Your respiratory system includes your mouth, nose, airways, lungs, and all the organs that connect them. When you have an infection in one of these areas, it is called a respiratory infection. The kind of infection you get depends on what part of your respiratory system is affected. Here are some of the most common infections. Colds The most widespread type of respiratory infection is the common cold. There are more than 200 viruses that can cause a cold. Most adults have 2 to 3 colds each year, and children can have many more than that. A cold is an infection in your upper respiratory tract, including your nose and throat. Most colds start with a runny nose and sore throat. Other symptoms develop slowly over a few days and can include: Cough Fever of up to 102 degrees Fahrenheit Headache Muscle aches Sneezing Tiredness Watery eyes You can treat a cold at home by getting rest and drinking plenty of fluids. You can also try over-the-counter medicines to help relieve symptoms, such as a pain reliever for a headache or cough medicine for a cough. Most colds clear up in 7 to 10 days. Bronchitis The bronchial tubes carry air to your lungs. When these tubes become infected, it causes bronchitis. The main symptom of bronchitis is a cough that brings up mucus. It may also cause: Low fever Chest pain Shortness of breath Wheezing Viruses are the most common cause of bronchitis, but it can also be caused by bacteria or fungi. Inflammation of the bronchial tubes from breathing in smoke, dust or fumes another type of bronchitis. In most cases, you can treat bronchitis at home, with ample rest and fluids. In some cases, your doctor may prescribe medicines to treat your cough or an antibiotic if the infection is caused by bacteria. The symptoms of bronchitis can last for up to two weeks, but your cough may linger for as long as eight weeks. If you are still coughing after two weeks, call your doctor. Sinus Infection The sinuses are small cavities around your nose, forehead and cheeks. Sinus infections are usually caused by bacteria, but they can also be caused by fungi. Common symptoms include: Cough Discolored nasal discharge or congestion Facial pain or pain in the teeth Fever Headaches Postnasal drip In most cases, you will need to take antibiotics to treat a sinus infection. Your doctor may also suggest other medicines—such as decongestants, antihistamines and corticosteroids—to help relieve symptoms. Sinus infections can last up to four weeks. Pneumonia Pneumonia is an infection in the lungs. It is most often caused by bacteria or viruses, but can also be caused by fungi. In some cases, you can develop pneumonia after being sick with a cold or the flu. Anyone can get pneumonia, but infants younger than two and adults older than age 65 are at higher risk for this infection. People with weakened immune systems from conditions, such as HIV/AIDS, or treatment, such as chemotherapy or organ transplant are also at higher risk. You may also have a higher risk if you have chronic obstructive pulmonary disease (COPD) or another lung disease. Pneumonia symptoms can range from mild to severe and include: Chest pain when breathing or coughing Cough Fatigue Feeling worse after having a cold or the flu High fever Shortness of breath The type of treatment you need for pneumonia depends on what type of germ is causing the pneumonia and how severe it is. Bacterial pneumonia is usually treated with antibiotics. If your pneumonia is caused by a virus, you may need to take antiviral medicine. In some cases, you may need treatment in a hospital if your pneumonia is severe. Once you start treatment for pneumonia, you should start to feel better in 2 to 3 days.