{"id":881,"date":"2020-04-15T10:48:08","date_gmt":"2020-04-15T10:48:08","guid":{"rendered":"https:\/\/uni.hi.is\/apalsson\/?p=881"},"modified":"2020-04-15T10:48:08","modified_gmt":"2020-04-15T10:48:08","slug":"icelandic-eru-til-tvo-eda-fleiri-afbrigdi-af-koronuveirunni-sem-veldur-covid-19","status":"publish","type":"post","link":"https:\/\/uni.hi.is\/apalsson\/IS\/2020\/04\/15\/icelandic-eru-til-tvo-eda-fleiri-afbrigdi-af-koronuveirunni-sem-veldur-covid-19\/","title":{"rendered":"Eru til tv\u00f6 e\u00f0a fleiri afbrig\u00f0i af k\u00f3r\u00f3nuveirunni sem veldur COVID-19?"},"content":{"rendered":"

Arnar P\u00e1lsson. \u201eEru til tv\u00f6 e\u00f0a fleiri afbrig\u00f0i af k\u00f3r\u00f3nuveirunni sem veldur COVID-19?\u201c V\u00edsindavefurinn<\/i>, 14. apr\u00edl 2020. S\u00f3tt 15. apr\u00edl 2020. http:\/\/visindavefur.is\/svar.php?id=79178.<\/p>\n

Afbrig\u00f0i l\u00edfvera eru skilgreind sem vissar ger\u00f0ir innan tegundar sem eru \u00f3l\u00edkar \u00ed h\u00e1ttum e\u00f0a eiginleikum. Munur \u00e1 afbrig\u00f0um getur veri\u00f0 mj\u00f6g yfirbor\u00f0skenndur, til d\u00e6mis bygg\u00f0ur \u00e1 lit fja\u00f0ra e\u00f0a \u00fev\u00ed hvort einstaklingar s\u00f6mu tegundar s\u00e9u sta\u00f0fuglar e\u00f0a farfuglar. Stundum er munurinn dj\u00fapst\u00e6\u00f0ari eins og \u00ed afm\u00f6rku\u00f0um stofnum sem g\u00e6tu veri\u00f0 forstig tegunda. St\u00f6kkbreytingar<\/a> eru algengari \u00ed veirum<\/a> en fl\u00f3knari l\u00edfverum og af \u00feeim s\u00f6kum er mikill breytileiki \u00ed erf\u00f0asamsetningu veira sem s\u00fdkja mannf\u00f3lk. \u00deegar tala\u00f0 er um afbrig\u00f0i k\u00f3r\u00f3nuveirunnar sem veldur COVID-19<\/a> er v\u00edsa\u00f0 \u00ed h\u00f3pa sem greina m\u00e1 a\u00f0 vegna mismunandi erf\u00f0abreytileika.<\/p>\n

\n
<\/div>\n
\n

Mynd 1. St\u00f6kkbreythra\u00f0i er meiri hj\u00e1 veirum en fl\u00f3knari l\u00edfverum sem hafa st\u00e6rra erf\u00f0amengi. \u00c1 myndinni sj\u00e1st \u00f3l\u00edkar veirur og l\u00edfverur. Fr\u00e1 vinstri, veirungur, s\u00ed\u00f0an \u00ferj\u00e1r \u00f3l\u00edkar ger\u00f0ir veira, bakter\u00edur og loks m\u00fas. \u00c1 x-\u00e1snum er svonefndur log-kvar\u00f0i sem \u00fe\u00fd\u00f0ir a\u00f0 h\u00e6kkun um eitt stig er t\u00edf\u00f6ldun.<\/p>\n<\/div>\n<\/div>\n

