RESUMEN
Toxoplasma gondii is a cyst-forming apicomplexan parasite of virtually all warm-blooded species, with all true cats (Felidae) as definitive hosts. It is the etiologic agent of toxoplasmosis, a disease causing substantial public health burden worldwide. Few intercontinental clonal lineages represent the large majority of isolates worldwide. Little is known about the evolutionary forces driving the success of these lineages, the timing and the mechanisms of their global dispersal. In this study, we analyse a set of 156 genomes and we provide estimates of T. gondii mutation rate and generation time. We elucidate how the evolution of T. gondii populations is intimately linked to the major events that have punctuated the recent history of cats. We show that a unique haplotype, whose length represents only 0.16% of the whole T. gondii genome, is common to all intercontinental lineages and hybrid populations derived from these lineages. This haplotype has accompanied wildcats (Felis silvestris) during their emergence from the wild to domestic settlements, their dispersal in the Old World, and their expansion in the last five centuries to the Americas. The selection of this haplotype is most parsimoniously explained by its role in sexual reproduction of T. gondii in domestic cats.
Asunto(s)
Felidae , Toxoplasma , Toxoplasmosis Animal , Américas , Animales , Gatos , Haplotipos , Toxoplasma/genética , Toxoplasmosis Animal/parasitologíaRESUMEN
We report a fatal case of measles inclusion-body encephalitis occurring in a woman from Romania with AIDS. After an extensive but unsuccessful diagnostic evaluation, a pan-pathogen shotgun metagenomic approach revealed a measles virus infection. We identified no mutations previously associated with neurovirulence.
Asunto(s)
Síndrome de Inmunodeficiencia Adquirida , Sarampión , Panencefalitis Esclerosante Subaguda , Adulto , Encéfalo/diagnóstico por imagen , Femenino , Francia , Humanos , Sarampión/diagnóstico , Virus del Sarampión/genética , RumaníaRESUMEN
The human skin is a complex ecosystem that hosts a heterogeneous flora. Until recently, the diversity of the cutaneous microbiota was mainly investigated for bacteria through culture based assays subsequently confirmed by molecular techniques. There are now many evidences that viruses represent a significant part of the cutaneous flora as demonstrated by the asymptomatic carriage of beta and gamma-human papillomaviruses on the healthy skin. Furthermore, it has been recently suggested that some representatives of the Polyomavirus genus might share a similar feature. In the present study, the cutaneous virome of the surface of the normal-appearing skin from five healthy individuals and one patient with Merkel cell carcinoma was investigated through a high throughput metagenomic sequencing approach in an attempt to provide a thorough description of the cutaneous flora, with a particular focus on its viral component. The results emphasize the high diversity of the viral cutaneous flora with multiple polyomaviruses, papillomaviruses and circoviruses being detected on normal-appearing skin. Moreover, this approach resulted in the identification of new Papillomavirus and Circovirus genomes and confirmed a very low level of genetic diversity within human polyomavirus species. Although viruses are generally considered as pathogen agents, our findings support the existence of a complex viral flora present at the surface of healthy-appearing human skin in various individuals. The dynamics and anatomical variations of this skin virome and its variations according to pathological conditions remain to be further studied. The potential involvement of these viruses, alone or in combination, in skin proliferative disorders and oncogenesis is another crucial issue to be elucidated.
Asunto(s)
Metagenoma , Piel/virología , Bacterias/genética , Bacterias/virología , Bacteriófagos/genética , Circoviridae/clasificación , Circoviridae/genética , Virus ADN/clasificación , Virus ADN/genética , Genoma Bacteriano , Genoma Viral , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Metagenoma/genética , Papillomaviridae/clasificación , Papillomaviridae/genética , Filogenia , Polyomaviridae/clasificación , Polyomaviridae/genética , Piel/microbiologíaRESUMEN
We have identified in a skin swab sample from a healthy donor a new virus that we have named human gyrovirus (HGyV) because of its similarity to the chicken anemia virus (CAV), the only previously known member of the Gyrovirus genus. In particular, this virus encodes a homolog of the CAV apoptin, a protein that selectively induces apoptosis in cancer cells. By PCR screening, HGyV was found in 5 of 115 other nonlesional skin specimens but in 0 of 92 bronchoalveolar lavages or nasopharyngeal aspirates and in 0 of 92 fecal samples.
Asunto(s)
Virus de la Anemia del Pollo/clasificación , Gyrovirus/clasificación , Secuencia de Aminoácidos , Secuencia de Bases , Líquido del Lavado Bronquioalveolar/virología , Proteínas de la Cápside/química , Humanos , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , Reacción en Cadena de la Polimerasa , Homología de Secuencia de AminoácidoRESUMEN
Japanese encephalitis virus (JEV) genotypes in Thailand were studied in pigs and mosquitoes collected near houses of confirmed human JEV cases in 2003-2005. Twelve JEV strains isolated belonged to genotype I, which shows a switch from genotype III incidence that started during the 1980s.