Role of Abandoned and Vacant Houses on Aedes aegypti Productivity

The control of container Aedes species by house inspections usually achieves insufficient coverage and impact because a percentage of residents are absent and some residents refuse inspections and treatments. In addition, another fraction of the buildings may be uninhabited, such as those for rent or sale, or abandoned. Although the productivity of Aedes aegypti has been investigated in abandoned lots, less is known about the importance of uninhabited buildings. We investigated Ae. aegypti pupal productivity in inhabited, vacant, and abandoned houses and its interaction with socioeconomic levels (SELs). We found pupae in containers of 386 houses (66 abandoned, 62 vacant, and 258 inhabited) in 19 neighborhoods in southern Puerto Rico from May to August 2017. Using a generalized linear model, we found a significant interaction between the status of the house (abandoned, vacant, and inhabited) and SELs (low, medium) on Ae. aegypti pupal abundance. More pupae were found in abandoned and inhabited houses of low SELs. The lowest productivity was found in vacant houses, regardless of the SEL. Most containers producing Ae. aegypti in low-SEL houses were discarded on backyards, whereas in medium SELs, most productivity came from containers in use. Septic tanks producing Ae. aegypti were found only in houses of low SELs, where most emerging mosquitoes came from inhabited houses. We did not find any pupae of Ae. aegypti on roofs. These results indicate that proper yard management could significantly reduce the production of Ae. aegypti and the risk of dengue infections in low-SEL neighborhoods.