H7N9 Avian Influenza
Introduction
Introduction to H7N9 Avian Influenza The H7N9 subtype avian influenza virus is one of influenza A. Human infection with H7N9 Avian Influenza is an acute respiratory infection caused by the H7N9 subtype avian influenza virus. H7N9 avian influenza is the first new subtype of influenza virus found in the world. At the end of March 2013, three people were found to have been infected with H7N9 avian influenza in Shanghai and Anhui. It has not been included in China's statutory reporting infectious disease surveillance reporting system. No vaccine has been introduced yet. Symptoms such as fever occur early in the infection with this virus. The H7N9 avian influenza virus is a novel reassortant virus, and its internal gene is derived from the H9N2 avian influenza virus, and the incubation period is generally within 7 days. basic knowledge The proportion of illness: 0.03% Susceptible people: no specific population Mode of infection: respiratory tract transmission, contact transmission Complications: heart failure, sinus bradycardia, sinus tachycardia
Cause
Causes of H7N9 avian influenza
Spread of the virus
The H7N9 avian influenza virus is a new type of reassortant virus. The infected people are currently found to be directly or indirectly exposed to sick or poultry or livestock.
Pathological mechanism
(1) Source of infection: It is still unclear. Based on past experience and epidemiological investigation of this case, it is speculated that it may be a bird carrying H7N9 avian influenza virus and its secretion or excrement.
(B) the route of transmission: through the respiratory tract, can also be infected by close contact with infected poultry secretions or excreta, direct contact with the virus can also be infected. There is no definitive evidence of communication between people.
(3) Susceptible population: There is no definite evidence to show that humans are susceptible to H7N9 avian influenza virus. Most of the existing confirmed cases are adults.
(4) High-risk groups: At this stage, they are mainly engaged in poultry farming, sales, slaughtering, processing, and those who have been exposed to poultry within 1 week before the onset of illness.
Prevention
H7N9 Avian Influenza Prevention
1. Strengthen physical exercise, pay attention to supplement nutrition, and ensure adequate sleep and rest to enhance resistance.
2. Minimize unnecessary contact with poultry, especially with sick and dead birds. Wash your hands frequently, keep away from the secretions of poultry, and contact with birds or bird droppings. Care should be taken to thoroughly clean your hands with disinfectant and water.
3, should try to buy quarantined poultry products in the formal sale of bird flu epidemic situation.
4, develop good personal hygiene habits, strengthen indoor air circulation, open the window 1 to 2 times a day for half an hour. Eat poultry meat to be cooked and cooked thoroughly. When eating eggs, the eggshell should be washed with running water. It should be cooked well and not eat raw or half-lived eggs. Have a good night's sleep and rest, a balanced diet, pay attention to eat more foods rich in vitamin C and other immune-enhancing foods. Exercise regularly to increase the body's resistance to the virus.
5. Schools and kindergartens should take measures to teach children not to feed wild pigeons or other birds. If you are exposed to bird or bird droppings, wash your hands thoroughly. When you are out on the road, try to avoid contact with birds. For example, don't go to the bird watching garden, farm, market or park; don't feed white pigeons or wild birds.
6. Don't underestimate the bad cold. The symptoms of avian flu are similar to other influenza diseases, such as fever, headache, cough and sore throat. In some cases, it can cause complications and lead to death. Therefore, if you have respiratory symptoms such as fever, headache, nasal congestion, cough, general malaise, etc., wear a mask, go to the hospital as soon as possible, and tell the doctor whether you have been to the bird flu epidemic area before the onset, whether it is in contact with sick birds, etc. Situation and treatment and medication under the guidance of a doctor.
Complication
H7N9 avian influenza complications Complications heart failure sinus bradycardia sinus tachycardia
Heart failure: The blood output of the heart is reduced, which is insufficient to meet the needs of the body.
Sinus bradycardia or sinus tachycardia: sinus rhythm is slower than 60 times per minute called sinus bradycardia; overspeed is the rate of heart rhythm more than 100 times per minute.
Symptom
H7N9 avian flu symptoms common symptoms high fever cough dyspnea cough cough with dyspnea muscle soreness acute respiratory distress syndrome
The incubation period of human infected H7N9 avian influenza is generally within 7 days. Patients generally present with flu-like symptoms such as fever, cough, and sputum, which can be accompanied by headache, muscle aches, and general malaise. Severe patients develop rapidly, manifested as severe pneumonia, most of the body temperature continues to be above 39, dyspnea, may be accompanied by hemoptysis; rapid progression of acute respiratory distress syndrome, mediastinal emphysema, sepsis, shock, disturbance of consciousness And acute kidney injury.
Examine
H7N9 bird flu inspection
Laboratory inspection
1, blood routine: the total number of white blood cells is generally not high or reduced. In severe cases, the total number of white blood cells and lymphocytes decreased, and platelets decreased.
2, blood biochemical examination: more creatine kinase, lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase increased, C-reactive protein increased, myoglobin can be elevated.
3. Pathogen detection:
(1) Nucleic acid detection: H7N9 avian influenza virus nucleic acid is detected by real time PCR (or RT-PCR) on a patient's respiratory specimens (such as nasopharyngeal secretions, oral sputum, tracheal aspirate or respiratory epithelial cells).
(2) Virus isolation: H7N9 avian influenza virus was isolated from patient respiratory specimens.
Chest imaging examination
A flaky image appears in the lungs of patients with pneumonia. In severe cases, the lesion progresses rapidly, and there are multiple images of the lungs and lungs in the lungs. A small amount of pleural effusion can be combined. When ARDS occurs, the lesions are widely distributed.
Diagnosis
Diagnosis and identification of H7N9 avian influenza
diagnosis
Diagnosis of human infection with H7N9 avian influenza can be made based on epidemiological exposure history, clinical manifestations, and laboratory findings. In the case of an epidemiological history, according to the clinical manifestations, auxiliary examinations and laboratory test results, especially the H7N9 avian influenza virus isolated from the patient's respiratory secretion samples, or the H7N9 avian influenza virus nucleic acid test positive, can be diagnosed.
1. History of epidemiology: There is a history of contact with poultry, its secretions, and excreta within 1 week before onset.
2. Diagnostic criteria:
(1) Suspected cases: in line with the above clinical symptoms and blood routine, biochemical and chest imaging features, influenza A virus universal primers positive and exclude seasonal influenza, may have epidemiological exposure history.
(2) confirmed cases: in accordance with the diagnostic criteria for suspected cases, and the H7N9 avian influenza virus or H7N9 avian influenza virus nucleic acid test positive in the respiratory secretion samples.
Severe cases: pneumonia with respiratory failure or other organ failure are severe cases.
Differential diagnosis
Should pay attention to human infection with highly pathogenic H5N1 avian influenza, seasonal influenza (including influenza A (H1N1)), bacterial pneumonia, SARS, new coronavirus pneumonia, adenovirus pneumonia, chlamydia pneumonia, mycoplasma Differential diagnosis of diseases such as pneumonia. Differential diagnosis relies mainly on pathogenic examination.
