Recommendations for building out mosquito-transmitted diseases in sub-Saharan Africa: the DELIVER mnemonic

Abstract

In sub-Saharan Africa, most transmission of mosquito-transmitted diseases, such as malaria or dengue, occurs within or around houses. Preventing mosquito house entry and reducing mosquito production around the home would help reduce the transmission of these diseases. Based on recent research, we make key recommendations for reducing the threat of mosquito-transmitted diseases through changes to the built environment. The mnemonic, DELIVER , recommends the following best practices: (i) D oors should be screened, self-closing and without surrounding gaps; (ii) E aves, the space between the wall and roof, should be closed or screened; (iii) houses should be L ifted above the ground; (iv) I nsecticide-treated nets should be used when sleeping in houses at night; (v) houses should be V entilated, with at least two large-screened windows to facilitate airflow; (vi) E nvironmental management should be conducted regularly inside and around the home; and (vii) R oofs should be solid, rather than thatch. DELIVER is a package of interventions to be used in combination for maximum impact. Simple changes to the built environment will reduce exposure to mosquito-transmitted diseases and help keep regions free from these diseases after elimination. This article is part of the theme issue ‘Novel control strategies for mosquito-borne diseases'.

The relationship between house height and mosquito house entry: an experimental study in rural Gambia

“…Raising houses off the ground, like any intervention, is not evolutionary proof, and over time, mosquitoes may adapt and feed higher off the ground than before. Nonetheless, we recommend elevating houses off the ground since they are likely to reduce mosquito biting and keep the occupants cooler at night [7] and therefore more likely to use an ITN. This research is likely to be relevant to many hot and humid parts of sub-Saharan Africa where An.…”

“…Similarly, a meta-analysis of 29 malaria surveys carried out in 21 sub-Saharan African countries between 2008 and 2015 found that modern housing was associated with a 9-14% reduction in the odds of malaria infection when compared with traditional housing, a level of protection comparable to ITNs in the same study [6]. Modern houses are more likely to have closed eaves (the gap between the top of the wall and the overhanging roof ), and screened windows and doors, all modifications known to reduce the entry of malaria mosquitoes into houses [7]. Completely closing a building in the hot humid tropics, however, will reduce ventilation and increase the temperature of the house before midnight, particularly if the roof is metal [8,9].…”

Risk factors associated with house entry of malaria vectors in an area of Burkina Faso with high, persistent malaria transmission and high insecticide resistance

“…Ultimately, whether a metal-roof house has more or less mosquitoes than a thatch-roof house will depend on how porous the house is to mosquitoes and the extent of ventilation [ 16 ]. Further research is needed to understand the importance of different house construction features on indoor climate and vector entry.…”

“…Several studies have demonstrated that malaria mosquito house entry can be reduced through simple changes to house design, such as closing eaves and screening windows and doors [ 16 ]. The use of personal protective measures such as ITNs and spatial repellents may also reduce transmission [ 17 , 18 ].…”

Novel control strategies for mosquito-borne diseases

“…Lindsay et al [30] explore relatively simple changes to the built environment, including the installation of tight-fitting screened doors, the closing or screening of eaves and replacement of thatched roofs with roofs made from solid materials, such as metal or tile. An important message is to combine a package of interventions for maximum impact.…”