March 17, 2020 / By Lenny Bernstein, Shawn Boburg, Maria Sacchetti and Emma Brown Dozens of health-care workers have fallen ill with covid-19, and more are quarantined after exposure to the virus, an expected but worrisome development as the U.S. health system girds for an anticipated surge in infections. From hotspots such as the Kirkland, Wash., nursing home where nearly four …