Question
Which of the following is the most sensitive indicator for surveillance of recent malaria transmission in a community?
| A. | Spleen rate |
| B. |
Parasite density index |
| C. |
Infant parasite rate |
| D. |
Proportional case rate |
|
Correct Answer » C Explanation |
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Surveillance in malaria involves tracking the extent and intensity of transmission in a population. Several indices are used for this purpose, but sensitivity refers to how early and reliably the indicator can detect the presence of transmission.
Infant Parasite Rate (IPR):
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Defined as the percentage of infants (under 1 year of age) who test positive for malaria parasites.
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It reflects recent transmission, since infants would only acquire the infection recently (no long-term exposure).
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Hence, it is considered the most sensitive index for ongoing or new malaria transmission in an area.
Reasons to Rule Out Other Options:
A. Spleen rate
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Measures proportion of children (2–10 years) with enlarged spleens.
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Useful for endemicity classification, but less sensitive for current or recent transmission.
B. Parasite density index
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Measures parasite load in positive individuals.
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Indicates severity, not necessarily transmission dynamics.
D. Proportional case rate
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Refers to the proportion of malaria cases out of all reported illnesses.
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Less specific and not as sensitive for detecting fresh transmission.