Date Published: March 11, 2016
Publisher: Public Library of Science
Author(s): Valerie A. Paz-Soldan, Karin Bauer, Amy C. Morrison, Jhonny J. Cordova Lopez, Kiyohiko Izumi, Thomas W. Scott, John P. Elder, Neal Alexander, Eric S. Halsey, Philip J. McCall, Audrey Lenhart, Pattamaporn Kittayapong. http://doi.org/10.1371/journal.pntd.0004409
Abstract: Dengue is an arthropod-borne virus of great public health importance, and control of its mosquito vectors is currently the only available method for prevention. Previous research has suggested that insecticide treated curtains (ITCs) can lower dengue vector infestations in houses. This observational study investigated individual and household-level socio-demographic factors associated with correct and consistent use of ITCs in Iquitos, Peru. A baseline knowledge, attitudes, and practices (KAP) survey was administered to 1,333 study participants, and ITCs were then distributed to 593 households as part of a cluster-randomized trial. Follow up KAP surveys and ITC-monitoring checklists were conducted at 9, 18, and 27 months post-ITC distribution. At 9 months post-distribution, almost 70% of ITCs were hanging properly (e.g. hanging fully extended or tied up), particularly those hung on walls compared to other locations. Proper ITC hanging dropped at 18 months to 45.7%. The odds of hanging ITCs correctly and consistently were significantly greater among those participants who were housewives, knew three or more correct symptoms of dengue and at least one correct treatment for dengue, knew a relative or close friend who had had dengue, had children sleeping under a mosquito net, or perceived a change in the amount of mosquitoes in the home. Additionally, the odds of recommending ITCs in the future were significantly greater among those who perceived a change in the amount of mosquitoes in the home (e.g. perceived the ITCs to be effective). Despite various challenges associated with the sustained effectiveness of the selected ITCs, almost half of the ITCs were still hanging at 18 months, suggesting a feasible vector control strategy for sustained community use.
Partial Text: Dengue viruses, transmitted primarily by the diurnal-biting mosquito, Aedes aegypti, are the cause of more human morbidity and mortality than any other arthropod-borne virus, with an estimated 96 million apparent infections and an additional 294 million inapparent infections occurring globally in 2010 . The Americas are one of the most affected areas in the world, and in 2013 had the largest number of cases ever reported in that region—2.3 million—of which 37,692 were severe and 1,208 resulted in death  Peru bears a substantial portion of the disease burden in the Americas, with 11,816 cases and 16 deaths reported in 2013 . In particular, the Department of Loreto, where this study was conducted, experienced nearly a third of the country’s cases in 2013, with 3,542 cases reported .
Our analysis revealed that perceived effectiveness (e.g. seeing a change in the amount of mosquitoes in the home) was significantly associated with two of our measures for correct and consistent use: having the ITCs hanging (even if tied up) and washing the ITCs correctly (Table 5). However, despite the ease of use of the ITCs, the use of the ITCs decreased from 68.6% at 9 months to 45.7% at 18 months after distribution. Two similar studies–one in Venezuela and Thailand on ITCs for dengue prevention, and another in Ethiopia on ITNs for malaria prevention–also found a decrease in usage over time, and found that long-term use of the ITCs was associated with perceived effectiveness: when participants perceived that their ITNs had lost effectiveness, they stopped using them [21,28]. Although the perception of effectiveness was high in our study at 9 and 27 months (over 90% reporting they felt ITCs worked well at both times), there was a high percentage of participants who perceived that the change in the amount of mosquitoes lasted only a few months (34.9% at 9 months, 55.7% at 27 months), which might have affected use or explain why so many ITCs were no longer in place at 18 months. However, the association between perception of effectiveness and future use of the ITCs was still significant at 27 months after distribution, and the odds of recommending ITCs to friends or family in the future was significantly higher among those who did perceive the ITCs to be effective (Table 5).