Influenza essays

Influenza essays As soon as the feeling of autumn is in the air, the leaves start to turn color and people move indoors, the influenza season will be on its way. Although the flu can hit individuals of all ages throughout the world anytime, the highest number of cases occurs between November and March. In 2001-2002, for example, the influenza season in the U.S. peaked in mid-to- late February, when 40 states reported regional or widespread flu activity to the Center of Disease Control and Prevention.1 Although in temperate climates influenza generally affects people in the colder months, it can occur all year round in tropical climates. A possible explanation for the high level of activity during winter is that the congregation of people indoors facilitates the transmission of the virus and viruses survive longer due to the dry indoor air.2 Influenza results from a virus that infects the upper respiratory tract, or the nose and throat. The viruses are divided into three major types, A, B and C, and alter from year to year because of changes in the antigens. This is also called antigenic shift in Type A flu and antigenic drift in Type A or B. Since the flu is so changeable, different vaccines are required for each form of the disease and every season. The greatest public health concern lies in the fact that Type A can shift suddenly and considerably, either through mutation or the exchange of influenza genes.3 The result is the sudden appearance of a new virus strain to which populations may have no immunity and no vaccine can offer protection. Viruses are known to infect animals, birds and humans. Scientists have also seen viruses switch in animals from being a diarrheal disease to a respiratory one as it evolves in the body. Viruses can spread from How fast the virus proliferates and how great its negative impact significantly depends on a number of factors. In the U ...