Hi, Thanks for posting in HCM. I understand your concern. H2N3 is a subtype of the influenza A virus. It is also known as bird flu. Symptoms include: Fever, chills, body ache, cough, congestion, headache, sore throat starting about 18-72 hours after exposure. You become contagious starting just around onset of symptoms or a bit before and continue for about 5-10 days. Hence, if you develop such symptoms, then you need to be isolated and treated. In case you do not develop any symptoms, then most often you wouldn t be the carrier of the virus. The best way to prevent the flu is by getting vaccinated each year. Hope the information provided would be helpful. All the best.