Browsing by Author "Msengwa, Amina S."

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    Assessing the Effects of Mosquito Nets on Malaria Mortality Using a Space Time Model: A Case Study of Rufiji and Ifakara Health and Demographic Surveillance System Sites in Rural Tanzania
    (BioMed Central, 2016) Selemani, Majige; Msengwa, Amina S.; Mrema, Sigilbert; Shamte, Amri; Mahande, Michael J.; Yeates, Karen; Mbago, Maurice C. Y.; Lutambi, Angelina M.
    Background: Although malaria decline has been observed in most sub-Saharan African countries, the disease still represents a significant public health burden in Tanzania. There are contradictions on the effect of ownership of at least one mosquito net at household on malaria mortality. This study presents a Bayesian modelling framework for the analysis of the effect of ownership of at least one mosquito net at household on malaria mortality with environmental factors as confounder variables. Methods: The analysis used longitudinal data collected in Rufiji and Ifakara Health Demographic Surveillance System (HDSS) sites for the period of 1999–2011 and 2002–2012, respectively. Bayesian framework modelling approach using integrated nested laplace approximation (INLA) package in R software was used. The space time models were established to assess the effect of ownership of mosquito net on malaria mortality in 58 villages in the study area. Results: The results show that an increase of 10 % in ownership of mosquito nets at village level had an average of 5.2 % decrease inall age malaria deaths (IRR = 0.948, 95 % CI = 0.917, 0.977) in Rufiji HDSS and 12.1 % decrease in all age malaria deaths (IRR = 0.879, 95 % CI = 0.806, 0.959) in Ifakara HDSS. In children under 5 years, results show an average of 5.4 % decrease of malaria deaths (IRR = 0.946, 95 % CI = 0.909, 0.982) in Rufiji HDSS and 10 % decrease of malaria deaths (IRR = 0.899, 95 % CI = 0.816, 0.995) in Ifakara HDSS. Model comparison show that model with spatial and temporal random effects was the best fitting model compared to other models without spatial and temporal, and with spatial–temporal interaction effects. Conclusion: This modelling framework is appropriate and provides useful approaches to understanding the effect of mosquito nets for targeting malaria control intervention. Furthermore, ownership of mosquito nets at household showed a significant impact on malaria mortality.
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    Clinician’s Awareness and Knowledge on the Management of Differentiated Thyroid Cancer and the Use of Radioactive Iodine in Tanzania
    (2016) Sakafu, Lulu; Mselle, Teddy; Mwaiselage, Julius; Msengwa, Amina S.; Maunda, Khamza; Eddin, Bouyoucef S.
    Introduction: Thyroid cancer is the most common endocrine malignancy worldwide with better outcome if timely and properly managed. Surgery followed by radioactive iodine (RAI) ablation remains the mainstay in the management of differentiated thyroid cancer (DTC). In Tanzania however, few patients with DTC receive RAI ablation post-surgery, and most of these present late, with advanced disease resulting in poor treatment outcome. The objective of this study was to determine the cause for late referral by assessing clinician’s awareness and knowledge on the management of DTC and the use of RAI in Tanzania. Methods: This descriptive cross sectional study was carried out in referral hospitals in Tanzania. Data collection used a standardized self-administered questionnaire. Information sought included awareness, knowledge and practices of clinicians on the management and the use of RAI on patients with DTC was explored. Results: Majority of clinicians managing DTC patients were males (86%), in-training surgeons (54%), and attended less than ten DTC patients per year (62%). About 44% of in-training surgeons never heard of nuclear medicine (p=0.04), and 20% were not aware of the role of RAI in the management of DTC (p=0.031). Only 7.3% of surgeons were aware of the role of thyroxine therapy, or RAI ablation post-surgery. Of all DTC patients managed surgically, only 16% had total thyroidectomy with lymphadenectomy (p=0.05). Conclusion: The findings of this study indicate there is insufficient knowledge on proper management and use of RAI on patients with DTC among clinicians in Tanzania.
