Kenmerken van SARS-CoV-2 en de Covid-19-infectie

05 May, 2020

Door: Selma Timmer

Corona-virus disease 2019, kortweg Covid-19, is de acute luchtwegaandoening, veroorzaakt door het nieuwe humane coronavirus SARS-CoV-2. Het heeft zich in goed twee maanden ontwikkeld tot een pandemie.¹ Zonder straffe maatregelen kan zestig procent van de wereldbevolking besmet raken. In dit artikel worden natuurlijke antivirale middelen benoemd en nutriënten voor cytoprotectie.

Sinds de eeuwwisseling is Covid-19, na SARS (severe acute respiratory syndrome) in 2002 en MERS (middle east respiratory syndrome) in 2012, de derde ernstige zoönose – een infectieziekte die van dier op mens overgaat – die door een coronavirus wordt veroorzaakt.^2,3 Niet alle coronavirussen zijn gevaarlijk; vier laagpathogene humane coronavirussen veroorzaken sinds jaar en dag een vijfde van alle verkoudheden. Een coronavirus is herkenbaar aan de uitsteeksels (spike-proteïnen) die als een kroon (corona) uit het celmembraan steken.

SARS-CoV-2, in eerste instantie 2019-nCoV (2019 novel coronavirus) genoemd, is een bèta-coronavirus: een enkelstrengs RNA-virus in een proteïne-envelop, subgenus Sarbecovirus, subfamilie Orthocoronavirinae, familie Coronaviridae. Waarschijnlijk is deze variant afkomstig van vleermuizen.³ Ondanks het lagere sterftepercentage – een voorlopige schatting dd. 30 maart is 3.85%⁴ – is het aantal sterfgevallen door Covid-19 al veel hoger dan bij SARS (sterftepercentage circa 10%) en MERS (sterftepercentage circa 35%). Dat komt door de veel snellere verspreiding van het virus.^2,5 Onderzoekers van het Erasmus MC in Rotterdam denken dat dit mede het gevolg is van gemakkelijke vermenigvuldiging van SARS-CoV-2 in de neus, terwijl het SARS- en MERS-virus voornamelijk dieper in de luchtwegen vermeerderen.
De belangrijkste besmettingsroutes zijn overdracht via druppels die loskomen door niezen, hoesten, praten en ademhalen, en via direct contact.³ SARS-CoV-2 is ook aangetoond in bloed en ontlasting van ernstig zieke coronapatiënten.³ Het coronavirus kan worden overdragen door mensen die nog niet ziek zijn en mogelijk ook door mensen die helemaal geen klachten krijgen na besmetting.⁶ Het nieuwe coronavirus kan enige dagen overleven op verschillende materialen; in hoeverre mensen na aanraking (en vervolgens aanraking van ogen, neus of mond) besmet raken is onduidelijk.

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