There are four types of influenza viruses: A, B, C, and D. Influenza A and B viruses cause seasonal epidemics of disease in people (known as flu season) almost every winter in the United States. Influenza A viruses are the only influenza viruses known to cause flu pandemics (i.e., global epidemics of flu disease).

2024年9月18日 · Understanding the stages of the flu—including the signs and symptoms that are likely to develop—can help you determine if you are recovering as you should. It can also help you figure out if you are still contagious and able to infect others. Day 0 …

Influenza, commonly known as the flu, is an infectious disease caused by influenza viruses. Symptoms range from mild to severe and often include fever, runny nose, sore throat, muscle pain, headache, coughing, and fatigue. These symptoms begin one to four (typically two) days after exposure to the virus and last for about two to eight days.

Flu is a contagious respiratory illness that infect the nose, throat, and sometimes the lungs. Learn about the current flu season and find resources related to flu surveillance and past seasons. …

2025年1月28日 · Flu, also called influenza, is an infection of the nose, throat and lungs, which are part of the respiratory system. The flu is caused by a virus. Influenza viruses are different from the "stomach flu" viruses that cause diarrhea and vomiting. Most people with the flu …

2025年2月28日 · Seasonal influenza (the flu) is an acute respiratory infection caused by influenza viruses. It is common in all parts of the world. Most people recover without treatment. Influenza spreads easily between people when they cough or sneeze. Vaccination is the best way to prevent the disease.

2024年8月13日 · Flu is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and sometimes the lungs. It can cause mild to severe illness, and at times can lead to death. The best way to prevent flu is by getting a flu vaccine each year. Flu can cause mild to severe illness, and at times can lead to death.

2023年4月12日 · Influenza (the flu) is a respiratory infection. It is caused by the influenza virus. Influenza typically is spread by air or by direct contact from one person to another. Influenza virus is very contagious. Most influenza cases occur during epidemics. Epidemics usually peak during the winter months.

Seasonal influenza, or flu, is a highly contagious respiratory illness caused by influenza viruses that infect the nose, throat and lungs. The two main types of influenza viruses—types A and B—are the viruses that typically spread in people (human …

What is the flu (influenza)? The flu is an illness you get from the influenza virus. It causes symptoms like head and body aches, sore throat, fever and respiratory symptoms, which can be severe. Flu is most common in winter months, when many people can get sick at once (an epidemic). Cleveland Clinic is a non-profit academic medical center.