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ANNEX 9. Treatment of Plasmodium vivax, P. ovale and P. malariae infections

episodes in this age group as P. falciparum. Severe vivax malaria presents as wide a range
of pathologies as is seen in severe P. falciparum malaria ranging from toxic shock and
cerebral malaria to multiple organ failure (8, 9). During pregnancy, infection with P. vivax,
as with P. falciparum, reduces birth weight due to chronic anaemia, sequestration and
pro-inflammatory cytokines in the placenta (10–12), and increases the risk of neonatal
death. In primegravidae, the reduction is approximately two thirds that associated with
P. falciparum, but the effect does not appear to decline with successive pregnancies; indeed,
in the one large series in which this was studied, it increased (12).

a9.2 diagnosis

Diagnosis of vivax malaria is based on microscopy. Rapid diagnostic tests based on
immunochromatographic methods are available for the detection of non-falciparum
malaria. However, their sensitivities for detecting parasitaemias of ≤ 500/μl are low (13–20).
The relatively higher cost of P. vivax tests compared to those for P. falciparum is a further
impediment to their large-scale use in endemic areas. Molecular markers for genotyping
P. vivax parasites are available for the dihydrofolate reductase (dhfr) gene, and those for
chloroquine resistance are under development.

a9.3 treatment

The objectives of treatment of vivax malaria are twofold: to terminate the acute blood
infection, to cure the clinical symptoms, and to clear hypnozoites from the liver to prevent
future relapses. This is known as a radical cure.

Before 2004, there were relatively few studies on the treatment of P. vivax. Only 11% of the
435 published antimalarial drug trials have been on P. vivax malaria (21). Thereafter, there
have been several trials on the efficacy of artemisinin-based combination therapies for the
treatment of vivax malaria (22–24).

A9
a9.3.1 standard oral regimen

Chloroquine monotherapy (25 mg base/kg body weight over 3 days) is recommended as the
standard treatment for vivax malaria, because the parasite remains sensitive to chloroquine
in much of the world. Primaquine (0.25 or 0.5 mg base/kg body weight in a single daily
dose for 14 days) is used as a supplement to the standard treatment for the purpose of
eradicating dormant parasites in the liver and preventing relapses. Although shorter 5-day

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