A fourth doctor has died in Sierra Leone from the Ebola virus amid the continuing outbreak because of a denial for funds to evacuate her, The Associated Press reported.

A government official said the news was a huge setback to the impoverished country that is battling the virulent disease amid a shortage of health care workers.

Dr. Olivet Buck died late Saturday, hours after the World Health Organization said it could not provide the funds to evacuate her to Germany, Chief Medical Officer Dr. Brima Kargbo told AP.

Sierra Leone had requested funds from WHO, saying the country could not afford to lose another doctor, but were denied and instead told that she would be given the "best care possible" and possible access to experimental drugs.

More than 300 health workers have become infected with Ebola in Guinea, Liberia and Sierra Leone, three of the four countries including Nigeria who are suffering from the spread of the virus, AP reported. Nearly half of infected health workers have died, according to WHO.

More than 1,800 have died from the virus in West Africa, along with more than 3,700 infected.

Though steps have been taken by WHO to garner financial and treatment support, including green-lighting experimental treatment drugs and vaccines, along with the recent donations like the $50 million by the Gates Foundation, there is a lag in the effectiveness of the actions.

An opinion published by The Star quoted CDC director Dr. Tom Frieden as saying that the "window of opportunity" to control the outbreak is closing fast.

Six months after the outbreak was identified, the WHO released a response plan. It asked for $600 million to fight the outbreak, facing budget cuts of its own, and only one-third of the funds have been committed.

As the financial burden continues to quash efforts, the outbreak is spreading and the death toll continues to rise.