Oropouche Virus Infection And Pathogenesis Is Restricted By Mavs, Irf-3, Irf-7, And Type I Ifn Signaling Pathways In Non-myeloid Cells.

Oropouche virus (OROV) is a member of the Orthobunyavirus genus in the Bunyaviridae family and a prominent cause of insect-transmitted viral disease in Central and South America. Despite its clinical relevance, little is known about OROV pathogenesis. To define the host defense pathways that control OROV infection and disease, we evaluated OROV pathogenesis and immune responses in primary cells and mice that were deficient in the RIG-I-like receptor signaling pathway (MDA5, RIG-I, or MAVS), downstream regulatory transcription factors (IRF-3 or IRF-7), IFN-β, or the receptor for type I IFN signaling (IFNAR). OROV replicated to higher levels in primary fibroblasts and dendritic cells lacking MAVS signaling, the transcription factors IRF-3 and IRF-7, or IFNAR. In mice, deletion of IFNAR, MAVS, or IRF-3 and IRF-7 resulted in uncontrolled OROV replication, hypercytokinemia, extensive liver damage, and death whereas wild-type (WT) congenic animals failed to develop disease. Unexpectedly, mice with a selective deletion of IFNAR on myeloid cells (CD11c Cre(+) Ifnar(f/f) or LysM Cre(+) Ifnar(f/f)) did not sustain enhanced disease with OROV or La Crosse virus, a closely related encephalitic orthobunyavirus. In bone marrow chimera studies, recipient irradiated Ifnar(-/-) mice reconstituted with WT hematopoietic cells sustained high levels of OROV replication and liver damage, whereas WT mice reconstituted with Ifnar(-/-) bone marrow were resistant to disease. Collectively, these results establish a dominant protective role for MAVS, IRF-3 and IRF-7, and IFNAR in restricting OROV virus infection and tissue injury, and suggest that IFN signaling in non-myeloid cells contributes to the host defense against orthobunyaviruses. Oropouche virus (OROV) is an emerging arthropod-transmitted orthobunyavirus that causes episodic outbreaks of a debilitating febrile illness in humans in countries of South and Central America. The continued expansion of the range and number of its arthropod vectors increases the likelihood that OROV will spread into new regions. At present, the pathogenesis of OROV in humans or other vertebrate animals remains poorly understood. To define cellular mechanisms of control of OROV infection, we performed infection studies in a series of primary cells and mice that were deficient in key innate immune genes involved in pathogen recognition and control. Our results establish that a MAVS-dependent type I IFN signaling pathway has a dominant role in restricting OROV infection and pathogenesis in vivo.

Tratamento clínico da epilepsia resistente

The authors analysed 34 cases of resistant epilepsy (20 males and 14 females, mean age 23 years), treated clinically between February/1984 and May/1986. The patients underwent neurological, neuropsychological, psychological, psychiatric, cerebrospinal fluid, electroencephalographic, tomographic and/or angiographic examination. Most of the patients had complex partial seizures. The etiology was unknown in 19 patients (55.8%), probable neurocysticercosis in 6, perinatal hypoxia in 5, delivery trauma in 3 and probable sequelae of encephalitis in 2 patients. There was a clear past history of infantile febrile convulsion in 2 patients. Most patients received carbamazepine (mean dose 24.5 mg/kg/day), phenytoin (5 mg/kg and valproic acid (28 mg/kg) as monotherapy or in association. Twenty-two patients (64.7%) had more than 80% decrease of the seizure frequency. Nine resistant epilepsy-cases (24.5%) were evaluated as candidates for surgical therapy. The authors concluded that the resistant epilepsy is best managed by a specialised, multidisciplinary team, and pointed out the need of a correct diagnosis of the seizure type, an adequate drug therapy and a good engagement of the patient and his family in the treatment.