Diagnosis was two days after Liberian - American man died from pneumonia . ` ` We know what needs to be done , '' CDC director says . Experts should also help implement stronger systems to fight the disease , CDC chief says .
Diagnosis comes three weeks after Liberian-American man died from virus . `` We know what needs to be done , '' CDC director says . Experts will also help implement stronger systems to fight the disease , CDC chief says .