China's Ministry of Health Thursday urged health administrative departments nationwide to tighten controls of imported malaria cases.

In the provinces of Anhui, Gansu and Liaoning, seven people who returned from Africa were infected with alged malaria, one of whom had died, said the notice issued Thursday on the ministry's website. But it did not reveal when exactly the cases happened.

Imported malaria is a huge threat to China's control of the disease, the notice said.

In places where malaria cases have been reported, there must be no let-up in control and treatment. In other places without reported cases, surveillance on people returning from high prevalence areas should be strengthened, the notice said.

Medical staff, especially those in grassroots and remote areas, should receive special training on the diagnosis and treatment of malaria, it said.

The notice also said imported malaria cases and new information must be reported timely to responsible institutions.

China has reported almost 12,000 malaria cases, including 832 alged malaria, for the first nine months of this year, a drop of 41 percent from last year, according to the notice.