Why do flu and winter go hand in hand? It would seem that the time of year is unimportant for the infection. The usual explanation for this phenomenon is crowding.
That is, in winter, people crowd inside buildings, giving the flu virus (as well as other colds) an ideal opportunity to cross-infect. But medical scientists and ordinary people have questioned this theory for years.
“Schools have classes in the spring, and in the summer people go to the movies together,” says Peter Palese, chairman of the microbiology division at New York Medical School. "Pandemonium alone does not explain this trend."
Alternative theories appear one after another. Some focus on how the human body responds to sun deficiency. The body produces less of the hormone melatonin and vitamin D, both of which can affect the immune system.
According to another theory, dry cold air is to blame. The latest research by Palese and his colleagues has provided her with a solid foundation. The scientists tried to infect guinea pigs with various strains of the flu and found that the guinea pigs were actively infecting each other in dry, cool air. The same pigs, but at 30 degrees, did not spread the disease at all.
However, do not rush to turn your house into a bathhouse and invite all your friends. The heat may harm the flu virus, but it creates an excellent environment for fungus, mold, and bacteria. “You need to be careful about any recommendations regarding health,” the scientists say.
Health experts say that while compact populations are not the main cause of seasonal epidemics, they do play a big role in their spread. Other diseases, such as SARS, are also very fond of the crowd.
“In fact, even before the discovery of viruses and bacteria, people knew that diseases, from the common cold to the plague, spread from person to person, and tried to avoid contact with the sick,” say medical historians. “It’s nothing but common sense, the more people in close contact, the higher the risk of getting sick.”
In short: stop contact with people, and you will avoid illness.
But does a student in a class of 30 take more risks than a child in a class of 20? Is there an ideal distance to keep in crowded places? Can influenza epidemics be slowed down by closing schools, workplaces, and banning public gatherings?
The answers to these questions are still within the framework of hypotheses. These answers are extremely important for scientists planning the actions of mankind in the event of a possible flu pandemic or other dangerous infections.
One thing is for sure: certain types of contagious diseases are especially well adapted to the conditions of close living of people. For example, such as adenoviruses that cause acute respiratory infections among recruits.
If you want to avoid getting sick, it's wise not to lock yourself in a windowless room, but to get a regular vaccination. Although it will not save you from the common cold, it will increase your chance of not getting the flu. Do not forget the classic advice of doctors - wash your hands often!
A seasonal influenza epidemic breaks out every year, but until recently no one knew why. As the correspondent of BBC Future found out, the reason lies in how exactly the virus is transmitted from one person to another.
Every year the same thing happens: it gets colder outside, the nights get longer, and we start sneezing.
If you're lucky, you can get off with a banal cold - it feels like a grater is stuck in your throat, but in principle the disease is not dangerous. If we are not lucky, then for a week, or even longer, we will suffer from high fever and aching limbs.
It's the flu.
Given the number of people who get sick with seasonal flu each year, it's hard to believe that, until recently, scientists had very little understanding of why cold weather helps spread the virus.
Only in the last 5 years have they managed to find the answer to this question and, perhaps, a way to stop the spread of the infection.
It's all about the peculiarities of the transmission of the virus by airborne droplets.
Remember prevention
Every year during the winter season, up to 5 million people around the world fall ill with the flu, and about 250,000 people die from it.
Part of the danger of the virus lies in the fact that it mutates very quickly - having been ill with a strain of one season, the human body, as a rule, is unprepared for the next year's strain.
“Antibodies raised against last year's strain don't recognize the mutated virus and immunity is lost,” says Jane Metz of the University of Bristol.
For the same reason, it is difficult to develop effective influenza vaccines, and although for each new strain, one is eventually created, medical calls for mass vaccination of the population, as a rule, end in nothing.
Scientists expect that understanding the causes of the spread of influenza in the winter and the fall in the incidence in the summer will help develop simple and effective preventive measures.
