Cost-sharing strategies combining targeted public subsidies with private-sector delivery achieve high bednet coverage and reduced malaria transmission in Kilombero Valley, southern Tanzania

Background: Cost-sharing schemes incorporating modest targeted subsidies have promoted insecticide-treated nets (ITNs) for malaria prevention in the Kilombero Valley, southern Tanzania, since 1996. Here we evaluate resulting changes in bednet coverage and malaria transmission. Methods: Bednets were sold through local agents at fixed prices representing a 34% subsidy relative to full delivery cost. A further targeted subsidy of 15% was provided to vulnerable groups through discount vouchers delivered through antenatal clinics and regular immunizations. Continuous entomological surveys (2,376 trap nights) were conducted from October 2001 to September 2003 in 25 randomly-selected population clusters of a demographic surveillance system which monitored net coverage. Results: Mean net usage of 75 % (11,982/16,086) across all age groups was achieved but now-obsolete technologies available at the time resulted in low insecticide treatment rates. Malaria transmission remained intense but was substantially reduced: Compared with an exceptionally high historical mean EIR of 1481, even non-users of nets were protected (EIR [fold reduction] = 349 infectious bites per person per year [×4]), while the average resident (244 [×6]), users of typical nets (210 [×7]) and users of insecticidal nets (105 [×14]) enjoyed increasing benefits. Conclusion: Despite low net treatment levels, community-level protection was equivalent to the personal protection of an ITN. Greater gains for net users and non-users are predicted if more expensive long-lasting ITN technologies can be similarly promoted with correspondingly augmented subsidies. Cost sharing strategies represent an important option for national programmes lacking adequate financing to fully subsidize comprehensive ITN coverage

Non-destructive determination of age and species of Anopheles gambiae s.l. using near-infrared spectroscopy

Determining malaria vector species and age is crucial to measure malaria risk. Although different in ecology and susceptibility to control, the African malaria vectors Anopheles gambiae sensu stricto and An. arabiensis are morphologically similar and can be differentiated only by molecular techniques. Furthermore, few reliable methods exist to estimate the age of these vectors, which is a key predictor of malaria transmission intensity. We evaluated the use of near-infrared spectroscopy (NIRS) to determine vector species and age. This non-destructive technique predicted the species of field-collected mosquitoes with approximately 80% accuracy and predicted the species of laboratory-reared insects with almost 100% accuracy. The relative age of young or old females was predicted with approximately 80% accuracy, and young and old insects were predicted with ≥ 90% accuracy. For applications where rapid assessment of the age structure and species composition of wild vector populations is needed, NIRS offers a valuable alternative to traditional methods. Copyright © 2009 by The American Society of Tropical Medicine and Hygiene

Crude biting rate estimates for mosquitoes (B) and monthly rainfall measurements in the Kilombero Valley during the study period

<p><b>Copyright information:</b></p><p>Taken from "Cost-sharing strategies combining targeted public subsidies with private-sector delivery achieve high bednet coverage and reduced malaria transmission in Kilombero Valley, southern Tanzania"</p><p>http://www.biomedcentral.com/1471-2334/7/121</p><p>BMC Infectious Diseases 2007;7():121-121.</p><p>Published online 25 Oct 2007</p><p>PMCID:PMC2211306.</p><p></p> Thin solid line: ; thick solid line: ; thin dotted line: species

Relationship between reported net usage (proportion of people sleeping under nets) and net ownership (number of nets per person)

<p><b>Copyright information:</b></p><p>Taken from "Cost-sharing strategies combining targeted public subsidies with private-sector delivery achieve high bednet coverage and reduced malaria transmission in Kilombero Valley, southern Tanzania"</p><p>http://www.biomedcentral.com/1471-2334/7/121</p><p>BMC Infectious Diseases 2007;7():121-121.</p><p>Published online 25 Oct 2007</p><p>PMCID:PMC2211306.</p><p></p

The distribution of sex and physiological status of mosquitoes caught in CDC light traps during the course of the study

<p><b>Copyright information:</b></p><p>Taken from "Cost-sharing strategies combining targeted public subsidies with private-sector delivery achieve high bednet coverage and reduced malaria transmission in Kilombero Valley, southern Tanzania"</p><p>http://www.biomedcentral.com/1471-2334/7/121</p><p>BMC Infectious Diseases 2007;7():121-121.</p><p>Published online 25 Oct 2007</p><p>PMCID:PMC2211306.</p><p></p