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Performance analysis of a runner for gravitational water vortex power plant
Get PDFThis research article published by Wiley & Sons Ltd, 2022Micro-hydropower can be used to meet the needs of both isolated and rural com munities for electricity. Due to its inexpensive initial investment, simple design,
easy maintenance and low-head utilisation, the gravitational water vortex power
plant (GWVPP) has recently piqued interest. The findings of numerical work
employing a numerical simulation and analytical approach for the GWVPP are
presented in this study. To understand the influence of each on the efficiency of
GWVPP, four parameters (speed, hub-blade angle, number of blades and run ner profile) were explored. Design-Expert software was used to investigate the
interplay of each parameter/factor in order to maximise the contribution of each.
Design-Optimal Expert's (custom) design tool was used to construct twenty-four
experimental runs. To calculate the system efficiency, these runs were simulated
in commercial computational fluid dynamics (CFD) software called Ansys CFX.
The numerical results were in good agreement with the experimental results, which
yieldedR2
values of 0.9507 and0.9603 forflat andcurvedprofiles,respectively.Furthermore,
the findings show that the chosen parameters have an impact on the GWVPP's efficiency
via interaction as seen in response surface methodology (RSM). Furthermore, numerical
analysis increased the curved blade profile runner's total efficiency by 3.65%. In compari son with the unoptimised scenarios, the efficiency of the flat runner profile increased by
1.69%
Development, feasibility and potential effectiveness of community-based continuous mass dog vaccination delivery strategies: lessons for optimization and replication
Get PDFThis research article was published by bioRxiv, 2022Objectives Dog vaccination can eliminate rabies, but annual delivery strategies do not sustain vaccination coverage between campaigns. We describe the development of a community-based continuous mass dog vaccination (CBC-MDV) approach designed to improve and maintain vaccination coverage in Tanzania and examine the feasibility of delivering this approach as well as lessons for its optimization.
Methods We developed three delivery strategies of CBC-MDV and tested them against the current annual vaccination strategy following the UK MRC’s guidance: i) developing an evidence-based theoretical framework of intervention pathways and ii) piloting to test feasibility and inform optimization. For our process evaluation of CBC-MDV we collected data using non-participant observations, meeting reports and implementation audits and in-depth interviews, as well as household surveys of vaccination coverage to assess potential effectiveness. We analyzed qualitative data thematically and quantitative data descriptively.
Results The final design included delivery by veterinary teams supported by village-level one health champions. In terms of feasibility, we found that less than half of CBC-MDV’s components were implemented as planned. Fidelity of delivery was influenced by the strategy design, implementer availability and appreciation of value intervention components, and local environmental and socioeconomic events (e.g. elections, funerals, school cycles). CBC-MDV activities decreased sharply after initial campaigns, partly due to lack of supervision. Community engagement and involvement was not strong. Nonetheless, the CBC-MDV approaches achieved vaccination coverage above the critical threshold (40%) all-year-round. CBC-MDV components such as identifying vaccinated dogs, which village members work as one health champions and how provision of continuous vaccination is implemented need further optimization prior to scale up.
Interpretation CBC-MDV is feasible to deliver and can achieve good vaccination coverage. Community involvement in the development of CBC-MDV, to better tailor components to contextual situations, and improved supervision of activities are likely to improve vaccination coverage in future.
AUTHOR SUMMARY Annual mass dog vaccination campaigns that reach at least 70% of the dog population, should maintain sufficient herd immunity between campaigns to interrupt rabies transmission. However, it is often challenging to reach 70% of the dog population with annual vaccination campaigns. We hypothesized that a community-based continuous approach to dog vaccination could better maintain high levels of vaccination coverage all-year-round. We describe the development of a community-based continuous approach to dog vaccination in Tanzania, and assessed the feasibility of delivering its components, its potential effectiveness and lessons for its optimization. We found that the approach was well accepted, as its development involved key stakeholders. Although less than half of the components of the community-based continuous approach were delivered exactly as planned, over 70% of dogs were vaccinated and the approach maintained coverage above the critical vaccination threshold throughout the year. We conclude that it is feasible to deliver a community-based continuous approach to dog vaccination, but that some components need further improvement; more supervision and community involvement should lead to better outcomes
Participatory Development of Practical, Affordable, Insecticide-Treated Mosquito Proofing for a Range of Housing Designs in Rural Southern Tanzania
Get PDFThis research article was published by Research Square, 2022Background
Insecticidal mosquito-proof netting screens could combine the best features of insecticide treated nets (ITNs) and indoor residual spraying (IRS), the two most important front line vector control interventions in Africa today, and also overcome the most important limitations of these two methods, such as pyrethroid resistance. This study engaged members of a rural Tanzanian community in developing and evaluating simple, affordable and scalable procedures for installing readily available screening materials on eave gaps and windows of their own houses, and then treating those screens with a widely used IRS formulation of the organophosphate insecticide pirimiphos-methyl (PM).
