Genomic epidemiology of Mycobacterium bovis infection in sympatric badger and cattle populations in Northern Ireland.

Bovine tuberculosis (bTB) is a costly, epidemiologically complex, multi-host, endemic disease. Lack of understanding of transmission dynamics may undermine eradication efforts. Pathogen whole-genome sequencing improves epidemiological inferences, providing a means to determine the relative importance of inter- and intra-species host transmission for disease persistence. We sequenced an exceptional data set of 619 Mycobacterium bovis isolates from badgers and cattle in a 100 km2 bTB 'hotspot' in Northern Ireland. Historical molecular subtyping data permitted the targeting of an endemic pathogen lineage, whose long-term persistence provided a unique opportunity to study disease transmission dynamics in unparalleled detail. Additionally, to assess whether badger population genetic structure was associated with the spatial distribution of pathogen genetic diversity, we microsatellite genotyped hair samples from 769 badgers trapped in this area. Birth death models and TransPhylo analyses indicated that cattle were likely driving the local epidemic, with transmission from cattle to badgers being more common than badger to cattle. Furthermore, the presence of significant badger population genetic structure in the landscape was not associated with the spatial distribution of M. bovis genetic diversity, suggesting that badger-to-badger transmission is not playing a major role in transmission dynamics. Our data were consistent with badgers playing a smaller role in transmission of M. bovis infection in this study site, compared to cattle. We hypothesize, however, that this minor role may still be important for persistence. Comparison to other areas suggests that M. bovis transmission dynamics are likely to be context dependent, with the role of wildlife being difficult to generalize.

Evolving spatial conservation prioritization with intraspecific genetic data.

Spatial conservation prioritization (SCP) is a planning framework used to identify new conservation areas on the basis of the spatial distribution of species, ecosystems, and their services to human societies. The ongoing accumulation of intraspecific genetic data on a variety of species offers a way to gain knowledge of intraspecific genetic diversity and to estimate several population characteristics useful in conservation, such as dispersal and population size. Here, we review how intraspecific genetic data have been integrated into SCP and highlight their potential for identifying conservation area networks that represent intraspecific genetic diversity comprehensively and that ensure the long-term persistence of biodiversity in the face of global change.

Genetic evidence further elucidates the history and extent of badger introductions from Great Britain into Ireland.

The colonization of Ireland by mammals has been the subject of extensive study using genetic methods and forms a central problem in understanding the phylogeography of European mammals after the Last Glacial Maximum. Ireland exhibits a depauperate mammal fauna relative to Great Britain and continental Europe, and a range of natural and anthropogenic processes have given rise to its modern fauna. Previous Europe-wide surveys of the European badger (Meles meles) have found conflicting microsatellite and mitochondrial DNA evidence in Irish populations, suggesting Irish badgers have arisen from admixture between human imported British and Scandinavian animals. The extent and history of contact between British and Irish badger populations remains unclear. We use comprehensive genetic data from Great Britain and Ireland to demonstrate that badgers in Ireland's northeastern and southeastern counties are genetically similar to contemporary British populations. Simulation analyses suggest this admixed population arose in Ireland 600-700 (CI 100-2600) years before present most likely through introduction of British badgers by people. These findings add to our knowledge of the complex colonization history of Ireland by mammals and the central role of humans in facilitating it.

The population and landscape genetics of the European badger (Meles meles) in Ireland.

The population genetic structure of free-ranging species is expected to reflect landscape-level effects. Quantifying the role of these factors and their relative contribution often has important implications for wildlife management. The population genetics of the European badger (Meles meles) have received considerable attention, not least because the species acts as a potential wildlife reservoir for bovine tuberculosis (bTB) in Britain and Ireland. Herein, we detail the most comprehensive population and landscape genetic study of the badger in Ireland to date-comprised of 454 Irish badger samples, genotyped at 14 microsatellite loci. Bayesian and multivariate clustering methods demonstrated continuous clinal variation across the island, with potentially distinct differentiation observed in Northern Ireland. Landscape genetic analyses identified geographic distance and elevation as the primary drivers of genetic differentiation, in keeping with badgers exhibiting high levels of philopatry. Other factors hypothesized to affect gene flow, including earth worm habitat suitability, land cover type, and the River Shannon, had little to no detectable effect. By providing a more accurate picture of badger population structure and the factors effecting it, these data can guide current efforts to manage the species in Ireland and to better understand its role in bTB.

Soil environment is a key driver of adaptation in Medicago truncatula: new insights from landscape genomics.

