H7N9 avian influenza

Gene origin

In early April 2013, the Key Laboratory of Pathogen Microbiology and Immunology of the Chinese Academy of Sciences conducted a genetic origin study of the H7N9 avian influenza virus, showing that the H7N9 avian influenza virus gene comes from the gene reassortment of wild birds in East Asia and chicken flocks in Shanghai, Zhejiang, and Jiangsu, China. The genetic variation of the virus itself may be the reason why the H7N9 avian influenza virus can infect humans and lead to a high mortality rate.

The preliminary results of the study show that the H7N9 avian influenza virus has not been found to have evolutionary traces in pig populations, suggesting that pigs did not play the role of an intermediate host in this virus gene reassortment.

Researchers said that the reassortment study results of the virus fragments in this laboratory showed that among the 8 gene fragments of the H7N9 avian influenza virus, the H7 fragment is similar to the avian influenza virus isolated from the duck flocks in Zhejiang, and the virus in the Zhejiang duck flocks can be traced back to the avian influenza virus genes isolated from wild birds in East Asia; the N9 fragment is similar to the avian influenza virus isolated from wild birds in East Asia. The other 6 gene fragments are similar to the H9N2 avian influenza virus. According to virus genome comparison and phylogenetic analysis, the H9N2 avian influenza virus originates from chicken flocks in Shanghai, Zhejiang, Jiangsu, and other places in China.

The likely site of gene reassortment is in the Yangtze River Delta region of China, and the process may be that wild birds (carrying the virus) migrating across the Eurasian continent (via East Asian regions such as South Korea) and the duck and chicken flocks in the Yangtze River Delta region of China undergo gene reassortment with avian influenza viruses carried by the flocks. [5]

Gene sequence

Scientists say that the gene sequence data of a deadly avian influenza virus that has never been found in humans shows that this virus has undergone certain mutations that may make it more likely to spread in humans.

On April 3, 2013, there was no evidence to show that the H7N9 avian influenza virus was spreading among humans, and there were also the following possibilities: this virus may gradually disappear, and it may not mutate completely into a human influenza. Just days after China announced that it had confirmed multiple cases of H7N9 avian influenza, flu experts from various laboratories around the world began to study the DNA sequence data of the samples isolated from patients to assess the possibility of a pandemic.

One of the world's top flu experts, Abu Osterhaus from the Erasmus Medical Center in the Netherlands, said that the sequence shows that certain mutations have occurred that are enough to put the government on alert and strengthen monitoring of animals and the population.

        The symptoms of the H7N9 subtype generally manifest as influenza-like symptoms, such as fever, cough, little phlegm, and may be accompanied by headache, muscle ache, and general malaise.

        Severe patients have a rapid progression of illness, manifested as severe pneumonia, with body temperature usually above 39℃, accompanied by difficulty breathing, coughing up bloodstained sputum; it can rapidly progress to acute respiratory distress syndrome, mediastinal emphysema, sepsis, shock, altered consciousness, and acute kidney injury, and other complications.

        These complications often become fatal factors and are the difficult problems that doctors have been trying to conquer.

The treatment plan points out that the incubation period of H7N9 avian influenza in humans is generally within 7 days. Patients usually present with influenza-like symptoms, such as fever, cough, little sputum, and may be accompanied by headache, muscle pain, and general malaise. Severe patients have a rapid progression of the disease, manifested as severe pneumonia, with body temperature usually above 39 degrees, difficulty breathing, and may be accompanied by hemoptysis; it can rapidly progress to acute respiratory distress syndrome, mediastinal emphysema, sepsis, shock, altered consciousness, and acute kidney injury, etc.

1. Strengthen physical exercise, pay attention to nutritional supplementation, ensure adequate sleep and rest to enhance resistance.

2. Try to minimize unnecessary contact with poultry, especially with sick or dead poultry. Wash hands frequently, stay away from the secretions of poultry, and when contacting birds or bird droppings, pay attention to thoroughly cleaning hands with disinfectant and clean water.

3. Try to buy quarantined poultry products from regular sales places.

4. Develop good personal hygiene habits, strengthen indoor air circulation, and open the windows for ventilation for half an hour 1 to 2 times a day. Cook poultry thoroughly before eating.

Preventive measures

Preventive measures

When boiling eggs, the eggshell should be washed with running water, and they should be cooked and heated thoroughly. Do not eat raw or semi-cooked eggs. Have enough sleep and rest, a balanced diet, and pay attention to eating more foods rich in vitamin C and other immune-enhancing nutrients. Regularly exercise to increase the body's resistance to viruses.

