Assessing the Intrinsic and Extrinsic Drivers and Targeting the Observed Resilience of Malaria in Northwestern and Southern Tanzania: A Protocol for a Cross-Sectional Exploratory Study

Abstract

Background Despite high coverage and successes in malaria control strategies, some areas of Tanzania have indicated stagnantion or revesal of malaria burden. In malaria research, most studies are designed to assess drivers of malaria transmission focusing only on one dimension, single location while very few studies assess multiple components and their interactions. This article describes the protocol used to assess intrinsic and extrinsic drivers of persistent malaria transmission (hotsposts) in four regions from northwestern (Geita and Kigoma) and southern (Ruvuma and Mtwara) Tanzania.Results: Preliminary results show that 6,297 HHs and 28,361 individuals with median age of 16yrs (IQR= 7-35yrs) were registered from the 16 villages. Over 49% of individuals used bed-nets in the previous night before the survey and 43.9% of HHs had bed-nets covering two members per household. For parasitological survey, 25.8% of registered individuals (n=7,313) were selected from 2,527 HHs (40.1%) and invited for assessment and sampling. The positivity rate (PR) by mRDTs was 33.3% (range = 21.9% to 41.1%); while by microscopy, the PR was 20.6% and varied from 8.0% to 29.0%. Socio-anthropology interviews were conducted with a total of 1,687 heads/representatives of HHs. For qualitative surveys 32 Focus group discussion (two from each village) and 16 key informant interviews (two per district) were conducted. Thirty-one health facilities were visited for health system survey; 19.4% (n=6) were hospitals; 41.9% (n=13) health centres and 38.7% (n=12) dispensaries. For entomological survey, 8,891 adult mosquitoes were collected, whereby Anopheles gambiae complex, An. funestus group and other mosquitoes accounted for 12.0%, 49.7% and 38.3%, respectively.Conclusion: An analysis plan using data from the five components surveyed has been proposed and results from this study are expected to determine factors potentially responsible for persistence of malaria (hotspots) in the study areas. Rather than the traditional methodology of focusing on one metric, the approach will triangulate observations from all five components, highlighting understanding of potential drivers while studying their complex interactions and map spatial heterogeneity. This study will provide an important framework and data which will guide future studies and malaria surveillance in Tanzania and other malaria endemic countries.

Describing the current status of Plasmodium falciparum population structure and drug resistance within mainland Tanzania using molecular inversion probes

“…2017). All individuals in 120 households from two villages selected from each district were tested for malaria, representing both symptomatic and asymptomatic malaria cases in adults and children (Chiduo et al, 2020). Parasitaemia (microscopy) was available for these subjects.…”

“…For the cross-sectional studies, 552 samples were collected between July and November 2017 from eight districts (Chato, Nyan'ghwale, Buhigwe, Uvinza, Nyasa, Tunduru, Nanyumbu, and Mtwara) with historically high transmission (Chacky et al, 2018; Ministry of Health, Community Development, Gender, Elderly, and Children (MoHCDGEC) (Tanzania Mainland) et al 2017). All individuals in 120 households from two villages selected from each district were tested for malaria, representing both symptomatic and asymptomatic malaria cases in adults and children (Chiduo et al, 2020).…”

Community-based surveys for Plasmodium falciparum pfhrp2 and pfhrp3 gene deletions in selected regions of mainland Tanzania

“…Two districts with high prevalence in the SMPS of 2014/2015 were purposively selected from each region; Nyang’hwale and Chato (Geita), Buhigwe and Uvinza (Kigoma), Mtwara DC and Nanyumbu (Mtwara) and Nyasa and Tunduru (Ruvuma). Within each district, two villages were purposively selected for sampling based on the malaria parasite positivity rates as reported from health facility reports, making a total of 16 villages sampled all members of the selected households (HHs) were asked to participate in the survey [37]. Blood samples were collected by finger prick, thin and thick films were prepared, and all study participants were screened with malaria mRDT as per the manufacturer’s instructions.…”

“…The database and the different data collection applications were created using the Open Data Kit (ODK) software. Data cleaning, validation and quality control were undertaken as described by Chiduo et al [37]. The data was later transferred to Microsoft Excel (Redmond, WA, USA) and STATA software (Texas, USA) used for analysis which involved generating a summary of basic features of the study population.…”

“…The copyright holder for this preprint this version posted May 18, 2020. ; https://doi.org/10.1101/2020.05.12.20097766 doi: medRxiv preprint sampling based on the malaria parasite positivity rates as reported from health facility reports, making a total of villages sampled all members of the selected households (HHs) were asked to participate in the survey [37]. Blood samples were collected by finger prick, thin and thick films were prepared, and all study participants were screened with malaria mRDT as per the manufacturer's instructions.…”