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Additional file 1. Supplementary information on methods, data and findings.

Additional file 1: Survey organization and Implementation.

Additional file 2: Analytical procedure for HFs data.

Maps of infection risk are a vital tool for the elimination of malaria. Routine surveillance data of malaria case counts, often aggregated over administrative regions, is becoming more widely available and can better measure low malaria risk than prevalence surveys. However, aggregation of case counts over large, heterogeneous areas means that these data are often underpowered for learning relationships between the environment and malaria risk. A model that combines point surveys and aggregated surveillance data could have the benefits of both but must be able to account for the fact that these two data types are different malariometric units. Here, we train multiple machine learning models on point surveys and then combine the predictions from these with a geostatistical disaggregation model that uses routine surveillance data. We find that, in tests using data from Colombia and Madagascar, using a disaggregation regression model to combine predictions from machine learning models trained on point surveys improves model accuracy relative to using the environmental covariates directly.

Background: Malaria is a complex health problem related to socio-economic and environmental factors that cut across a number of sectors. Establishing intersectoral linkages is important to facilitate joint efforts to address the problem at all levels. The objectives of this study were to explore key sectoral engagements in malaria control policy formulation and implementation, and to determine decision and policy makers’ opinions about different sectoral activities that contribute to malaria transmission and control in Tanzania.Methods: This study included documentary review, self-administered interviews and group discussion. Interviews and group discussions involved key informants at district and national levels. The sectors involved were health, agriculture, environment, livestock, fisheries, education, works, irrigation, water resources, land development, forestry, and community development.Results: Institutions and organizations that were involved in the development of the previous and current National Malaria Strategic Plan (2007-2013 and 2013-2020) were the Ministries of Health and Social Welfare, Prime Minister’s Office of Regional Administration and Local Government, Public universities and non-governmental organizations. All the individuals involved in the development of the plans were either medical or health professionals. According to key informants, sectoral activities identified to contribute to malaria transmission included farming systems, deforestation, fishing, nomadic pastoralism, household water storage, water resource development projects, road and house construction and mining. The lack of intersectoral approaches in malaria control programme included the facts that the Health Sector does not involve other sectors during planning and development of policy guidelines, differences in sectoral mandates and management culture, lack of a national coordinating framework and lack of budget for intersectoral activities.Conclusion: The current strategies for malaria control in Tanzania need to address socio-economic and development activities across sectors and emphasise the need for intersectoral collaboration. It is recommended that the future of malaria control strategies should, therefore, be broad based and intersectoral in planning and implementation.

Malaria is a complex health problem that cuts across a number of sectors. Establishing intersectoral linkages is important to facilitate joint efforts to address the problem at the national, district and community levels. The objectives of this study were to explore key stakeholder engagement in malaria control policy formulation and implementation; and to determine decision and policy makers’ opinions as regards to different sectoral activities that contribute to malaria transmission and control and the likelihood that an intersectoral approach in malaria control will be adopted in Tanzania. This study included document analysis, self-administered interviews and group discussions. Interviews and group discussions involved key stakeholders at district and national levels. The sectors involved were health, agriculture, environment, livestock, fisheries, education, works, irrigation, water resources, land development, forestry, and community development. The Ministry of Health and Social Welfare (MoHSW) and the Prime Minister’s Office for Regional Administration and Local Government (PMORALG) were the two key ministries involved in malaria control in both policy formulations and guidelines. Sectoral activities that contribute to malaria transmission to include farming systems, deforestation, fishing, nomadic pastoralism, household water storage, water resource development projects, road/ house construction, brick making, mining, and water drainage systems. The lack of intersectoral approaches in malaria control programme included the fact that the MoHSW does not involve other sectors during planning and development of policy guidelines; different sectoral mandates; differences in disciplines and management culture; lack of a national coordinating body; lack of budget for intersectoral activities, and selfishness among sectors to share resources. In conclusion, the current strategies for malaria control in Tanzania must address issues of livelihoods and human development activities and emphasise the need for intersectoral collaboration. It is recommended that all development projects take into account the potential for an adverse impact on malaria and other health problems. The future of malaria control strategy should therefore, be broad based, and intersectoral in planning and operation.