5. Schools and kindergartens should take measures to teach children not to feed wild pigeons or other birds. After contacting birds or bird droppings, wash hands thoroughly immediately. When traveling, try to avoid contact with birds, such as not going to bird watching gardens, farms, markets, or parks; do not feed pigeons or wild birds.

6. Do not underestimate the serious cold, the symptoms of avian influenza are similar to those of other epidemic colds, such as fever, headache, cough, and throat pain. In some cases, it may cause complications leading to death of the patient. Therefore, when respiratory symptoms such as fever, headache, nasal congestion, cough, and general malaise occur, wear a mask and go to the hospital as soon as possible. Be sure to tell the doctor whether you have been to an avian influenza epidemic area before getting sick and whether you have had contact with sick or dead poultry, and follow the doctor's guidance for treatment and medication. [33]

7. Regularly disinfect the environment, eliminate the transmission of air or environment, and the disinfection methods are as follows: (1) Fumigation method: Take the original liquid of the disinfectant and place it in plastic containers in the room or office, one place per 15 square meters. Maintain air circulation when there are people staying or working. When there is no one, it is better to close and place it for half an hour or more for better effect. (2) Washing method: Dilute the disinfectant and it can be used to wash floors, nests of pets or poultry, wipe the places where pets or poultry stay, or rinse plastic tableware. (3) Spraying method: Dilute the disinfectant with water and spray it on the places that need to be disinfected using a plastic spray bottle. [34]

Food prevention

It should be noted that since some food prevention can only increase the success rate of disease prevention by increasing the body's nutritional components, and cannot effectively prevent a specific disease, the following so-called food prevention has not been proven by clinical experiments and has a subjective guess. People with allergic constitution should consider carefully.

1. Garlic: Garlic has the effects of antibacterial and anti-inflammatory, can protect the liver, regulate blood sugar, protect the cardiovascular system, anti-hyperlipidemia and atherosclerosis, and anti-platelet aggregation. Nutrition experts have found that garlic extract has anti-tumor effects, and it is recommended to eat 3-5 grams of raw garlic daily.

2. Aloe vera: Aloe vera, like lily, garlic, onion, and wild lily, belongs to the lily family of perennial herbaceous plants, mainly growing in dry and hot areas, with a strong vitality. It can clear heat and detoxify, relieve constipation, anti-inflammatory and antibacterial, enhance immunity, and can also protect the stomach, liver, and skin beauty.

3. Mushroom: It improves the body's immune function, and the polysaccharides in mushrooms can improve the phagocytic function of peritoneal macrophages, and also promote the production of T lymphocytes, and improve the killing activity of T lymphocytes;

4. Tomato: It is rich in vitamins, minerals, carbohydrates, organic acids, and a small amount of protein. It promotes digestion, diuresis, and inhibits various bacteria. At the same time, research shows that tomatoes contain carotenoids that can produce vitamin A, mainly alpha-carotene and beta-carotene. A period of drinking tomato juice can significantly increase the lycopene in the body, and at the same time, the immune function of T lymphocytes is enhanced.

5. Fresh radish: It has immune effects due to its rich interferon inducer.

6. Fresh royal jelly: It contains royal jelly acid and antibacterial active substances, which have strong bactericidal and antibacterial effects, effectively improving and enhancing the human immune function.

Through the above introduction, I hope you have a certain understanding of this new type of virus. Try to eat less meat and more vegetables during this period to enhance your resistance.

In the 'Spring and Summer Nourishing Yang' period, avoid cold and cool foods that may damage Yang.

Diet should be light: From the thick and greasy foods of winter, it should transition to the light and warm vegetables of the season. For example: spinach, garlic sprouts, scallions, and small rapeseed.

Eating should be sweet rather than sour: In spring, it is advisable to eat sweet foods to strengthen the spleen and stomach and warm up the Yang; the liver is responsible for ascending, and it corresponds to spring. Sour enters the liver, so it is recommended to eat less sour foods to prevent the excessive rise of Yang and to nourish the liver, thus improving the body's resistance to disease.

Take honeysuckle, forsythia, and Platycodon grandiflorus in decoction to prevent infection. Natural drinks made from pure plants such as 1/2 honeysuckle plant drinks sold in large supermarkets can replace the drinks we usually drink.

