The summer heat in our country continues. This long summer just doesn’t seem to want to give way to autumn. But the arrival of respiratory viruses, including the famous “flu paramyxovirus,” will not be delayed by this weather.
The first cases of influenza have already been reported in northern Italy, and even in Europe the virus has been arriving for a few weeks, still manifesting itself in sporadic cases. Once again this year, respiratory diseases will characterize the autumn-winter period. Indeed, it is better to identify the period at risk of virosis between the months of October 2023 and April 2024, since talking about seasons is increasingly relative, alas!
A bad climate situation that also undermines our responsiveness to infection. We need to be aware that these climatic alterations will increasingly affect our state of response to disease. And we have already seen the first signs of this all over the world.
With seasonal flu, virologists have identified the arrival of 262 different types of respiratory viruses. And let’s not forget Covid-19, always present and also on the rise. Covid which, however, with its variants, has learned to live with our bodies and defenses, thanks to past vaccination campaigns.
There are issues related to co-infections with other viruses. The issue of vaccinations becomes a priority in order to control the development of the disease.; who should and how to do them; and again all the issues related to respiratory syndromes, with an ever watchful eye on the Covid-19 situation.
National and international reports confirm that we are in the presence of an increasing circulation of Covid-19 worldwide, with its newer and also newer variants. These cases have also spread to Italy and have increased with the start of post-summer production and commercial activities and the opening of schools.
The attention of all of us, insiders, is also caught by an early onset of cases of the new flu, which will grow between October and November and then peak between December and February 2024. During this period, the real problem will be cases of co-infection between the two viruses in older, weaker individuals with debilitating diseases.
Since the Sars-CoV-2 virus appeared, we have realized how aggressively influenza/Covid co-infections occur and put the previously mentioned population groups at risk. Influenza illness becomes more severe with the presence of a Covid that becomes even more aggressive. These population groups should follow the advice to have both vaccinations. We will discuss this in detail in another article, but in the meantime we can say that in the same session it is possible to get the flu vaccine and the Covid vaccine inoculated. And now let us begin to delve into the topic regarding influenza in its characterizing aspects.
Influenza is a respiratory, infectious, acute disease caused by a virus of the Orthomyxovirus family (influenza viruses) that infects the superficial cells of the mucosa of the upper airways of our body, i.e., the nose, pharynx, and larynx (throat) causing a major inflammatory reaction that is often painful.
The infection can involve the mucosa of the trachea even going so far as to infect the mucosa of the lower airways involving the bronchi, and even the cells of the pulmonary alveoli (a story known to all by Covid).
This virus aggression triggers a reaction of local immune cells, under the superficial mucosa of the respiratory tract, which triggers the activation of the inflammatory system. This process aims to defend the respiratory mucous membranes and the whole organism from virus attack.
The result is an increasing inflammation, fever elevation, dilation of local vessels with edema and swelling. This reaction of our body aims to defend ourselves but the result is the appearance of symptoms that grow by the hour. We are in the midst of flu symptoms. But also of other less aggressive viruses.
By now we know this defensive (but also offensive) mechanism that also characterizes the response to Coronavirus, see responses to Covid-19, and many other microorganisms. Typical flu symptoms thus result from the body’s inflammatory response to the virus, and this causes the malaise and the great state of prostration. Many viruses and bacteria generate this type of response, which is labeled “flu,” but which, in most cases does not stem from the “flu virus sensu strictu.”
More than 200 flu-like viruses have been surveyed that attack our respiratory system and beyond and manifest themselves with more limited symptoms creating reduced health problems compared to those caused by the “real flu virus.”
From this we can understand why almost always those who have taken the flu vaccine still get sick.With the flu vaccine we protect ourselves from the more aggressive seasonal virus. So-called winter “flu” is in most cases caused by all the other viruses with which, in winter, we come in contact.
We protect ourselves against the most aggressive virus, the Orthomyxovirus seasonal flu virus.In fact, when the influenza virus circulates, many other viruses and bacteria that cause symptoms quite similar to those caused by influenza, but less severe and less widespread, circulate simultaneously in Italy during the autumn-winter period. Among the most frequent viruses are Adenoviruses, Rhinoviruses, Coronaviruses and also the respiratory syncytial virus, which is particularly aggressive in children.
