Corona virus (COVID-19) disease is a contagious onecaused by severe acute respiratory syndrome corona virus2 (SARS-Cov-2). The first case was identified in Wuhan,China on December 2019. Since then it spreads worldwideas an ongoing pandemic. The Corona virus can spread froman infected person's mouth or nose in small liquid particleswhen they cough, sneeze, speak, sing or breathe. Theseparticles range from larger respiratory droplets to smalleraerosols. The virus spreads mainly between people who arein close contact with each other, typically within 1 meter(short-range).

Corona, a type of virus of many different kinds and among1them some cause disease. On 31 December 2019, theWorld Health Organization (WHO) was formally notifiedabout a cluster of cases of pneumonia in Wuhan City, hometo 11 million people and the cultural and economic hub ofcentral China. By 5th January, 59 cases were known andnone had been fatal. Ten days later, WHO was aware of 282confirmed cases, of which four were in Japan, South Koreaand Thailand. There had been six deaths in Wuhan, 51people were severely ill and 12 were in a critical condition.The virus responsible was isolated on 7th January and itsgenome shared on 12th January. The cause of the severeacute respiratory syndrome that became known as COVID-219 was a novel corona virus, SARS-CoV-2. On January 30,2020, the WHO declared the COVID-19 outbreak a globalhealth emergency. On March 11, 2020, the WHO declared3COVID-19 a global pandemic. This virus has a large familythat cause illnesses ranging from the common cold to moresevere diseases like Middle East Respiratory Syndrome4(MERS) and Severe Acute Respiratory Syndrome (SARS).4Corona viruses are zoonotic, however no animal reservoir5has yet been found. Several known corona viruses arecirculating in animals that have not yet infected humansbutit appears that COVID-19 has crossed species from batsto snakes , and pangolins then to humans, initially via the6live animal 'wet markets' of Wuhan. As of 12 May, 82,591new cases of COVID-19 worldwide were being confirmed daily and the death rate was over 4200 per day. The US hasthe highest number of reported infections and deaths in theworld. India, Brazil, Russia, and France have the highestnumber of infections and Brazil, India, Mexico, and Peru4have the highest number of deaths after the US. InBangladesh, from 3rd January 2020 to 3rd September 2021,there have been 1,510,283 confirmed cases of COVID-197with 26,432 deaths, reported to WHO