Background. In recent years, Tanzania's National Malaria Control Program (NMCP), with the support of USAID, has implemented an incremental Insecticide Treated Net (ITN) distribution program which intended to distribute nets to all households with pregnant women and children under 5 in late 2009, and then to all households in early 2011.

Methods. Cross-sectional randomized household surveys were conducted in the rural village of Kijumbura, in northwestern Tanzania during the summers of 2009 (before the bednet distribution), 2010 (after distribution to women and children), and 2011 (after universal distribution). Data were collected on ownership and usage of ITNs through interviews with household heads, and malaria prevalence was assessed using a Rapid Diagnostic Test (RDT) on each available household member.

Results. From 2009 to 2011, a total of 285 households were visited and data were obtained for 1,318 individuals. The point prevalence of malaria decreased from 15.8 percent in 2009 to 6.5 percent in 2010 (χ ²=17.9, p<0.001), and increased from 6.5 percent in 2010 to 10.7 percent in 2011 (not statistically significant at the p=0.05 level). Individual net usage increased each year from 9.7 percent in 2009 to 22.2 percent in 2010 (χ²=22.49, p<0.001) and then to 55.3 percent in 2011 (χ²=54.65, p<0.001). Net usage was associated with decreased malaria in 2009 and 2010 but not in 2011. The largest increase in net usage was seen in participants over age 5. Older age or age under 5 and household head receiving bednet or malaria education were associated with increased individual bednet use and decreased malaria incidence.

Conclusions. The 2009 and 2011 distributions succeeded in increasing bednet coverage in the village of Kijumbura. However, in 2011 increased bednet use was not associated with decreased malaria, possibly due to factors such as weather fluctuations or incorrect use that should be addressed with further studies.