garrapatas resistes. La resistencia a ixodicidas es un problema creciente que necesita ser atendido, por que en este momento está afectando la competitividad de la ganadería y la economía de miles de productores en México. La solución de este problema requiere de la implementación de programas de investigación que coadyuven a dilucidar los mecanismos moleculares de la resistencia con el fin de encontrar nuevos blancos moleculares para el diagnóstico y para el desarrollo de vacunas recombinantes. El uso reciente de nuevas herramientas genómicas y los enfoques de genética reversa, son una extraordinaria herramienta que podría ayudar en el descubrimiento de nuevos genes de interés diagnóstico ó imunoprofiláctico, contribuyendo así al mejoramiento de las estrategias de control de garrapatas y los programas de mitigación de la resistencia a ixodicidas. El propósito de esta revisión es compilar diferentes tópicos actuales relacionados con la biología de las garrapatas, resistencia a los ixodicidas, y las perspectivas de la investigación genómica en la garrapata Boophilus microplus, iniciando con algunas consideraciones biológicas y moleculares acerca de la nueva clasificación de este ectoparásito, hasta el análisis de la resistencia a los ixodicidas, su impacto en la industria ganadera en México y la aplicación de la genómica en la solución de problemas asociados con el control de las garrapatas mediante el diseño de nuevos métodos diagnósticos así como el desarrollo de vacunas contra garrapatas.[EN]: The application of Ixodicides has been considered for a long time the alternative for control of the cattle tick Boophilus microplus, however, its use is currently limited in reducing tick infestations, due to the appearance of resistant field tick populations. Ixodicide resistance is a growing problem that needs to be attended, because, it is currently affecting the competitiveness of the Mexican cattle industry in general and in particular the income of cattle producers. The solution to this problem needs to increase the budget dedicated to basic research in order to elucidate the molecular mechanisms of ixodicide resistance leading to the discovery of new molecular targets for ixodicide resistance detection and recombinant vaccine development. The recent use of new genomic tools, as well as reverse genetics approaches, will provide an extraordinary contribution to the improvement of tick control strategies and ixodicide resistance mitigation programs. The aim of the present review is to make a compilation of different topics related with acaricide resistance in the cattle tick Boophilus microplus, starting with some biological and molecular considerations on its new classification, to the analysis of ixodicide resistance, its impact on the Mexican cattle industry and the perspective of the genomic research in order to solve the problems associated to tick control, new diagnostic tools and development of tick vaccines.Al Consejo Nacional de Ciencia y Tecnología por la beca otorgada a la MC Delia Inés Domínguez García inscrita en el programa doctoral de Ciencias Biológicas y de la Salud de la Universidad Autónoma Metropolitana. Este trabajo fue parcialmente financiado por el proyecto 90195 del programa de CONACYT de apoyos complementarios otorgado a Dr. Rodrigo Rosario Cruz.Peer Reviewe

Differential expression of genes in salivary glands of male Rhipicephalus (Boophilus)microplus in response to infection with Anaplasma marginale