Spatial differences in environmental selective pressures interact with the genomes of organisms, ultimately leading to local adaptation. Landscape genomics is an emergent research area that uncovers genome-environment associations, thus allowing researchers to identify candidate loci for adaptation to specific environmental variables. In the present study, we used latent factor mixed models (LFMMs) and Moran spectral outlier detection/randomization (MSOD-MSR) to identify candidate loci for adaptation to 10 environmental variables (climatic, soil and atmospheric) among 43 515 single nucleotide polymorphisms (SNPs) from 202 accessions of the model legume Medicago truncatula. Soil variables were associated with a large number of candidate loci identified through both LFMMs and MSOD-MSR. Genes tagged by candidate loci associated with drought and salinity are involved in the response to biotic and abiotic stresses, while those tagged by candidates associated with soil nitrogen and atmospheric nitrogen, participate in the legume-rhizobia symbiosis. Candidate SNPs identified through both LFMMs and MSOD-MSR explained up to 56% of variance in flowering traits. Our findings highlight the importance of soil in driving adaptation in the system and elucidate the basis of evolutionary potential of M. truncatula to respond to global climate change and anthropogenic disruption of the nitrogen cycle.

Detection of stabilizing selection in favor of the Santa Cruz homokaryotype in Drosophila pseudoobscura populations from the high plateau of the Colombian Andes.

Chromosome 3 rearrangements were studied in five Drosophila pseudoobscura populations from the high plateau of the Colombian Andes. As in previous studies, the Santa Cruz and Tree Line rearrangements were predominant in these populations, but for the first time other rearrangements such as the Olympic, Cuernavaca and a rearrangement similar to the endemic Mexican Amecameca rearrangement were also discovered. Researchers in the early 1960's showed that Colombian D. pseudoobscura populations were not in accordance with Carson's theory. They found a special heterotic system in this geographically isolated population. Our current results do not support these findings but instead favor Carson's theory, because in practically all the populations studied the homokaryotype excess was close to fixation. These new results indicate that some stabilizing selective pressures in favor of the homokaryotypes (especially Santa Cruz) have appeared in the Colombian plateau during the last 10-12 years. These new changes may be related to deforestation and habitat destruction by human beings and/or climatic changes motivated by the El Niño phenomenon. Genetic heterogeneity between populations was not significant and there was no isolation-by-distance between them, findings which are contrary to those observed in some North American populations and which show that the Colombian populations now have rigid genetic systems. The frequency of the Santa Cruz rearrangement was also found to have increased in some populations over the last few years.

Enfermedad de Kawasaki / Kawasaki disease

Entre 5.399 niños ingresados entre enero de 1984 y diciembre de 1986 a un servicio de pediatría de un hospital metropolitano de Santiago, 6 cumplían los criterios de diagnóstico para la enfermedad de Kawasaki; su edad al comienzo de los síntomas variaba entre 8 meses y 10 años, 3 eran varones; la fiebre duró entre 13 y 32 días, todos tuvieron erupción cutánea, enantema bucal y faríngeo e inyección conjuntival, 5 tuvieron lesiones en las extremidades y en 5 se detectaron adenopatías. La erupción cutánea fue recurrente en 4 pacientes, uno de los cuales sufrió 3 recidivas, la última 7 meses después de la primera hospitalización. Tres niños afectados mostraron evidencia ecográfica de lesiones coronarias y, aunque ninguno tuvo clara evidencia clínica de infarto, uno tenía además reducción de la fracción de acortamiento de ventrículo izquierdo y ondas Q anormales en el electrocardiograma, las que también fueron detectadas en un cuarto paciente sin anomalías ecográficas coronarias. Otro niño presentó simultáneamente signos de anemia hemolítica por anticuerpos calientes IgG y anticuerpos antipenicilina en concentraciones bajas. Todos los niños afectados fueron tratados con aspirina en las dosis recomendadas para este efecto. Ninguno de nuestros pacientes mostró signos clínicos de irritación meníngea pero uno de ellos tuvo marcado compromiso de conciencia y su electroencefalograma mostró severa depresión neuronal, recuperándose completamente más tarde

Meningitis recidivante por Streptococcus pneumoniae / Recurrent meningitis due to Streptococcus pneumoniae

Se presenta el caso de un escolar de seis años de edad, quién desde los cuatro años había sufrido cuatro episodios de meningitis bacteriana, una de ellas a germen desconocido, y las otras por Streptococcus pneumoniae. El estudio del paciente demostró infección crónica tímpano-mastoídea, que se interpretó como probablereservorio bacteriano. Fue sometido a vaciamiento quirúrgico. Los estudios neurológico e inmunológico descartaron otras causas, y el paciente no ha vuelto a presentar nuevos episodios de meningitis, habiendo transcurrido un año después del alta. A propósito de este caso se revisa el tema de las meningitis recidivantes