Yunnan Province, due its international borders with Myanmar, Vietnam and Lao PDR has a large number of imported cases of malaria, including a high proportion of Plasmodium falciparum, as a result of the mobility of the population. This movement is due to workers coming from other provinces where there is no malaria to work in the productive tropical lowlands. Chinese nationals who have gone to work in neighboring countries, border trade and refugees from Myanmar. Much of Yunnan is peopled by ethnic minorities living in remote mountainous and forested areas which are difficult to reach. However, surveillance has been strengthened by training 3,900 primary health care workers and combining the search for visiting foreigners, returning Chinese and people from other provinces with public security, customs formalities and employers. Any visitor detected by these services is obliged to have a blood slide taken. This has resulted in an earlier and more complete detection of malaria cases, reducing incidence from 19.19 to 12.12/10,000 in the border area over the last 10 years. This is despite a considerable increase in population movement and the threat of drug resistant malaria.