Browsing by Author "Neal Alexander"
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- PublicationAssociation between Landscape Factors and Spatial Patterns of Plasmodium knowlesi Infections in Sabah, Malaysia(2016)
;Kimberly M. Fornace ;Tommy Rowel Abidin ;Neal Alexander ;Paddy Brock ;Matthew J. Grigg ;Amanda Murphy ;Timothy William ;Jayaram Menon ;Chris J. DrakeleyJonathan CoxThe zoonotic malaria species Plasmodium knowlesi has become the main cause of human malaria in Malaysian Borneo. Deforestation and associated environmental and population changes have been hypothesized as main drivers of this apparent emergence. We gathered village-level data for P. knowlesi incidence for the districts of Kudat and Kota Marudu in Sabah state, Malaysia, for 2008-2012. We adjusted malaria records from routine reporting systems to reflect the diagnostic uncertainty of microscopy for P. knowlesi. We also developed negative binomial spatial autoregressive models to assess potential associations between P. knowlesi incidence and environmental variables derived from satellite-based remote-sensing data. Marked spatial heterogeneity in P. knowlesi incidence was observed, and village-level numbers of P. knowlesi cases were positively associated with forest cover and historical forest loss in surrounding areas. These results suggest the likelihood that deforestation and associated environmental changes are key drivers in P. knowlesi transmission in these areas. - PublicationTargeted outdoor residual spraying, autodissemination devices and their combination against Aedes mosquitoes: field implementation in a Malaysian urban setting(Cambridge University Press, 2020)
;Nurulhusna Ab Hamid ;Neal Alexander ;Remco Suer ;Nazni Wasi Ahmed ;Rose Nani Mudin ;Topek Omar ;Rahmat Dapari ;Shahrom Nor Azian Che Mat Din ;Roslinda Abdul Rahman ;Ropiah Jaraee ;Frederic Baur ;Frederic Schmitt ;Nick Hamon ;Jason H. Richardson ;Carole Langlois-Jacques ;Muriel RabilloudMitra Saadatian-ElahiCurrently, dengue control relies largely on reactive vector control programmes. Proactive vector-control using a rational, well-balanced integrated vector management approach may prove more successful for dengue control. As part of the development of a cluster randomized controlled epidemiological trial, a study was conducted in Johor Bahru, Malaysia. The study included one control site (three buildings) and three intervention sites which were treated as follows: targeted outdoor residual spraying only (TORS site, two buildings); deployment of autodissemination devices only (ADD site, four buildings); and the previous two treatments combined (TORS + ADD site, three buildings). The primary entomological measurement was per cent of positive ovitraps—ovitrap index (OI). The effect of each intervention on OI was analyzed by a modified ordinary least squares regression model. Relative to the control site, the TORS and ADD sites showed a reduction in the Aedes OI (−6.5%, P = 0.04 and −8.3%, P = 0.10, respectively). Analysis by species showed that, relative to control, the Ae. aegypti OI was lower in ADD (−8.9%, P = 0.03) and in TORS (−10.4%, P = 0.02). No such effect was evident in the TORS + ADD site. The present study provides insights into the methods to be used for the main trial. The combination of multiple insecticides with different modes of action in one package is innovative, although we could not demonstrate the additive effect of TORS + ADD. Further work is required to strengthen our understanding of how these interventions impact dengue vector populations and dengue transmission.