Methods
A cohort of 54 households were recruited upon consent, following which the structural features and occupant demographics of their houses were surveyed. Indoor mosquito densities were surveyed longitudinally, both before and after a participatory house modification, and screening was done using locally available materials. Each house was randomly assigned to one of three study arms: (1) No screens installed until the end of the study (negative control), (2) untreated screens installed, and (3) screened installed and then those screens treated with PM. The longevity of the activity of the insecticide applied to these screens was assessed using standard WHO cone assays.
Results
Of the 54 households, 52 participated until to the end, at which point all houses had been successfully screened. In most cases, screening was only installed after making enabling structural modifications that were accepted by the enrolled households. Screening installations almost entirely excluded Anopheles arabiensis (Relative reduction (RR) ≥ 96%, P < < 0.0001), the most abundant malaria vector in the area; but was less effective against Culex quinquefasciatus, a non-malaria vector with significant biting nuisance (RR ≤ 46%, P < < 0.0001). While the PM treatment of these netting screens reduced indoor densities of Cx. quinquefasciatus by only 24%, An. arabiensis was reduced by 63% and treated screens exhibited satisfactory residual efficacy eight months after treatment.
Conclusions
This study demonstrates that participatory approaches to mosquito proofing houses may be acceptable and effective, and that installed screens may be suitable targets for treatment with residual insecticides
Efficacy and effect of entomopathogenic fungi (aspergillus oryzae) for control of ticks of major economic importance of cattle in Tanzania
Get PDFA Dissertation Submitted in Partial Fulfilment of the Requirements of the Degree of Master’s in Life Sciences of the Nelson Mandela African Institution of Science and TechnologyTicks are important ectoparasites that are responsible for severe economic losses. The use of
chemical acaricides is the most common method used to control ticks in livestock. This study was
conducted to determine the efficacy of Aspergillus oryzae in controlling ticks to enhance livestock
productivity. The efficacy of A. oryzae at different concentrations was evaluated against different
stages (larva and adult) of the life cycle of hard tick genera (Rhipicephalus, Boophilus and
Amblyomma) using immersion test under laboratory conditions. Field trials were conducted in two
cattle herds, which were purposively selected, and a spraying method was used to apply A. oryzae
at a concentration of 1 x 106 conidial/mL on all tick infested areas. The results demonstrated a
concentration-related increase in mortality in all tested tick genera. The mean mortality of larvae
and engorged ticks was statistically significant at p˂0.05 and p˂0.001 respectively in all the tested
genera. Egg production was found to decrease with increased A. oryzae concentration.
Additionally, there was a statistically significant difference in egg production index and
oviposition reduction (p=0.009) while there was no significant difference in egg hatching and
product effectiveness at p=0.089 and p=0.004 respectively between the tested tick genera. Under
field conditions, trials demonstrated a statistically significant tick reduction on all the treated cattle.
This study concludes that A. oryzae has a good acaricidal activity against ticks and hence is one of
the potential tick control methods for sustainable tick control schemes
Epidemiology of Q-fever in domestic ruminants and humans in Africa. A systematic review
Get PDFThis research article was published by CABI One Health in 2022Q-fever is a zoonotic infectious disease caused by the gram-negative, intracellular, spore-forming bacterium Coxiella burnetii .
Infected ruminants (cattle, sheep, and goats) are the reservoirs of the pathogen and thus an important source of infection in
humans. This systematic review aims to consolidate the knowledge and awareness of Q-fever in Africa and identify future
research opportunities and possible interventions in low-resource settings. We review information on Q-fever epidemiology and
the diagnostic challenges in humans and domestic ruminants in Africa from the last 23 years. Six databases including university
repositories were searched for relevant articles. A total of 84 studies and 4 theses met the selection criteria and were thus
included in the review. They include serological and molecular studies of Q-fever in humans or domestic ruminants in 24/54
African countries. The mean seroprevalence estimates were 16% (95%CI 11–23%) in humans; 14% (95%CI 10–20%) in cattle;
13% (95%CI 9–18%) in sheep; and 21% (95%CI 15–29%) in goats. The mean prevalence for molecular detection of the pathogen
were 3% (95%CI 0–16%) in humans; 9% (95%CI 4–19%) in cattle; 16% (95%CI 5–41%) in sheep; and 23% (95%CI 20–80%) in
goats. The number of studies that identified risk factors for exposure among domestic ruminants was: sex (n = 6), age (n = 17),
contact with other animals (n = 5), lack of quarantine of newly purchased animals (n = 1), extensive grazing system (n = 4), herd
size (2), history of abortion (n = 5), absence of vaccination (n = 2), and high temperature (n = 1). The number of studies that
reported protective factors was: sanitation (n = 2), burying and/ or burning the aborted foetus (n = 2), and young (age) (n = 2).
