1) Percentage of children age 6-59 months classified as having malaria according to a rapid diagnostic test (RDT).
2) Percentage of children age 6-59 months classified as having malaria according to microscopy.
Coverage:
Population base: De facto children age 6-59 months (PR file)
Time period: Current status at the time the blood sample was taken
Numerators:
1) Number of de facto children tested using RDT who are positive for malaria (hv042 = 1 & hv103 = 1 & hc1 in 6:59 & hml35 = 1)
2) Number of de facto children tested using microscopy who are positive for malaria (hv042 = 1 & hv103 = 1 & hc1 in 6:59 & hml32 = 1)
Denominators:
a) Number of de facto children tested using RDT (hv042 = 1 & hv103 = 1 & hc1 in 6:59 & hml35 in 0,1)
b) Number of de facto children tested using microscopy (hv042 = 1 & hv103 = 1 & hc1 in 6:59 & hml32 in 0,1,6)
Variables: PR file.
|
hv042 |
Household selected for hemoglobin |
|
hv103 |
Slept last night |
|
hc1 |
Child's age in months |
|
hml32 |
Final result of malaria from blood smear test |
|
hml35 |
Result of malaria rapid test |
|
hv005 |
Household sample weight |
Numerator divided by the denominator, multiplied by 100.
Children who were not tested and those children whose values were not recorded are excluded from both the denominator and the numerators.
Some studies of malaria interventions showing mortality reductions have found large decreases in parasite prevalence; however, other studies of control interventions have found that despite reductions in mortality, parasite prevalence changes little.
As measurement of parasite prevalence requires finger stick blood, some caretakers may not consent to parasitemia testing of their child. Additionally, survey personnel require extra training to use RDTs or to collect blood on slides for microscopy.
Parasite prevalence can fluctuate dramatically throughout the course of a year with the seasonality of malaria, and thus values of the indicator may be influenced by the timing of a survey in relation to peak transmission. Accordingly, parasite prevalence should not be used for tracking the short-term impact of scaling up prevention efforts, as the prevalence rates may merely reflect differences in the timing of surveys in relation to within year variation in parasite prevalence. Parasite prevalence is better suited to measuring changes in malaria burden of over a longer term during which changes in parasite prevalence are expected to be much greater and outweigh within-year variation. To demonstrate a reliable trend, no more than four data points within a ten-year span are generally needed.
When interpreting this indicator, the method of measuring parasite prevalence should be considered (microscopy vs. RDT). Microscopy detects parasites present in the blood at the time of the survey and therefore provides point parasite prevalence. By contrast, HRP2-based RDTs detect antigens to malaria parasites, which may endure for some weeks after treatment. This is especially important when interpreting trends over time, as parasite prevalence before the advent of RDTs was measured primarily using microscopy.
Microscopy testing used to be considered the gold standard for measuring malaria parasitemia prevalence in household survey settings. The Roll Back Malaria Monitoring and Evaluation Reference Group currently recommend using only RDTs in most settings.
Alegana, V.A., J. Wright, C. Bosco, E.A. Okiro, P.M. Atkinson, R.W. Snow, A.J. Tatem, and A.M. Noor. 2017. “Malaria prevalence metrics in low-and middle-income countries: an assessment of precision in nationally-representative surveys.” Malaria journal, 16(1), p.475. https://malariajournal.biomedcentral.com/articles/10.1186/s12936-017-2127-y
Dalrymple, U., R. Arambepola, P.W. Gething. and E. Cameron. 2018. “How long do rapid diagnostic tests remain positive after anti-malarial treatment?” Malaria journal, 17(1), p.228. https://malariajournal.biomedcentral.com/articles/10.1186/s12936-018-2371-9
Florey, Lia. 2014. Measures of Malaria Parasitemia Prevalence in National Surveys: Agreement between Rapid Diagnostic Testing and Microscopy. DHS Analytical Studies No. 43. Rockville, Maryland, USA: ICF International. https://dhsprogram.com/publications/publication-as43-analytical-studies.cfm
Florey, L., and C. Taylor. 2016. Using Household Survey Data to Explore the Effects of Improved Housing Conditions on Malaria Infection in Children in Sub-Saharan Africa. DHS Analytical Studies No. 61. Rockville, Maryland, USA: ICF International. https://dhsprogram.com/publications/publication-as61-analytical-studies.cfm
Roll Back Malaria Monitoring and Evaluation Reference Group Survey and Indicator Task Force. 2018. Household Survey Indicators for Malaria Control.
Zgambo, M., B.C. Mbakaya, and F.W. Kalembo. 2017. “Prevalence and factors associated with malaria parasitaemia in children under the age of five years in Malawi: A comparison study of the 2012 and 2014 Malaria Indicator Surveys (MISs).” PloS one, 12(4), p.e0175537. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0175537
DHS-8 Tabulation plan: Table 12.15
API Indicator IDs:
ML_PMAL_C_RDT, ML_PMAL_C_MSY
Household Survey Indicators for Malaria Control Indicator 12: Parasite prevalence: proportion of children aged 6-59 months with malaria infection