DAS181 is a potentially first-in-class therapeutic that can be used to treat respiratory viral infections, including, but not limited to influenza, parainfluenza, and metapneumovirus. DAS181 is a recombinant sialidase protein that can cleave sialic acid, the virus receptors located on the surface of epithelial cells aligning the human respiratory track. Treatment with DAS181 can block virus entry into respiratory epithelial cells, thus preventing viral infection and spreading. DAS181 is a host-directed therapeutic that has demonstrated anti-viral activity against all strains and subtypes of viruses that utilize this receptor, including influenza strains that have developed resistance to other drugs and pandemic strains, such as H7N9, H5N1, and H1N1 and many others. This broad activity provides Ansun a unique opportunity to develop and commercialize DAS181 for treatment of many different viral infections. To date, Ansun has created formulations of this drug which it is developing to treat both hospitalized influenza and hospitalized parainfluenza , both of which are areas of unmet medical need that cause hundreds of thousands of deaths each year around the world.