What does the nine-item test for respiratory pathogens include?

People breathe every moment, and the air they inhale is actually a mixed gas. In addition to oxygen, the inhaled air contains many components. Especially now that many cities have serious air pollution, the inhaled gas is likely to contain harmful substances. In particular, some pathogens may be inhaled, leading to respiratory diseases. Therefore, nine medical tests for respiratory pathogens have emerged. The detailed inspection contents are as follows.

Nine respiratory pathogen tests:

1. Legionella pneumophila

The most susceptible bacteria to humans is Legionella pneumophila serotype I. Atypical pneumonia is often accompanied by systemic symptoms, and 10% of pneumonia is caused by Legionella pneumophila serotype I. In serological diagnosis, indirect immunofluorescence is the only standard technique. Clinically, Legionella infection has two main manifestations: pneumonia and Pontiac fever. Prodromal symptoms: fatigue, headache, muscle aches all over the body, sudden fever within 1 to 2 days, which may reach above 40°C, and is mostly a prolonged fever. Symptoms of multi-system involvement can appear in the early stage of the disease, which is a prominent feature of this disease. The vast majority of patients have cough, which is dry cough at first. Half of the patients develop non-purulent viscous sputum or slightly purulent sputum, which often contains a small amount of blood, and some may cough up blood. A small number of patients experience chest pain, and dyspnea is more common. Fine moist rales may be heard in the lungs. Obvious signs of pulmonary consolidation may then appear. About 25% have gastrointestinal symptoms such as nausea, vomiting and diarrhea, and in some cases diarrhea is the only initial symptom. Neurological symptoms are more common in the extreme stage and are sometimes very prominent, including varying degrees of impaired consciousness, increased muscle tone or tremors, unstable gait, etc., and may have temporary limb flaccidity; some may have diarrhea or watery stools. Or neurological manifestations such as insomnia, dizziness, memory loss, confusion, neck stiffness, tremors, etc.

2. Mycoplasma pneumoniae

Pneumonia caused by Mycoplasma pneumoniae is most common in children and adolescents. Mycoplasma pneumoniae can lurk in the respiratory mucosal epithelium, and some patients have no obvious symptoms; but most patients have overt infections. Upper respiratory tract infections are more common in children under 3 years old, while pneumonia is the main symptom in adults. In the early stages of the disease, there are symptoms such as sore throat, headache, fever, fatigue, muscle aches, loss of appetite, nausea, and vomiting. The fever is generally moderate, and obvious respiratory symptoms appear after 2 to 3 days, with paroxysmal irritating cough, which is more severe at night, and a small amount of sticky sputum or mucopurulent sputum, sometimes with blood in the sputum. There may also be difficulty breathing and chest pain. The fever may last for 2 to 3 weeks, and cough may still occur after the body temperature returns to normal. The prominent symptom of mycoplasma pneumonia is paroxysmal irritating cough, which may be accompanied by multi-system and multi-organ damage. Skin lesions may manifest as maculopapular rash, erythema nodosum, vesicular rash, etc. Vomiting, diarrhea and liver damage may occur in the gastrointestinal system. Hemolytic anemia is a common blood system damage. Central nervous system damage may include multiple radiculitis, meningoencephalitis, and cerebellar damage. Cardiovascular system diseases occasionally include myocarditis and pericarditis.

3. Q fever Rickettsia

Systemic illness caused by Q fever rickettsiae may cause fever, atypical pneumonia, hepatitis, or endocarditis. In serological diagnosis, indirect immunofluorescence detection is the most sensitive and indicative serological diagnostic method. At the beginning, it is accompanied by chills, headache, myalgia, fatigue, and fever, which rises to 39-40℃ within 2-4 days, showing a remittent fever. Severe headache is the prominent feature of this disease, which is often seen in the forehead, behind the eye sockets and occipital region. It is often accompanied by myalgia, especially in the lumbar muscles and gastrocnemius muscles, and may also be accompanied by joint pain.

About 30% to 80% of patients have lung lesions. Dry cough and chest pain begin on the 5th to 6th day of the disease. A few people have mucus or bloody sputum. The physical signs are not obvious, and sometimes fine moist rales can be heard. Patients have symptoms such as poor appetite, nausea, vomiting, right upper abdominal pain, long-term irregular fever, fatigue, anemia, clubbing, heart murmur, and difficulty breathing.

4. Chlamydia pneumoniae

Chlamydia pneumoniae can easily cause respiratory infections, especially bronchitis and pneumonia. The incidence rate is higher among the elderly, and the pneumonia caused by it accounts for 10% of all pneumonia cases. Indirect immunofluorescence is the most sensitive and specific diagnostic method. The symptoms and signs of pneumonia caused by Chlamydia pneumoniae infection are non-specific, and most cases have a slow onset; mild cases may have no obvious symptoms. Adolescents often have symptoms of pharyngitis, laryngitis, sinusitis, otitis media and bronchitis such as hoarseness, dry cough, sometimes fever and sore throat, which can last for several weeks. Pneumonia is usually mild and is very similar to the clinical manifestations of Chlamydia pneumoniae infection, and may be accompanied by extrapulmonary manifestations such as erythema nodules, thyroiditis, encephalitis and Guillain-Barré syndrome. Pneumonia in adults is often more severe, especially in the elderly, who often need hospitalization and respiratory support treatment. The onset is insidious, usually without fever, and only mild respiratory symptoms such as runny nose, nasal congestion, and cough. The cough may persist and gradually worsen, with whooping cough-like paroxysms but no echo. Rapid breathing is a typical symptom, with occasional apnea or expiratory wheezing, and moist rales or wheezing may be heard in both lungs. Pleural effusion may occur occasionally, and conjunctivitis and abnormal appearance of the tympanic membrane may be seen in half of the patients. Peripheral blood often shows eosinophilia.

