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nd
Guidelines for the treatment of malaria – 2 edition

12. case manaGement in tHe context
of malaria elimination

12.1 use of gametocytocidal drugs to reduce transmission

Two antimalarial medicines have an effect specifically on gametocytes: primaquine and
artemisinins. This can be of particular benefit in epidemic control and in programmes
aiming for malaria elimination.

Primaquine selectively kills gametocytes. Especially in South-East Asia and South
America, before the use of ACTs for the treatment of P. falciparum malaria, a single oral
dose of 0.75 mg base/kg body weight primaquine (45 mg base maximal for adults) was
added to a fully effective blood schizontocide to eliminate gametocytes and thus reduce
transmission. Studies on the impact of this strategy are very limited. Where it has been
used, the single dose of primaquine was well tolerated, and prior testing for G6PD
deficiency was not required. There is no experience with its use in Africa, where there is
the highest prevalence of G6PD deficiency in the world.
ACTs reduce gametocyte carriage. One randomized comparison of ACTs and primaquine
has reported a greater effect for ACT than primaquine on gametocyte carriage. A
more recent study compared the added value of primaquine to AS+SP combination in
the treatment of falciparum malaria in United Republic of Tanzania. It reported that
primaquine clears gametocytes that persist after treatment with AS+SP, including those
at a submicroscopic level: this demonstrates an added benefit of combining a single
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dose of primaquine with an ACT . The addition of a single dose of primaquine to ACT
treatment is, therefore, recommended in programmes aimed at reducing transmission,
provided the risks of haemolysis in G6PD deficient patients are considered. Primaquine
should not be given in pregnancy and in children less than 4 years old.

12.2 mass screening and treatment

Mass screening for parasitaemia and treating all infected persons in a targeted area or
population, irrespective of whether they are symptomatic aims to reduce the size of the
infectious reservoir in the targeted area. Mass screening and treatment may be indicated
in areas where the parasite reservoir (or parasite gene pool) needs to be quickly and
selectively reduced. This type of intervention also plays a significant role in reducing
the infectious reservoir of parasites in a given location and is very useful in the pre-
elimination and elimination phases of malaria control. It requires considerable logistics,
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capacity and preparation.
16 Shekalaghe S et al. Primaquine clears submicroscopic Plasmodium falciparum gametocytes that persist after
treatment with sulphadoxine-pyrimethamine and artesunate. PLoS ONE, 2007, 2: e1023. doi:10.1371.
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