<p>Abstract</p> <p>Background</p> <p>Bovine anaplasmosis, caused by the rickettsial tick-borne pathogen <it>Anaplasma marginale </it>(Rickettsiales: Anaplasmataceae), is vectored by <it>Rhipicephalus </it>(<it>Boophilus</it>)<it>microplus </it>in many tropical and subtropical regions of the world. <it>A. marginale </it>undergoes a complex developmental cycle in ticks which results in infection of salivary glands from where the pathogen is transmitted to cattle. In previous studies, we reported modification of gene expression in <it>Dermacentor variabilis </it>and cultured <it>Ixodes scapularis </it>tick cells in response to infection with <it>A. marginale</it>. In these studies, we extended these findings by use of a functional genomics approach to identify genes differentially expressed in <it>R. microplus </it>male salivary glands in response to <it>A. marginale </it>infection. Additionally, a <it>R. microplus</it>-derived cell line, BME26, was used for the first time to also study tick cell gene expression in response to <it>A. marginale </it>infection.</p> <p>Results</p> <p>Suppression subtractive hybridization libraries were constructed from infected and uninfected ticks and used to identify genes differentially expressed in male <it>R. microplus </it>salivary glands infected with <it>A. marginale</it>. A total of 279 ESTs were identified as candidate differentially expressed genes. Of these, five genes encoding for putative histamine-binding protein (22Hbp), von Willebrand factor (94Will), flagelliform silk protein (100Silk), Kunitz-like protease inhibitor precursor (108Kunz) and proline-rich protein BstNI subfamily 3 precursor (7BstNI3) were confirmed by real-time RT-PCR to be down-regulated in tick salivary glands infected with <it>A. marginale</it>. The impact of selected tick genes on <it>A. marginale </it>infections in tick salivary glands and BME26 cells was characterized by RNA interference. Silencing of the gene encoding for putative flagelliform silk protein (100Silk) resulted in reduced <it>A. marginale </it>infection in both tick salivary glands and cultured BME26 cells, while silencing of the gene encoding for subolesin (4D8) significantly reduced infection only in cultured BME26 cells. The knockdown of the gene encoding for putative metallothionein (93 Meth), significantly up-regulated in infected cultured BME26 cells, resulted in higher <it>A. marginale </it>infection levels in tick cells.</p> <p>Conclusions</p> <p>Characterization of differential gene expression in salivary glands of <it>R. microplus </it>in response to <it>A. marginale </it>infection expands our understanding of the molecular mechanisms at the tick-pathogen interface. Functional studies suggested that differentially expressed genes encoding for subolesin, putative von Willebrand factor and flagelliform silk protein could play a role in <it>A. marginale </it>infection and multiplication in ticks. These tick genes found to be functionally relevant for tick-pathogen interactions will likely be candidates for development of vaccines designed for control of both ticks and tick-borne pathogens.</p

Anaplasma phagocytophilum and Anaplasma marginale Elicit Different Gene Expression Responses in Cultured Tick Cells

The genus Anaplasma (Rickettsiales: Anaplasmataceae) includes obligate tick-transmitted intracellular organisms, Anaplasma phagocytophilum and Anaplasma marginale that multiply in both vertebrate and tick host cells. Recently, we showed that A. marginale affects the expression of tick genes that are involved in tick survival and pathogen infection and multiplication. However, the gene expression profile in A. phagocytophilum-infected tick cells is currently poorly characterized. The objectives of this study were to characterize tick gene expression profile in Ixodes scapularis ticks and cultured ISE6 cells in response to infection with A. phagocypthilum and to compare tick gene expression responses in A. phagocytophilum- and A. marginale-infected tick cells by microarray and real-time RT-PCR analyses. The results of these studies demonstrated modulation of tick gene expression by A. phagocytophilum and provided evidence of different gene expression responses in tick cells infected with A. phagocytophilum and A. marginale. These differences in Anaplasma-tick interactions may reflect differences in pathogen life cycle in the tick cells

Expression of Heat Shock and Other Stress Response Proteins in Ticks and Cultured Tick Cells in Response to Anaplasma spp. Infection and Heat Shock

Ticks are ectoparasites of animals and humans that serve as vectors of Anaplasma and other pathogens that affect humans and animals worldwide. Ticks and the pathogens that they transmit have coevolved molecular interactions involving genetic traits of both the tick and the pathogen that mediate their development and survival. In this paper, the expression of heat shock proteins (HSPs) and other stress response proteins (SRPs) was characterized in ticks and cultured tick cells by proteomics and transcriptomics analyses in response to Anaplasma spp. infection and heat shock. The results of these studies demonstrated that the stress response was activated in ticks and cultured tick cells after Anaplasma spp. infection and heat shock. However, in the natural vector-pathogen relationship, HSPs and other SRPs were not strongly activated, which likely resulted from tick-pathogen coevolution. These results also demonstrated pathogen- and tick-specific differences in the expression of HSPs and other SRPs in ticks and cultured tick cells infected with Anaplasma spp. and suggested the existence of post-transcriptional mechanisms induced by Anaplasma spp. to control tick response to infection. These results illustrated the complexity of the stress response in ticks and suggested a function for the HSPs and other SRPs during Anaplasma spp. infection