Habitual prevention

Keep your hands clean and wash them properly.

Avoid touching your eyes, nose, and mouth with your hands.

Cover your mouth and nose when sneezing or coughing.

Do not spit on the ground. If you need to spit, wrap the sputum and dispose of it in a covered trash can.

When you have symptoms of respiratory infection or a fever, you should wear a mask and seek medical attention as soon as possible.

Herbal medicine prevention

1. Prevention formula for the general population

Herba Lysimachiae 9g, Notopterygium 10g, Isatis 15g, Licorice 3g

Dosage and administration: Take 1 dose per day, decocted in water, taken twice, for 3 days in a row.

2. Prevention formula for the elderly or physically weak people

Astragalus 10g, Forsythia 10g, Atractylodes 6g, Notopterygium 10g, Isatis 15g, Licorice 3g

Dosage and administration: Take 1 dose per day, decocted in water, taken twice, for 3 days in a row.

According to the website of the National Center for Disease Control and Prevention, frequent hand washing, indoor ventilation and air exchange, attention to nutrition, and maintaining good physical fitness are conducive to preventing respiratory tract infections such as influenza. When symptoms of respiratory infection such as sneezing and coughing occur, use tissues or handkerchiefs to cover the mouth and nose to prevent infection of others. In addition, it is especially important to avoid direct contact with dead poultry and livestock as much as possible.

The World Health Organization issued a notice in Geneva on the 4th that there is still no available vaccine for H7N9 avian influenza, and it is recommended that people maintain basic personal hygiene. At the same time, the organization does not recommend special inspections at entry points for H7N9 avian influenza, nor does it recommend restricting tourism and trade due to H7N9 avian influenza.

       Laboratory examination

       1. Blood routine. The total white blood cell count is generally not high or low. In severe patients, there is a decrease in the total white blood cell count and lymphocytes, and a decrease in platelets.

       2. Blood biochemistry. There is an increase in creatine kinase, lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, C-reactive protein, and myoglobin may increase.

       3. Pathogen detection.

        (1) Nucleic acid testing. Detect the nucleic acid of the H7N9 avian influenza virus in respiratory specimens of patients (such as nasopharyngeal secretions, oral mouthwashes, tracheal aspirates, or respiratory epithelial cells) using real-time PCR (or RT-PCR).

        (2) Virus isolation. Isolate the H7N9 avian influenza virus from respiratory specimens of patients. Chest imaging in patients with pneumonia shows patchy shadows in the lungs. In severe patients, the lesions progress rapidly, showing multiple ground-glass shadows and lung consolidation shadows in both lungs, and a small amount of pleural effusion may occur. When ARDS occurs, the lesions are widely distributed.

The H7 virus of influenza A is usually a group of influenza viruses that spread among birds. The influenza A virus (H7N9) belongs to a subgroup under the H7 virus category, although there have been reports of certain H7 viruses (H7N2, H7N3, H7N7) infecting humans occasionally, there were no reports of human infection with H7N9 virus in the past, until recently human infection cases were reported.

The H7N9 avian influenza virus is generally sensitive to heat and has strong resistance to low temperatures. It can be inactivated by heating at 65℃ for 30 minutes or boiling (at 100℃) for more than 2 minutes. The H7N9 avian influenza virus can survive in feces at low temperatures for 1 week and in water at 4℃ for 1 month. In addition to transmission through the respiratory tract, it can also be infected through close contact with secretions or excreta of infected poultry, or by direct contact with the virus. Although the source of infection and the mode of transmission have not yet been determined, the following measures are effective in preventing infection:

1. Do not touch or eat sick (dead) poultry and livestock meat, do not buy fresh, live, frozen poultry and livestock and their products without quarantine certificates.

2. Poultry, livestock meat, and eggs must be cooked and boiled thoroughly.

3. In the process of food processing and consumption, it is necessary to separate raw and cooked foods to avoid cross-contamination, and the chopping boards, knives, and containers used for raw poultry and livestock meat cannot be used for cooked food;

4. Maintain good personal hygiene habits, do not drink unboiled water.

Do not eat or eat less sliced chicken

Poultry meat cooked and boiled thoroughly usually will not lead to the spread of H7N9 avian influenza virus. However, if the sick poultry is not cooked and boiled thoroughly before eating, the H7N9 avian influenza virus is likely to enter the human body. The processing method of sliced chicken may not be fully cooked, so if this chicken is infected with avian influenza virus before it dies, the virus may not be completely killed during the cooking process, and may enter the human body. However, whether it can enter various tissues of the human body through the digestive tract, and how the virus operates in the human body, these mechanisms are not yet clear. In this case, it is best to eat cooked and thoroughly boiled food, and eat less or no sliced chicken.

