Namango, Isaac Haggai. Monitoring and control of "Anopheles" vectors in the context of residual malaria transmission in Ulanga, Tanzania. 2024, Doctoral Thesis, University of Basel, Associated Institution, Faculty of Science.
![]()
|
PDF
5Mb |
Official URL: https://edoc.unibas.ch/96522/
Downloads: Statistics Overview
Abstract
The global burden of malaria is disproportionately high in sub Saharan Africa (SSA) where prolific cases and deaths affect some of the world’s poorest populations. However, historically, malaria was widespread in virtually all habitable regions of the world. The current global map of malaria risk can be attributed to three factors: (i.) SSA was largely sidestepped during the Global Malaria Eradication Programme (GMEP), the first global attempt to interrupt completely widespread endemic malaria transmission. (ii.) Majority of SSA countries lack adequate resources and robust health systems that can support effective and consistent malaria control programmes necessary for malaria elimination. (iii.) A hot-humid tropical and sub-tropical climate supports breeding of some of the most effective malaria vector populations. In addition, designs of most traditional African huts particularly in the rural settings where malaria transmission tends to be high often allow easy entry of mosquitoes through openings on doors, windows and eaves. Such houses have often been associated with increased human-mosquito interactions and risk of malaria. Many African cultural traditions, perceptions, beliefs and practices have been found to be counter-effective to malaria control initiatives. For example, gatherings outdoors in the evenings during events such as funerals tend to expose people to mosquito bites and greatly undermine the effectiveness of ITNs. Across many high burden areas, measures to protect people from malaria infection include use of insecticides treated nets (ITNs) and the indoor residual spraying (IRS) with insecticides. In areas where campaigns by the two core interventions have been implemented effectively, there has been dramatic reductions of malaria transmission and a general decline of the burden of disease. However, despite being highly effective, vector control faces some major challenges that primarily include resistance to insecticides by local vector populations and mosquito behavioural avoidance of the indoor-based insecticidal interventions typically manifested by increased outdoor biting. The World Health Organisation (WHO) warns of stagnated global progress of malaria. Evidence suggests reduced effectiveness of ITNs and IRS across malarious parts. There is increased skepticism by malariologists regarding malaria elimination by the status quo majorly through relying heavily on ITNs and IRS. Going forward, the WHO encourages review and reassessments of the effectiveness of ITNs and IRS across malarious areas and recommends efforts to determine gaps in effective protection against malaria vectors in the context of universal coverage by the core vector control tools. This PhD took advantage of population-wide ITN and IRS studies in Ulanga, a rural area in south-eastern Tanzania, one among the highest burden countries, and investigates, discusses and reflects on the effectiveness of the core vector control and potential of residual malaria transmission. Findings of this PhD suggest that in a typical SSA setting where malaria transmission is endemic and where transmission is primarily by An. funestus and An. arabiensis that bite both indoors and outdoors, ITNs afford high protection against malaria transmission. Malaria control programmes should therefore ensure high household ownership and use of efficacious ITNs across all malarious areas. Strategies that promote high use of ITNs in the households by each member over all the times when they are in their sleeping spaces at night need to be encouraged to guarantee optimal protection by ITNs for everyone in the population. IRS with the use of effective insecticides such as clothianidin and that function by a different mode of action from that of pyrethroids can be employed to mitigate the spread of Anopheles resistance to pyrethroids and help complement ITNs to drive higher effectiveness for vector control and greater impact on malaria transmission. Appropriate IRS deployment strategies need to be employed to ensure that pyrethroid insecticides are not used alongside ITNs, and that insecticides with similar modes of action are not used in the same locations but instead insecticides with dissimilar modes of action are used alternatingly or in combinations. Sampling tools for estimating human biting by local malaria vector populations need to be considered on a case-by-case basis appreciating fundamental limitations of exposure-free mosquito traps for specific entomological survey tasks in different settings. HLC should be preferred over exposure-free traps where the purpose of surveying mosquitoes is to quantify absolute estimates of malaria risk more specifically the EIR. HLC-standardised entomological metrics estimated from catches by exposure-free mosquito traps may be used for evaluating malaria vector control interventions and for monitoring changes in behaviours in Anopheles populations including possible shifts in species composition, biting behaviours and occurrence or spread of insecticide resistance.
Advisors: | Hetzel, Manuel W. |
---|---|
Committee Members: | Moore, Sarah Jane and Utzinger, Jürg and Bradley, John |
Faculties and Departments: | 05 Faculty of Science 09 Associated Institutions > Swiss Tropical and Public Health Institute (Swiss TPH) > Department of Epidemiology and Public Health (EPH) > Health Interventions > Intervention Effectiveness and Impact (Hetzel) |
UniBasel Contributors: | Hetzel, Manuel W. and Utzinger, Jürg |
Item Type: | Thesis |
Thesis Subtype: | Doctoral Thesis |
Thesis no: | 15394 |
Thesis status: | Complete |
Number of Pages: | xii, 173 |
Language: | English |
Identification Number: |
|
edoc DOI: | |
Last Modified: | 19 Jul 2024 04:30 |
Deposited On: | 18 Jul 2024 09:13 |
Repository Staff Only: item control page