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    Design, Implementation and Evaluation of a National Campaign to Deliver 18 Million Free Long-Lasting Insecticidal Nets to Uncovered Sleeping Spaces in Tanzania
    (2013) Renggli, Sabine; Mandike, Renata; Kramer, Karen; Patrick, Faith; Brown, Nick J.; McElroy, Peter D.; Rimisho, Wilhelmina; Msengwa, Amina S.; Mnzava, Ally; Nathan, Rose; Mtung’e, Romanus; Mgullo, Rita; Lweikiza, Jane; Lengeler, Christian
    Background: Since 2004, the Tanzanian National Voucher Scheme has increased availability and accessibility of insecticide-treated nets (ITNs) to pregnant women and infants by subsidizing the cost of nets purchased. From 2008 to 2010, a mass distribution campaign delivered nine million long-lasting insecticidal nets (LLINs) free-of -charge to children under-five years of age in Tanzania mainland. In 2010 and 2011, a Universal Coverage Campaign (UCC) led by the Ministry of Health and Social Welfare (MoHSW) was implemented to cover all sleeping spaces not yet reached through previous initiatives. Methods: The UCC was coordinated through a unit within the National Malaria Control Programme. Partners were contracted by the MoHSW to implement different activities in collaboration with local government authorities. Volunteers registered the number of uncovered sleeping spaces in every household in the country. On this basis, LLINs were ordered and delivered to village level, where they were issued over a three-day period in each zone (three regions). Household surveys were conducted in seven districts immediately after the campaign to assess net ownership and use. Results: The UCC was chiefly financed by the Global Fund to Fight AIDS, Tuberculosis and Malaria with important contributions from the US President’s Malaria Initiative. A total of 18.2 million LLINs were delivered at an average cost of USD 5.30 per LLIN. Overall, 83% of the expenses were used for LLIN procurement and delivery and 17% for campaign associated activities. Preliminary results of the latest Tanzania HIV Malaria Indicator Survey (2011–12) show that household ownership of at least one ITN increased to 91.5%. ITN use, among children under-five years of age, improved to 72.7% after the campaign. ITN ownership and use data post-campaign indicated high equity across wealth quintiles. Conclusion: Close collaboration among the MoHSW, donors, contracted partners, local government authorities and volunteers made it possible to carry out one of the largest LLIN distribution campaigns conducted in Africa to date. Through the strong increase of ITN use, the recent activities of the national ITN programme will likely result in further decline in child mortality rates in Tanzania, helping to achieve Millennium Development Goals 4 and 6.
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    Mass Distribution of Free Insecticide-Treated Nets Do Not Interfere with Continuous Net Distribution in Tanzania
    (2014) Eze, Ikenna C.; Kramer, Karen; Msengwa, Amina S.; Mandike, Renata; Lengele, Christian
    Background: To protect the most vulnerable groups from malaria (pregnant women and infants) the Tanzanian Government introduced a subsidy (voucher) scheme in 2004, on the basis of a public-private partnership. These vouchers are provided to pregnant women at their first antenatal care visit and mothers of infants at first vaccination. The vouchers are redeemed at registered retailers for a long-lasting insecticidal net against the payment of a modest top-up price. The present work analysed a large body of data from the Tanzanian National Voucher Scheme, focusing on interactions with concurrent mass distribution campaigns of free nets. Methods: In an ecologic study involving all regions of Tanzania, voucher redemption data for the period 2007–2011, as well as data on potential determinants of voucher redemption were analysed. The four outcome variables were: pregnant woman and infant voucher redemption rates, use of treated bed nets by all household members and by under- five children. Each of the outcomes was regressed with selected determinants, using a generalized estimating equation model and accounting for regional data clustering. Results: There was a consistent improvement in voucher redemption rates over the selected time period, with rates >80% in 2011. The major determinants of redemption rates were the top-up price paid by the voucher beneficiary, the retailer- clinic ratio, and socio-economic status. Improved redemption rates after 2009 were most likely due to reduced top-up prices (following a change in policy). Redemption rates were not affected by two major free net distribution campaigns. During this period, there was a consistent improvement in net use across all the regions, with rates of up to 75% in 2011. Conclusion: The key components of the National Treated Nets Programme (NATNETS) seem to work harmoniously, leading to a high level of net use in the entire population. This calls for the continuation of this effort in Tanzania and for emulation by other countries with endemic malaria.
