Variations of Influenza: A Review

Abstract

The seasonal influenza or flu remains a major cause of illness and death all over the world. It is the transmissible viral disease that affects whole of the respiratory tract and its severity ranges from mild to severe. The activity of influenza virus shows great periodic rhythm in different areas of the globe where neither hot nor cold and it is very uncertain in equatorial region where temperature is high throughout the year indicating that climatic components can drives periodic rhythm. Seasonal variability in infectious disease conditions is one of the ancient studies in human bioscience, dating from at least archaic Greece. Each year around the globe despite decade of research and drug development, annual flu viruses constantly cause outbreaks of influenza. Albeit we are starting to recognize the mechanisms that support the emergence of annual flu microorganisms, the onset and character of the evolving recent viruses remains unexpected. The flu pandemic is an important cause of the sickness and death of the elderly. Decreased immune function plays an important role in the worst outcome.  Several factors which impact on the severity of annual influenza includes characteristics of the specific virus, use of antiviral drugs, and vaccination of influenza. The population which has high chances of getting this serious illness are: gravid mother, kids below the 5 years of age, the older age group, people with persistent cases (such as long-standing heart disease, lung disease, kidney, digestive, neuropsychiatric, hepatic disease or blood related disorder) with people with low immune status (such as HIV / AIDS, taking chemotherapy or steroids.  In cooler climates, occasional outbreaks take place predominantly in the cold climate, while in hot climates, colds can occur year-round, originates the unusual epidemic.