Image copyright Sipa Media Image caption A bird flu outbreak, that killed thousands of fowl, was a possible source of the virus
There have been more cases of Severe Acute Respiratory Syndrome (Sars) in the Czech Republic than ever before.
It is believed that the virus came from animals in neighbouring Germany. Two people have died after contracting the infection, including a health worker.
The virus is known as coronavirus (Cor).
There has been an increase in cases of the Sars-like coronavirus (Cav) in Germany too. There have been 21 confirmed cases, with a further 13 deaths.
Switzerland and Germany have been most severely affected.
What are coronaviruses?
Coronaviruses are viruses which typically cause respiratory disease.
But they can cause other illnesses too. The primary Sars-related symptoms are cold, sore throat, fever and coughing. In rarer cases they can result in a pneumonia-like disease.
Image copyright Getty Images Image caption The first Sars-like coronavirus (Cav) appeared in Saudi Arabia in 2002 and spread around the world
Is the Avian Flu virus Coronavirus?
No. There is no evidence it is either a coronavirus or a strain of Coronavirus, so it does not have the same association with Sars.
What is the bird flu outbreak in Germany?
The strain, known as the “bird flu” H5N1, is responsible for most of the infections in Germany.
It is sometimes referred to as the “surge” because the H5N1 virus has become more dangerous to humans.
The World Health Organisation (WHO) says that, since the outbreak, at least 93 people have been infected, of whom 61 have died.
The WHO says Germany also has strong links with the Czech Republic, the Czech Republic having suffered its own bird flu outbreaks.
Image copyright Reuters Image caption An epidemic of avian flu in Vietnam has seen 3,000 chickens killed
Where has this outbreak happened?
It has been concentrated in the Viernheim area of Bavaria in Germany.
The first outbreak in China caused deaths in South Korea and in 2015, in Vietnam, 8 million chickens and birds died, triggering an epidemic.
A second strain, the H7N9 virus, has also broken out in China.
Has the virus spread elsewhere?
Eighty cases have been reported in the Middle East, most in Saudi Arabia and Qatar.
Botswana also has seen an outbreak, as have more than a dozen European countries, including France, Greece, Greece, Italy, Serbia, Spain, Sweden, Switzerland and the UK.
Contagion control measures in some countries, such as Chile, have had “fruitful results”, says the WHO.
Image copyright AFP Image caption A Thai doctor was buried in a coffin with her shirt on, so it could be disinfected
Does Sars-like Sars-like Coronavirus pose an epidemic risk?
No. If the virus did spread to other countries, it would cause alarm, but it would not be an epidemic.
A major outbreak of an associated respiratory disease would be capable of putting millions of people at risk.
How is the Hong Kong health department dealing with the outbreak?
Image copyright AFP Image caption Health workers wearing protective suits to clear the spread of the virus
The Hong Kong department of health is coordinating the response and has ordered an investigation into the origin of the epidemic.
It says a number of poultry farms in the region were found to be infected, but no more details have been released.
Meanwhile, an epidemiological surveillance programme will be established in Hong Kong and neighbouring Chinese territories, with the help of the WHO.