Aspectos gerais da infecção pelo vírus Zika: uma revisão

• Autor(a) principal: Silva, Ana Beatriz Ramalho da
• Data de Publicação: 2017
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da UFRN
• Texto Completo: https://repositorio.ufrn.br/handle/123456789/43144
• topic: Vírus Zika; Resposta imune; Patogenia

Zika vírus (ZIKV) is an arthropod-borne virus which belongs to the family Flaviviridae, being transmitted by Aedes species mosquitoes, mainly by Aedes aegypti. The virus was discovered in 1947 in the Zika Forest, Uganda. Since its discovery, the cases were sporadic and confined to a zone across Africa and Asia until the beginning of 21st century, when the virus emerged in differents parts of the world, causing sequential outbreaks on Yap Island (2007), French Polynesia (2013) and Brazil (2015) from where the virus spreads to others American countries. Besides the vectorial transmission, the ZIKV can be transmitted by sexual intercourse, by blood transfusion and from the mother to the baby. ZIKV is a RNA virus that encodes a large polyprotein, which encode a large polyprotein that is cleaved in three structural proteins: capisid protein (C), membrane glycoprotein precursor (prM) and envelope protein (E) and seven nonstructural proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B, NS5). About immune response to ZIKV, researches points out that the virus elicits the activation of intracellular innate immune receptors like TLR3, RIG-I, MDA-5, resulting in the production of type I interferons (IFN-I) and proinflammatory cytokines. Moreover, the virus doesn’t induce strong stimulation of dendritric cells and active NK cells more by cytokine production than its cytotoxic function. About adaptive immune response, the ZIKV stimulates a strong humoral response with producing neutralizing antibody, activating TCD4+ cells, which induce multiple cytokine production and TCD8+ cells activation that present high level of memory cells. Likely, sequential infections by ZIKV and others flavivirus cause ADE phenomenon due cross-reactivy, however this mechanism in this disease it’s not fully clear. Regarding the clinic, the infection is commonly asymptomatic, but the symptomatic cases are self-limiting and characterized by rash, arthralgia, myalgia and mild fever. However, complications involving the nervous system, like microcephaly in newborn babies and Guillain-Barré syndrome have been associated with ZIKV infection