Homeland Security Secretary Alejandro Mayorkas said Monday that the “rate of illness” among illegal immigrants who have arrived at the US-Mexico border in recent months is “approximately 20 percent” — days after admitting that thousands of Haitian migrants who set up a temporary encampment under a bridge in Del Rio, Texas were not tested for COVID-19. “When one is speaking of 7,000 or 7,500 people encountered at the border every day, if one takes a look at that system, it is not built for that in a COVID environment where isolation is required,” Mayorkas said during remarks at the Immigration Law and Policy Conference. Mayorkas did not specify whether the “illness” he was referring to was COVID-19, though he also said that he did not expect “the tragic rise of the Delta variant” over recent months. “We took a step back by reason of that,” he added. “I did not expect to be in late September where we are.” The encampment under the bridge linking Del Rio with Ciudad Acuña, Mexico was cleared Friday, less than a week after approximately 15,000 migrants had congregated there and waited to be picked up by border authorities.