Potential species distribution and richness of ixodidae ticks associated with wild vertebrates from Michoacán, Mexico

Ticks are regarded as the most relevant vectors of disease-causing pathogens in domestic and wild animals. The diversity of Ixodidae is known for a very small number of genera. Ixodes are repre- sented by 26 species, and in 2007 the first reported ticks vectors in Mexico for the causal agent of Lyme disease. Recent rise in tick-borne disease in many parts of the world is a phenomenon in need of an explanation. The main objective of the present work was to map at a regional scale (1:2,000,000) of the distribution of ticks of the family Ixodidae that are potentially present on the wild fauna of state of Michoacan, Mexico. We compiled all available literature on ticks at a national level together with complete cartographic and bibliographic georeferenced information of the distribution of hosts in order to build a spatial database in ArcView 3.3. The results indicated that the wild fauna in the state’s territory could potentially include 31 species of ticks of Ixodidae. The map of potential species richness of ixodid ticks on the wild fauna of the state can be categorized into five classes of species richness. The highest potential concentration of ixodid species on wild fauna occurs in the volcanic area of Pico de Tancítaro

Primer análisis filogenético de Ehrlichia canis en perros y garrapatas de México. Estudio preliminar

RESUMEN Objetivos. Caracterizar filogenéticamente Ehrlichia canis a partir de perros naturalmente infectados y sus garrapatas, mediante PCR y secuenciación del gene 16SrRNA para compararlos con diferentes aislados encontrados en el continente Americano. Material y métodos. Se colectaron muestras sanguíneas de 139 perros con manifestaciones clínicas sugestivas a Ehrlichiosis, y que estuvieran infestados con garrapatas; una parte del gene 16SrRNA, fue secuenciada y alineada junto con las 17 secuencias reportadas en los países de América. Se construyeron dos árboles filogenéticos utilizando el método de Máxima verosimilitud compuesta, y Máxima parsimonia. Resultados. Fueron positivos  a E. canis 25/139 (18.0%) perros y 29/139 (20.9%) garrapatas colectadas sobre los perros. Las manifestaciones clínicas presentadas fueron fiebre, astenia, depresión y vómito. Las garrapatas Rhipicephalus sanguineus, Dermacentor variabilis y Haemaphysalis leporis-palustris fueron positivas para E. canis. El análisis filogenético mostró que las secuencias 16SrRNA de Ehrlichia canis aisladas de perros y garrapatas en este estudio forman un tercer grupo que diverge de las secuencias de Sudamérica y EUA. Conclusiones. Es el primer análisis filogenético de E. canis en México. Hay diferencias entre las secuencias de este estudio, con las reportadas en otros países de Sudamérica y en EUA. Esta investigación sienta las bases para profundizar en el estudio de la variabilidad genética

Very high energy particle acceleration powered by the jets of the microquasar SS 433

SS 433 is a binary system containing a supergiant star that is overflowing its Roche lobe with matter accreting onto a compact object (either a black hole or neutron star). Two jets of ionized matter with a bulk velocity of $\sim0.26c$ extend from the binary, perpendicular to the line of sight, and terminate inside W50, a supernova remnant that is being distorted by the jets. SS 433 differs from other microquasars in that the accretion is believed to be super-Eddington, and the luminosity of the system is $\sim10^{40}$ erg s$^{-1}$. The lobes of W50 in which the jets terminate, about 40 pc from the central source, are expected to accelerate charged particles, and indeed radio and X-ray emission consistent with electron synchrotron emission in a magnetic field have been observed. At higher energies (>100 GeV), the particle fluxes of $\gamma$ rays from X-ray hotspots around SS 433 have been reported as flux upper limits. In this energy regime, it has been unclear whether the emission is dominated by electrons that are interacting with photons from the cosmic microwave background through inverse-Compton scattering or by protons interacting with the ambient gas. Here we report TeV $\gamma$-ray observations of the SS 433/W50 system where the lobes are spatially resolved. The TeV emission is localized to structures in the lobes, far from the center of the system where the jets are formed. We have measured photon energies of at least 25 TeV, and these are certainly not Doppler boosted, because of the viewing geometry. We conclude that the emission from radio to TeV energies is consistent with a single population of electrons with energies extending to at least hundreds of TeV in a magnetic field of $\sim16$~micro-Gauss.Comment: Preprint version of Nature paper. Contacts: S. BenZvi, B. Dingus, K. Fang, C.D. Rho , H. Zhang, H. Zho

The Sensitivity of HAWC to High-Mass Dark Matter Annihilations

The High Altitude Water Cherenkov (HAWC) observatory is a wide field-of-view detector sensitive to gamma rays of 100 GeV to a few hundred TeV. Located in central Mexico at 19 degrees North latitude and 4100 m above sea level, HAWC will observe gamma rays and cosmic rays with an array of water Cherenkov detectors. The full HAWC array is scheduled to be operational in Spring 2015. In this paper, we study the HAWC sensitivity to the gamma-ray signatures of high-mass (multi- TeV) dark matter annihilation. The HAWC observatory will be sensitive to diverse searches for dark matter annihilation, including annihilation from extended dark matter sources, the diffuse gamma-ray emission from dark matter annihilation, and gamma-ray emission from non-luminous dark matter subhalos. Here we consider the HAWC sensitivity to a subset of these sources, including dwarf galaxies, the M31 galaxy, the Virgo cluster, and the Galactic center. We simulate the HAWC response to gamma rays from these sources in several well-motivated dark matter annihilation channels. If no gamma-ray excess is observed, we show the limits HAWC can place on the dark matter cross-section from these sources. In particular, in the case of dark matter annihilation into gauge bosons, HAWC will be able to detect a narrow range of dark matter masses to cross-sections below thermal. HAWC should also be sensitive to non-thermal cross-sections for masses up to nearly 1000 TeV. The constraints placed by HAWC on the dark matter cross-section from known sources should be competitive with current limits in the mass range where HAWC has similar sensitivity. HAWC can additionally explore higher dark matter masses than are currently constrained.Comment: 15 pages, 4 figures, version to be published in PR