A Background On Influenza

Influenza, or the flu, is a disease that rapidly produces symptoms such as body aches, headache, fever, chills, sore throat, runny nose, and nonproductive cough. Influenza is highly contagious and is easily passed from person to person, primarily through small droplets produced from a cough or sneeze of an infected individual.

Two types of influenza viruses can cause disease in humans: type A and type B. The type B virus is most commonly associated with seasonal influenza. Seasonal influenza is seen periodically in the fall and winter in the United States, and outbreaks are generally limited. In the type A virus, on the other hand, major changes can occur in its genetic material. These genetic changes produce a novel virus for which humans have little or no natural immune protection. Such a lack of immune resistance poses and elevated threat for worldwide outbreak. Such outbreaks, or pandemics, have occurred three times in the last century: in 1918, 1957, and 1968. All were a result of either an antigenic shift or mutation in a type A virus.

What is a Pandemic?

A pandemic refers to a worldwide outbreak of influenza when a new strain of a virus emerges. In early stages of the pandemic, people may have little or no natural immunity to the virus; so the disease may spread quickly. Vaccines to protect people from the illness may not be widely available until months after the pandemic begins. Pandemics have occurred throughout history, and scientists believe is is only a matter of time before another occurs.

Avian Influenza (H5N1) is an influenza A subtype that occurs mainly in birds and can be deadly to them. While H5N1 does not usually infect people, human cases of Avian Influenza infection have been recorded. Because all influenza viruses have the ability to change, scientists are concerned that the H5N1 virus could one day infect humans and spread from person to person. Would health officials are keeping close watch on the H5N1 situatio and are preparing for the possibility that the virus may begin to spread more freely from human to human.