Existing until recently explanations for this phenomenon were reduced to the behavior of people. In winter, we spend more time indoors - and therefore in closer contact with other people who may be carriers of the virus.
We are also more likely to use public transport in which we are surrounded by sneezing and coughing passengers. As a result, scientists concluded, the risk of an influenza epidemic in winter increases.
Another previously common explanation was related to human physiology: in cold weather, the body's defense against infection is reduced.
During the short winter days, we don't get enough sunlight, and the body's stores of vitamin D, which helps to strengthen the immune system, are reduced. Thus, we become more vulnerable to infection.
Also, when we inhale cold air, the blood vessels in the nose constrict to prevent heat loss. This, in turn, prevents white blood cells (the "soldiers" who fight germs) from reaching the nasal mucosa and destroying the viruses we breathe in.
As a result, the latter freely penetrate the body. (It is possible that for the same reason you can catch a cold by going out on a cold day with a wet head).
Although the above factors play a role in the spread of the influenza virus, they alone do not fully explain the annual epidemics of the disease.
The answer may lie in the air we breathe.
To be continued...
The content of the article:
For many years now, we have been experiencing an influenza epidemic in the winter. The reasons for the development of colds during this period are known - hypothermia, dampness, etc. However, only for these, generally banal reasons, do annual epidemics of the pandemic occur? Today we will try to figure out not only what to do if you get sick with the flu in winter, but also the reasons for the development of the disease.
Influenza - why is the epidemic rampant in winter?
The fact that influenza is spread by a virus is quite obvious, and there is no point in arguing it. It is transmitted by airborne droplets and it is absolutely not necessary for someone to cough on you for the development of the disease. The flu virus can stay in the air for a long time and you can get sick at any time. However, this does not give grounds to assert that the flu is exclusively a winter disease. The virus that provokes the development of the disease can survive perfectly at any time of the year.
However, there is an answer to the question why epidemics are active only in winter. During this period of time, people are more actively in contact with each other. Since it is cold outside, we use public transport more often than walk. If at this time there was a carrier of influenza not far from you, then several people will definitely pick up the disease, not excluding you.
In addition, in winter, the body is weakened, as it receives little micronutrients, and daylight hours are reduced, which leads to a decrease in the rate of vitamin D production. Because of the cold, we rarely open windows to ventilate the premises. This leads to the fact that in various institutions the virus can be in the air for a long time and at the same time maintain its life. We actively use various preventive medications, but still we get sick, and many are interested in what to do if we get the flu in winter.
However, we will talk about this a little later, but now we will still find out the reasons for this. Many people believe that high humidity is one of the reasons for the development of colds and infectious diseases. And this is, perhaps, the main mistake that we make. Scientists are very actively exploring not only ways to treat influenza, but also the causes of the development of this disease.
After conducting one study on guinea pigs, they got sensational results. The higher the air humidity, the less active the influenza virus is. If the air humidity is low, then the spread of influenza can be compared to a forest fire in the heat.
When the virus is exposed to moist air, it is quickly removed from it. Those particles of water that are in the air are able to “wash away” the virus, which leads to a decrease in the time it stays in an active state. In dry air, the flu virus can stay for several hours and therefore you should not be surprised that you get sick, although there might not have been anyone around. Before you, there was probably a person in the room who was already sick and he left behind you a “gift”. Thus, we can say that in winter a person inhales a "cocktail" of dead cells, mucus and viruses left after everyone who visited this room before you. Scientists have found that, among other things, the 2016 flu virus can be transmitted not only by airborne droplets, but also through common objects, such as doorknobs.
In pharmacies, you can always find a large number of different medications designed to fight the flu virus. In the cold season, pharmaceutical companies also become active, which leads to a flood of advertisements for new and extremely effective drugs against this disease. However, every year it becomes more and more difficult to be treated, and the duration of even ordinary acute respiratory viral infections increases.
