Key variables | Operational definitions |
---|---|
Malaria case | Occurrence of malaria infection in a person in whom the presence of malaria parasites in the blood has been confirmed by a diagnostic test |
Malaria elimination | Interruption of local transmission (reduction to zero incidence of indigenous cases) of a specified malaria parasite in a defined geographical area as a result of deliberate activities. Continued measures to prevent re-establishment of transmission are required. |
Indigenous case | A case contracted locally with no evidence of importation and no direct link to transmission from an imported case |
Introduced case | A case contracted locally, with strong epidemiological evidence linking it directly to a known imported case (first-generation local transmission) |
Imported case | Malaria case or infection in which the infection was acquired outside the area in which it is diagnosed. |
Relapse case | Malaria case attributed to activation of hypnozoites of P. vivax or P. ovale acquired previously. |
Induced case | Other types of transmission (by blood transfusion, from mother to child transmission) |
Recrudescent case | Recurrence of asexual parasitaemia of the same genotype(s) that caused the original illness, due to incomplete clearance of asexual parasites after antimalarial treatment. |
Focus | A defined circumscribed area situated in a currently or formerly malarious area that contains the epidemiological and ecological factors necessary for malaria transmission Note: Foci can be classified as active, residual non-active or cleared. |
Active foci | A focus with ongoing transmission. |
Residual non-active foci | Transmission interrupted recently (1–3 years ago). |
Cleared foci | A focus with no local transmission for more than 3 years and which is no longer considered residual non-active. |