Pandemic Influenza

On 11 June 2009, a new influenza pandemic was declared by the World Health Organization. One of the most important lessons learned from this pandemic was the difficulty of estimating the pathogenicity of newly emergent pathogens, especially in the initial phase of the outbreak. Clinicopathological analysis of the first patients in Mexico revealed that this virus infection had accelerated the death of patients suffering from underlying diseases, although a small percentage of otherwise healthy people also suffered from rapidlyprogressing lethal pneumonia. Even under medical observation, the prognostication of the disease for individual patients remains difficult. Gathering a patient’s basic background information and making a proper physical examination likely remain the most important and effectivemethods by which severe cases can be diagnosed at an early stage. An increased incidence in cases of severe pneumonia has been repeatedly observed in the early phases of both past and recent pandemics. By the time an outbreak has been identified, it is almost certainly impossible to prevent the transmission of the airborne pathogen worldwide. In planning for future pandemics, a compromise between attempts to contain the spread of the pathogen and reliance upon the standard clinical medical procedures will be needed.