Earth observation in support of malaria control and epidemiology: MALAREO monitoring approaches

Malaria affects about half of the world’s population, with the vast majority of cases occuring in Africa. National malaria control programmes aim to reduce the burden of malaria and its negative, socioeconomic effects by using various control strategies (<em>e.g.</em> vector control, environmental management and case tracking). Vector control is the most effective transmission prevention strategy, while environmental factors are the key parameters affecting transmission. Geographic information systems (GIS), earth observation (EO) and spatial modelling are increasingly being recognised as valuable tools for effective management and malaria vector control. Issues previously inhibiting the use of EO in epidemiology and malaria control such as poor satellite sensor performance, high costs and long turnaround times, have since been resolved through modern technology. The core goal of this study was to develop and implement the capabilities of EO data for national malaria control programmes in South Africa, Swaziland and Mozambique. High- and very high resolution (HR and VHR) land cover and wetland maps were generated for the identification of potential vector habitats and human activities, as well as geoinformation on distance to wetlands for malaria risk modelling, population density maps, habitat foci maps and VHR household maps. These products were further used for modelling malaria incidence and the analysis of environmental factors that favour vector breeding. Geoproducts were also transferred to the staff of national malaria control programmes in seven African countries to demonstrate how EO data and GIS can support vector control strategy planning and monitoring. The transferred EO products support better epidemiological understanding of environmental factors related to malaria transmission, and allow for spatio-temporal targeting of malaria control interventions, thereby improving the cost-effectiveness of interventions.

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MALAREO: a user-driven project

Geospatial health ◽

10.4081/gh.2015.329 ◽

2015 ◽

Vol 10 (2) ◽

Author(s):

Michael T. Gebreslasie ◽

Ides Bauwens

Keyword(s):

South Africa ◽

Vector Control ◽

Malaria Vector ◽

Malaria Control ◽

Spatial Epidemiology ◽

Earth Observation ◽

Malaria Vector Control ◽

Mosquito Vector ◽

Control Programs ◽

Control And Management

The aim of this study is to assess the capacity gaps and requirements of Earth observation (EO) and related technologies for malaria vector control and management in the Lubombo Spatial Development Initiative regions of South Africa, Swaziland and Mozambique. In order to achieve the core objective of this study, available EO data (including main characteristics and resources required to utilize them) and their potential applications for malaria epidemiology are reviewed. In addition, a survey was conducted to assess the availability of human and facility resources to operate EO and related technologies for control and management of the malaria control programs in these countries resulting in an analysis of capacity gaps, priorities and requirements. Earth observation in malaria vector control and management has two different applications: i) collection of relevant remotely sensed data for epidemiological use; and ii) direct support of ongoing malaria vector control activities. All malaria control programs and institutions recognize the significance of EO products to detect mosquito vector habitats, to monitor environmental parameters affecting mosquito vector populations as well as house mapping and distribution of information supporting residual spray planning and monitoring. It was found that only the malaria research unit (MRU) of the medical research council (MRC) in South Africa and the national malaria control program (MCP) in Swaziland currently have a fully functional geographic information systems (GIS), whereas the other surveyed MCPs in South Africa and Mozambique currently do not have this in place. Earth observation skills only exist in MRU of MRC, while spatial epidemiology is scarce in all institutions, which was identified as major gap. The survey has also confirmed that EO and GIS technologies have enormous potential as sources of spatial data and as analytical frameworks for malaria vector control. It is therefore evident that planning and management require capacity building with respect to GIS, EO and spatial epidemiology.

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Impact of seasonality and malaria control interventions on Anopheles density and species composition from three areas of Uganda with differing malaria endemicity

Malaria Journal ◽

10.1186/s12936-021-03675-5 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Henry Ddumba Mawejje ◽

Maxwell Kilama ◽

Simon P. Kigozi ◽

Alex K. Musiime ◽

Moses Kamya ◽

...