Every year we are faced with new strains of influenza, requiring more and more new drugs for treatment. Simply put, the mutation of the virus does not stop, and every new year we see a new virus. Moreover, the process of virus mutation proceeds so aggressively that the human body cannot adapt. The antibodies he created last year can no longer identify the new virus.
Pharmaceutical companies are constantly creating new vaccines, but many people have developed a wrong attitude towards them and they do not agree to be vaccinated. Based on the foregoing, one should not be surprised that many are interested in what to do if they get sick with the flu in winter. This is what we will talk about in the second part of the article.
What to do with the flu in winter: treatment features
Scientists note that serious influenza epidemics tend to recur every 40 or even 50 years. Since the last strong epidemic of this disease was recorded in 2009, according to their observations, one can be calm until 2049. But we have already said above that this virus mutates very quickly and you should not count on the fact that you are not in danger until the specified date.
As you know, any disease is easier to prevent than to treat. It is the prevention of influenza that you should pay special attention to. Vaccination is the most effective in this case. However, if for some reason you do not want to be vaccinated, then you can take arbidol or rimantadine at the beginning of the epidemic.
The first drug is less effective, but not as toxic as rimantadine. If you have problems with the functioning of the kidneys or liver, then you should definitely opt for Arbidol. No less effective for solving this problem can be herbal preparations. Let's say Influcid will help your family avoid the flu. It is available in several versions and is designed for different age categories.
Take this medicine as soon as the first symptoms of flu come on. Note that it can also be useful for coughing. This prophylactic drug is quite capable of stopping the development of influenza, as it stimulates the immune system. But you should forget about antibiotics, as they cannot destroy the influenza virus.
To reduce the risk of disease, before going outside, it can be recommended to lubricate the nostrils with oxalin ointment or laundry soap. This will help make it difficult for the virus to enter the mucosa. When you return home, be sure to wash your hands with soap and rinse your throat with any disinfectant solution. Limit your time in crowded places. This seemingly simple rule is often ignored, resulting in the flu. It should also be said that a ski trip in the forest, especially coniferous, can be an excellent means of preventing influenza.
However, let's see what to do if you get the flu in winter. First of all, when you get the flu, you need bed rest. Physical activity at this time will only harm, as the activity of the immune system will decrease. We also recommend continuing to take medications that were used for prevention, but increase their dosage. In addition to all of the above, you should call a doctor at home, especially if you have chronic diseases.
To prevent the epidemic from spreading among your family members, try not to cough or sneeze in their direction. Ideally, they should wear gauze bandages. A mandatory rule for influenza is the use of large amounts of liquid. This will allow you to more actively utilize the toxins that accumulate in the body.
Excellent drinks during this period will be ai with lemon and honey, blackcurrant and milk with honey. But vodka with pepper will definitely not help you, so it’s better to refuse this idea right away. If you are wondering what to do if you get sick with the flu in winter, then give up heavy fatty foods. It is best to consume boiled white and red meat, fish, kefir, fruits, yogurt and vegetables during the period of illness. At the same time, eating through force is also not worth it.
Unfortunately, people like to self-medicate and as a result actively use various medications or traditional medicine. If you are already sick, then you are contraindicated in alcohol, visits to the sauna or bath, the use of antibiotics and aspirin. All these actions are stressful for the body, which needs to fight the disease at the moment. If you overload your body, then serious complications are possible after the flu. We recommend that you immediately call a doctor at home after the onset of flu symptoms.
And now I would like to talk about some facts related to the flu. The disease begins quite unexpectedly and among the first symptoms it is worth noting high fever, chills, aching joints, but there are no signs of the development of colds - runny nose and cough. They may appear a little later, in three or four days.
People are extremely susceptible to influenza, and one person can infect about two and a half dozen. It is enough to be at a distance of two or three meters from the carrier of the virus, as you will immediately fall into the risk group. It is for this reason that gauze bandages should be worn during an epidemic.
