Navy Medical Entomology Research in Southeast Asia . LT Kathryn A. Barbara US Naval Medical Research Unit #2 Jakarta, Indonesia DoD Pest Management Workshop, Feb 8-12, 2010 . Disclaimer.
Navy Medical Entomology Research in Southeast Asia LT Kathryn A. Barbara US Naval Medical Research Unit #2 Jakarta, Indonesia DoD Pest Management Workshop, Feb 8-12, 2010
Disclaimer The opinions or assertions expressed herein are the private views of the authors and are not to be construed as representing those of the US Navy, the Department of Defense, or the Cambodia, Singapore, or Indonesia Ministry of Health.
Effect of Land Use on Malaria Vector Diversity and Distribution in Pursat Province, Cambodia K. A. Barbara, S. Rusmiarto, R. Pudiantari, A. Farzeli, I. Nurlaila, and S. Sovannaroth2 US Naval Research Unit No. 2 Jakarta, Indonesia 2 The National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
Effect of Land Use on Malaria Vector Diversity and Distribution in Pursat Province, Cambodia • Before 1970 over 73% of Cambodia was forest cover, currently 58% (70% primary forest in 1970, 3.1% currently) • Rate of deforestation in Cambodia: • 1990-2005: 19.3% lost = 2,499,00 hectares (444,000 hectares primary forest) • Annual Change 2000-2005: 218,800 ha • Deforestation in Cambodia is driven by • agricultural development/expansion • road construction • mining • hydropower development • extensive commercial forest exploitation
Effect of Land Use on Malaria Vector Diversity and Distribution • Conduct bionomics studies in areas bordering old forest growth and areas cleared of forest trees and reestablished as small agricultural areas • Hypotheses: • Anopheles dirus will be the most abundant Anopheles spp. collected bordering the primary forest areas. • An. minimus (Theobald) will be the most abundant Anopheles spp. collected in the areas cleared for agricultural use. • An. dirus will be the main malaria vector in the forest sites; An. minimus will be the dominant malaria vector in the agriculture site.
Mosquito Collections • Collections were conducted from October 2008 to January 2009 • Indoor/outdoor, 12h human landing collections (1800-0600) over 8 days • 8 houses served as permanent collection sites • 22 nights (agricultural site), 23 nights (forest site)
Agricultural ~ 4km Forest
Results HBR = mosquitoes/human/12 hour collection period * Significance at p < 0.05
Discussion • An. dirus HBRhighest inFOREST • An. maculatus HBR highest inAGRICULTURE • An. minimus more prevalent in agriculture site • An. dirus prevalent mosquito in both locations • Forest mosquitoes occasionally collected at forest fringes • Highly anthropophilic- our results show no significant difference between indoor and outdoor collections • Very difficult to control
ELISA Results(Preliminary) • Pv = P. vivax • Pf = P. falciparum • An. dirus collected from forest not yet tested • An. maculatus not yet tested
PCR ResultsAnopheles minimus s.l.(Preliminary) Percent of individuals identified morphologically as An. minimus
Conclusion • Literature states deforestation may reduce the populations of An. dirus followed by invasion by other efficient vectors such as An. maculatus and An. minimus. Our data agrees with this and also suggests reestablishment of An. dirus in former forested areas. • Species complex members demonstrate different behaviors, need to fully elucidate which members are present IN PROGRESS • Correlate CSP+ data with species complex identification data IN PROGRESS
Future Study • Observe one complete year (wet and dry seasons) of anopheline population bionomics. • Determine which vectors are most efficient and how habitat change will drive infection • Correlate mosquito infection rates with human malaria prevalence in the two sites • Larval surveillance compare with adult bionomics information • Susceptibility of species complex members to current methods of control (insecticide treated bed nets, pesticides)
Control of Adult Mosquito Vectors on Military Installations in Singapore Using Mass Trapping Techniques K. A. Barbara1, A. Wilson2, L. C. Ng3, C. H. Tan3, and G. T. Brice1 1US Naval Medical Research Unit #2 2Navy Region Center Singapore 3Singapore National Environment Agency
Navy Region Center Singapore Mass Trapping • To determine the efficacy of a commercial mosquito trap (Mosquito Magnet Liberty Plus) in reducing prevalence of disease infected mosquito populations in a designated area • Correlate trap catch with prevalence of infected mosquitoes and overall reduction in mosquito populations • Determine the species composition and infection ratio of collected vectors
Navy Region Center Singapore Mass Trapping • 2 weeks CDC light trap “pre-treatment” surveillance (baseline) • Trap line of 4 Mosquito Magnets in three areas with CDC light traps in control and treatment areas • 6 week “treatment” period • 2 weeks “post-treatment” surveillance
Navy Region Center Singapore Mass Trapping • Study initiated in January 2010 • Currently collecting data • First field trial scheduled to be completed in March • Second field trial to be conducted on Singapore Armed Forces training grounds • FY11 funding requested to continue study on islands off the coast of Cambodia and Indonesia
Future Studies NAMRU2 Entomology • FY10 Febrile Syndrome Surveillance in Cambodia (vector component) • FY10/FY11 Mass Trapping on islands off Cambodia and Palau Seribu area near Jakarta • FY12 Field collections of vectors to be tested using rapid dipstick testing being developed at WRAIR
Acknowledgements • The National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia • National Environment Agency, Singapore • Navy Region Center Singapore Public Works • NAMRU2 entomology laboratory staff