Keyword(s):

Species Composition ◽

Vector Control ◽

Malaria Control ◽

Mosquito Species ◽

Density Ratio ◽

Indoor Residual Spraying ◽

Sub Saharan Africa ◽

Malaria Vector Control ◽

Vector Density ◽

Llin Distribution

Abstract Background Long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) are the malaria control interventions primarily responsible for reductions in transmission intensity across sub-Saharan Africa. These interventions, however, may have differential impact on Anopheles species composition and density. This study examined the changing pattern of Anopheles species in three areas of Uganda with markedly different transmission intensities and different levels of vector control. Methods From October 2011 to June 2016 mosquitoes were collected monthly using CDC light traps from 100 randomly selected households in three areas: Walukuba (low transmission), Kihihi (moderate transmission) and Nagongera (high transmission). LLINs were distributed in November 2013 in Walukuba and Nagongera and in June 2014 in Kihihi. IRS was implemented only in Nagongera, with three rounds of bendiocarb delivered between December 2014 and June 2015. Mosquito species were identified morphologically and by PCR (Polymerase Chain Reaction). Results In Walukuba, LLIN distribution was associated with a decline in Anopheles funestus vector density (0.07 vs 0.02 mosquitoes per house per night, density ratio [DR] 0.34, 95% CI: 0.18–0.65, p = 0.001), but not Anopheles gambiae sensu stricto (s.s.) nor Anopheles arabiensis. In Kihihi, over 98% of mosquitoes were An. gambiae s.s. and LLIN distribution was associated with a decline in An. gambiae s.s. vector density (4.00 vs 2.46, DR 0.68, 95% CI: 0.49–0.94, p = 0.02). In Nagongera, the combination of LLINs and multiple rounds of IRS was associated with almost complete elimination of An. gambiae s.s. (28.0 vs 0.17, DR 0.004, 95% CI: 0.002–0.009, p < 0.001), and An. funestus sensu lato (s.l.) (3.90 vs 0.006, DR 0.001, 95% CI: 0.0005–0.004, p < 0.001), with a less pronounced decline in An. arabiensis (9.18 vs 2.00, DR 0.15 95% CI: 0.07–0.33, p < 0.001). Conclusions LLIN distribution was associated with reductions in An. funestus s.l. in the lowest transmission site and An. gambiae s.s. in the moderate transmission site. In the highest transmission site, a combination of LLINs and multiple rounds of IRS was associated with the near collapse of An. gambiae s.s. and An. funestus s.l. Following IRS, An. arabiensis, a behaviourally resilient vector, became the predominant species, which may have implications for malaria vector control activities. Development of interventions targeted at outdoor biting remains a priority.

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Competing interests, clashing ideas and institutionalizing influence: insights into the political economy of malaria control from seven African countries

Health Policy and Planning ◽

10.1093/heapol/czaa166 ◽

2020 ◽

Author(s):

Justin Parkhurst ◽

Ludovica Ghilardi ◽

Jayne Webster ◽

Robert W Snow ◽

Caroline A Lynch

Keyword(s):

Decision Making ◽

Malaria Control ◽

Qualitative Interviews ◽

Sub Saharan Africa ◽

African Countries ◽

Health Community ◽

Control Programmes ◽

Control Decision ◽

Sub Saharan ◽

Economic Considerations

Abstract This article explores how malaria control in sub-Saharan Africa is shaped in important ways by political and economic considerations within the contexts of aid-recipient nations and the global health community. Malaria control is often assumed to be a technically driven exercise: the remit of public health experts and epidemiologists who utilize available data to select the most effective package of activities given available resources. Yet research conducted with national and international stakeholders shows how the realities of malaria control decision-making are often more nuanced. Hegemonic ideas and interests of global actors, as well as the national and global institutional arrangements through which malaria control is funded and implemented, can all influence how national actors respond to malaria. Results from qualitative interviews in seven malaria-endemic countries indicate that malaria decision-making is constrained or directed by multiple competing objectives, including a need to balance overarching global goals with local realities, as well as a need for National Malaria Control Programmes to manage and coordinate a range of non-state stakeholders who may divide up regions and tasks within countries. Finally, beyond the influence that political and economic concerns have over programmatic decisions and action, our analysis further finds that malaria control efforts have institutionalized systems, structures and processes that may have implications for local capacity development.

