Wang Jingbo (L,1) takes a photo with his colleague after an operation on National Day. Photo provided to China Daily

The extreme natural environment also makes it quite difficult for them to get fresh vegetable and fruit.

"We can only buy onions, potatoes and cabbages in the local markets," he told China Daily. "Every month we get such things as peppers, tomatoes and Chinese chives from Nouakchott, capital of the country, which is 700 kilometers away."

However, after several hours' of driving and the hot temperature, the vegetables shrivel and don't last more than one week.

"But all these difficulties can't dampen the spirit of the Chinese doctors. From the first day we set foot here, we knew we had to stick to our posts," he said.

"Serious anemia is quite common among the children in the city due to the shortage of fresh vegetables and inundant parasites."