Chicken essence and chicken powder can be safely consumed

The H7N9 avian influenza virus is not very resistant to the external environment, and can be inactivated by heating at 56℃ for 30 minutes, 60℃ for 10 minutes, 70℃ for several minutes, direct sunlight for 40-48 hours, and commonly used disinfectants. Chicken powder, chicken essence, and other chicken-related products are made from chicken as raw material, and go through special processes, generally speaking, high temperature is an indispensable process. Chicken powder, chicken essence, and other chicken-related products from regular manufacturers (with health permits) are safe. High-risk groups should consume more vitamin C, and high-risk groups for H7N9 avian influenza include breeders, slaughterhouse workers, and others who are in close contact with live poultry, as well as the elderly, children, and patients with chronic diseases with poor resistance, especially children under 12 years old. Breeders and slaughterhouse workers should wear protective clothing and protective equipment at the workplace, and thoroughly disinfect before and after work; the elderly, children, and patients with chronic diseases should avoid going to markets and other places with a lot of live poultry, and pay attention to consuming more foods and drugs rich in vitamin C and other immunity-enhancing substances, and perform moderate physical exercise to increase the body's resistance to the virus.

How to prevent H7N9 avian influenza in daily life

1. Food hygiene: Poultry meat and eggs should be cooked thoroughly, and when processing and storing food, pay attention to separate raw and cooked foods, do not eat raw meat and offal of sick or dead poultry and livestock, and the egg whites and yolks should become firm before eating when boiling eggs;

2. Isolation of infectious sources: Avoid contact with chickens and feces, do not use the mouth and nose to approach the tail of chickens. When contact is unavoidable, wear masks and gloves, and thoroughly wash hands with clean liquid or soap after handling live or frozen chickens; thoroughly wash hands after dissecting live (dead) poultry, livestock, and their products. When contacting patients with avian influenza, wear masks, gloves, and isolation gowns, and wash hands after contact;

3. Develop good living habits and a healthy lifestyle: Maintain personal hygiene such as frequent hand washing, covering the mouth and nose when coughing and sneezing, and strengthen physical exercise regularly, avoiding overexertion;

4. Keep the indoor air fresh, clean, and well-ventilated: Open the windows for at least 10 minutes twice a day for air exchange, or use exhaust fans to maintain air circulation, and try to avoid places with poor air circulation;

5. Pay attention to the disinfection of daily items: Avian influenza virus is not heat-resistant and can be inactivated in 1 minute at 100℃, and it is sensitive to common disinfectants such as dryness, ultraviolet radiation, mercury, and chlorine;

6. Seek medical attention immediately: If you have symptoms such as fever, cough, runny nose, general malaise, high fever, body aches, fatigue, joint pain, nasal congestion, and exposure to dead birds or returning from an avian influenza outbreak area, seek medical attention at a regular medical institution immediately and inform the doctor of your contact with birds and travel history.

        H7N9 avian influenza is a new subtype of influenza virus discovered for the first time globally, which has not been included in the national legal reporting infectious disease monitoring and reporting system, and as of early April 2013, no vaccine has been launched.

        Herbal medicine prevention

        1. Prevention formula for the general population: Huoxiang 9g, Guanzhong 10g, Daqingye 15g, Gancao 3g. Dosage and administration: Take one dose per day, decocted in water for oral administration, divided into two doses, taken for 3 consecutive days.

        2. Prevention formula for the elderly or physically weak people: Astragalus 10g, Fangfeng 10g, Baizhu 6g, Guanzhong 10g, Daqingye 15g, Gancao 3g. Dosage and administration: Take one dose per day, decocted in water for oral administration, divided into two doses, taken for 3 consecutive days.

        According to the introduction on the website of the National Center for Disease Control and Prevention, frequent hand washing, ventilation and air exchange in indoor areas, attention to nutrition, and maintaining good physical condition are conducive to the prevention of influenza and other respiratory infectious diseases. When symptoms of respiratory infection such as sneezing and coughing occur, cover the mouth and nose with tissues or handkerchiefs to prevent infection of others. In addition, it is especially important to avoid direct contact with dead birds and animals as much as possible.