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Nextgen Vector Surveillance Tools: sensitive, specific, cost-effective and epidemiologically relevant

Malaria Journal ◽

10.1186/s12936-020-03494-0 ◽

2020 ◽

Vol 19 (1) ◽

Author(s):

Robert Farlow ◽

Tanya L. Russell ◽

Thomas R. Burkot

Keyword(s):

Decision Making ◽

Vector Control ◽

Malaria Control ◽

Cost Effective ◽

Effective Control ◽

Next Generation ◽

Vector Data ◽

Vector Surveillance ◽

Current Vector ◽

Control Programmes

Abstract Background Vector surveillance provides critical data for decision-making to ensure that malaria control programmes remain effective and responsive to any threats to a successful control and elimination programme. The quality and quantity of data collected is dependent on the sampling tools and laboratory techniques used which may lack the sensitivity required to collect relevant data for decision-making. Here, 40 vector control experts were interviewed to assess the benefits and limitations of the current vector surveillance tools and techniques. In addition, experts shared ideas on “blue sky” indicators which encompassed ideas for novel methods to monitor presently used indicators, or to measure novel vector behaviours not presently measured. Algorithms for deploying surveillance tools and priorities for understanding vector behaviours are also needed for collecting and interpreting vector data. Results The available tools for sampling and analysing vectors are often hampered by high labour and resource requirements (human and supplies) coupled with high outlay and operating costs and variable tool performance across species and geographic regions. The next generation of surveillance tools needs to address the limitations of present tools by being more sensitive, specific and less costly to deploy to enable the collection and use of epidemiologically relevant vector data to facilitate more proactive vector control guidance. Ideas and attributes for Target Product Profiles (TPPs) generated from this analysis provide targets for research and funding to develop next generation tools. Conclusions More efficient surveillance tools and a more complete understanding of vector behaviours and populations will provide a basis for more cost effective and successful malaria control. Understanding the vectors’ behaviours will allow interventions to be deployed that target vulnerabilities in vector behaviours and thus enable more effective control. Through defining the strengths and weaknesses of the current vector surveillance methods, a foundation and initial framework was provided to define the TPPs for the next generation of vector surveillance methods. The draft TTPs presented here aim to ensure that the next generation tools and technologies are not encumbered by the limitations of present surveillance methods and can be readily deployed in low resource settings.

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Readjustment of the malaria vector control strategy in the Rusizi Valley, Burundi

Bulletin of Entomological Research ◽

10.1017/s0007485300033046 ◽

1995 ◽

Vol 85 (4) ◽

pp. 541-548 ◽

Cited By ~ 5

Author(s):

A. Smits ◽

M. Coosemans ◽

W. Van Bortel ◽

M. Barutwanayo ◽

Ch. Delacollette

Keyword(s):

Vector Control ◽

Control Strategy ◽

Parasite Load ◽

Sensu Stricto ◽

Malaria Vector Control ◽

Dense Area ◽

Resting Sites ◽

Control Programmes ◽

The Village ◽

Vector Control Strategy

AbstractBased on a longitudinal survey performed in 1982–1983, a vector control strategy was implemented from 1985 onwards in a malarial-dense area of Burundi. One annual round of indoor spraying with malathion greatly reduced both the parasite load and the parasite rate in the population until 1989. However, from 1990 to 1993, a progressive resurgence of malaria was observed in most villages. For the present study, two villages were selected on the basis of their differential response to house spraying. In the village of Mulira surrounded by rice fields, the excellent results observed in the past have been followed by recent increases in parasite rates. In the village of Murengeza, also located in the rice growing area but near a river, the spraying had less impact. The inoculation rate was found to be similar in both villages, but the transmission peak occurred at the end of April in Mulira, and two months earlier in Murengeza. Indoor spraying with lambdacyhalothrin was carried out on 26 April 1993, one month too late according to the strategy intended. As no sporozoite mosquitoes were observed during the six months following spraying, this strategy should be maintained but, in villages near rivers, the application should commence much earlier, in mid-January. Anopheles gambiae Giles sensu stricto (Diptera: Culicidae) and A. funestus Giles were found to be very endophilic species, whereas the dominant A. arabiensis. Patton was highly exophilic. Therefore it is recommended that treatments should not only be applied to human dwellings but also to other structures such as animal sheds, kitchens, etc, shown by earlier studies to be resting sites of A. arabiensis. This study underlines the need for regular reassessment in vector control programmes.

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Malaria vector control practices in an irrigated rice agro-ecosystem in central Kenya and implications for malaria control

Malaria Journal ◽

10.1186/1475-2875-7-146 ◽

2008 ◽

Vol 7 (1) ◽

Cited By ~ 18

Author(s):

Peter N Ng'ang'a ◽

Josephat Shililu ◽

Gayathri Jayasinghe ◽

Violet Kimani ◽

Charity Kabutha ◽

...

