The outbreak of the coronavirus in Louisiana has become one of the most explosive in the country. Today, we explore how New Orleans became a petri dish for the virus, why Mardi Gras was likely to have been an accelerator for the spread of infections and what it is like now inside the city’s hospitals. Guest: Yanti Turang, a nurse in New Orleans. For more information on today’s episode, visit nytimes.com/thedaily.  Background reading: As Mardi Gras came to a close, patients with mysterious respiratory illnesses began appearing in hospitals — many who had not recently left the country. The first Covid-19 diagnosis soon followed.