5. Adenovirus

Adenovirus is an important respiratory pathogen that can cause upper respiratory tract disease with acute fever and mild respiratory tract infection. The differences between typical adenovirus pneumonia in infants and young children and general bacterial pneumonia in the early stage are: ① Most cases have persistent high fever at the onset or shortly after the onset; ② Neurological symptoms such as drowsiness and lethargy appear from the 3rd to 6th day of the disease, and drowsiness sometimes alternates with irritability. The complexion is pale and gray, and the liver is significantly enlarged. Complications such as heart failure and convulsions are likely to occur later. The above symptoms indicate that adenovirus pneumonia not only involves the respiratory tract, but also affects other systems; ③ Pulmonary signs appear later, usually with moist rales appearing after the 3rd to 5th day of illness, the area of ​​lesions gradually increases, and there is prone to dullness to percussion and decreased breath sounds. Wheezing and shortness of breath become increasingly severe on the second day of onset; adenovirus pneumonia is most common in infants and young children aged 6 months to 2 years.

6. Respiratory syncytial virus

In the past decade, syncytial virus pneumonia and bronchiolitis have ranked first among viral pneumonia in infants and young children in the country. Respiratory syncytial virus (RSV) is the main pathogen of respiratory tract infection in children under two years old. It breaks out in winter and infants and young children have more severe symptoms, such as high fever, rhinitis, pharyngitis and laryngitis, which may later manifest as bronchiolitis and pneumonia. A small number of children may develop complications such as otitis media, pleurisy and myocarditis. In adults and older children, infection mainly presents as upper respiratory tract infection. The disease

It is more common in infants and young children, more than half of whom are infants under 1 year old. There are more boys than girls, with a ratio of about 1.5 to 2:1. The incubation period is about 4 to 5 days. Cough and nasal congestion may be seen in the early stages. About 2/3 of the cases have high fever, which can reach up to 41°C, but the fever is generally not persistent and is easily reduced by antipyretics. The high fever lasts mostly for 1 to 4 days, and a few for 5 to 8 days. About 1/3 of the children have moderate fever, which usually lasts 1 to 4 days. In most cases, the fever lasts for 4 to 10 days. Mild cases have no obvious dyspnea and neurological symptoms, while moderate and severe cases have obvious dyspnea, wheezing, cyanosis of lips, scalloped nose and three-recess sign. A few severe cases may also be complicated by heart failure. Chest auscultation usually produces fine, coarse or medium rales, and percussion usually produces no dull sounds, although a few may produce clear sounds.

7. Influenza A

The symptoms of influenza A (H1N1) are similar to those of a cold, and patients may experience fever, cough, fatigue, loss of appetite, etc. It has been reported that the main symptoms of cases found in the 2009 epidemic in the United States were sudden fever, cough, muscle pain and fatigue, and some patients also had diarrhea and vomiting symptoms; including fever, cough, sore throat, body pain, headache, fatigue, poor spirits, loss of appetite, chills and fatigue, etc. Some also experienced diarrhea or vomiting, muscle pain or fatigue, red eyes, etc.

8. Influenza B virus

It is the causative agent of influenza and can produce serious complications in patients with underlying pathology. Because it is easily confused with other respiratory diseases, clinical diagnosis is difficult during epidemic periods. Therefore, laboratory diagnosis is very important. The onset of the disease often has general flu symptoms, such as sudden onset, cough, sore throat accompanied by fever, headache, myalgia, and malaise. The symptoms continue to progress, with persistent high fever, shortness of breath, cyanosis, paroxysmal cough, and hemoptysis. The amount of sputum is often small, but may contain blood. Secondary bacterial infection often occurs within 2 weeks of onset, manifested by high fever or symptoms that are alleviated and then worsened. The sputum becomes purulent, and symptoms and signs of bacterial pneumonia appear. The pathogens are mostly Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae, etc.

9. Parainfluenza virus

Parainfluenza virus types 1, 2, and 3 can cause laryngotracheobronchitis (croup) in children 2 to 4 years of age. Type 3 is epidemic, while types 1 and 2 are local. Parainfluenza virus types 1 and 3 infection are common in young children. Local epidemics occur in nurseries, pediatric wards, primary schools, and other children's settings. Type 3 is endemic and highly contagious, occurring in all seasons and in most children within one year of age. Epidemics caused by parainfluenza virus type 1 or type 2 tend to occur every year and alternately dominate. Type 2 causes a more sporadic form of the disease. Types 1, 2, and 3 may become prevalent in autumn. Type 4 causes mild respiratory illness. In the early stages of the disease, there is moderate sore throat and dry cough, and in many cases hoarseness and croup are prominent symptoms; this croup (acute laryngotracheobronchitis) is the most serious and dangerous symptom of parainfluenza virus infection in children.