Keyword(s):

Vector Control ◽

Malaria Vector ◽

Malaria Control ◽

Malaria Vector Control ◽

Irrigated Rice ◽

Central Kenya

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Malaria vector control tools in emergency settings: What do experts think? Results from a DELPHI survey

Conflict and Health ◽

10.1186/s13031-021-00424-y ◽

2021 ◽

Vol 15 (1) ◽

Author(s):

Christophe Boëte ◽

Sakib Burza ◽

Estrella Lasry ◽

Silvia Moriana ◽

William Robertson

Keyword(s):

Vector Control ◽

Malaria Vector ◽

Malaria Control ◽

Substantial Reduction ◽

Indoor Residual Spraying ◽

Delphi Survey ◽

Malaria Vector Control ◽

Free Text ◽

List Type ◽

Snowball Sampling

Abstract Background The use and implementation of novel tools for malaria control such as long lasting impregnated bednets (LLINs) and Indoor Residual Spraying (IRS) over the last decade has contributed to a substantial reduction in malaria burden globally. However numerous challenges exist particularly in relation to vector control in emergency settings. This study seeks to explore expert opinion on the utility of existing tools within the emergency context setting and to better understand the attitude towards emerging and innovative tools (including Genetically Modified Mosquitoes) to augment current approaches. Methods 80 experts in the field of malaria and vector control were invited to participate in a two-round Delphi survey. They were selected through a combination of literature (academic and policy publications) review and snowball sampling reflecting a range of relevant backgrounds including vector control experts, malaria programme managers and emergency response specialists. The survey was conducted online through a questionnaire including the possibility for free text entry, and concentrated on the following topics: Utility and sustainability of current vector control tools, both in and outside emergency settings Feasibility, utility and challenges of emerging vector control tools, both in and outside emergency settings Current and unmet research priorities in malaria vector control and in malaria control in general. Results 37 experts completed the first round and 31 completed the second round of the survey. There was a stronger consensus about the increased utility of LLIN compared to IRS in all settings, while insecticide-treated covers and blankets ranked very high only in emergency settings. When considering the combination of tools, the ones deemed most interesting always involved LLINs and IRS regardless of the setting, and the acceptability and the efficacy at reducing transmission are essential characteristics. Regarding perceptions of tools currently under development, consensus was towards improvement of existing tools rather than investing in novel approaches and the majority of respondents expressed distrust for genetic approaches. Conclusion Malaria vector control experts expressed more confidence for tools whose efficacy is backed up by epidemiological evidence, hence a preference for the improvement rather than the combination of existing tools. Moreover, while several novel tools are under development, the majority of innovative approaches did not receive support, particularly in emergency settings. Stakeholders involved in the development of novel tools should involve earlier and raise awareness of the potential effectiveness amongst a wider range of experts within the malaria community to increase acceptability and improve early adoption once the evidence base is established.

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Malaria Vector Control Practices in an Irrigated Agroecosystem in Central Kenya: Implications for Malaria Control

Epidemiology ◽

10.1097/01.ede.0000291888.77714.81 ◽

2008 ◽

Vol 19 (1) ◽

pp. S215-S216

Author(s):

P Ngáng'a ◽

J Shililu ◽

V K Kimani ◽

G Jayasinghee ◽

C Kabutha

Keyword(s):

Vector Control ◽

Malaria Vector ◽

Malaria Control ◽

Malaria Vector Control ◽

Central Kenya

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Evaluating the Efficacy, Impact and Feasibility of Community-based House Screening as a Complementary Malaria Control Intervention in Southern Africa: a Study Protocol for a Household Randomized Trial.

10.21203/rs.3.rs-458248/v1 ◽

2021 ◽

Author(s):

Peter Onyango Sangoro ◽

Ulrike Fillinger ◽

Kochelani Saili ◽

Theresia Estomih Nkya ◽

Rose Marubu ◽

...

Keyword(s):

