The world's response to the outbreak shows progress and problems: Scientists have more tools, but early detection remains difficult in some places.
Schools and nightclubs are closed. Health officials have new powers to quarantine homes.
Cleaner-burning fuel is reducing dangerous levels of pollution – and saving money, too.
Readers write about why the US attorney general should not be elected, how healthcare in the US could be improved, and how to make digital health records safe from identity theft.
The Jewish ethical tradition means embracing Palestinians, too.