Implementation of G6PD testing and primaquine for P. vivax radical cure: operational perspectives from Thailand and Cambodia

ABSTRACT

Following progressive success in reducing the burden of malaria over the past two decades, countries ofthe Asia Pacific are now aiming for elimination of malaria by 2030. Plasmodium falciparum and Plasmodiumvivax are the two main malaria species that are endemic in the region. P. vivax is generally perceived to beless severe but will be harder to eliminate, owing partly to its dormant liver stage (known as a hypnozoite)that can cause multiple relapses following an initial clinical episode caused by a mosquito-borne infection.Primaquine is the only anti-hypnozoite drug against P. vivax relapse currently available, with tafenoquine inthe pipeline. However, both drugs may cause severe haemolysis in individuals with deficiency of the enzymeglucose-6-phosphate dehydrogenase (G6PD), a hereditary defect. The overall incidence of malaria hassignificantly declined in both Thailand and Cambodia over the last 15 years. However, P. vivax has replacedP. falciparum as the dominant species in large parts of both countries. This paper presents the experience ofthe national malaria control programmes of the two countries, in their efforts to implement safe primaquinetherapy for the radical cure, i.e. relapse prevention, of P. vivax malaria by introducing a rapid, point-of-caretest to screen for G6PD deficiency.