Local Population Structure and Patterns of Western Hemisphere Dispersal for Coccidioides spp., the Fungal Cause of Valley Fever.

UNLABELLED: Coccidioidomycosis (or valley fever) is a fungal disease with high morbidity and mortality that affects tens of thousands of people each year. This infection is caused by two sibling species, Coccidioides immitis and C. posadasii, which are endemic to specific arid locales throughout the Western Hemisphere, particularly the desert southwest of the United States. Recent epidemiological and population genetic data suggest that the geographic range of coccidioidomycosis is expanding, as new endemic clusters have been identified in the state of Washington, well outside the established endemic range. The genetic mechanisms and epidemiological consequences of this expansion are unknown and require better understanding of the population structure and evolutionary history of these pathogens. Here we performed multiple phylogenetic inference and population genomics analyses of 68 new and 18 previously published genomes. The results provide evidence of substantial population structure in C. posadasii and demonstrate the presence of distinct geographic clades in central and southern Arizona as well as dispersed populations in Texas, Mexico, South America, and Central America. Although a smaller number of C. immitis strains were included in the analyses, some evidence of phylogeographic structure was also detected in this species, which has been historically limited to California and Baja, Mexico. Bayesian analyses indicated that C. posadasii is the more ancient of the two species and that Arizona contains the most diverse subpopulations. We propose a southern Arizona-northern Mexico origin for C. posadasii and describe a pathway for dispersal and distribution out of this region. IMPORTANCE: Coccidioidomycosis, or valley fever, is caused by the pathogenic fungi Coccidioides posadasii and C. immitis The fungal species and disease are primarily found in the American desert southwest, with spotted distribution throughout the Western Hemisphere. Initial molecular studies suggested a likely anthropogenic movement of C. posadasii from North America to South America. Here we comparatively analyze eighty-six genomes of the two Coccidioides species and establish local and species-wide population structures to not only clarify the earlier dispersal hypothesis but also provide evidence of likely ancestral populations and patterns of dispersal for the known subpopulations of C. posadasii.

Envenenamiento mortal por hongos en Guatemala / Mortal poisoning by mushrooms in Guatemala

Una mezcla de posibles hongos comestibles, provocó un envenenamiento en dos familias de San Yuyo, en el Departamento de Jalapa, al SO de Guatemala. Se intoxicaron 19 personas, de las cuales murieron 8 con síntomas de ataque hepático. Los hongos que se identificaron según las investigaciones entre la población, son Amanita caesarea (Scop. ex. Fr.) Grev., A. gemmata (Fr.) Gill. y A. magnivelaris Peck, el primero es comestible de excelente calidad, el segundo provoca únicamente molestias gastrointestinales y el tercero produce la muerte; dicha especie pertence al grupo de A. bisporigera Atk., caracterizada por su contenido en alcaloides altamente venenosos. Este es el primer registro de A. magnivelaris en Guatemala