What is virus
Virus is a micro organism, also called microbe, which can’t be seen through naked eyes. It can be seen under microscope. Virus may or may not be harmful to humans. Different kinds of virus are found everywhere, in extremes of cold or hot, high pressure or low pressure, high radiation or low radiation etc.
Some virus are useful to us and some cause different types of diseases. The microbes which act as infectious agents to spread diseases are called pathogens or germs. Virus is one of such infectious agents.
Virus replicates itself in the living cells of an organism and spread infection in humans, plants, animals etc. There are approximately 5000 varieties of viruses classified so far in the world. Most common human diseases caused by viruses are common cold, Chickenpox, Polio, Rabies, AIDS, Ebola Fever etc. Millions of people die globally due to virus borne diseases every year. Such diseases are transmitted to others through contaminated air, water, blood, touch, sneezing, sexual contact etc.
Our body has an immune system to kill these viruses. However, when the immune system is weak or the virus attack is severe, the infection takes over. For many known viruses, the vaccines are formulated and injected to the people to fight such infections.