Subolesin expression in response to pathogen infection in ticks

<p>Abstract</p> <p>Background</p> <p>Ticks (Acari: Ixodidae) are vectors of pathogens worldwide that cause diseases in humans and animals. Ticks and pathogens have co-evolved molecular mechanisms that contribute to their mutual development and survival. Subolesin was discovered as a tick protective antigen and was subsequently shown to be similar in structure and function to akirins, an evolutionarily conserved group of proteins in insects and vertebrates that controls NF-kB-dependent and independent expression of innate immune response genes. The objective of this study was to investigate subolesin expression in several tick species infected with a variety of pathogens and to determine the effect of subolesin gene knockdown on pathogen infection. In the first experiment, subolesin expression was characterized in ticks experimentally infected with the cattle pathogen, <it>Anaplasma marginale</it>. Subolesin expression was then characterized in questing or feeding adult ticks confirmed to be infected with <it>Anaplasma</it>, <it>Ehrlichia</it>, <it>Rickettsia</it>, <it>Babesia </it>or <it>Theileria </it>spp. Finally, the effect of subolesin knockdown by RNA interference (RNAi) on tick infection was analyzed in <it>Dermacentor variabilis </it>males exposed to various pathogens by capillary feeding (CF).</p> <p>Results</p> <p>Subolesin expression increased with pathogen infection in the salivary glands but not in the guts of tick vector species infected with <it>A. marginale</it>. When analyzed in whole ticks, subolesin expression varied between tick species and in response to different pathogens. As reported previously, subolesin knockdown in <it>D. variabilis </it>infected with <it>A. marginale </it>and other tick-borne pathogens resulted in lower infection levels, while infection with <it>Francisella tularensis </it>increased in ticks after RNAi. When non-tick-borne pathogens were fed to ticks by CF, subolesin RNAi did not affect or resulted in lower infection levels in ticks. However, subolesin expression was upregulated in <it>D. variabilis </it>exposed to <it>Escherichia coli</it>, suggesting that although this pathogen may induce subolesin expression in ticks, silencing of this molecule reduced bacterial multiplication by a presently unknown mechanism.</p> <p>Conclusions</p> <p>Subolesin expression in infected ticks suggested that subolesin may be functionally important for tick innate immunity to pathogens, as has been reported for the akirins. However, subolesin expression and consequently subolesin-mediated innate immunity varied with the pathogen and tick tissue. Subolesin may plays a role in tick innate immunity in the salivary glands by limiting pathogen infection levels, but activates innate immunity only for some pathogen in the guts and other tissues. In addition, these results provided additional support for the role of subolesin in other molecular pathways including those required for tissue development and function and for pathogen infection and multiplication in ticks. Consequently, RNAi experiments demonstrated that subolesin knockdown in ticks may affect pathogen infection directly by reducing tick innate immunity that results in higher infection levels and indirectly by affecting tissue structure and function and the expression of genes that interfere with pathogen infection and multiplication. The impact of the direct or indirect effects of subolesin knockdown on pathogen infection may depend on several factors including specific tick-pathogen molecular interactions, pathogen life cycle in the tick and unknown mechanisms affected by subolesin function in the control of global gene expression in ticks.</p

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

Silencing of genes involved in Anaplasma marginale-tick interactions affects the pathogen developmental cycle in Dermacentor variabilis

<p>Abstract</p> <p>Background</p> <p>The cattle pathogen, <it>Anaplasma marginale</it>, undergoes a developmental cycle in ticks that begins in gut cells. Transmission to cattle occurs from salivary glands during a second tick feeding. At each site of development two forms of <it>A. marginale </it>(reticulated and dense) occur within a parasitophorous vacuole in the host cell cytoplasm. However, the role of tick genes in pathogen development is unknown. Four genes, found in previous studies to be differentially expressed in <it>Dermacentor variabilis </it>ticks in response to infection with <it>A. marginale</it>, were silenced by RNA interference (RNAi) to determine the effect of silencing on the <it>A. marginale </it>developmental cycle. These four genes encoded for putative glutathione S-transferase (GST), salivary selenoprotein M (SelM), H+ transporting lysosomal vacuolar proton pump (vATPase) and subolesin.</p> <p>Results</p> <p>The impact of gene knockdown on <it>A. marginale </it>tick infections, both after acquiring infection and after a second transmission feeding, was determined and studied by light microscopy. Silencing of these genes had a different impact on <it>A. marginale </it>development in different tick tissues by affecting infection levels, the densities of colonies containing reticulated or dense forms and tissue morphology. Salivary gland infections were not seen in any of the gene-silenced ticks, raising the question of whether these ticks were able to transmit the pathogen.</p> <p>Conclusion</p> <p>The results of this RNAi and light microscopic analyses of tick tissues infected with <it>A. marginale </it>after the silencing of genes functionally important for pathogen development suggest a role for these molecules during pathogen life cycle in ticks.</p