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    Spatial and Space-Time Clustering of Mortality Due To Malaria in Rural Tanzania: Evidence from Ifakara and Rufiji Health and Demographic Surveillance System Sites
    (BioMed Central, 2015) Selemani, Majige; Mrema, Sigilbert; Shamte, Amri; Shabani, Josephine; Mahande, Michael J.; Yeates, Karen; Msengwa, Amina S.; Mbago, Maurice C. Y.; Lutambi, Angelina M.
    Background: Although, malaria control interventions are widely implemented to eliminate malaria disease, malaria is still a public health problem in Tanzania. Understanding the risk factors, spatial and space–time clustering for malaria deaths is essential for targeting malaria interventions and effective control measures. In this study, spatial methods were used to identify local malaria mortality clustering using verbal autopsy data. Methods: The analysis used longitudinal data collected in Rufiji and Ifakara Health Demographic Surveillance System (HDSS) sites for the period 1999–2011 and 2002–2012, respectively. Two models were used. The first was a non-spatial model where logistic regression was used to determine a household’s characteristic or an individual’s risk of malaria deaths. The second was a spatial Poisson model applied to estimate spatial clustering of malaria mortality using SaTScan™, with age as a covariate. ArcGIS Geographical Information System software was used to map the estimates obtained to show clustering and the variations related to malaria mortality. Results: A total of 11,462 deaths in 33 villages and 9328 deaths in 25 villages in Rufiji and Ifakara HDSS, respectively were recorded. Overall, 2699 (24 %) of the malaria deaths in Rufiji and 1596 (17.1 %) in Ifakara were recorded during the study period. Children under five had higher odds of dying from malaria compared with their elderly counterparts aged five and above for Rufiji (AOR = 2.05, 95 % CI = 1.87–2.25), and Ifakara (AOR = 2.33, 95 % CI = 2.05–2.66), respectively. In addition, ownership of mosquito net had a protective effect against dying with malaria in both HDSS sites. Moreover, villages with consistently significant malaria mortality clusters were detected in both HDSS sites during the study period. Conclusions: Clustering of malaria mortality indicates heterogeneity in risk. Improving targeted malaria control and treatment interventions to high risk clusters may lead to the reduction of malaria deaths at the household and probably at country level. Furthermore, ownership of mosquito nets and age appeared to be important predictors for malaria deaths.
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    Spatially Explicit Burden Estimates of Malaria in Tanzania: Bayesian Geostatistical Modeling of the Malaria Indicator Survey Data
    (2012) Gosoniu, Laura; Msengwa, Amina S.; Lengeler, Christian; Vounatsou, Penelope
    A national HIV/AIDS and malaria parasitological survey was carried out in Tanzania in 2007–2008. In this study the parasitological data were analyzed: i) to identify climatic/environmental, socio-economic and interventions factors associated with child malaria risk and ii) to produce a contemporary, high spatial resolution parasitaemia risk map of the country. Bayesian geostatistical models were fitted to assess the association between parasitaemia risk and its determinants. Bayesian kriging was employed to predict malaria risk at unsampled locations across Tanzania and to obtain the uncertainty associated with the predictions. Markov chain Monte Carlo (MCMC) simulation methods were employed for model fit and prediction. Parasitaemia risk estimates were linked to population data and the number of infected children at province level was calculated. Model validation indicated a high predictive ability of the geostatistical model, with 60.00% of the test locations within the 95% credible interval. The results indicate that older children are significantly more likely to test positive for malaria compared with younger children and living in urban areas and better-off households reduces the risk of infection. However, none of the environmental and climatic proxies or the intervention measures were significantly associated with the risk of parasitaemia. Low levels of malaria prevalence were estimated for Zanzibar island. The population-adjusted prevalence ranges from in Kaskazini province (Zanzibar island) to in Mtwara region. The pattern of predicted malaria risk is similar with the previous maps based on historical data, although the estimates are lower. The predicted maps could be used by decision-makers to allocate resources and target interventions in the regions with highest burden of malaria in order to reduce the disease transmission in the country.