Page 7 - 80 guidelines for the treatment of malaria_opt

Glossary

Glossary

Artemisinin-based combination therapy (ACT). A combination of artemisinin or one
of its derivatives with an antimalarial or antimalarials of a different class.

Asexual cycle. The life-cycle of the malaria parasite in host from merozoite invasion of
red blood cells to schizont rupture (merozoite → ring stage → trophozoite → schizont →
merozoites). Duration approximately 48 h in Plasmodium falciparum, P. ovale and P. vivax;
72 h in P. malariae.
Asexual parasitaemia. The presence in host red blood cells of asexual parasites. The
level of asexual parasitaemia can be expressed in several different ways: the percentage
of infected red blood cells, the number of infected cells per unit volume of blood, the
number of parasites seen in one microscopic field in a high-power examination of a thick
blood film, or the number of parasites seen per 200–1000 white blood cells in a high-
power examination of a thick blood film.

Cerebral malaria. Severe P. falciparum malaria with cerebral manifestations, usually
including coma (Glasgow coma scale < 11, Blantyre coma scale < 3). Malaria with coma
persisting for > 30 min after a seizure is considered to be cerebral malaria.

Combination treatment (CT). A combination of two or more different classes of
antimalarial medicines with unrelated mechanisms of action.
Cure. Elimination of the symptoms and asexual blood stages of the malaria parasite that
caused the patient or caregiver to seek treatment.

Drug resistance. The World Health Organization (WHO) defines resistance to
antimalarials as the ability of a parasite strain to survive and/or to multiply despite the
administration and absorption of a medicine given in doses equal to or higher than
those usually recommended but within the tolerance of the subject, provided drug
exposure at the site of action is adequate. Resistance to antimalarials arises because
of the selection of parasites with genetic mutations or gene amplifications that confer
reduced susceptibility.

Gametocytes. Sexual stages of malaria parasites present in the host red blood cells.

Hypnozoites. Persistent liver stages of P. vivax and P. ovale malaria that remain dormant
in host hepatocytes for an interval (most often 3–45 weeks) before maturing to hepatic
schizonts. These then burst and release merozoites, which infect red blood cells.
Hypnozoites are the source of relapses.

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