STUDY TYPE 2: SUMMARY The goal of this project is to conduct mixed methods, social network-based, socio-behavioral studies to determine what types of malaria-preventive interventions reduce malaria through good coverage and use, and to identify demand and/or supply side barriers to malaria control measures in the northeastern state of Meghalaya, India. In this area the malaria situation is dynamic. Cases steadily increased from 2012-2015, but since then there has been a downward trend, and 2017 had the fewest cases ever reported. This steep decline has been attributed to the distribution of long-lasting insecticide impregnated bednets (LLINs) in 2016 and partial adoption of indoor residual spraying (IRS) with DDT. Nevertheless, residual cases remain endemic, and to design an appropriate elimination strategy, we must try to understand the reasons for these cases. Data from the Meghalaya Department of Health Malaria Division and from the Center for the Study of Complex Malaria in India (CSCMi) ongoing epidemiology studies suggest that community resistance to IRS, misuse of LLINs, unprotected outdoor activity, and hidden reservoirs of asymptomatic, submicroscopic, and hypnozoite infections all contribute to the endemic persistence of malaria. At Barato PHC (primary health center) and Nonglang PHC in Meghalaya, 10 villages in each site will be subjects of epidemiological studies funded through the parent CSCMi 2.0 grant. In Aim 1 we plan to examine how malaria-preventive measures are adopted in practice, using ethnographic methods of non-participant observations; in Aim 2 we will explore the cultural and social barriers preventive measures may face, using qualitative interviews and focus group discussions (FGDs); and in Aim 3 we will assess which community members are most likely to influence villagers to accept or reject such measures, using social network analysis surveys. When these Aims have been concluded, their findings will be summarized and integrated with those of other CSCMi studies (epidemiology, vector) underway at the Barato and Nonglang PHCs into a malaria situation analysis for the villages involved. This will yield a better understanding of the focal malaria epidemiology, as well as barriers and opportunities to current interventions used (e.g., LLINs, IRS), and possibilities for additional interventions (e.g., treatment of household members of malaria cases). It will also enable us to provide recommendations to the state malaria control program for additional measures that are likely to foster or improve the effectiveness of IRS and LLINs, with the long-term objective of complete elimination of malaria in Meghalaya.