Improved dengue fever prevention through innovative intervention methods in the city of Salto, Uruguay

Abstract

BackgroundUruguay is located at the southern border of Aedes aegypti distribution on the South American sub-continent. The reported dengue cases in the country are all imported from surrounding countries. One of the cities at higher risk of local dengue transmission is Salto, a border city with heavy traffic from dengue endemic areas.MethodsWe completed an intervention study using a cluster randomized trial design in 20 randomly selected ‘clusters’ in Salto. The clusters were located in neighborhoods of differing geography and economic, cultural and social aspects.ResultsEntomological surveys were carried out to measure the impact of the intervention on vector densities. Through participatory processes of all stakeholders, an appropriate ecosystem management intervention was defined. Residents collected the abundant small water holding containers and the Ministry of Public Health and the Municipality of Salto were responsible for collecting and eliminating them. Additional vector breeding places were large water tanks; they were either altered so that they could not hold water any more or covered so that oviposition by mosquitoes could not take place.ConclusionsThe response from the community and national programme managers was encouraging. The intervention evidenced opportunities for cost savings and reducing dengue vector densities (although not to statistically significant levels). The observed low vector density limits the potential reduction due to the intervention. A larger sample size is needed to obtain a statistically significant difference.

Assessing the effects of interventions for Aedes aegypti control: systematic review and meta-analysis of cluster randomised controlled trials

“…Our findings are similar to those reported by Bowman in 2016, where community based interventions for dengue vector control showed higher impact than those using insecticide-treated curtains [25]. The four CRCTs of community participation in our review reported continuation of government vector control (usually temephos application and area fumigation) in both intervention and control sites [46, 47, 52, 53]. The observed decreases in the HI, CI and BI represent added effectiveness from community mobilisation.…”

“…BI significantly lower at 15 m. PPI significantly reduced in intervention clusters.Household and community involvement helped reduce solid waste containers which are major site of dengue breeding.Castro (2012) Cuba [49]Oct 2004 –Dec 2007Participatory strategy:> Organisation and management structures  > entomological risk surveillance>capacity building at local & intermediate level>community work in vector control, led by community working groups (CWGs) who visited HH, planned actionsGovernment routine vector control programme continued16389Government routine vector control programme: House inspections, temephos to water containers, space spraying with cypermethrin or cloripyriphos, health education, fines for law infringements16390BI measured monthly from government surveillance figures before and during intervention from mid 2005 to Dec 2007.Over the intervention period, the BI remained significantly lower in the intervention clusters than in the control clusters; the difference was bigger after the CWGs began their activities.The empowerment strategy increased community involvement and added effectiveness to routine vector control.Caprara (2015) Brazil [50]Jun 2012 – May 2013>Community workshops>Mobilising elders and schoolchildren for solid waste management>Government workers encouraged covering water containers>Educational materials101689Routine government vector control programme.101580HI, CI, BI, PPI measured at baseline and 6 mAll indices significantly lower in the intervention clusters at 6 m.Social participation and environmental management is feasible and significantly reduced vector indices.Mitchell-Foster (2015)Ecuador [51]Nov 2012 – Nov 2013An integrated intervention strategy (IIS)>Elementary school education programme>Clean Patio Safe Container programme with community volunteer activators10993Government control programme:>Initially temephos and space spraying with insecticide>Midway, changed to biolarvicide (Bti) and HH education for source reduction10993HI, BI and PPI measured at baseline and 12 mPPI was significantly reduced in intervention clusters vs the control clusters (now with Bti) but only when clusters without full implementation were excluded.Complicated by change in government programme midway through trial period. Need to explore integration of biolarvicide with the IIS approach.Basso (2015) Uruguay [52]MANov 2012 – Apr 2013Campaign with community members & health institutions for removal of water containers around households (bags with containers collected). Engagement of community opinion makers, leaflets, & press conference.101000Routine removal of the containers by services101000BI, CI, HI, PPI & PHI measured at baseline and 5 m (1 m after intervention)The increase in indices from dry t...…”

Innovative community-based vector control interventions for improved dengue and Chagas disease prevention in Latin America: introduction to the special issue

“…The Uruguay study 17 was carried out in the city of Salto, in northwestern Uruguay, on the border with Argentina, a city that currently does not face dengue transmission due to the marked seasonality of vector breeding. The intervention targeted productive container types and included household-based awareness and communication strategies, local media campaigns, roundtable discussions with doctors and health workers, and a partnership with the departmental health authorities.…”

Yellow fever in China is still an imported disease

“…Health program planners should improve people's knowledge of yellow fever prevention and control, inform the public that mosquitoes are vectors for transmission of yellow fever, and educate the public to instill hygiene in daily life to eliminate breeding grounds. In a successful approach to control of dengue fever in Uruguay, the public collected containers that could hold water where mosquitoes could breed and the Government then disposed of those containers (30). Large cisterns need to be covered, modified so that they no longer hold water, or treated with long-lasting larvicide.…”