An Observational Study on Influenza- An Infectious Disease in India

Abstract

Influenza viruses constantly circulate in many animal hosts, such as humans, birds, horses, dogs and pigs. Seasonal Influenza virus infections in humans cause annual epidemics that result in millions of human infections worldwide and have significant health and economic burdens. Influenza pandemics can also have devastating effects globally, resulting in millions of deaths. Influenza is a globally important respiratory pathogen that continues to pose a significant public health problem. Influenza infects 10 to 20% of the world’s population annually and is one of the leading causes of infectious respiratory disease today. Seasonal infections result in 3 to 5 million cases of severe disease worldwide (World Health Organization WHO factsheet 211: Influenza; 2003) and between 17,000 to 51,000 deaths in the United States every year. The annual economic burden associated with these recurrent infections and hospitalizations is estimated to be a staggering $87 billion, with a majority of this burden borne by young children and individuals over the age of 65. In temperate zones, annual epidemics tend to peak during winter, while in tropical regions, infections can occur throughout the year. The exact cause for this seasonality is not clear.