Influenza disease is caused by 3 types of viruses in the Orthomyxoviridae family :
type 1 ” Influenzavirus A.”
type 2 ” Influenzavirus B”;
type 3 ” Influenzavirus C”.
Influenza A and C viruses have the characteristic of infecting different animal species, including humans, and can be transmitted between species.
Influenza B viruses infect humans practically exclusively.
Influenza viruses of types A and B have 2 molecules (glycoproteins) in their surface that characterize them and mutate continuously (the famous annual mutations for which the vaccine constantly changes).
These are the glycoproteins present in the outer part of the virus:
– Hemagglutinin molecule labeled H and constitutes the viral portion that binds to respiratory mucosal cells.
– Neuraminidase molecule marked with the letter N and has the function of facilitating the escape of the virus from cells once it has replicated.
Hemagglutinins (H) and neuraminidases (N) are glycoproteins with antigenic characteristics, i.e., molecules recognized by the cells of the immune system that activate the body’s defense functions. Influenza viruses are recognized by our defense system through these molecules present on the surface of influenza viruses.
Hemagglutinin, which is found in the outer capsule of the virus, acts as a key to enter respiratory cells.In fact, the virus’ hemagglutinin binds to the surface of the respiratory mucosal cell and allows viral DNA to enter the cell itself.Within the respiratory cell, the virus reproduces in millions of copies (daughter viruses).
Neuraminidase, on the other hand, comes into play when the influenza virus, which has reproduced thousands and thousands of times, has to leave the infected cell to infect new ones and begin a new reproductive cycle. And the infection spreads into the respiratory mucosa. The neuraminidase is a molecule that is responsible for releasing the virus from the surface of the cell itself, to which it is attached, so that it can be released and get it out of the cell, infect other respiratory cells, and allow the virus to reproduce, which grows exponentially. In this way, the symptoms also grow exponentially.This is the mechanism, expressed in a simplified way, of how the virus acts inside us.
Influenza is a disease characterized by a series of symptoms resulting from the body’s response to the invasion and reproduction of the virus within our respiratory cells.The reaction of the immune defense system causes the sudden onset of fever, even high fever, accompanied by coughing, muscle aches.A particularly uncomfortable headache also characterizes the growth of symptoms.These are accompanied by chills, poor appetite, great feeling of fatigue, and inflammation and soreness of the upper airway.
Nausea, vomiting, and diarrhea also characterize the flu particularly in children.Symptoms generally wear off within a week, or ten days, the response time for the immune system to neutralize the virus and its reproduction.But in the over-65s, young children, particularly under one year of age, and those with chronic illnesses, symptoms can be more severe, persistent, with greater risk of more serious complications or worsening of the underlying condition.
Influenza is transmitted by air, through the droplets of our saliva. So in outdoor environments, even more so those that are closed and poorly ventilated. It can be direct transmission through coughing, sneezing, or very close contacts of people who have the virus. Or indirect transmission by contaminating oneself with the virus present on objects or surfaces contaminated with it.
To decrease the risk of infection, it is best to (1) avoid crowded and unventilated places; (2) wash hands with soap and water to avoid contamination by virus spread on surfaces of all kinds, better soap than disinfectants such as alcohol-based cleaners or disinfectant wipes that ruin the defensive bacterial flora on our skin; (3) do not touch your eyes, nose and mouth with your own contaminated hands; if you cough or sneeze, cover your nose or mouth with a paper towel; (4) it is most important to keep rooms ventilated and sunny if possible.
If you want to avoid spreading the virus to other people, and especially to the elderly and frail, use a face mask in case of flu symptoms.
The incubation period of seasonal flu is usually 4 to 5 days. Generally, adult people begin to spread viruses from one two days before the onset of symptoms, and this spreading ability remains until 5 days after the onset of symptoms. In children and people who are more frail and have underactive immune systems, the infection may last longer, up to 8 to 10 days.
aumento fino alla fine del 2023 con oltre 4000 casi segnalati e nessun decesso.