The virus has a high ability to survive and stays for a long time not only in the air, but also on various objects. Try to separate the sick person from the rest of the family and keep contact with him to a minimum. The room in which the patient is located should be ventilated more often and wet cleaning should be carried out.
For more on the flu, watch this video:
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When does the influenza epidemic most often occur? Of course, in winter. And, despite the fact that the flu is actively studied by scientists and physicians, until now, few people knew why it manifests itself only in the cold season. After all, it cannot be the only reason for this that a person is less resistant to negative external influences in winter?.. On the contrary, when the temperature outside is below zero, it is possible to overcome viruses - they cannot withstand severe frosts. Today we propose to understand in more detail, is it really so? Why is the flu dangerous? Why does it show up in winter? How to protect yourself from a seasonal epidemic?
Why is the flu dangerous?
Influenza, in fact, is considered one of the most dangerous seasonal diseases by doctors around the world. According to statistics, almost 5 million people get sick with it every year, and what is really sad is that about 250 thousand of them die. The biggest "trick" lies in the fact that the flu manifests itself every winter in a new way, forming a new strain. The virus has the ability to mutate and adapt to human immunity. If you have been ill with the flu, you automatically have immunity against it - antibodies. But after a year, a new strain of flu will be insensitive to them, and you risk getting sick again. This is also the main reason why it is rather difficult and financially costly to invent new vaccines against new viruses, since they are insufficiently studied.
Why does the flu appear in winter?
Until recently, the most important explanation was that in winter a person spends most of his time indoors. As a result, dozens and hundreds of people can be in the same room, and this is fraught with very easy transmission of the virus by airborne droplets. Moreover, dry heated air due to heating systems will be an ideal environment for the reproduction of the virus. The same can be said about public transport: if in summer we are happy to walk to work, then in winter, early in the morning or late in the evening in the dark, and due to weather conditions, we don’t feel like walking at all. And in the subway or on the bus, the crowds are even higher per square meter.
Many doctors were also inclined to believe that it was during the cold season that the defenses of the human body would be lowered, since it needed more strength and energy to warm up. We also get less vitamins and nutrients from food, and lack of vitamin D due to minimal daylight hours, and because of this, immunity also decreases. Also, our blood vessels and airways are greatly narrowed due to cold air, and white blood cells do not reach the nasal mucosa and do not fight viruses. Agree, there are quite enough reasons for humanity to be prone to an influenza epidemic in winter.
But there is another discovery!
It was produced quite recently by scientists from two universities at once - Bristol and Columbia. Previously, the factor of air humidity was not given much importance. Moreover, it was believed that the colder the air, the less likely the flu was to spread. However, as it turned out, everything happens exactly the opposite. The humidity of warm air is much higher than that of cold air. And the lower the air temperature, the less vapor will be in the air we breathe. This is not affected by rain or snow - the air will still be drier. And the flu virus "feels" great in dry air - and therefore it is able to spread very quickly.
Many may consider such conclusions illogical, because it has always been believed that the flu spreads well in a humid environment. But, it turned out that it wasn’t, and the peculiarities of the airborne route through which diseases are transmitted are to blame. In humid air, all that mucus that is released from the mouth with a sharp stream of air from the lungs immediately settles on the floor - precisely under the influence of moisture and the inability to disperse into smaller particles in humid air. In a dry environment, the slime is sprayed into smaller particles and “hangs” in the air for a long time - even for several hours! Therefore, anyone who passes by can inhale this explosive mixture.
Therefore, air humidification will be the “first commandment” for those who want to prevent disease. Water vapor in the air really has a negative effect on the flu virus. It is able to change the acidity in the environment where pathogenic microbes are located, which is why they die. But be sure not to forget about personal hygiene - after all, the influenza virus is transmitted not only by airborne droplets, but also by contact. Humidifying the air, wearing a mask, washing your hands regularly, wet cleaning - this is what will help you cope with the epidemic and not get sick!