Over the years, malaria has remained the number one cause of morbidity and mortality in Tanzania. Population based studies have indicated a decline in overall malaria prevalence among under-fives from 18.1% in 2008 to 9.7% in 2012. The decline of malaria infection has occurred in all geographical zones of the country. Malaria mortality and cumulative probability of deaths have also shown a marked decline from 2000 to 2010. During the same period, area specific studies in Muheza, Korogwe, Muleba and Mvomero have also reported a similar declining trend in malaria prevalence and incidence. The decline in malaria prevalence has been observed to coincide with a decline in transmission indices including anopheline mosquito densities. The decline in malaria prevalence has been attributed to a combination of factors including improved access to effective malaria treatment with artemisinin combination therapy and protection from mosquito bites by increased availability of insecticide treated bednets and indoor residual spraying. The objective of this paper was to review the changing landscape of malaria and its implication for disease management, vector control, and livelihoods in Tanzania. It seeks to examine the links within a broad framework that considers the different pathways given the multiplicity of interactions that can produce unexpected outcomes and trade-offs. Despite the remarkable decline in malaria burden, Tanzania is faced with a number of challenges. These include the development of resistance of malaria vectors to pyrethroids, changing mosquito behaviour and livelihood activities that increase mosquito productivity and exposure to mosquito bites. In addition, there are challenges related to health systems, community perceptions, community involvement and sustainability of funding to the national malaria control programme. This review indicates that malaria remains an important and challenging disease that illustrates the interactions among ecosystems, livelihoods, and health systems. Livelihoods and several sectoral development activities including construction, water resource development and agricultural practices contribute significantly to malaria mosquito productivity and transmission. Consequently, these situations require innovative and integrative re-thinking of the strategies to prevent and control malaria. In conclusion, to accelerate and sustain malaria control in Tanzania, the prevention strategies must go hand in hand with an intersectoral participation approach that takes into account ecosystems and livelihoods that have the potential to increase or decrease malaria transmission.

The endemicity of malaria in Tanzania is heterogenous, mainly associated with physical factors such as topography, climate and socio-economic status. The contributions of these factors in many regions of Tanzania have not been studied in detail. This study was carried out to determine the prevalence and transmission of malaria and mosquito nets coverage among schoolchildren in relation to altitude in villages with or without healthcare facilities in Iringa District,Tanzania. A cross-sectional survey of schoolchildren was carried out in six villages in three altitude transects (965-2075 m). In each transect a village with and without a healthcare facility were selected. The villages included Idodi (965m), Makifu (985m), Tosamaganga (1561m) Mangalali (1520m) Lulanzi (1917) and Kilolo (2075m). For the purpose of this study, the villages were categorised as lowlands (Idodi and Makifu), intermediate (Tosamaganga and Mangalali) and highlands (Lulanzi and Kilolo. Healthcare facilities were available at Idodi,Tosamaganga and Kilolo. Each child was asked whether or not slept under a mosquito net during the previous night. Mosquitoes were collected using pyrethrum spray catch technique in ten houses in each study village. Blood smears from a total of 1643 schoolchildren (mean age = 5.9-12.3 years) were examined for malaria infection. Plasmodium falciparum accounted for 93.1% of the malaria parasites. The prevalence of P. falciparum among children in Idodi, Makifu, Mangalali,Tosamaganga, was 51.51%, 73.66%, 22.79%, and 14.83%, respectively. Malaria parasites were not found among children in the highland villages of Lulanzi and Kilolo). The prevalence of malaria parasitaemia, packed cell volume, geometric mean parasite density and spleen rates were higher in children living in villages without healthcare facilities (P