Which index is calculated as the number of positive containers per 100 houses examined?

• A. Ovitrap Index
• B. House Index
• C. Container Index
• D. Breteau Index

Answer: (D)

This item is about how mosquito surveillance summarizes breeding sites. The Breteau Index is defined as the number of positive containers per 100 houses examined. It shows how widespread breeding sites are across the households you inspected, by relating every positive container to the number of houses visited. The calculation is BI = (positive containers / houses inspected) × 100.

For context, a House Index looks at the proportion of houses with at least one positive container (per 100 houses), a Container Index looks at the proportion of positive containers per 100 containers inspected, and an Ovitrap Index uses eggs found in ovitraps relative to the number of ovitraps placed. Because this definition explicitly ties positive containers to the number of houses examined, it matches the Breteau Index.