A little bit about coronavirus and why a medical mask is a bad choice
This family of RNA viruses typically causes mild respiratory infections. They can infect various species of animals, including humans. The range of species is very wide and includes, in addition to humans, bats, dogs, pigs, cats, camels and many others. They have a specific structure of the outer shell resembling the solar corona, which is why they got their name.
They would be especially unremarkable if not for the heavy varieties of MERS-CoV and SARS-CoV.
Severe Acute Respiratory Syndrome (SARS) was first reported in China in 2002. The causative agent was SARS-CoV coronavirus. I must say that viruses can have large differences in the context of the fate of the host cell. Part of the viruses during reproduction minimally injures the host cell and leaves it alive. Part - leaves on Wednesday only after the destruction of the cytoplasm of the eukaryotic cell. SARS-CoV belonged exactly to the species that destroys the carrier during reproduction, which led to the destruction of pulmonary alveoli cells during the acute period of the disease.
After incubation for 2-10 days, the disease began as a mild runny nose and typical SARS. Further development proceeded according to the following scenario:
stage of primary flu-like infection (lasts 2-3 days), the condition of the patient is moderate
stage of immunodeficiency (a sharp decrease in immunity, a critical drop in the number of lymphocytes, worsening of the condition of patients, lasts 3-4 days)
stage of SARS, which develops against the background of a decrease in immunity and is accompanied by distress syndrome. Respiratory failure, pulmonary edema
terminal stage, accompanied by toxic shock with severe organ failure
Mortality and epidemiology
The course is generally favorable. 90% of patients recovered without any serious consequences on the 6-7th day. This is the approximate time required to develop antibodies to any unfamiliar antigen.
In the remaining group, the virus caused a severe acute respiratory syndrome, the mortality rate of which was 6-15%, while the distribution was uneven. In patients older than 50 years, mortality reached 50%. Patients needed mechanical ventilation, additional oxygen to compensate for acute pulmonary failure.
A total of 8437 cases of the disease were recorded, of which 813 were fatal.
The even more unpleasant MERS-CoV virus that caused the Middle East respiratory syndrome is zoonosis, that is, animals are the reservoir of the disease. The primary carriers, apparently, are bats and, possibly, camels. From person to person, he was transmitted with great difficulty, only with close contact. The clinic is very similar to SARS, but has a more aggressive course and greater mortality.
Epidemiology and Mortality
A relatively favorable epidemiological factor was the low contagiousness of this coronavirus. Some researchers believe that the majority of patients are not infected from other people, but from sick animals.
According to various sources, the mortality rate among infected people is from 27% to 40%. A total of 1,154 confirmed cases were recorded and no less than 431 dead.
The 2019-nCoV outbreak, which began in Wuhan, is potentially one of the most significant dangers that humanity has faced. Coronaviruses of bats, in particular Asian horseshoe bats, are supposedly the initial reservoir. In this region of China, bats are eaten, which greatly increases the risks of interspecific transfer in case of mutation.
Which is very disturbing
It is already possible to draw certain primary conclusions on this disease. The incubation period depends on the source of the virus. When infected from an animal, it is 6-12 days. When infected from humans - no more than 5 days. There are fears that the carrier is contagious in the asymptomatic period when thermal monitoring methods at airports and train stations are useless. It can be assumed that after recruiting the primary pool of null patients, the infection factor from animals will play a small role in the spread of the epidemic.
The virus can be transmitted from person to person and is highly contagious, which radically distinguishes it from previous SARS-CoV and MERS-CoV. There is such an indicator as basic reproduction number - R0. It shows how many people manage to infect the patient during the period of the disease. If the number is less than 1, then the epidemic goes out by itself. If more, it determines the rate of rise of the epidemic and the possibility of a pandemic. For measles, for example, this is 12-18. It is practically enough to look at the patient from afar to become infected. Rubella has something similar. Normal flu has an R0 in the region of 2-3.
The latest 2019-nCoV data suggests a range of 3.3 (95% CI: 2.73-3.96) - 5.47 (95% CI: 4.16-7.10). Significantly more than the flu. In general, this is confirmed by the growth rate of patients.
The clinic is very similar to SARS / MERS. Initially, a flu-like condition, cough, fever. Then a sharp deterioration in the condition and the appearance of breathing problems on the 8-9th day with the development of acute respiratory syndrome. The virus causes very severe pneumonia, destroying the cells of the pulmonary alveoli. There are risks of bacterial infection.
Standard. Wash our hands, avoid crowded places such as the subway. We are not suitable for anyone who coughs.
Conventional masks are ineffective. Masks with a class of at least N95 with a HEPA filter are required. There are risks of infection through open eyes and the conjunctiva. That is why conventional masks are ineffective because they do not provide eye protection.
Can a regular mask protect against a virus?
Some viruses spread when an infected person sneezes or coughs and small infected droplets fall into the air that a healthy person can breathe. Also, the virus can be picked up if you touch the infected surface with your hands and then touch the face.
The BBC quotes Dr. David Carrington of the University of London: "Surgical masks do not protect against viruses or bacteria that are transmitted by airborne droplets." This is due to the fact that the usual mask is too loose on the face and does not have an air filter. In this case, the eyes, through which the mucous membrane can also be infected, remain unprotected (it is proved, for example, that the influenza virus can enter the body when it enters the eye membrane, and then through the nasolacrimal channels to the nasal mucosa). In addition, medical masks leave the face of the face unprotected.
The decision to use a full face mask or gas mask protecting the face completely.
Which filter to use and what to do so that CoronaVirus 2019-nCoV is not infected
Remember. The main transmission of the virus occurs through coughing, sneezing, and even simple breathing. A person exhales the moist air that contains the virus. The main task of the filter is to let in moist air containing bacteria and viruses, and filter it out, all the rubbish just settles on the filter, at the exit you should get clean air ....
1. Minimum filter class that is required at least N95 with a HEPA filter are required. Almost any gas mask filter, especially the military and police filters, provide protection against gases, fumes, bacteriological weapons, and radioactive dust. These filters provide good protection against viruses, therefore they have a complex composition.
Examples of such filters
Filter for gasmask
I especially want to note the filter Filter PA-2002
This is a simple and inexpensive filter with a 40mm mount, compatible with 95% of all gas masks including ppm-88, this filter provides protection against small particles of dust, moist air containing infected particles. Its main advantage is it is collapsible, the internal contents can be pulled out, you can use your own filler, for example gauze soaked with an antiseptic ... This is ideal if you are away from civilization, if the situation with the epidemic is out of control and there is no way to buy and install a good filter, you just change the filler yourself. This may be your last chance not to get infected at hour X.
2. Remember to timely replace the gas mask filter.
3. Hygiene .... Hygiene and hygiene again.
Doctors remind that the rules of personal hygiene are much more effective than wearing a mask. And here are some recommendations for those who are afraid to catch a viral infection:
- do not touch your face with dirty hands;
- wash your hands thoroughly with soap (at least 20 seconds);
- lead a healthy lifestyle to strengthen your immunity.