The studies that identified risk factors for human disease infection included: close contact to animals (n = 7), age (n = 3), and
gender (n = 5), while those identifying protective factors included: living in non-irrigated areas (n = 1), awareness/knowledge
about zoonosis (n = 1), rodent control (n = 1), sanitation/disinfection of equipment after and before use (n = 1), occasional grazing
(n = 1), and do nothing to aborted materials (n = 1). Diagnostic challenges such as poverty, lack of a well-equipped laboratory with
biosafety level 3 specific for Q-fever testing, unspecific and self-limiting clinical signs/symptoms, lack of gold standard test, and
variation in test specificity and sensitivity were identified. The disease is likely to be widespread in Africa and of public importance
and underreported thus ‘One Health’ approaches to future studies are recommended. Further studies should focus on concurrent
studies of human and livestock populations
Building sustainable societies through vertical soilless farming: A cost-effectiveness analysis on a small-scale non-greenhouse hydroponic system
Get PDFThis research article was published by Elsevier in 2022The growing rate of population and urbanization among African cities versus the reducing arable land has roused curiosity in soilless farming as an urban farming method to enhance food security and urban sustainability. This study investigated the economic viability of producing 60 heads of lettuce using a vertical non-circulating hydroponic system outside the green house as a low cost sustainable urban food production prospect for Africa. This was based on a hydroponic experiment set up in Uganda, East Africa 4 capital budgeting techniques were used for the analysis, that is; Net Present Value (NPV), Profitability index (PI), Internal Rate of Return (IRR) and Non-discounted Pay Back Period (NDPBP). A sensitivity and scenario analysis were adopted for risk analysis while regression analysis was considered for forecasting and modelling purposes. A discount rate of 10% was considered for the analysis based on the loan borrowing rate. The unit production cost equaled to 0.46. Results showed the following economic values: NPV (16.37$), IRR (12.57%), PI (1.1) and NDPBP (4,5) for annual crop production of 6 cycles. NPV was sensitive to changes in discount rate and unit price while revenue varied with a change in quantities sold and unit price as per the scenario analysis. A significant negative and positive linear relationship was found between unit price of lettuce versus quantity sold and revenue earned correspondingly. Adoption of vertical hydroponic lettuce production can be considered an equally cost-effective venture with substantial profits cetris paribus with the potential to increase food security and sustainability around urbanities. Further research needs to be done to assess the profitability of producing other vegetables using the same system across various seasons and cities
Understanding the role of serological and clinical data on assessing the dynamic of malaria transmission: a case study of Bagamoyo district, Tanzania
Get PDFThis research article was published in Pan African Medical Journal, Volume 43, 2022.Introduction: naturally acquired blood-stage malaria antibodies and malaria clinical data have been reported to be useful in monitoring malaria change over time and as a marker of malaria exposure. This study assessed the total immunoglobulin G(IgG) levels to Plasmodium falciparum schizont among infants (5-17 months), estimated malaria incidence using routine health facility-based surveillance data and predicted trend relation between anti-schizont antibodies and malaria incidence in Bagamoyo. Methods: 252 serum samples were used for assessment of total IgG by enzyme-linked immunosorbent assay and results were expressed in arbitrary units (AU). 147/252 samples were collected in 2021 during a blood-stage malaria vaccine trial [ClinicalTrials.gov NCT04318002], and 105/252 were archived samples of malaria vaccine trial conducted in 2012 [ClinicalTrials.gov NCT00866619]. Malaria incidence was calculated from outpatient clinic data of malaria rapid test or blood smear positive results retrieved from District-Health-Information Software-2 (DHIS2) between 2013 and 2020. Cross sectional data from both studies were analysed using STATA version 14. Results: this study demonstrated a decline in total anti-schizont IgG levels from 490.21AU in 2012 to 97.07AU in 2021 which was related to a fall in incidence from 58.25 cases/1000 person-year in 2013 to 14.28 cases/1000 person-year in 2020. We also observed a significant difference in incidence when comparing high and low malaria transmission areas and by gender. However, we did not observe differences when comparing total anti-schizont antibodies by gender and study year.
