**2. Background**

Resistance in *Plasmodium falciparum* has already developed to all antimalarial drug classes deployed for treatment. Paradoxically, the number of antimalarials available or in development has remained small. For most of the twentieth century, chloroquine was the main drug used to treat or prevent malaria. The discovery of chloroquine after World War II, and the widespread use of DDT for vector control, had triggered hope that malaria eradication was possible [3]. Unfortunately, chloroquine resistance did emerge and spread to the African continent within two decades annihilating the prospect of malaria eradication [4]. Although several countries did achieve malaria elimination (in Europe and the Americas), others saw a dramatic resurgence of the disease [3]. Over the following period, *P. falciparum* developed resistance to all antimalarial drugs, including sulfadoxine, pyrimethamine, mefloquine, atovaquone, artemisinin derivatives and piperaquine [5–8]. The most accurate and up-to-date data repository of the clinical trials on the efficacy of antimalarials, and the temporal and geographical spread of resistance is accessible at the Worldwide Antimalarial Resistance Network (WWARN: www.wwarn.org).

In 2007, the Bill and Melinda Gates Foundation announced that it was investing millions of dollars to revitalise the efforts of malaria elimination [9]. Ten years later, this seems to be an achievable goal since the global malaria burden has diminished (**Figure 1**), an encouraging The Artemisinin Resistance in Southeast Asia: An Imminent Global Threat to Malaria Elimination http://dx.doi.org/10.5772/intechopen.76519 17

**Figure 1.** World atlas showing the countries with different stages of malaria endemicity [10] and status of drug resistance [121]. Right side: Prevalence (small pin: <10%, medium pin: 10–50%, large pin: >50% prevalence) of *Pfmdr-1* CNV [25, 122], Plasmepsin 2–3 CNV [26, 87], K-13 mutation [101, 123, 124] and possible spread [125, 126].

result attributed to the widespread deployment of long-lasting impregnated nets (LLINs), the ACTs and increased availability of malaria diagnostic tests [10]. However, the failure of the ACTs, the extension of vector resistance to the insecticides and the recent increase in the number of malaria cases are clear reminders that malaria is a formidable foe. Without new strategies, the same causes will lead to the same consequences [10] .
