Symptoms of Viral Diseases. Symptoms of a viral disease range from silent to agonizing and life-threatening. For example, many people infected by the Zika or West Nile virus do not know that they have it, or the symptoms are so mild that they dismiss them. People who have been infected by the rabies virus have vague symptoms that progress to delirium, bizarre, violent behavior, hallucinations, insomnia. They show a horror of water that comes with the inability to swallow, which gives the disease its other name of hydrophobia. When the symptoms of this viral disease appear, it is almost always fatal.
Most people who have a viral disease experience symptoms between nothing to the devastating symptoms of rabies. They have body aches, fever, cough, sore throat and runny nose. They are tired and have chills and headache. Sometimes they have diarrhea, nausea and vomiting. Other symptoms of viral diseases include the skin eruptions of chickenpox, the swollen and painful salivary glands caused by the mumps and the rash caused by measles.