What is a coronavirus? - Elizabeth Cox

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For almost a decade, scientists chased the source of a deadly new virus

Gotovo su cijelo desetljeće znanstvenici lovili izvor novog smrtonosnog virusa

through China’s tallest mountains and most isolated caverns.

po visokim planinama i osamljenim špiljama Kine.

They finally found it here: in the bats of Shitou Cave.

Konačno su ga pronašli ovdje: u šišmišima špilje Shitou.

The virus in question was a coronavirus

Taj je virus bio koronavirus

that caused an epidemic of severe acute respiratory syndrome,

koji je uzrokovao epidemiju teškog akutnog respiratornog sindroma,

or SARS, in 2003.

poznatijeg kao SARS, 2003. godine.

Coronaviruses are a group of viruses

Koronavirusi su skupina virusa

covered in little protein spikes that look like a crown—

prekriveni proteinskim izbočenjima koji podsjećaju na krunu,

or "corona" in Latin.

tj. "corona" na latinskom.

There are hundreds of known coronaviruses.

Postoje stotine poznatih koronavirusa.

Seven of them infect humans, and can cause disease.

Sedmero vrsta može zaraziti čovjeka.

The coronavirus SARS-CoV causes SARS, MERS-CoV causes MERS,

Koronavirus SARS-CoV uzrokuje SARS, MERS-CoV uzrokuje MERS,

and SARS-CoV-2 causes the disease COVID-19.

a SARS-CoV-2 uzrokuje COVID-19.

Of the seven human coronaviruses, four cause colds,

Od sedmero ljudskih koronavirusa, četiri ih uzrokuje prehlade:

mild, highly contagious infections of the nose and throat.

iznimno zarazne, no blage, infekcije nosa i grla.

Two infect the lungs, and cause much more severe illnesses.

Dva zahvaćaju pluća i uzrokuju mnogo teže bolesti.

The seventh, which causes COVID-19, has features of each:

Sedmi, koji uzrokuje COVID-19, ima značajke oba:

it spreads easily, but can severely impact the lungs.

lako se širi, no može imati značajan utjecaj na pluća.

When an infected person coughs, droplets containing the virus spray out.

Kada zaražena osoba zakašlje, kapljice s virusom rasprše se.

The virus can infect a new person when the droplets enter their nose or mouth.

Virus može zaraziti osobu kada kapljice uđu u nos ili usta.

Coronaviruses transmit best in enclosed spaces,

Koronavirusi se najbrže šire u zatvorenim prostorima

where people are close together.

gdje je razmak među ljudima malen.

Cold weather keeps their delicate casing from drying out,

Hladnije temperature sprječavaju sušenje osjetljive ovojnice

enabling the virus to survive for longer between hosts,

i omogućavaju dulji životni vijek virusa u okolini.

while UV exposure from sunlight may damage it.

Izloženost UV-zrakama danjeg svjetla može ga oštetiti.

These seasonal variations matter more for established viruses.

Te su razlike u uvjetima važnije za poznate viruse.

But because no one is yet immune to a new virus,

Nitko još nije razvio imunitet na ovaj novi virus

it has so many potential hosts that it doesn’t need ideal conditions to spread.

pa ima brojne moguće domaćine i ne treba idealne uvjete za širenje.

In the body, the protein spikes embed in the host’s cells and fuse with them—

U tijelu se proteinska izbočenja hvataju za stanice te se s njima se sjedine,

enabling the virus to hijack the host cell’s machinery

što virusu omogućava upravljanje stanicom domaćina

to replicate its own genes.

u svrhu replikacije vlastitih gena.

Coronaviruses store their genes on RNA.

Koronavirusi gene čuvaju u RNK.

All viruses are either RNA viruses or DNA viruses.

Virusi mogu biti DNK ili RNK virusi.

RNA viruses tend to be smaller, with fewer genes,

RNK virusi su manji i imaju manji broj gena,

meaning they infect many hosts and replicate quickly in those hosts.

a to znači da mogu zaraziti veći broj domaćina i brže se razmnožiti.

In general, RNA viruses don’t have a proofreading mechanism,

Općenito, RNK virusi nemaju mehanizam provjere

whereas DNA viruses do.

kao DNK virusi.

So when an RNA virus replicates,

Prilikom replikacije RNK virusa

it’s much more likely to have mistakes called mutations.

greške su česte, a te su greške mutacije.

