Influenza, referred to as influenza, is an acute respiratory infectious disease caused by influenza virus. It often spreads in winter and spring and is spread by air droplets. Influenza is different from the general cold in that it has the following characteristics:
1. Influenza has a specific pathogen – influenza virus. Influenza virus has complex antigenicity and is divided into three types based on its core protein antigenicity: A, B, and C. According to its surface antigen hemagglutinin (H) and neuraminidase (N), the same type of virus is further divided into several subtypes, with no cross immunity between each type. Due to the lack of cross immunity between different types of viruses, they can be infected multiple times and develop recurrent diseases.
2. The hemagglutinin and neuraminidase of influenza A and B viruses are particularly prone to mutations. The mutations of type A virus can be divided into three types: large group mutations (both N and H undergo large mutations), occurring approximately every 30-40 years; Subtype variation (N undergoes major variation, H remains unchanged or only minor variation), occurring approximately once every 10 years; The variation of variants (plants) (both N and H have small variations) often occurs. The hepatitis B virus only has variants. According to the size of antigen variation, the original immunity of * may be completely or partially ineffective against the mutated new virus. Virus mutations lead to repeated outbreaks and pandemics of influenza. Variations often cause minor epidemics, subtype variations lead to pandemics, and large group variations lead to larger epidemics (such as global epidemics). Since 1918, the Type A virus has undergone five major mutations, including Type A 0, Type A 1, Type A 2, Type A 3, and Type A 1. Since the 1950s, there have been three global pandemics, and there have been countless other epidemics of varying scales. Since the beginning of winter this year, the influenza that has been prevalent in some areas of China is type A. According to relevant reports, although multiple strains of influenza virus have been isolated, type A3 is the main subtype. The medical community recognizes that this subtype causes a more severe influenza condition and a longer course of illness.
3. The influenza A virus is widely distributed in mammals and birds, and some share common antigen components with human influenza viruses. Research in our country has shown that influenza viruses A, B, and C can all naturally infect pigs, and it is believed that pigs may be long-term hosts of influenza A or intermediate hosts for virus recombination between humans and ducks. It is precisely because of the presence of animal protected hosts that it poses great difficulties in controlling and ultimately eliminating influenza.
4. Influenza virus is highly contagious and has a short incubation period, mostly between 18 and 72 hours, and some even only a few hours, transmitted through the respiratory tract. Therefore, it often occurs suddenly and spreads rapidly. The epidemic caused by the new subtype of the A virus often forms a clear peak, with a short epidemic period, but there will be a second and third wave after the first wave; It often spreads along transportation lines, first collective and then scattered, first urban and then rural. This year’s flu (mainly caused by the H1N1 influenza virus) has been fierce, widespread, and long-lasting.
5. The clinical characteristics of influenza are severe systemic poisoning symptoms, characterized by sudden onset of high fever, chills, significant fatigue, headache, and systemic soreness, but mild respiratory symptoms. Pneumonia type influenza is more common in elderly people, infants and young children, and those with other serious chronic diseases. It is characterized by worsening of the condition 1-2 days after onset, persistent high fever, severe cough, shortness of breath, cyanosis, hemoptysis, and sputum. In a few severe cases, death may occur due to cardiovascular dysfunction and pulmonary edema. Although influenza is not a serious illness, it has many complications and can lead to acute exacerbation or exacerbation of the patient’s existing chronic disease. According to statistics, influenza can cause up to 1% -3% of patients to die during the pandemic due to these reasons.
The key to controlling this disease is to do a good job of prevention and take preventive measures. Practical and feasible measures for influenza prevention and control include:
1. Strengthen epidemic detection, timely understand the dynamics of the epidemic, detect patients early, take preventive measures in a timely manner, and prevent the spread of the epidemic. More than 100 laboratories have formed a global influenza monitoring network, closely monitoring the dynamics of influenza. The influenza collaboration center of the World Health Organization regularly monitors influenza outbreaks and virus mutations around the world, and publishes recommendations for the antigen composition of influenza vaccines for the next year in the weekly epidemic report in February each year. When testing vaccines in our country, the primary requirement is that their strain composition must be consistent with the recommendations of the World Health Organization at that time and match the strains that are expected to cause epidemics in our country.
2. During the influenza epidemic, gatherings will be suspended, family and friends will not be visited, and activities will not be conducted in crowded areas. Masks will be worn when going out. Strengthen ventilation in public places and spray bleach solution for disinfection. Many collective units use vinegar fumigation to prevent influenza, and in some places, traditional Chinese medicine is used for prevention, such as oral administration of Banlangen, Chaihu, Daqingye mixture, and other newly developed traditional Chinese medicine preparations, which are believed to have certain effects. Some may also have preventive effects by eating garlic or drinking ginger soup.
3. Whether the influenza virus invades the body and causes disease is mainly related to the body’s immune function. Malnutrition and overwork reduce the body’s resistance, making it particularly susceptible to various pathogens (including influenza viruses). Therefore, it is important to maintain a balanced diet and avoid overwork, which is the fundamental measure for preventing influenza.
4. The best way to prevent influenza is vaccination. At present, China uses live attenuated influenza vaccine, which is safe and reliable. The target of vaccination is healthy adults and children, and the method is nasal spray; Subcutaneous injection of inactivated vaccines is recommended for the elderly, infants, and those with severe chronic diseases. It should be noted that immune protection only occurs about 2 weeks after receiving the influenza vaccine, and the effective time can only last for 1 year. Therefore, it is necessary to receive the vaccine in a timely manner every year before the peak period of influenza.
5. The mutation phenomenon of influenza virus, especially the type A virus, which poses the greatest threat to human beings, is an objective law and does not transfer according to human will. As long as the influenza virus exists, this mutation phenomenon will not disappear and can invade humans at any time. Therefore, preventing and controlling influenza is a long-term task, and it is necessary to prevent it year by year and fight a protracted war.