Coronavirus disease (COVID-19) outbreak
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The answers to all your questions on the disease outbreak spreading across the world
The new coronavirus (Covid-19) is spreading fast. More than 218,000 people are known to be infected and over 8,800 deaths have been recorded – including 104 people in the UK who were diagnosed with the virus.
While the outbreak started in China, the bulk of cases and fatalities are now outside the country and the virus is spreading internationally.
What is a coronavirus?
Coronaviruses are a family of viruses that cause disease in animals. Seven, including the new virus, have made the jump to humans, but most just cause cold-like symptoms.
Two other coronaviruses – Middle East respiratory syndrome (Mers) and severe acute respiratory syndrome (Sars) – are much more severe, having killed more than 1,500 people between them since 2002.
The new virus, officially called Covid-19, is also dangerous – so far, around 20 percent of confirmed cases have been classed as severe or critical. So far, around 15 to 20 percent of hospital cases have been classed as “severe” and the current death rate varies between 0.7 percent and 3.4 percent depending on the location and, crucially, access to good hospital care.
This is much lower than fatality rates for Mers (30 percent) and Sars (10 percent), but still a significant threat.
Scientists in China believe that Covid-19 has mutated into two strains, one more aggressive than the other, which could make developing a vaccine more complicated.
How did the outbreak start?
The source of the coronavirus is believed to be a “wet market” in Wuhan which sold both dead and live animals including fish and birds.
Such markets pose a heightened risk of viruses jumping from animals to humans because hygiene standards are difficult to maintain if live animals are being kept and butchered on-site. Typically, they are also densely packed.
The animal source of the latest outbreak has not yet been identified, but the original host is thought to be bats. Bats were not sold at the Wuhan market but may have infected live chickens or other animals sold there.
Bats are host to a wide range of zoonotic viruses including Ebola, HIV, and rabies.
Could the outbreak grow bigger?
What are the symptoms of coronavirus?
The most common symptoms of COVID-19 are fever, tiredness, and dry cough. Some patients may have aches and pains, nasal congestion, runny nose, sore throat or diarrhea. These symptoms are usually mild and begin gradually. Some people become infected but don’t develop any symptoms and don’t feel unwell. Most people (about 80%) recover from the disease without needing special treatment. Around 1 out of every 6 people who get COVID-19 becomes seriously ill and develops difficulty breathing. Older people, and those with underlying medical problems like high blood pressure, heart problems or diabetes, are more likely to develop serious illness. People with fever, cough and difficulty breathing should seek medical attention.
The findings suggest the virus might last this long on door handles, plastic-coated or laminated worktops and other hard surfaces. The researchers did find, however, that copper surfaces tended to kill the virus in about four hours.
But there is a speedier option: research has shown that coronaviruses can be inactivated within a minute by disinfecting surfaces with 62-71% alcohol, or 0.5% hydrogen peroxide bleach or household bleach containing 0.1% sodium hypochlorite. Higher temperatures and humidity also tend to result in other coronaviruses dying quicker, although research has shown that a related coronavirus that causes Sars could be killed by temperatures above 56°C or 132°F (hotter than even a bath scalding enough to cause injury) at a rate of about 10,000 viral particles every 15 minutes.
Although there is no data on how many virus particles will be in a single droplet coughed up by an infected person, research on the flu virus suggests smaller droplets can contain many tens of thousands of copies of the influenza virus. However, this can vary depending on the virus itself, wherein the respiratory tract is found and at what stage in the infection the person is.
The researchers did find, however, that copper surfaces tended to kill the virus in about four hours
On clothing and other surfaces harder to disinfect, it is not yet clear how long the virus can survive. The absorbent natural fibers in cardboard, however, may cause the virus to dry up more quickly than on plastic and metal, suggests Vincent Munster, head of the virus ecology section at Rocky Mountain Laboratories and one of those who led the NIH study.
“We speculate due to the porous material, it desiccates rapidly and might be stuck to the fibers,” he says. Changes in temperature and humidity may also affect how long it can survive, and so may explain why it was less stable in suspended droplets in the air, as they are more exposed. “[We’re] currently running follow-up experiments to investigate the effect of temperature and humidity in more detail.”