Mystery continues to surround the sudden death of six pupils in a tiny primary school in north China's Shanxi Province.

Two boys and four girls aged six to ten became violently ill after eating supper Monday evening at a primary school in Nanyao Village, Puxian County, Linfen City.

Just over an hour later, they were dead -- before getting to hospital. Because they became violently ill it was first thought they had died of food poisoning.

But food poisoning was ruled out of as the cause of death after vomit samples were analyzed, said Yang Zhiping, party chief of Puxian.

Nanyao Village primary school only has 11 pupils who are all boarders. On Tuesday, the other five students were transferred to a nearby school. The provincial education bureau ordered schools to strengthen food safety checkups and management and raise health awareness among students and staff at school canteens.

It also ordered schools to ban canteen staff from entering the food processing and storage rooms.

"The tragic event has set off alarm bells in our schools, and we must learn a lesson from it," said Yang Zhiping.

But the questions remain: what did the children die of? What lesson can be learned when the cause of death is still a mystery?

(Xinhua News Agency December 7, 2006)