The recent outbreak of human infection with a novel Swine-Origin Influenza A (H1N1) virus is spreading rapidly through sustained human-to-human transmission in multiple countries. Human-to-human transmission occurs by inhalation of infectious droplets and droplet nuclei, and by direct contact, which is facilitated by air and land travel and social gatherings. The most frequently reported symptoms are fever, cough, myalgia, and sore throat. Detailed contact and travel histories and knowledge of viral activity in community are essential for prompt case detection by the health personnel. Real-time Reverse Transcriptase-Polymerase Chain Reaction analysis of throat swabs or lower respiratory samples is a sensitive means of diagnosis. Use of oral oseltamivir may be warranted for the treatment of severe illness.