Image copyright SPL Image caption Microbes and viruses are able to "hang" in the air for many hours and even days.
A seasonal influenza epidemic breaks out every year, but until recently no one knew why. As the correspondent found out, the reason lies in how exactly the virus is transmitted from one person to another.
Every year the same thing happens: it gets colder outside, the nights get longer, and we start sneezing.
If you're lucky, you can get off with a banal cold - it feels like a grater is stuck in your throat, but in principle the disease is not dangerous. If we are not lucky, then for a week, or even longer, we will suffer from high fever and aching limbs.
It's the flu.
Given the number of people who get sick with seasonal flu each year, it's hard to believe that, until recently, scientists had very little understanding of why cold weather helps spread the virus.
Only in the last 5 years have they managed to find the answer to this question and, perhaps, a way to stop the spread of the infection.
It's all about the peculiarities of the transmission of the virus by airborne droplets.
Remember prevention
Every year during the winter season, up to 5 million people around the world fall ill with the flu, and about 250,000 people die from it.
Part of the danger of the virus lies in the fact that it mutates very quickly - having been ill with a strain of one season, the human body, as a rule, is unprepared for the next year's strain.
Image copyright getty Image caption Subway cars are a comfortable environment for viruses“Antibodies raised against last year's strain don't recognize the mutated virus and immunity is lost,” says Jane Metz of the University of Bristol.
For the same reason, it is difficult to develop effective influenza vaccines, and although for each new strain, one is eventually created, medical calls for mass vaccination of the population, as a rule, end in nothing.
Antibodies developed against last year's strain will not recognize the mutated virus, and immunity will be lost.
Scientists expect that understanding the causes of the spread of influenza in the winter and the fall in the incidence in the summer will help develop simple and effective preventive measures.
Existing until recently explanations for this phenomenon were reduced to the behavior of people. In winter, we spend more time indoors - and therefore in closer contact with other people who may be carriers of the virus.
We are also more likely to use public transport in which we are surrounded by sneezing and coughing passengers. As a result, scientists concluded, the risk of an influenza epidemic in winter increases.
Another previously common explanation was related to human physiology: in cold weather, the body's defense against infection is reduced.
During the short winter days, we don't get enough sunlight, and the body's stores of vitamin D, which helps to strengthen the immune system, are reduced. Thus, we become more vulnerable to infection.
Also, when we inhale cold air, the blood vessels in the nose constrict to prevent heat loss. This, in turn, prevents white blood cells (the "soldiers" who fight germs) from reaching the nasal mucosa and destroying the viruses we breathe in.
As a result, the latter freely penetrate the body. (It is possible that for the same reason you can catch a cold by going out on a cold day with a wet head).
Although the above factors play a role in the spread of the influenza virus, they alone do not fully explain the annual epidemics of the disease.
The answer may lie in the air we breathe.
The secret of moist air
According to the laws of thermodynamics, the relative humidity of cold air is lower than that of warm air. That is, when the dew point is reached, at which water vapor falls in the form of precipitation, the content of this vapor in cold air will be less than in warm air.
An epidemic of the virus almost always occurs after a drop in relative humidity.
Therefore, in the cold season it may rain or snow outside, but the air itself will be drier than in the warm period.
At the same time, a number of studies conducted in recent years confirm that the influenza virus feels better in dry air than in humid air.
In one of these studies, scientists observed the spread of influenza in guinea pigs in the laboratory.
In more humid air, the epidemic had difficulty gaining momentum, while in drier conditions, the virus spread at lightning speed.
Image copyright iStock Image caption Air humidification is one of the ways to combat the spread of harmful microorganisms.Comparing climate change observations collected over a 30-year period with flu statistics, a research team led by Columbia University's Jeffrey Sheiman found that an epidemic of the virus almost always occurs after a drop in relative humidity.