Conclusion: total anti-schizont antibody levels appear to be an important serological marker of exposure for assessing the dynamic of malaria transmission in infants living in malaria-endemic regions
Prospective cohort study reveals unexpected aetiologies of livestock abortion in northern Tanzania
Get PDFThis research article was published by Springer Nature Limited in 2022Livestock abortion is an important cause of productivity losses worldwide and many infectious causes of abortion are zoonotic pathogens that impact on human health. Little is known about the relative importance of infectious causes of livestock abortion in Africa, including in subsistence farming communities that are critically dependent on livestock for food, income, and wellbeing. We conducted a prospective cohort study of livestock abortion, supported by cross-sectional serosurveillance, to determine aetiologies of livestock abortions in livestock in Tanzania. This approach generated several important findings including detection of a Rift Valley fever virus outbreak in cattle; high prevalence of C. burnetii infection in livestock; and the first report of Neospora caninum, Toxoplasma gondii, and pestiviruses associated with livestock abortion in Tanzania. Our approach provides a model for abortion surveillance in resource-limited settings. Our findings add substantially to current knowledge in sub-Saharan Africa, providing important evidence from which to prioritise disease interventions
Towards an Integrated Mobile Technology on Animal Disease Surveillance Framework in Tanzania: A Systematic Review
Get PDFThis research article was published by IADITI 2022Tanzanian Government, through its national audit office in March 2020, reported the prevalence decline of two
animal diseases, namely; Foot and Mouth Disease (FMD) and Contagious Bovine Pleuropneumonia (CBPP).
Similarly, an increase in three animal diseases, which are African Swine Fever (ASV), Contagious Caprine
Pleuropneumonia (CCPP), and Lumpy Skin Disease (LSD). The national audit office mentioned inadequate animal
disease surveillance system in the country was among the challenges that hinder diseases control. Therefore, this
study reviews the existing animal diseases surveillance systems global and suggests measures to enhance animal
diseases surveillance systems in Tanzania. This review focuses on the possibility of sharing surveillance data among
livestock stakeholders (including livestock keepers) in Tanzania, considering available resources such as animal
diseases existing prediction models and mobile-based surveillance systems. Also, the availability of mobile
technologies such as Short Message Service (SMS), Unstructured Supplementary Service Data (USSD) and
automatic voice calls (Robocalls). Reviews synthesize the previous studies to explore strengths, opportunities,
weaknesses and challenges for better future interventions through proper and timely information sharing. This
study selected 46 records from the 147 identified for review. The selected records include 24 from bibliographic
databases, 14 from full-text journals and other non-bibliographic databases, and 8 from the open search on website
What influences individuals to invest in improved sanitation services and hygiene behaviours in a small town? A formative research study in Babati, Tanzania
Get PDFThis research article was published in Plos one Journal, 2022.Sub-Sahara African countries face immense challenges in ensuring adequate sanitation
and hygiene behaviours to the rapidly growing populations. Attempts to address these chal lenges require empirical evidence to inform policy and planning. We contribute toward that
goal by unveiling findings of formative research conducted in Babati, a rapidly growing town
in Tanzania. We conducted a cross-sectional study involving 486 households, to unwind
motives and barriers for individuals to invest in improved sanitation services and hygiene
behaviour change. We used several methods including household survey, focus group dis cussions, behaviour observations and spot checks. The findings revealed that households
derive their motivation to invest in improved sanitation and hygiene practices from comfort,
raising social status, and the need for personal safety and privacy. Other motives include
fear of penalties and fines and fear of disease outbreaks, whilst the barriers include, limited
water availability and accessibility, environmental factors, property rights, cultural issues,
financial constraints, and a person’s attitude. Quantitative data were subjected to multivari ate analysis to identify determinants of households to invest in sanitation and hygiene prac tices. The logistic regression analyses revealed that sources of water, property rights, and
education level were the main determinants of households to invest in sanitation and
hygiene facilities, while household income was the main determinant for households to
invest in both construction of handwashing facility and water treatment. We argue that the
initiative to promote sanitation and hygiene behaviour change in small towns should focus
on promoting motivation factors and abating the determinant factors identified in this study