Coronavirus disease COVID-19 - virus infection
COVID-19 is a new disease caused by a virus belonging to the Coronaviruses class, subfamily Orthocoronavirinae, in the family Coronaviridae.

Coronaviruses affect mammals and birds and were discovered in the 1960's. In humans they cause respiratory tract infections that can be mild to extremely severe.
Types of coronaviruses include: 229E (alpha coronavirus), NL63 (alpha coronavirus), OC43 (beta coronavirus), SARS (beta coronavirus that causes severe acute respiratory syndrome), MERS (beta coronavirus that causes Middle East Respiratory Syndrome) and SARS-CoV-2 (the newest strand of coronavirus that causes coronavirus disease 19 or COVID-19).
The known origin of the virus
COVID-19 is believed to have appeared at a food market in the Chinese city of Wuhan at the end of 2019. Bats are hosts to a wide variety of viruses and are considered to be the original source of COVID-19. They were not sold at the food market but may have infected the live animals sold there.
The Chinese government alerted the World Health Organisation about several cases of "unusual pneumonia" on the 31st of December 2019. A week later they have announced the discovery of a new virus named 2019-nCoV. As the number of confirmed cases and fatalities increased rapidly, the Chinese authorities started to place several cities in quarantine and eventually closed the country's borders to foreign travellers. The total number of confirmed cases in China exceeded 80.000 with over 3000 deaths.
The infection with Covid-19 has swiftly spread around the world with a significant number of deaths. In February 2020 the World Health Organisation declared a pandemic with more than half a million confirmed cases and almost 30.000 deaths. Europe had become the most affected area with the highest numbers of deaths recorded in Italy and Spain. Special rules have been put in place for funerals when the death came as a result of infection with the COVID-19 virus, to protect population. Governments and local authorities got the power of decision if a death body will be ground buried or cremated.
In March 2020, the US became the country with the highest number of confirmed cases in the world which exceeded 100000 and more than 1500 deaths. However, Germany recorded 50000 cases with a low mortality rate of 340 people, the lowest number among the most affected countries. One of the reasons may be that 80% of the people infected are younger than 60. Another reason may be that Germany has a different criteria for testing people.
If a country's policy is to test only seriously ill patients they will have a higher rate of fatalities recorded. On the contrary, if more tests are carried out and people with milder forms of the disease are identified, the figures will look totally different.
Testing for coronavirus involves taking swabs from the nose and throat or obtaining sputum samples which will be sent to specialised laboratories.
How Coronavirus (COVID-19) spreads
Like most respiratory viruses, coronavirus spreads through small particles released from the nose and mouth of an infected person when they cough and sneeze. A single cough or sneeze can produce as many as 3000 tiny droplets which can reach other people, surfaces or remain in the air. It is also believed that the virus can survive for a long time in faecal matter.
Symptoms of the viral infection
The main symptoms of infection with COVID-19 are: high temperature, dry cough, tiredness, fatigue, nasal congestion, sore throat, aches and pains throughout the body, diarrhoea and in more severe cases shortness of breath. Some people may have the virus and remain asymptomatic.
The incubation period can vary from person to person. This means the time between contracting the virus and the start of the symptoms. According to the Centers for Disease Control and Prevention (CDC), the incubation period is 2 to 14 days. The average period for most cases seems to be around 5 days but a person is considered contagious even before showing symptoms.
High risk groups include: over 60 year olds (over 75 year olds are considered extremely vulnerable), those suffering long term medical conditions (lung disease, heart disease, cancer, diabetes, liver disease, renal disease, high blood pressure), immunosuppressant users, nursing home and specialist disability care residents especially if they have preexisting medical conditions.
How to protect against the COVID-19 virus
The best ways to prevent the spread of infection with COVID-19 is by: washing hands thoroughly with soap, using hand sanitiser, not touching the eyes, nose and mouth with unwashed hands and disinfecting surfaces. Restrictions such as social distancing, home isolation and closures of non essential businesses have been put in place by two thirds of the countries affected by the virus. The police have been given special powers and in some countries the army is on the streets to enforce the protective measures.
Coronavirus disease treatment
There is no treatment for coronavirus at the present time, the aim is to relieve the symptoms while the body's immune system fights the infection. Doctors across the world are working to develop a vaccine which would be the main effective way to slow down the spread of the disease.