Smallest organism; highest threat.

Ever since the discovery of virus in beginning of 20th century, infections caused by these organisms have captured attention of researchers. The evolution of viruses is still a controversy, even same for their categorization in either living or non-living. It is clear that besides many controversies virus remains challenging to treat as well as to control in some extent. Though vaccines are available as prophylactic tool and antiviral drugs for treatment, still virus exist in host cells if they successfully invade biological machinery. Now it remains as challenge to treat these smallest organisms with high degree of efficacy and safety. To answer the demand of the present world there is urgent need of more potent and novel drugs for treatment and vaccines to prevent infection. Answer to this problem will definitely reduce casualties occurring worldwide. This review presents few of the pandemics, their causative agents, current status of treatment and future prospective.