Vector Control ◽

Malaria Transmission ◽

Malaria Control ◽

Malaria Incidence ◽

Indoor Residual Spraying ◽

Clinical Malaria ◽

Sub Saharan Africa ◽

Substantial Impact ◽

Transmission Season ◽

The Impact

Abstract Background: Concerted effort to control malaria has had a substantial impact on transmission of the disease in the past two decades. In areas where reduced malaria transmission is being sustained through insecticide-based vector control interventions, primarily long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS), non-insecticidal complementary tools will likely be needed to push towards malaria elimination. Once interruption in local disease transmission is achieved, insecticide-based measures can be scaled down gradually and eventually phased out, saving on costs of sustaining control programmes and mitigating any unintended negative health and environmental impacts posed by insecticides. These non-insecticidal methods could eventually replace insecticidal methods of vector control. House screening, a non-insecticidal method, has a long history in malaria control, but is still not widely adopted in sub-Saharan Africa. This study aims to add to the evidence-base for this intervention in low transmission settings by assessing the efficacy, impact and feasibility of house screening in areas where LLINs are conventionally used for malaria control. Methods: A two-armed, household randomized clinical trial will be conducted in Mozambique, Zambia and Zimbabwe to evaluate whether combined use of house screens and LLINs affords better protection against clinical malaria in children between 6 months and 13 years compared to the sole use of LLINs. Eight hundred households will be enrolled in each study area, where 400 households will be randomly assigned the intervention, house screening and LLINs while the control households will be provided with LLINs only. Clinical malaria incidence will be estimated by actively following up one child from each household for 6 months over the malaria transmission season. Cross-sectional parasite prevalence will be estimated by testing all participating children for malaria parasites at the beginning and end of each transmission season using rapid diagnostic tests.CDC light traps and pyrethrum spray catches (PSC) will be used to sample adult mosquitoes and evaluate the impact of house screening on indoor mosquito density, species distribution and sporozoite rates.Discussion: This study will contribute epidemiological data on the impact of house screening on malaria transmission and assess the feasibility of its implementation on a programmatic scale. Trial registration: This trial was retrospectively registered on 11th August 2020. Registration number PACTR202008524310568.

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Impact of Seasonality and Malaria Control Interventions on Anopheles Density and Species Composition From Three Areas of Uganda With Differing Malaria Endemicity.

10.21203/rs.3.rs-131540/v1 ◽

2020 ◽

Author(s):

Henry Mawejje ◽

Maxwell Kilama ◽

Simon P. Kigozi ◽

Alex K. Musiime ◽

Moses Kamya ◽

...

Keyword(s):

Species Composition ◽

Vector Control ◽

Malaria Control ◽

Mosquito Species ◽

Density Ratio ◽

Indoor Residual Spraying ◽

Sub Saharan Africa ◽

Malaria Vector Control ◽

Vector Density ◽

Llin Distribution

Abstract Background Long lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) are malaria control interventions primarily responsible for reductions in transmission intensity across sub-Saharan Africa. These interventions, however, may have differential impact on Anopheles species composition and density. Here, we studied the changing pattern of Anopheles species in three areas of Uganda with markedly different transmission intensities and different levels of vector control.Methods From October 2011 to June 2016 mosquitoes were collected monthly using CDC light traps from 100 randomly selected households in three areas: Walukuba (low transmission), Kihihi (moderate transmission) and Nagongera (high transmission). LLINs were distributed in November 2013 in Walukuba and Nagongera and in June 2014 in Kihihi. IRS was implemented only in Nagongera, with three rounds of bendiocarb delivered between December 2014 and June 2015. Mosquito species were identified morphologically and by PCR (Polymerase Chain Reaction). Results In Walukuba, LLIN distribution was associated with a decline in Anopheles funestus vector density (0.07 vs 0.02 mosquitoes per house per night, density ratio [DR] 0.34, 95% CI: 0.18-0.65, p=0.001), but not An. gambiae s.s. nor An. arabiensis. In Kihihi, over 98% of mosquitoes were An. gambiae s.s. and LLIN distribution was associated with a decline in An. gambiae s.s. vector density (4.00 vs 2.46, DR 0.68, 95% CI: 0.49-0.94, p=0.02). In Nagongera, the combination of LLINs and multiple rounds of IRS was associated with almost complete elimination of An. gambiae s.s. (28.0 vs 0.17, DR 0.004, 95% CI: 0.002-0.009, p<0.001), and An. funestus s.l. (3.90 vs 0.006, DR 0.001, 95% CI: 0.0005-0.004, p<0.001), with a less pronounced decline in An. arabiensis (9.18 vs 2.00, DR 0.15 95% CI: 0.07-0.33, p<0.001). Conclusions LLIN distribution was associated with reductions in An. funestus s.l. in the lowest transmission site and An. gambiae s.s. in the moderate transmission site. In the highest transmission site, a combination of LLINs and multiple rounds of IRS was associated with the near collapse of An. gambiae s.s. and An. funestus s.l. Following IRS, An. arabiensis, a behaviorally resilient vector, became the predominant species, which may have implications for malaria vector control activities.

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