Many of these mutations are useless or even harmful.

Većina je mutacija beskorisna ili čak štetna za virus.

But some make the virus better suited for certain environments—

Zbog nekih pak virus bolje opstaje u određenim okruženjima,

like a new host species.

kao kod nove vrste domaćina.

Epidemics often occur when a virus jumps from animals to humans.

Epidemije se često javljaju kada virus prijeđe s životinje na čovjeka.

This is true of the RNA viruses that caused

To se dogodilo s RNK virusima

the Ebola, Zika, and SARS epidemics, and the COVID-19 pandemic.

koji su uzrokovali epidemije ebole, Zike i SARS-a te pandemiju COVID-19.

Once in humans, the virus still mutates—

Kada zarazi ljude, virus i dalje mutira,

usually not enough to create a new virus,

no ne dovoljno kako bi stvorio novi virus,

but enough to create variations, or strains, of the original one.

ali dovoljno kako bi nastale varijacije, ili sojevi prvotnog virusa.

Coronaviruses have a few key differences from most RNA viruses.

Koronavirusi se razlikuju od drugih RNA virusa.

They’re some of the largest, meaning they have the most genes.

Iznimno su veliki, što znači da imaju velik broj gena.

That creates more opportunity for harmful mutations.

To stvara veći broj mogućnosti za nastanak štetnih mutacija.

To counteract this risk, coronaviruses have a unique feature:

Za smanjenje rizika, koronavirusi imaju jedinstvenu moć:

an enzyme that checks for replication errors and corrects mistakes.

imaju enzim koji traži greške replikacije i ispravlja ih.

This makes coronaviruses much more stable,

Zato su koronavirusi stabilniji

with a slower mutation rate, than other RNA viruses.

i sporije mutiraju od drugih RNK virusa.

While this may sound formidable,

Možda ne zvuči obećavajuće,

the slow mutation rate is actually a promising sign

no sporije mutacije su dobre

when it comes to disarming them.

jer ih je lakše zaustaviti.

After an infection, our immune systems can recognize germs

Nakon infekcije, imunosni sustavi mogu prepoznati patogene

and destroy them more quickly if they infect us again

i brže ih uništiti ako se opet zarazimo

so they don’t make us sick.

pa mi ne obolimo.

But mutations can make a virus less recognizable to our immune systems—

Zbog mutacija virusi također mogu biti teže prepoznatljivi imunosnom sustavu

and therefore more difficult to fight off.

te se tako teže s njima boriti.

They can also make antiviral drugs and vaccines less effective,

Zato lijekovi i cjepiva mogu izgubiti na efikasnosti -

because they’re tailored very specifically to a virus.

oni su osmišljeni za specifičan virus.

That’s why we need a new flu vaccine every year—

Zato svake godine trebamo novo cjepivo protiv gripe.

the influenza virus mutates so quickly that new strains pop up constantly.

Influenza mutira toliko brzo da novi sojevi nastaju stalno.

The slower mutation rate of coronaviruses means

Sporija mutacija koronavirusa

our immune systems, drugs, and vaccines

znači da ih imunosustavi, lijekovi i cjepiva

might be able to recognize them for longer after infection,

mogu prepoznati duže nakon što se zarazimo

and therefore protect us better.

i tako nas bolje zaštititi.

Still, we don’t know how long our bodies remain immune to different coronaviruses.

Ipak, ne znamo koliko dugo zadržavamo imunitet na koronaviruse.

There’s never been an approved treatment or vaccine for a coronavirus.

Nikada nije postojao odobreni lijek ili cjepivo za koronavirus.

We haven’t focused on treating the ones that cause colds,

Nismo se usredotočili na one koji uzrokuju prehlade.

and though scientists began developing treatments for SARS and MERS,

Znanstvenici su počeli terapiju protiv SARS-a i MERS-a,

the epidemics ended before those treatments completed clinical trials.

no te su epidemije završile prije kliničkih testiranja lijekova.

As we continue to encroach on other animals’ habitats,

I dalje zadiremo u staništa životinja

some scientists say a new coronavirus jumping to humans is inevitable—

te znanstvenici kažu da je prijelaz novog koronavirusa na ljude neizbježan.

but if we investigate these unknowns, it doesn’t have to be devastating.

Ako istražimo nepoznanice, taj prijelaz ne mora biti koban.