Israeli airstrikes killed at least 15 people including women and children overnight in Gaza, according to hospital officials and a body count by an Associated Press journalist on Sunday. The latest strikes occurred as Israeli Prime Minister Benjamin Netanyahu prepared to leave Monday for the United States, where he was expected to meet with President Joe Biden and address Congress to make his case for the nine-month war on Gaza while ceasefire negotiations continue. The already precarious humanitarian conditions inside besieged Gaza have worsened with the discovery of the polio virus as water …