Organizations funded by the United States helped keep dangerous pathogens in check around the world. Now many safeguards are gone, and Americans may pay the price.Dangerous pathogens left unsecured at labs across Africa. Halted inspections for mpox, Ebola and other infections at airports and other checkpoints. Millions of unscreened animals shipped across borders. The Trump administration’s pause on foreign aid has hobbled programs that prevent and snuff out outbreaks around the world, scientists say, leaving people everywhere more vulnerable to dangerous pathogens. That includes Americans. Outbreaks that begin overseas can travel quickly: The coronavirus may have first appeared in China,...