Trends of insecticide resistance monitoring in mainland Tanzania, 2004-2020.

BACKGROUND: Insecticide resistance is a serious threat to the continued effectiveness of insecticide-based malaria vector control measures, such as long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS). This paper describes trends and dynamics of insecticide resistance and its underlying mechanisms from annual resistance monitoring surveys on Anopheles gambiae sensu lato (s.l.) populations conducted across mainland Tanzania from 2004 to 2020. METHODS: The World Health Organization (WHO) standard protocols were used to assess susceptibility of the wild female An. gambiae s.l. mosquitoes to insecticides, with mosquitoes exposed to diagnostic concentrations of permethrin, deltamethrin, lambdacyhalothrin, bendiocarb, and pirimiphos-methyl. WHO test papers at 5× and 10× the diagnostic concentrations were used to assess the intensity of resistance to pyrethroids; synergist tests using piperonyl butoxide (PBO) were carried out in sites where mosquitoes were found to be resistant to pyrethroids. To estimate insecticide resistance trends from 2004 to 2020, percentage mortalities from each site and time point were aggregated and regression analysis of mortality versus the Julian dates of bioassays was performed. RESULTS: Percentage of sites with pyrethroid resistance increased from 0% in 2004 to more than 80% in the 2020, suggesting resistance has been spreading geographically. Results indicate a strong negative association (p = 0.0001) between pyrethroids susceptibility status and survey year. The regression model shows that by 2020 over 40% of An. gambiae mosquitoes survived exposure to pyrethroids at their respective diagnostic doses. A decreasing trend of An. gambiae susceptibility to bendiocarb was observed over time, but this was not statistically significant (p = 0.8413). Anopheles gambiae exhibited high level of susceptibility to the pirimiphos-methyl in sampled sites. CONCLUSIONS: Anopheles gambiae Tanzania's major malaria vector, is now resistant to pyrethroids across the country with resistance increasing in prevalence and intensity and has been spreading geographically. This calls for urgent action for efficient malaria vector control tools to sustain the gains obtained in malaria control. Strengthening insecticide resistance monitoring is important for its management through evidence generation for effective malaria vector control decision.

Modelling Insecticide Resistance of Malaria Vector Populations in Tanzania.

Anopheline mosquito insecticide resistance is a major threat to malaria control efforts and ultimately countries' ability to eliminate malaria. Using publicly available and published data we conducted spatial analyses to document and model the geo-spatial distribution of Anopheles gambiae s.l. insecticide resistance in Tanzania at national, regional, district and sub-district levels for the 2011 - 2017 period. We document anopheline mosquito resistance to all four major insecticide classes, with overall mosquito mortality declining from 2011 to 2016, and mean reductions of 1.6%, 0.5%, 0.4%, and 9.9% observed for organophosphates, carbamates, organochlorines and pyrethroids, respectively. An insecticide resistance map modeled for 2017 predicted that anopheline vector mortality was still above the 90% susceptibility threshold for all insecticide classes, except for pyrethroids. Using the model's output we calculated that resistance to organophosphates, carbamates, organochlorines, and pyrethroids is expected to exist in 11.6%, 15.6%, 8.1%, and 19.5% of Tanzania's territory, respectively, with areas in the Lake Zone and eastern Tanzania particularly affected. The methodology to predictively model available insecticide resistance data can readily be updated annually, allowing policy makers and malaria program management staff to continuously adjust their vector control approaches and plans, and determine where specific insecticides from various classes should be used to maximize intervention effectiveness.

Developing a multisectoral National Action Plan for Health Security (NAPHS) to implement the International Health Regulations (IHR 2005) in Tanzania.

The Ebola outbreak in West Africa precipitated a renewed momentum to ensure global health security through the expedited and full implementation of the International Health Regulations (IHR) (2005) in all WHO member states. The updated IHR (2005) Monitoring and Evaluation Framework was shared with Member States in 2015 with one mandatory component, that is, States Parties annual reporting to the World Health Assembly (WHA) on compliance and three voluntary components: Joint External Evaluation (JEE), After Action Reviews and Simulation Exercises. In February 2016, Tanzania, was the first country globally to volunteer to do a JEE and the first to use the recommendations for priority actions from the JEE to develop a National Action Plan for Health Security (NAPHS) by February 2017. The JEE demonstrated that within the majority of the 47 indicators within the 19 technical areas, Tanzania had either 'limited capacity' or 'developed capacity'. None had 'sustainable capacity'. With JEE recommendations for priority actions, recommendations from other relevant assessments and complementary objectives, Tanzania developed the NAPHS through a nationwide consultative and participatory process. The 5-year cost estimate came out to approximately US$86.6 million (22 million for prevent, 50 million for detect, 4.8 million for respond and 9.2 million for other IHR hazards and points of entry). However, with the inclusion of vaccines for zoonotic diseases in animals increases the cost sevenfold. The importance of strong country ownership and committed leadership were identified as instrumental for the development of operationally focused NAPHS that are aligned with broader national plans across multiple sectors. Key lessons learnt by Tanzania can help guide and encourage other countries to translate their JEE priority actions into a realistic costed NAPHS for funding and implementation for IHR (2005).

