The death toll from the May 22 tornado that destroyed much of the city Joplin in Missouri has risen to 151, and three of the latest victims suffered from a rare fungal infection that can occur when dirt becomes embedded under the skin, authorities said Friday. Chief investigating officer Rob Chappel of Missouri's Jasper County said the three had been hospitalized with the unusually aggressive infection sometimes found in survivors of other natural disasters. He said it was difficult to identify the fungus as a cause of death since the people infected also suffered other severe injuries. “These people had multiple traumas, pneumonia, all kinds of problems,” said Dr. Uwe Schmidt, an infectious disease specialist at Freeman Health System in Joplin. “It is difficult to say how much the fungal infections contributed to their demise.”