Coronavirus belongs to the Coronaviridae, a group of viruses that infect not only humans but also other mammals as well as birds and can cause a variety of diseases. In humans, the coronavirus causes diarrheal diseases and respiratory infections in particular. The virus became known worldwide in connection with the SARS epidemic in 2002 and 2003.
What is coronavirus?
Coronavirus is an RNA virus with an unusually large genome. A viral envelope made of proteins and a lipid membrane makes it extremely resistant to environmental influences. The Coronaviridae family is very diverse and common in both mammals and birds. Currently, about five different coronavirus species are known to cause respiratory tract infections in humans. A large proportion of common colds in the winter months are thought to be caused by coronaviruses. An exception is the best-known coronavirus, the SARS coronavirus, which, in addition to respiratory illnesses, can also cause inflammatory gastrointestinal diseases. Transmission for all coronaviruses is usually by droplet infection, but smear infection cannot be ruled out. Transmission by animals carrying the coronavirus is also considered possible.
Transmission, infection, and significance
While most coronaviruses cause rather harmless illnesses, the SARS coronavirus causes a life-threatening respiratory infection that has become known as severe acute respiratory syndrome, or SARS. Symptoms are essentially similar to those of a classic flu: headache, aching limbs, a severe cough, shortness of breath and a sore throat accompanied by hoarseness. Typical of an infection with the SARS coronavirus, however, is the sudden and unusually rapid increase in fever to over 38°C. In the further course, bilateral pneumonia is added. As a result of the disease, the number of platelets and white blood cells also decreases, further weakening the immune defense system. The incubation period is up to seven days. During the SARS pandemic of 2002/2003, nearly 1,000 people died, corresponding to about ten percent of those infected. Some of the survivors retained damage to the lungs, spleen, spinal cord and nervous system. In particular, long-term damage included pulmonary fibrosis, osteoporosis, and bone necrosis.
Diseases and treatment
To date, there are no effective treatments for coronavirus. Various antibiotics can be administered to combat secondary bacterial infections. The immune system can be strengthened by administration of antivirals and cortisone. Depending on the severity of the infection, artificial respiration may also need to be used. Ultimately, however, the course of the disease can hardly be influenced by current means. That is why the fight against the SARS pandemic in 2002/2003 focused mainly on isolating the sick and preventing further spread. Although the genome of the SARS coronavirus has now been decoded, it has not yet been possible to develop an appropriate vaccine or an effective drug. Since the coronavirus mutates very quickly, current research is focusing on the proteins of the viral envelope. Initial results have been obtained here, but it is not yet possible to predict when practical application will be possible. In 2012, the human coronavirus EMC, which has become known as the “new coronavirus,” made its first appearance. The diseases known so far have been much slower than SARS, but very severe and the majority fatal. Ten of the seventeen people known to have contracted the disease have died. Infected individuals usually develop atypical pneumonia from a general respiratory infection and suffer acute kidney failure early in the course of the disease. Due to the low number of cases and the fact that no other illnesses have occurred in the personal environment of the infected persons, it is currently assumed that the human coronavirus EMC has only a very low transmission rate. Unlike other coronaviruses, it is probably not transmitted by droplets but by smear infection, so that even simple hygiene measures can effectively prevent its spread. Since all people who have contracted the new coronavirus so far come from the Middle East, the origin of this virus is suspected to be the Arabian Peninsula.There may be a relationship to a coronavirus that affects a species of bat found there.
