Table 2.
Operational definition of case detection and key surveillance activities
| Key surveillance activities | Operational definition |
|---|---|
| Case detection | |
| Passive case detection | Detection of malaria cases among people who go to a health facility or a community health worker (CHW) on their own initiative to get treatment, usually for fever |
| Active case detection | Detection by health workers of malaria cases in the community and in households, sometimes among population groups who are considered to be at high risk |
| Reactive case detection (RACD) | RACD is triggered by the identification and notification of an index case. After the investigation and classification of the index case, RACD may be implemented within the household of the index case, or over a radius around the household or within the whole focus. |
| Malaria cases | |
| 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 Plasmodium vivax or P. ovale acquired previously. |
| Induced case | A case the origin of which can be traced to a blood transfusion or other form of parenteral inoculation of the parasite but not to transmission by a natural mosquito-borne inoculation |
| Recrudescent case | Recurrence of asexual parasitemia of the same genotype(s) that caused the original illness, due to incomplete clearance of asexual parasites after antimalarial treatment |
| Type of foci | |
| Active foci | A focus with ongoing transmission |
| Residual non-active foci | Transmission interrupted recently (1–3 years previously) |
| Cleared foci | A focus with no local transmission for more than 3 years and which is no longer considered residual non-active |
Source: “malaria-surveillance-monitoring-and-evaluation---a-reference-manual” (link: https://www.who.int › docs › default-source › documents › publications › gmp)