November 1, 2023 is the sixth World Influenza Day. With the coming of autumn and winter, the weather is getting colder and colder, which is the high season of respiratory infectious diseases, and influenza (hereinafter referred to as "flu") is one of the most common respiratory infectious diseases.
What is the flu?
Influenza is an acute respiratory infection caused by influenza virus, which is a highly contagious and fast-spreading disease and belongs to Class C infectious disease.
Influenza viruses are divided into four types: A, B, C and D.
Typical clinical symptoms: sudden onset of high fever, the body temperature can reach 39 ~ 40℃, chills, accompanied by headache, aching muscles and joints, extreme fatigue, loss of appetite and other systemic symptoms, often with sore throat, dry cough, nasal congestion, runny nose and other symptoms.
source of infection
Influenza patients and recessive infected people are the main sources of infection.
Patients are contagious 1-7 days after onset, and the most contagious is 2-3 days after onset.
Transmission route
Influenza is mainly spread by droplets such as sneezing and coughing. Influenza virus lives in the air for about half an hour, and can be infected by direct or indirect contact with mucous membranes such as mouth, nose and eyes, or by contact with articles contaminated by virus.
In crowded, closed and poorly ventilated places, influenza may also spread in the form of aerosol.
susceptible population
People are generally susceptible to influenza.
Some people are easy to develop into severe cases after being infected with the virus, so we should pay attention to:
Children under 5 years old (children under 2 years old are more likely to have serious complications);
Old people over 65 years old;
Accompanied by the following diseases or conditions: chronic respiratory diseases, cardiovascular diseases (except hypertension), nephropathy, liver diseases, blood system diseases, nervous system and neuromuscular diseases, metabolic and endocrine system diseases, malignant tumors, immunosuppression, etc.
Obese (BMI > 30);
Pregnant and perinatal women.
Minhang CDC reminds you
The most effective way to prevent influenza is to get flu vaccine. The World Health Organization recommends annual influenza vaccination. In addition to vaccination, the following protective measures should be taken:
one
Wash your hands frequently;
2
Develop good hygiene habits and cover your mouth and nose when coughing or sneezing;
three
Isolate yourself as soon as possible when you feel unwell, have a fever and other flu symptoms;
four
Avoid close contact with influenza patients;
five
Avoid touching the eyes, nose, mouth and other parts where viruses are easy to invade.
Schools, nurseries and nurseries
How to prevent the clustering epidemic of influenza-like cases
one
Strengthen daily morning check-up and health patrol to observe whether students have the following symptoms:
Fever, rash or herpes (skin, oral mucosa), swelling and pain of parotid gland, respiratory symptoms (runny nose, cough, sore throat), gastrointestinal symptoms (vomiting, diarrhea, abdominal pain), etc. If so, promptly advise.
2
Do a good job in daily preventive disinfection:
Classroom, activity room and dining place should be ventilated for at least 30 minutes every day;
Regular preventive disinfection shall be carried out for items that are frequently contacted, such as doorknobs, faucets and toys, once a day (for child care) and 2-5 times a week (for primary and secondary schools);
Towels should be one towel per person and disinfected once; Bedding should be one set, cleaned at least once or twice a month, and exposed to sunlight once every two weeks;
Clean and disinfect the air conditioner regularly, and clean the filter screen and filter in time.
three
health education
The health care teacher or class teacher can issue a notice to parents, suggesting that parents should pay attention to their children’s health status in time, and seek medical treatment in time if they have respiratory symptoms such as fever, cough and sore throat, and report to the school.
Promote the knowledge of disease prevention through school bulletin boards, broadcasts, distribution of leaflets, and opening health classroom lectures, so as to enhance students’ and parents’ awareness and ability to prevent respiratory infectious diseases such as influenza.
Global profile
Globally, it is estimated that influenza causes about 3 million to 5 million serious cases and about 290,000 to 650,000 deaths related to respiratory diseases every year. In developed countries, most influenza-related deaths occur in people aged 65 and over. Studies have shown that 99% of children under the age of 5 who died of lower respiratory tract infection caused by influenza came from developing countries.
General situation of China
Influenza-like case report
In the 42nd week of 2023 (October 16, 2023-October 22, 2023), the percentage of influenza-like cases (ILI%) reported by sentinel hospitals in southern provinces was 5.4%, which was higher than the previous week’s level (4.7%) and higher than the same period in 2020-2022 (3.1%, 3.0% and 3.0%).
Percentage of influenza-like cases reported by sentinel hospitals in southern provinces in 2020 -2023
Note: influenza-like illness, ILI), that is, fever (body temperature greater than or equal to 38℃) accompanied by cough or sore throat (data from national sentinel hospitals).
Pathogenic monitoring
According to the monitoring data of National Influenza Center, in the 42nd week of 2023, 744 influenza virus positive samples were detected in southern provinces, of which 627 were A(H3N2), 109 were B(Victoria) and 8 were A(H1N1)pdm09, suggesting that influenza virus subtype A(H3N2) was the main epidemic strain and subtype B(Victoria) was co-prevalent.
Detection results of influenza-like cases (ILI) in southern provinces
Original title: "The flu season is coming! The CDC reminds: The most effective prevention methods and protective measures are … "
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