Ebola cases in Congo have reached 2,011, with 754 deaths, according to government data. Health workers at Bunia General Hospital went on strike on Wednesday over unpaid wages. Many health professionals say they're working under difficult conditions without adequate compensation. Congo has been battling the outbreak since May 15, caused by the rare Bundibugyo virus. The World Health Organization said Tuesday that 80% of new cases are from unknown transmission chains. The outbreak continues to spread faster than officials can track. Efforts are challenged by the lack of approved vaccines or treatments for this virus strain.