Both the common cold and flu are viral respiratory illnesses, which often makes it difficult to tell them apart.  Generally, the onset of the flu is faster than that of a cold, and the symptoms are typically much more intense.  While the flu is typically caused by influenza A or B viruses, there are hundreds of different strains that can cause a cold.  Symptoms of a cold can include runny nose, cough, and sore throat.  The flu will include these symptoms, as well as a fever, headache, body chills, and general fatigue.  A simple test performed at Niagara Falls Urgent Care can determine whether your illness is caused by a flu strain, making treatment more easily tailored to your exact needs.