Table 1 Major Indices of Malaria Transmission: Advantages and Disadvantages
Index | What is Measured | Advantages | Disadvantages |
|---|---|---|---|
Entomological Inoculation Rate (EIR) | Infectious bites per unit time (usually per year) | Direct reflection of vector control and antigametocytocidal drugs | - No standard protocols - Variability in methodologies - Few trained specialists |
Parasite Rate (PR) | Proportion of the population found to carry asexual parasites in RBCs; can also assess gametocyte rates; by age group | Direct reflection of inoculations, immunity, and treatment effectiveness in humans | - Microscopy "gold standard"; lacks sensitivity - Prone to technical efforts - Changes may occur following environmental and control factors |
Annual Parasite Index (API) | Number of parasite infections in a well-defined geographical area; usually per 1,000 persons per year | Direct reflection of all prevention and control effects on humans | - Depends on active case detection system, which is often poor |
Spleen Rate (SR) | Proportion of children 2-9 years of age with a palpable spleen | Non-invasive, indirect way of measuring impact of malaria on spleen | - Variability in examiners; many causes of splenomegaly - Point prevalence measurements can vary/change rapidly |