What causes atypical pneumonia?
Atypical pneumonia is caused by coronaviruses. For the first time the virus was isolated in 1965 from a patient with acute rhinitis, and in 1968 the family Coronaviridae was organized . In 1975, coronavirus was detected by E. Caul and S. Clarke in feces of children suffering from gastroenteritis.
Coronaviruses are large RNA-containing viruses of spherical shape with a diameter of 80-160 nm. The surface of the virion is covered with clavate processes from the glycoprotein, which give it an easily recognizable shape in electron microscopy, reminiscent of the solar corona during a solar eclipse, hence the name of this family of viruses. The virion has a complex structure, the spiral single-stranded RNA molecule is located in the center, the nucleocapsid is surrounded by a protein-lipid shell, which consists of 3 structural proteins (membrane protein, transmembrane protein and hemagglutinin). Virus replication occurs in the cytoplasm of affected cells.
Coronaviruses have a complex antigenic structure, they are divided into antigenic groups that have different antigenic crossings.
- The first group is human coronavirus 229 E and viruses that infect g pigs, dogs, cats and rabbits. S
- The second group is the human OS-43 virus and viruses of mice, rats, pigs, cattle and turkeys.
- The third group is human intestinal coronaviruses and chicken and turkey viruses.
The causative agent of SARS is a previously unknown variant of coronavirus.
Sequencing of the SARS virus showed that it differs by nucleotide sequences from the previously known groups of coronaviruses by 50-60%. The results of the sequencing of virus isolates conducted by Chinese scientists differ significantly from the data obtained by Canadian and American researchers, which suggests the ability of the virus to rapidly mutate. Coronaviruses are unstable in the environment, instantly die when heated to 56 ° C, under the influence of disinfectants. There is evidence of a higher resistance of the SARS virus. So. On a plastic surface the virus can persist up to 2 days. In sewage waters up to 4 days. However, during these terms the number of virus particles is constantly falling. It is believed that the SARS virus was the result of mutations of previously known coronavirus species.
Coronaviruses 229EI, OC43 are known for a long time as causing colds. At the end of 2002, an outbreak of respiratory viral disease, called SARS, was reported. SARS was caused by coronavirus, which was genetically different from known human and animal viruses.
It is assumed that it is a human pathogen that was first registered in Guangdong province (China) in November 2002. The virus was found in palm wyvers, raccoon dogs, ferret badger. SARS is spread in more than 30 countries. As of mid-July 2003, more than 8,000 cases of the disease and more than 800 deaths have been reported (mortality of about 10%); In the late 2003 period, all cases of the disease were identified in China.
Transmission of the infection is probably carried out by airborne droplets and requires close personal contact. Nevertheless, transmission can be carried out accidentally, by aerosol. People are affected from 15 to 70 years.
Outbreak of coronavirus infection in 2013
The government of the Kingdom of Saudi Arabia, like the WHO experts, is concerned about the outbreak of a new, yet unexplained disease that is provoked by the coronavirus of the nCov or nCoV. The first case of an unknown disease was recorded in 2012, but starting from the month of May this year, 13 patients were hospitalized in the country for the first week, seven people have now died. According to the updated information of the World Health Organization website, the virus can be transmitted from person to person, that is, by contact.
Coronavirus nCoV (nCoV) is a strain that was not previously found in humans, it is genetically different from the virus that causes SARS - atypical pneumonia. The new strain of the virus is indiscriminate in terms of age limits, the youngest patient was 24 years old, the oldest - 94 years old, mostly infected with men. Literally a month ago, WHO experts believed that the main difference between coronavirus and SARS is low transmissibility and rapid development of renal failure. However, in May, French doctors reported a case of human infection after being in the same room with a sick coronavirus infection, the same information was confirmed by UK experts. At a recent press conference in Riyadh, Assistant Director-General of the World Health Organization, K. Fukuda, officially announced the possibility of a contact route for the transfer of a new dangerous coronavirus. Since Mr. Fukuda is responsible for safety in the field of public health and epidemiological control, his words were taken very seriously.
Symptoms that can cause coronavirus nCov begin with acute respiratory complications. The clinical picture is very similar to the picture SARS - SARS or Tori (severe acute respiratory syndrome or severe acute respiratory infection), the symptomatology develops rapidly, accompanied by renal insufficiency. The vaccine against nCoV (nCoV) has not yet been developed, since the virus itself is still being studied.
Meanwhile, on May 9, 2013, the Minister of Health of Saudi Arabia provided WHO with information about two regular, laboratory-confirmed diseases. Both patients are alive, one is already discharged. The condition of the second patient is assessed as stably heavy.
In analyzing the alarming current situation, WHO strongly encourages all countries, especially those in the south-western sector of Asia, to conduct thorough epidemiological surveillance, to record and notify WHO of all atypical cases of infection. As of today, the detected strain does not have high transmissibility, however, a sharp outbreak of diseases in Saudi Arabia in May this year causes quite legitimate anxiety.
The official statistical data on the number of cases affected by coronavirus nCoV (nCoV) are as follows:
- From September 2012 to May 2013, 33 cases of coronavirus infection with nCoV confirmed by laboratory tests were recorded.
- One case of the disease in Jordan still raises doubts in the sense of belonging of the pathogen to the coronavirus group.
- From September 2012 to May 9, 2013 from the coronavirus nCoV (nCoV) killed 18 people.
WHO specialists continue to coordinate the actions of doctors of those countries, in which the majority of diseases are diagnosed. In addition, experts have developed a surveillance guide through which clinicians can differentiate the signs of infection, the infection control manual and the algorithms of the doctors' actions are already being distributed. Thanks to the joint efforts of microbiologists, physicians, analysts and experts, modern laboratory tests have been created to determine the strain of the virus, all major hospitals in Asia and Europe are equipped with reagents and other materials for testing that reveal a new strain.