MANGALURU/UDUPI: The coastal districts of Udupi and Dakshina Kannada recorded the highest single-day spike of 53 Covid-19 cases on Thursday. Udupi saw 29 fresh cases, and D-K recorded 24 cases. More than 95 percent of the patients are Maharashtrareturnees. Sources said all the 53 people tested positive in their 12th day swab tests. Results of 1,004 persons are awaited.