Effectiveness of MRA on embolized intracranial aneurysms: a comparison of DSA, CE-MRA, and TOF-MRA.

Purpose: The endovascular treatment of intracranial aneurysms was proven safe and effective compared to the alternative method of surgical clipping, despite the high recurrence rate. Follow-up of embolized intracranial aneurysms is mandatory for the early detection of recurrence and improved outcomes. DSA is used as the reference standard for this assessment. To determine the effectiveness of MRA in follow-up evaluations of intracranial aneurysms after embolization by comparing DSA, CE-MRA, and TOF-MRA. Materials and Methods: Sixty-eight consecutive patients undergoing DSA, TOF-MRA, and CE-MRA during an interval of <1 week were enrolled in this 6-month study. Images were evaluated for occlusion status, patency of the parent vessels, and artifacts. The modified Raymond-Roy occlusion classification and Aneurysm Embolization Grades were used to assess the occlusion status and initial DSA images for detection of recurrence in two filtered study phases with optimized selection criteria. Seventeen observers (phase I: 9, phase II: 8) independently interpreted the double-blinded images. Agreement was expressed with a Fleiss kappa value; p < 0.05 was considered significant. Results: This study included 68 patients with 77 aneurysms; 38 (49.35%) were treated with coil alone and 39 (50.65%) with stent-assisted coiling. In both phases, DSA was superior to TOF-MRA and CE-MRA using MRRC (Phase I: k = 0.567, p ≤ 0.001; k = 0.287, p ≤ 0.001; k = 0.117, p ≤ 0.001, respectively; Phase II: k = 0.503, p ≤ 0.001; k = 0.303, p ≤ 0.001; k = 0.115, p = 0.038, respectively). TOF-MRA was as effective as DSA (TOF: k = 0.335, p ≤ 0.001; DSA: k = 0.323, p ≤ 0.001) for recurrence detection. Conclusion: We suggest TOF-MRA as a first-line follow-up tool to detect aneurysm recurrence, and DSA to quantify the filling space to make a definite decision on re-embolization.

Profile of plasma lipids and degree of derangements among the elderly of Morogoro region, Tanzania.

Changes in lifestyles and ageing have been associated with growing rates of modifiable cardiovascular risk factors (CRF). Dyslipidemia is one ofthe CRF associated with numbers of cardiovascular diseases. This descriptive cross-sectional study was conducted to determine the profile and degree of derangements of plasma lipids among 300 (176 females and 124 males) elderly individuals aged ≥ 60 years in Morogoro, Tanzania. The calorimetric enzymatic methods and the Friedewal's equation were used for determination of cholesterols and triglycerides (TG). Social and demographic characteristics were gathered by structured questionnaires. The logistic regression models were used to identify the determinants of abnormal serum lipids level. Mean Total Cholesterols (TC) and Low Density Lipoprotein Cholesterols (LDL-C) in females exceeded significantly that of males. Mean TC, LDL-C as well as TG (mg/dL) declined significantly with age while mean High Density Lipoprotein Cholesterols (HDL-C) also declined but only slightly. Elderly females were two times more likely to have elevated TC (OR = 2.11; 95% CI: 1.04-4.28: P = 0.05) and LDL-C (OR = 2.15; 95% CI: 1.17- 3.97: P = 0.019) and three times to have lowered HDL-C (OR = 3; 95% CI: 1.97-5.30: P < 0.001) than males. Urban residents were about two times more likely to have elevated LDL-C (OR = 1.84; 95% CI: 1.04-3.25: P = 0.047) than their rural counterparts. Body Mass Index of ≥ 30 kg/m2 was also associated with elevated LDL-C (OR = 1.89; 95% CI: 1.05-3.42: P = 0.045) and lowered HDL-C (OR = 2.18; 95% CI: 1.3-3.65: P = 0.004), respectively. The present study has established the profile and level of derangements of serum lipids among the elderly of Morogoro region in Tanzania. It appears that, female sex and BMI of ≥ 30 kg/m2 are significant factors for elevated TC, LDL-C and lowered HDL-C while urban life is a significant factor for elevated LDL-C.