Why does the influenza virus of "afraid of" heat cause high seasons?Expert interpretation

Recently, the national influenza monitoring information released by the National Influenza Center showed that since June, some provinces in the south have entered a high incidence of influenza, and the number of influenza cases has reached a new high in recent years.

Under normal circumstances, the influenza is mostly high in winter and spring. How can we effectively prevent it? The reporter interviewed relevant experts.

Fluid is not only popular in winter and spring

Influenza, that is, the abbreviation of influenza virus, is caused by influenza virus, with strong infectious respiratory diseases. In people's general impressions, the flu virus seems to be "scared", generally only spread in winter and spring, but this year it is "activity" in summer, which makes many people feel puzzled.

In this regard, Guo Wei, deputy chief physician of the respiratory department of Tianjin Children's Hospital, said in an interview with reporters that in fact, summer flu is not available this year. In 1918, the Spanish influenza began to start from May, and at that time, it also affected Guangzhou, Shanghai, Wenzhou and other places in my country.

"The reason why there are many summer influenza in southern my country this year, mainly related to the low temperature of these places." Guo Wei analyzed that in May of previous years, the temperature in Fuzhou, Xiamen and other places could reach about 33 degrees Celsius. The temperature is only about 20 degrees Celsius, and the lowest temperature is only 13 degrees Celsius. In addition, due to the continuous rainfall in the south, the temperature also lowered. Such temperature conditions can prolong the time when influenza virus maintains contagious, and also creates a suitable environment for its large -scale communication.

Chen Chunqi, a professor at the School of Life Sciences of Hubei University, further explained in an interview with reporters that in high temperature environment, the influenza virus state is unstable and easy to lose activity, and its communication ability will decline. "Generally, the temperature exceeds 40 degrees Celsius, and the spread of influenza virus is very weak; but in a low temperature environment of 4 degrees Celsius, the flu virus may survive for up to one month," she said.

With the high incidence of summer flu, many elderly people and children, especially preschool children, have "recruited". "It is prone to influenza with low immunity, such as elderly people over 60 years old and preschool children, as well as pregnant women, patients with chronic diseases, and obese people with BMI (physical quality index) greater than 30." Guo Wei It is said that if the work pressure is high and overworked, it is also easy to be "stared" by the flu virus.

The flow of A is more likely to cause a large -scale popularity than the B flow

The main influenza is A (H3N2) subtype influenza virus. It belongs to the type A influenza (hereinafter referred to as A flow) virus, which has the characteristics of strong infectious power and fast transmission speed. "Fluids that have many large -scale outbreaks in history are related to it." Guo Wei said.

Not only is the transmission speed of A virus, but also the symptoms of their infected people are usually heavier. In addition to the general symptoms of upper respiratory tract infection (runny nose, sore throat, cough), the infected person will also have a high fever of more than 39 degrees Celsius, accompanied by discomfort such as tremor, headache and muscle pain.

In addition, the influenza virus family does not only have only A virus, and there are two types of viruses and B virus (hereinafter referred to as C) virus, but the "fame" of the latter two is not as large as the former.

"In fact, the A and B virus is similar in terms of form, structure, and biological functions, but the statistical results show that the chance of occurring in the flow of A is three times that of the B. It is very 'good change'. "Chen Chunqi explained that the flu virus is a different combination of the RNA (ribosome) virus, according to the different combinations of the hemagenin antigen (HA) and the neuropine enzyme antigen (NA) on the surface of the virus particles. The virus can be further divided into various subtypes, theoretically as many as 198. More importantly, during the replication process, the participation of RNA correction enzymes is prone to errors, and the characteristics of the segmented genome make different sub -type A virus infection at the same time. Essence

"During the replication process, the HA gene and the NA gene have caused the antigen drift after mutation. It can be infected with the host who has been immunized before, leading to the repeated influenza. One of the reasons. "Chen Chunqi introduced that due to the high frequency of mutation during the replication process, the probability of reconstruction of the virus genome or even the new virus is also high, but it is difficult for scientists to accurately predict the new Alide virus virus accurately. The accurate time appears.

In contrast, the variation speed of the B virus is relatively slow, and its variation speed is only 10%to 20%of A. Many people who have suffered from the B will produce antibody immunity. Therefore, the B virus usually has only local and small -scale transmission, which rarely causes a large range of transmission.

"The symptoms of the B flow are relatively mild. Generally, those infected with nausea, vomiting, diarrhea and other digestive tract symptoms, similar to the gastrointestinal colds often said by the people. , Rarely cause popularity, "Chen Chunqi said.

Vaccination is the most effective prevention method

Today, in order to fight against the new crown pneumonia, strict prevention and control measures have been implemented throughout the country to effectively control the spread of new crown pneumonia virus in the crowd. But in the face of the aggressive influenza, some people inevitably have such doubts: Fluid and new crown pneumonia are also respiratory infectious diseases. Why can it control the former but cannot curb the latter's popularity?

"This is more due to the different degrees of importance to influenza and new crown pneumonia. The" Prevention and Treatment of the People's Republic of China "stipulates that my country will divide the infectious diseases into category A, B, and C. High, the stricter the management measures it takes. Fluid belongs to Class C infectious diseases, and new coronary pneumonia belongs to class B infectious diseases, but now it will be managed according to class A infectious disease. "Guo Wei analyzed. Even if the influenza virus is confirmed, the public does not have to panic and anxiety. "A small number of patients need to be hospitalized because of complications, and most infected people can recover within a week." Guo Wei said that after the infection of the virus, pay attention to avoid cross -infection of family members. Life in life, do not contact other members of the family, etc.

For prevention, Guo Wei said that inoculation of influenza vaccines is the most effective prevention method, which can significantly reduce the risk of influenza and severe complications in the vaccinator. Influenza vaccines currently approved by my country have three -valent vaccine (mainly used for vaccination in June and above), three -price drug reduction vaccine (mainly used for vaccination of people 3 to 17 years old), four -valent vaccine ( Mainly used for vaccination for people over 3 years old). The three -valent flu vaccine mainly prevent H1N1, H3N2 and BV influenza; in addition to preventing the above three types of influenza, the quasal influenza vaccine can also prevent BY influenza.

Hand -shaving is one of the simplest and most important measures to prevent influenza transmission. "After contacting public items and sneezing, you should wash your hands in time. In addition, you must ventilate and maintain the environmental hygiene of the family. In the high incidence of influenza in the influenza, the flu. Guo Wei added.

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