{"id":1993,"date":"2019-01-05T11:00:56","date_gmt":"2019-01-05T10:00:56","guid":{"rendered":"https:\/\/ellipse.prbb.org\/?p=1993"},"modified":"2025-03-04T18:48:16","modified_gmt":"2025-03-04T17:48:16","slug":"la-grip-una-historia-interminable","status":"publish","type":"post","link":"https:\/\/ellipse.prbb.org\/ca\/la-grip-una-historia-interminable\/","title":{"rendered":"La grip: una hist\u00f2ria interminable"},"content":{"rendered":"<p>La grip \u00e9s una infecci\u00f3 causada per un virus, anomenat <strong><em>Influenza<\/em><\/strong>, que provoca unes 500.000 morts al m\u00f3n cada temporada.<\/p>\n<p>Els virus s\u00f3n organismes d\u2019estructura molt senzilla que utilitzen les c\u00e8l\u00b7lules de l\u2019hoste per reproduir-se. El de la grip \u00e9s de la fam\u00edlia dels <em>Orthomyxoviridae,<\/em> amb <strong>8 segments d\u2019ARN<\/strong> com a material gen\u00e8tic. Els dos tipus principals que causen la grip s\u00f3n:<\/p>\n<ul>\n<li>el tipus A, que es classifica en funci\u00f3 de la combinaci\u00f3 de dues prote\u00efnes de superf\u00edcie, la <strong>hemaglutinina<\/strong> (HA) i la<strong> neuraminidasa<\/strong> (NA).<\/li>\n<li>el tipus B.<\/li>\n<\/ul>\n<figure id=\"attachment_2003\" aria-describedby=\"caption-attachment-2003\" style=\"width: 193px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-2003\" src=\"https:\/\/ellipse.prbb.org\/wp-content\/uploads\/2018\/12\/Flu_virus-1.jpg\" alt=\"Estructura del virus influenza amb les prote\u00efnes de superf\u00edcie i 8 segments de RNA.\" width=\"193\" height=\"256\" srcset=\"https:\/\/ellipse.prbb.org\/wp-content\/uploads\/2018\/12\/Flu_virus-1.jpg 1601w, https:\/\/ellipse.prbb.org\/wp-content\/uploads\/2018\/12\/Flu_virus-1-169x224.jpg 169w, https:\/\/ellipse.prbb.org\/wp-content\/uploads\/2018\/12\/Flu_virus-1-768x1016.jpg 768w, https:\/\/ellipse.prbb.org\/wp-content\/uploads\/2018\/12\/Flu_virus-1-454x600.jpg 454w\" sizes=\"auto, (max-width: 193px) 100vw, 193px\" \/><figcaption id=\"caption-attachment-2003\" class=\"wp-caption-text\">Estructura del virus influenza amb les prote\u00efnes de superf\u00edcie i 8 segments d&#8217;ARN (Imatge de Wikimedia).<\/figcaption><\/figure>\n<p>\u00c9s una malaltia <strong>estacional<\/strong>; normalment agafem la grip a l\u2019hivern, ja que el virus sobreviu millor en condicions de baixa temperatura i humitat. Per\u00f2 tot i haver tingut ja la grip, la majoria som susceptibles a tornar-la a tenir cada any. Aix\u00f2 \u00e9s degut a l\u2019<strong>alta variaci\u00f3 antig\u00e8nica<\/strong> del virus, \u00e9s a dir, l\u2019alta capacitat d\u2019introduir canvis en el seu genoma que li confereixen resist\u00e8ncia immunit\u00e0ria.<\/p>\n<p>La RNA polimerasa del virus de la grip no t\u00e9 capacitat de correcci\u00f3 d\u2019errors i, per tant, permet la introducci\u00f3 de petits canvis durant la replicaci\u00f3 del virus. Mutacions a les prote\u00efnes de superf\u00edcie HA i NA fan que els punts antig\u00e8nics reconeguts pels anticossos canvi\u00efn i, per tant, aquests virus puguin escapar del sistema immune, produint epid\u00e8mies estacionals. Aquests canvis s\u00f3n anomenats <strong><em>deriva antig\u00e8nica<\/em><\/strong>.<\/p>\n<p>Un altre fenomen de variaci\u00f3 antig\u00e8nica \u00e9s la combinaci\u00f3 de material gen\u00e8tic de diferents tipus de virus circulants, el que s\u2019anomena <em><strong>reagrupaci\u00f3 de gens<\/strong>.<\/em> Aix\u00f2 pot passar gr\u00e0cies al genoma segmentat del virus de la grip i, tot i que \u00e9s molt poc freq\u00fcent, produeix noves soques de virus que poden ser totalment diferents, amb la qual cosa es generen pand\u00e8mies particularment devastadores.<\/p>\n<p>Aquesta alta taxa de mutacions del virus comporta que <strong>cada any s\u2019hagin de fer noves<\/strong> <strong>vacunes<\/strong> per prevenir la malaltia en les poblacions de risc. La Organitzaci\u00f3 Mundial de la Salut i centres col\u00b7laboradors fan un seguiment continu dels virus gripals circulants a la poblaci\u00f3 humana i actualitzen la composici\u00f3 de les vacunes dos cops a l\u2019any.<\/p>\n<p>&nbsp;<\/p>\n<p><iframe loading=\"lazy\" src=\"https:\/\/www.youtube.com\/embed\/dUulSRZmQBA\" width=\"560\" height=\"315\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Som susceptibles a agafar la grip cada any degut a l\u2019alta variaci\u00f3 antig\u00e8nica del virus. <\/p>\n","protected":false},"author":2,"featured_media":1990,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[30],"tags":[513,332,303,415,475],"new-type":[38,35],"class_list":["post-1993","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-ciencia-i-societat","tag-ciencia-al-descobert","tag-gens","tag-salut-publica","tag-vacunes","tag-virus-ca","new-type-a-fons","new-type-noticies"],"acf":[],"_links":{"self":[{"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/posts\/1993","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/comments?post=1993"}],"version-history":[{"count":6,"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/posts\/1993\/revisions"}],"predecessor-version":[{"id":46885,"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/posts\/1993\/revisions\/46885"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/media\/1990"}],"wp:attachment":[{"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/media?parent=1993"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/categories?post=1993"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/tags?post=1993"},{"taxonomy":"new-type","embeddable":true,"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/new-type?post=1993"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}