The two graphs showing how fast the virus spreads against the degree of air humidity matched so much that “one could practically be superimposed on the other,” says Metz, who, along with colleague Adam Finn, recently wrote an article about these studies for a scientific periodical of the British Infectious Diseases Association. Journal of Infection.
The discovery of the relationship between air humidity and the incidence of influenza has been repeatedly confirmed experimentally, including on the basis of an analysis of the swine flu pandemic that broke out in 2009.
In winter, we breathe in a “cocktail” of dead cells, mucus and viruses along with the air.
The conclusion reached by scientists may seem illogical: it is generally accepted that the risk of getting sick is higher just in a humid environment.
To understand why this is not the case with the flu, we need to look at what happens when we cough and sneeze.
A thin mist of drops escapes from the nose and mouth. When exposed to moist air, they remain quite large and settle on the floor.
But in dry air, these droplets break up into smaller particles - so small that they can remain in a “suspended” state for several hours or even days.
Image copyright getty Image caption To understand why dry air helps spread the flu, we need to look at what happens when we sneeze and cough.As a result, in winter, we breathe in the air with the “cocktail” of dead cells, mucus and viruses left behind by anyone who has recently sneezed or coughed indoors.
In addition, water vapor in the air appears to be harmful to the influenza virus.
Perhaps moist air somehow changes the acidity or salt content of the mucus in which the microbes are located, deforming their outer shell.
As a result, the virus loses the weapon that helps it attack human cells.
In dry air, viruses can remain active for several hours until someone inhales or swallows them, after which they can enter the cells of the nasopharynx.
The whole arsenal
There are several exceptions to this general rule.
Although the air in an aircraft cabin is generally fairly dry, the risk of getting the flu on board is no higher than on the ground, perhaps because the air conditioning system removes viruses from the cabin before they have a chance to spread.
Image copyright getty Image caption Can a surgical mask protect against infection? Not alwaysIn addition, while dry air appears to facilitate the spread of influenza in temperate European and North American climates, there is speculation that the virus behaves differently in the tropics.
In humid air, the survival of influenza viruses is reduced, and mold feels quite comfortable.
Will a mask protect you from the flu?
Scientists answer
In public places, we are surrounded on all sides by a suspension of secretions that enter the air when someone sneezes or coughs.
A gauze mask is a common way to prevent viral diseases. How effective is it?
Australian scientists observed families of people who went to the doctor with flu-like symptoms. Those who wore masks in the presence of a sick person were 80% less likely to become infected than those who neglected them.
But the mask is effective only in combination with regular hand washing and personal hygiene in general. Relying on a mask alone is like locking the windows but leaving the front door wide open.
One possible explanation is that in warm, humid tropical climates, the influenza virus may be more likely to settle on indoor surfaces.
So while viruses don't survive very well in moist air, they thrive on anything you can touch, making them more likely to get hand-to-mouth.
In the Northern Hemisphere, however, scientists' discovery may lead to the development of a simple technique to combat the influenza virus while it is still in the air.
Tyler Kep of the Mayo Clinic in Rochester, Minnesota, has calculated that if you run a humidifier in a school for one hour, about 30% of all airborne viruses will die.
Similar measures can be applied in other public places, such as hospital emergency rooms and transport.
“This method can prevent large outbreaks of influenza that occur every few years after the virus mutates,” says Kep. “Savings on the cost of work and school days missed due to illness, as well as the cost of treatment, would be significant.”
Now Sheiman is conducting a number of additional experiments with air humidification, however, in his opinion, not everything is so simple.
“Although influenza viruses are less likely to survive in wetter air, there are other pathogens, such as mold, that thrive in high humidity conditions. Therefore, do not overestimate the humidification of the air - it also has disadvantages,” Sheiman warns.
Scientists emphasize that vaccination and personal hygiene are still the best ways to prevent influenza.
Air humidification is just one of the additional methods of combating its spread.
But when dealing with an enemy as dangerous and pervasive as the influenza virus, it makes sense to use the full arsenal of available means.
