How can one determine if a child has contracted influenza A?

To determine whether a child has contracted influenza A, one can rely on typical symptoms, nasal pharyngeal swab testing, serological examination, and routine blood tests. If any abnormalities are detected, prompt medical attention is recommended. Detailed analysis is as follows:

1. Typical Symptoms

If a child suddenly develops a high fever, with body temperature rapidly rising to above 39°C, even exceeding 40°C, accompanied by flu-like symptoms such as muscle pain, fatigue, headache, cough, and sore throat, influenza A should be highly suspected. Influenza A typically has a sudden onset with prominent systemic symptoms, distinguishing it from the common cold.

2. Nasal Pharyngeal Swab Testing

This is a commonly used method for confirming influenza A. A healthcare provider collects a nasal pharyngeal swab specimen from the child and uses polymerase chain reaction (PCR) technology to detect the nucleic acid of the influenza A virus. This method offers high sensitivity and strong specificity, enabling rapid and accurate diagnosis of influenza A.

3. Serological Examination

Serological testing primarily detects influenza A virus-specific antibodies in the child's serum. After infection with the influenza A virus, the body produces corresponding antibodies. By measuring changes in antibody titers between acute-phase and convalescent-phase serum samples, influenza A can be diagnosed. However, since antibody production takes time, results may be negative during the early stages of infection.

4. Routine Blood Test

A routine blood test can provide supportive information. After infection with the influenza A virus, a child's total white blood cell count may remain normal or decrease, while the proportion of lymphocytes may increase. These changes in blood parameters can help physicians initially assess the possibility of a viral infection.

5. Imaging Studies

Imaging studies are not specific for diagnosing influenza A but can be helpful in assessing disease severity in certain situations. For example, when influenza A is complicated by pneumonia, imaging studies may reveal inflammatory changes in the lungs, providing reference information for developing a treatment plan.

During flu season, parents should take preventive measures to protect their children, such as vaccination, frequent handwashing, and avoiding crowded places, to prevent the occurrence of influenza A.