BEIJING, Aug. 12 -- Nine Chinese disease control experts have arrived in West Africa to help fight Ebola after departing on Sunday evening and Monday, Sun Jiwen, spokesman of the Ministry of Commerce, said on Tuesday.

China announced on Sunday it would send three expert teams and medical supplies to Guinea, Liberia and Sierra Leone to assist in the prevention and control of the Ebola virus, with each medical team composed of one epidemiologist and two specialists in disinfection and protection.

Sun said emergency humanitarian aid supplies have also arrived in the affected countries after leaving Shanghai on Sunday.

The government announced on Aug. 7 that China would provide relief worth 30 million yuan (4.9 million U.S. dollars) to Liberia, Sierra Leone and Guinea. It was the second round of Ebola relief from China so far.

Ebola, which spreads through the mucus and other body fluids or secretions such as stool, urine, saliva and semen of infected people, is believed to be very difficult to control.

Four western African countries -- Guinea, Liberia, Nigeria and Sierra Leone -- have been hit by the Ebola epidemic. So far, 1,779 cases have been reported, including 961 deaths, according to the World Health Organization (WHO).

Though the epidemic is currently restricted to West Africa, the WHO warned that the disease is a "public health emergency of international concern" and called for a coordinated international response to prevent the spread of the deadly virus.