Veiru- og l\u00edffr\u00e6\u00f0ingarnir Nathan D. Grubaugh, Mary E. Petrone og Edward C. Holmes fjalla um breytileika \u00ed veirunni sem veldur COVID-19 \u00ed greininni \u201eWe shouldn\u2019t worry when a virus mutates during disease outbreaks\u201c sem kom \u00fat \u00ed t\u00edmaritinu Nature Microbiology<\/cite> snemma \u00ed febr\u00faar 2020. \u00dear leggja \u00feau \u00e1herslu \u00e1 a\u00f0 vi\u00f0 eigum ekki a\u00f0 \u00f3ttast st\u00f6kkbreytingar heldur n\u00fdta okkur \u00fe\u00e6r til a\u00f0 skilja smitlei\u00f0ir og framvindu faraldursins<\/a>.<\/span>[1]<\/a><\/sup> Veiran sem veldur COVID-19 st\u00f6kk einu sinni \u00far d\u00fdri yfir \u00ed mann, einhvern t\u00edma undir lok \u00e1rsins 2019. \u00dea\u00f0 er r\u00f3t \u00e6ttartr\u00e9s veirunnar. Allar veirurnar sem valda faraldrinum eru afkomendur \u00feessarar upprunalegu veiru. Veiran hefur einn litning og fj\u00f6lgar s\u00e9r kynlaust. Segja m\u00e1 a\u00f0 h\u00fan kl\u00f3ni sig. Allar veirur sem berast fr\u00e1 s\u00fdktum einstaklingi bera afrit erf\u00f0amengis veirunnar sem s\u00fdkti \u00feann einstakling, me\u00f0 nokkrum fr\u00e1vikum vegna st\u00f6kkbreytinga. Hver s\u00fdktur einstaklingur s\u00fdkir a\u00f0 me\u00f0altali 2 til 4 einstaklinga, og \u00ed hverri veirukynsl\u00f3\u00f0 ver\u00f0a einhverjar st\u00f6kkbreytingar \u00e1 erf\u00f0aefni veiranna.<\/span>[2]<\/a><\/sup> St\u00f6kkbreytingar ber ekki a\u00f0 \u00f3ttast heldur nota til a\u00f0 rekja smiti\u00f0. St\u00f6kkbreyting sem var\u00f0 \u00ed veiru snemma \u00ed faraldrinum merkti alla afkomendur hennar. St\u00f6kkbreyting sem ver\u00f0ur seinna au\u00f0kennir undirh\u00f3p sem er kominn fr\u00e1 tiltekinni veiru (2. mynd). Til a\u00f0 mynda tilkynnti \u00cdslensk erf\u00f0agreining a\u00f0 40 s\u00e9r\u00edslenskar st\u00f6kkbreytingar hef\u00f0u fundist h\u00e9r (23. mars 2020).<\/span>[3]<\/a><\/sup><\/p>\n

\n
<\/div>\n
\n

Mynd 2. St\u00f6kkbreytingar \u00e1 erf\u00f0aefni veiru sem berst milli einstaklinga (gr\u00e1ir hringir) m\u00e1 nota til a\u00f0 rekja smiti\u00f0. \u00c6ttartr\u00e9 veiranna endurspeglar smits\u00f6guna. Myndin s\u00fdnir einfalda\u00f0 tilfelli. S\u00fdndir eru litningar 5 ger\u00f0a af veiru, sem eru \u00f3l\u00edkir vegna 7 st\u00f6kkbreytinga (lita\u00f0ar l\u00ednur). \u00deessir litningar mynda \u00fe\u00e1 fimm \u00f3l\u00edkar setra\u00f0ir (e. haplotypes) sem einnig m\u00e1 kalla afbrig\u00f0i. Sumar st\u00f6kkbreytingar eru eldri (og finnast \u00ed tveimur e\u00f0a fleiri ger\u00f0um), en a\u00f0rar yngri og finnast bara \u00ed einni ger\u00f0.<\/p>\n<\/div>\n<\/div>\n

Ef veira greinist \u00ed einstaklingi sem ekki er vita\u00f0 hvernig smita\u00f0ist, er h\u00e6gt a\u00f0 ra\u00f0greina erf\u00f0amengi veirunnar og m\u00e1ta \u00fea\u00f0 vi\u00f0 \u00fe\u00e6r \u00fe\u00fasundir erf\u00f0amengja sem n\u00fa<\/span>[4]<\/a><\/sup> eru \u00feekkt. \u00deannig var h\u00e6gt a\u00f0 komast a\u00f0 \u00fev\u00ed a\u00f0 hva\u00f0an veirurnar sem b\u00e1rust til \u00cdslands komu. Smiti\u00f0 barst snemma me\u00f0 f\u00f3lki sem kom fr\u00e1 Austurr\u00edki, en greinilegt var a\u00f0 \u00fea\u00f0 kom einnig fr\u00e1 nokkrum \u00f6\u00f0rum l\u00f6ndum.<\/span>[5]<\/a><\/sup> Sama hugmynd var n\u00fdtt til a\u00f0 meta uppruna veirunnar sem veldur COVID-19. Samanbur\u00f0ur \u00e1 erf\u00f0amengi hennar vi\u00f0 a\u00f0rar \u00feekktar veirur s\u00fdna a\u00f0 skyldasta veiran (96% eins DNA-r\u00f6\u00f0) finnst \u00ed le\u00f0urbl\u00f6kum. \u00dea\u00f0 sannar ekki a\u00f0 veiran hafi borist \u00fea\u00f0an. M\u00f6gulegt er a\u00f0 k\u00f3r\u00f3nuveira me\u00f0 99,9% erf\u00f0asamsv\u00f6run s\u00fdki a\u00f0ra tegund d\u00fdra.<\/span>[6]<\/a><\/sup> Le\u00f0urbl\u00f6kur eru reyndar v\u00ed\u00f0fr\u00e6gar fyrir a\u00f0 vera su\u00f0upottur veira, sem berast \u00ed \u00fe\u00e6r \u00far m\u00f6rgum \u00e1ttum. Samantekt<\/strong><\/p>\n