Can coronavirus be transmitted by door handles? And other questions

There have now been more than 43,000 cases of the new coronavirus, which has been declared a global health emergency. The disease has spread to many countries, including the UK.

The BBC News Health team's answers to a selection of readers' questions about the new virus are below.

Can coronavirus be transmitted by things like door handles and how long does it survive? 

If someone infected with the virus coughs on to their hand and then touches something, that surface may become contaminated. Door handles are a good example of a surface that might pose a risk.

It's not yet known how long the new coronavirus might be able to live on such surfaces. Experts suspect it is hours rather than days but it is best to wash your hands regularly to help reduce the risk of infection and spread of the virus.

Does climate and temperature affect the transmission of the coronavirus? 

We still have much to learn about this virus. It is not yet clear whether seasonal temperature changes will affect its spread.

Some other viruses, such as flu, follow a seasonal pattern, peaking in colder months. There is some research suggesting Middle East respiratory syndrome (Mers) - another virus from the same family as coronavirus - is influenced by climate conditions, being slightly more common in warmer months.

Can you catch the virus from food prepared by an infected individual? 

Someone infected with coronavirus could potentially pass it on to someone else if the food they prepare has not been handled hygienically. Coronavirus can be spread by cough droplets on hands. Washing your hands before touching and eating food is good advice for anyone, to stop the spread of germs.

Once you've had coronavirus, will you then be immune?

When people recover from an infection, their body is left with some memory of how to fight it should they encounter it again. This immunity is not always long-lasting or totally efficient, however, and can decrease over time. It is not known how long immunity might last after being infected.

What are differences between coronavirus and flu? 

Coronavirus and flu share many similar symptoms, making it difficult to diagnose without a test. The main coronavirus symptoms to look out for are fever and a cough. Flu often has other symptoms too, such as aching muscles and a sore throat, while people with coronavirus may feel short of breath.

Anyone who suspects they may have caught coronavirus, because they have had close contact with another infected person or have travelled to an area where the virus is circulating, should talk to their doctor.

Is a face mask useful against the virus and how often does it have to be replaced?

There is very little evidence wearing face masks makes a difference. Experts say good hygiene - such as regularly washing your hands and certainly before putting them near your mouth - is vastly more effective.

Can coronavirus be transmitted sexually?

It is not clear yet whether this is a route of transmission we should be concerned about. Currently, coughs and sneezes are thought to be the main source of spread.

What is the incubation period for the coronavirus?

The World Health Organization says the incubation period, which is the time before symptoms appear, ranges from two to 10 days.

These estimates will be narrowed down as more data becomes available.

Do people who have contracted coronavirus return to full health? 

Yes. Many of those who contract coronavirus will experience only mild symptoms and most people are expected to make a full recovery.

However, it can pose a particular risk for elderly people and those with pre-existing problems such as diabetes or cancer, or weak immune systems.

An expert at China's National Health Commission has said it can take a week to recover from mild coronavirus symptoms.

Can the coronavirus be transferred through items bought from Wuhan and posted to UK? 

There is no evidence this is a risk. Some diseases, including coronavirus, can spread through surfaces contaminated by people coughing or sneezing on them, but it is thought that the virus does not survive for long. Something that has been sent in the post is unlikely to be contaminated by the time it arrives at its destination.

Is there any reason such viruses are emerging more from China? 

Yes - large populations of people living in close proximity to animals.

This coronavirus almost certainly came from an animal source - a bat, although this may not be the host that spread it to people. Sars, another coronavirus that originated in China, came from bats and the civet cat.

The early cases of this new infection were traced to the South China Seafood Wholesale Market, where live wild animals were also sold, including chickens, bats and snakes.

Is it possible to vaccinate in order to prevent this respiratory illness?

At the moment, there is no vaccine that can protect people against this type of coronavirus but researchers are looking to develop one.

It is a new strain that hasn't been seen in humans before, which means doctors still have lots to learn about it.