Influenza H1N1 is a flu like illness. It spreads from human to human via secretions of nose and droplets from coughing.This does not occur by contact with pigs, So the earlier term " Swine flu" is not used now. Since it's a new virus almost all of us are not immune to this. So this novel influenza spreads very fast in a non immune society. It is more common among children and young adults.
It is an Influenza virus - A H1N1 sub type.
Generally it is a mild illness. The usual symptoms are fever, headache, body aches, sore throat, cough, runny nose and occasionally vomiting and diarrhea. It is like the usual common cold. So H1N1 influenza cannot be differentiated from any other influenza clinically.
Small percentage can develop Pneumonia. Then you may find it difficult to breathe.Rarely the illness can get severe in a few days and such patients can develop pneumonia, fits, confusion or altered level of consciousness. You have to seek medical advice especially if high fever, increasing shortness of breath, altered consciousness, increasing severity of symptoms and debility. There is high risk group who may get severe disease. They are extremes of age ( less than 2 years and above 65 years ), pregnant females, patients already suffering from chronic diseases like diabetes, asthma, kidney diseases, cancer, patients on long term prednisolone etc.
Anti viral drugs - Tami flu, oseltamivir etc is used to treat severe disease and patients who fall in to high risk group.