corona virus

corona  virus   Corona viruses  are a group of  viruses  that cause diseases in mammals and birds. In humans, corona viruses cause  respiratory tract infections  that are typically mild, such as the  common cold , though rarer forms such as  SARS ,  MERS  and  COVID-19  can be lethal. Symptoms vary in other species: in chickens, they cause an  upper respiratory tract disease , while in cows and pigs they cause  diarrhea . There are no  vaccines  or  antiviral drugs  to prevent or treat human corona virus infections. Discover Corona viruses  were discovered in the 1960s. [8]  The earliest ones discovered were  infectious bronchitis virus  in chickens and two viruses from the  nasal cavities  of human patients with the  common cold  that were subsequently named  human corona virus 229E  and  human corona virus OC43 . [...