BEIJING - China has stepped up domestic quarantine controls to stop imported cases of malaria and dengue fever spreading.

From January to February, south China's Guangdong province reported five recent entrants into the country suffering from malaria and three from dengue fever. The entrants came from Vietnam, Malaysia, Thailand, Indonesia, Mozambique, Sudan and the Democratic Republic of Congo.

The General Administration of Quality Supervision, Inspection and Quarantine issued an alert Monday, asking local quarantine authorities to tighten medical inspections and temperature monitoring on visitors from those countries.

Entrants who reported fever, chills, headaches or other symptoms of the diseases should be treated immediately, according to the alert.

Malaria and dengue are mosquito-borne, potentially fatal diseases. Malaria claims more than 1 million lives annually across the globe, mainly African children under the age of five, according to the World Health Organization. Dengue affects between 50 and 100 million people in the tropics and subtropics each year, resulting in fever and muscle and joint aches.