SCOTT SIMON, HOST: Doctors Without Borders says that a catastrophe is unfolding in the Yemeni city of Aden. Doctors and aid workers talk of hospitals being overwhelmed and of the ill dying in their homes. And as NPR’s Ruth Sherlock reports, the doctors themselves are falling ill. RUTH SHERLOCK, BYLINE: Yemen is divided between warring armies. And it already faces a humanitarian crisis. There’s famine and widespread disease, like cholera and dengue. Official numbers for the spread of the coronavirus are unreliable. But Dr. Amr Al-Turkey (ph) a critical care physician in Aden, knows people are dying. AMR AL-TURKEY: Many of the people there die daily. SHERLOCK: Yemen’s health care system has already collapsed in the war and now Al-Turkey says the country is losing doctors.