A number of local health workers contracted the disease while caring for sick patients without the use of appropriate personal protective equipment, such as a heavy biohazard suit. Because Ebola had not previously surfaced in West Africa, some healthcare personnel may have forgone the use of protective equipment thinking patients were suffering from diseases with similar symptoms, such as malaria, typhoid fever and Lassa fever, the agency said.
A number of prominent healthcare professionals have succumbed to the disease during the outbreak. In July, Dr. Sheik Umar Khan, a leading physician from Sierra Leone died after contracting the virus while treating patients. In the same month, the virus killed Dr. Samuel Brisbane, a prominent Liberian physician who once served as medical adviser to former Liberian President Charles Taylor.
On Monday Liberian health officials reported the death of Dr. Abraham Borbor, deputy chief medical doctor of the country's largest hospital and one of the recipients of the experimental Ebola treatment drug ZMapp, which was also given to two infected American aid workers.
Several challenges have made the current outbreak difficult to contain. Healthcare systems in the countries hit hardest by the virus are rudimentary and were quickly overwhelmed as the number of cases climbed. Also, the infections have not been confined to rural areas as in previous Ebola outbreaks, making it harder to identify undiagnosed patients.
A number of health workers in the affected countries have reportedly refused to treat Ebola patients out of fear of contracting the disease, forcing the closure of several hospitals and clinics throughout the region.
Follow Steven Ross Johnson on Twitter: @MHsjohnson