training module for medical officers primary health centre - NVBDCP

If ABER is satisfactory, API becomes the most important criterion to assess the malaria prevalencein the community.API is also used under the MPO for decision on spray operations.Annual Falciparum Index (AfI)AfI = Total number of blood smears positive for P.falciparum in a year x 1000Total populationIt is the proportion of total positives for P.falciparum infection in the total population under malariasurveillance.Similar interpretation should be applied to AfI as for API.Slide Positivity Rate (SPR)SPR = Total No. of blood smears found positive for malaria parasite x 100Total no. of blood smears examinedSPR is less dependent on ABER; it is more reliable than API even for those years when ABERfluctuates from year to year.Whenever the case detection mechanism is inadequate, this is a dependable parameter fordetermining the progress of containment measures.SPR assumes greater significance, if the ABER is low and gives better indication of parasite load inthe community.Slide Falciparum Rate (SfR)SfR = Total No. of blood smears found positive for P.falciparum x 100Total no. of blood smears examinedSfR is also less dependent on ABERIt pinpoints areas of P.falciparum preponderance for prioritizing control measures.P.falciparum percentage (Pf %)Pf % = Total no. of blood smears found positive for P.falciparum x 100Total no. of blood smears positive for malaria parasitePf % gives the relative proportion of P.falciparum infection and trends in relation to total case load.Any rise in P.falciparum percentage also indicates breakdown of malaria control activities leading tohigh morbidity and high mortality.Entomological parameters19