What you should know about the flu virus

It is the season of transition from winter to spring, which is the peak season for various respiratory infectious diseases such as influenza and respiratory syncytial virus. Recently, the positive rate of influenza virus detection in southern and northern provinces has continued to rise. Therefore, when going out in crowded places, you must wear a mask and take personal protection. However, what kind of protection is correct?

1. Things you should know about influenza virus:

Influenza, or flu for short, is an acute respiratory infectious disease caused by influenza viruses; influenza viruses can also be divided into three types: A, B, and C. Among them, influenza A viruses often cause pandemics with more severe symptoms; influenza B and C are relatively milder. There is no obvious seasonality in influenza pandemics, and sporadic outbreaks are more common in spring and winter.

The influenza virus is mainly spread through droplets such as sneezing and coughing, and through direct or indirect contact with mucous membranes such as the mouth, nose, and eyes. Contact with objects contaminated by the virus can also be transmitted through the above routes. In certain places, such as crowded, closed or poorly ventilated rooms, it may also be transmitted in the form of aerosols, so be vigilant.

2. How to distinguish influenza from the common cold?

The symptoms of influenza are very similar to those of the common cold. Many people often mistake influenza for the common cold, or even mistakenly believe that the common cold and influenza are the same disease, which leads to incorrect treatment methods and worsens the condition.

Below I will use this table to briefly introduce the differences between influenza and the common cold so that you can distinguish them in the future.

3. The main clinical symptoms of influenza:

Flu is mainly manifested by fever, headache, myalgia and general malaise. The body temperature can reach 39-40℃, and there may be chills and shivering. It is often accompanied by systemic symptoms such as muscle and joint pain, fatigue, and loss of appetite. There is often sore throat and dry cough. There may be nasal congestion, runny nose, discomfort behind the sternum, facial flushing, conjunctival congestion, etc. Some patients have mild symptoms or no symptoms.

Children usually have a higher fever than adults, and digestive tract symptoms such as nausea, vomiting, and diarrhea are more common in children with influenza B than in adults. Newborns may only show symptoms such as lethargy, refusal to feed, and respiratory arrest.

In patients without complications, the course of the disease is self-limited. The fever gradually subsides and systemic symptoms improve within 3 to 5 days after onset, but coughing and physical recovery often take a long time. [1]

4. High-risk groups for severe cases:

The following groups of people are more likely to develop severe cases after being infected with the influenza virus and should be given high attention, undergo influenza virus nucleic acid testing and other necessary examinations as soon as possible, and be given antiviral drug treatment.

(1) Children under 5 years old (children under 2 years old are more likely to develop serious complications);

(2) Elderly people aged ≥65 years;

(3) Those with the following diseases or conditions: chronic respiratory diseases, cardiovascular diseases (except hypertension), kidney disease, liver disease, blood system diseases, nervous system and neuromuscular diseases, metabolic and endocrine system diseases, malignant tumors, immunosuppression, and those under 19 years of age who take aspirin for a long time;

(4) Obese people [Body Mass Index (BMI)>30];

(5) Pregnant and perinatal women.

5. How to prevent influenza virus:

Co-infection with influenza and COVID-19 can cause COVID-19 patients to have a more intense inflammatory response, a more severe illness, a longer course of illness, and an increased mortality rate. Therefore, influenza prevention is of great practical significance. [2]

To prevent influenza, you must wash your hands frequently, drink plenty of water, eat more vegetables, enhance immunity, pay attention to the combination of work and rest, strengthen indoor ventilation and environmental disinfection, and wearing a mask can prevent some diseases. Vaccination is a basic measure to prevent influenza.

Many viruses in nature attach to particles and are inhaled by the human body, causing respiratory infections. Therefore, wearing a mask when going out can prevent respiratory infections. Wearing a mask during illness can not only isolate bacteria in time and prevent your body from suffering secondary damage, but also protect the respiratory tract from being invaded by pathogens. It can also keep you warm and prevent the nose and throat from being invaded by cold air. The nasal defense function will not be reduced, and it is not easy to cause cross infection. [3]

6. Treatment measures for influenza:

(1) Isolation: Isolate suspected and confirmed patients;

(2) General treatment: Patients should rest in bed and drink plenty of water. Those with high fever and poisoning symptoms should be given oxygen and fluid supplements.

(3) Symptomatic treatment: antipyretics, drugs to relieve nasal congestion, cough suppressants and expectorants, etc.

(4) Antiviral treatment: Use within 48 hours of onset. Neuraminidase inhibitors (oseltamivir, zanamivir) can inhibit influenza virus replication, reduce pathogenicity, alleviate symptoms, and reduce complications.

In short , during the spring and winter when influenza is prevalent, we should try to avoid going to crowded places. When we really have to go out, we must also take personal protection, wash our hands frequently, and wear masks to better protect our health.

The picture is from the Internet. Please contact us to delete it if there is any infringement.

Author: Hong Qiaoyun, Yang Jie, Dai Zhaori, Su Longteng, School of Basic Medical Sciences, Putian University

Instructor: Zhao Chengfei

References:

[1] Diagnosis and treatment plan for influenza (2020 edition)[J]. Chinese Journal of Viral Diseases, 2021, 11(01): 1-5. DOI: 10.16505/j.2095-0136.2020.0085.

[2] Chen Chen, Liu Guoen, Zeng Guang. Current status, problems and challenges of influenza disease burden in China and its response strategies[J]. Chinese Journal of Public Health, 2022, 38(11): 1494-1498.

[3] Wearing a mask correctly can effectively isolate the virus[J]. Rural Science and Technology, 2010(01):41.