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Climate Change, Malaria, & Data: Getting Ahead of the Spread

April 25, 2022

Challenges in areas ranging from education to the environment, gender to governance, health to housing don’t exist in a vacuum. Each month, Abt experts from two disciplines explore ideas for tackling these challenges in our monthly podcast, The Intersect. Sign up for monthly e-mail notifications here. Catch up with previous episodes here.

We all know climate change is leading to rising temperatures and sea levels, which threaten catastrophic results. But some environmental impacts are less obvious, such as the growing incidence of malaria. Drs. Caroline Staub and Matt Kirby discuss how we can use climatological data and technical assistance to combat the spread of this deadly disease.

Read the Transcript

Eric Tischler: Hi, and welcome to The Intersect; I'm Eric Tischler. Abt Global tackles complex challenges around the world, ranging from improving health and education to assessing the impact of environmental changes. For any given problem, we bring multiple perspectives to the table. We thought it would be enlightening and maybe even fun to pair up colleagues from different disciplines so they can share their ideas and perhaps spark new thinking about how we solve these challenges. Today I'm joined by two of those colleagues, Caroline Staub and Matt Kirby.

Caroline is an analytical and strategic international development professional with 10-plus years leading programs in climate change, adaptation, resilience, environmental science, natural resources management, sustainable agriculture, and food security across a variety of geographical settings. Matt is a medical entomologist with an expertise in mosquitoes, insecticidal products, and insectory management procedures. He's Abt's technical director for the President's Malaria Initiative—or PMI—VectorLink project. Thank you both for joining me.

Matt Kirby: Thanks, Eric. Great to be on.

Caroline Staub: Thanks for having me.

Eric: When we think about climate change, many of us see cataclysmic change due to rising temperatures and sea levels, but climate change also is exacerbating human health at a more human scale. Caroline, I know you address some of these macro concerns with your work on agriculture and food security, but can you talk about some of the health concerns you look at when you're thinking about climate change and resilience?

Caroline: Yes, absolutely. So what I've seen is that the focus on climate adaptation is unequally distributed across sectors. The latest report published by the Intergovernmental Panel on Climate Change shows that most adaptation actions are concentrated in the food sector, in agriculture, while the health sector has the least. So most public health practitioners are poorly equipped to understand or manage the effects of climate change, despite a major push to alert the health community about the risk. So our team, at the moment, and we just submitted a proposal focused on increasing access to actionable information on climate risks, on adaptation options, and capacity building to help decision makers in the health sector consider climate risks and climate smart options in planning and operations. Related to that, we are working on improving climate risk assessment and management in vector control in Africa. We'll talk a little bit about that today.

There's also a major funding issue. Adaptation projects are chronically underfunded. There's a need for targeted funding to sustain capacity building for users of climate information in the health sector, for delivering disease forecasting tools, for down-scaling climate information for decision making at the district level. There's also an important equity issue. Countries that are most impacted by climate change receive the least amount of adaptation funding. So here's where we're working on an effort to partner with the private sector to mobilize finance and actions that support adaptation and resilience across climate-sensitive sectors worldwide and also ensure that the funding goes where it's most needed.

Eric: Great, thank you. So you just mentioned vectors and surveillance and data. So let's turn to Matt. Matt, as Abt's technical director for the PMI VectorLink project, can you tell us what your mandate is and what you're seeing on the ground?

Matt: Yeah, sure. Thanks Eric. So the PMI VectorLink project is implementing vector control, primarily indoor residual spraying [IRS], but we're certainly involved more now with distributing insecticide-treated nets and also doing some larvae sighting. And this is really building on the work that was done under the predecessor project, the AIRS project, but we now have very much an expanded focus, as I say, supporting nets distribution, as well as IRS and entomological surveillance under a broader vector control mandate. So, last year, we sprayed IRS in 17 countries, covering about 6 million structures and protecting about 21 million people, and then also directly involved with distributing about 7 million nets, protecting over 13 million people. So in almost all of our VectorLink countries, we are implementing entomological surveillance activities, and those are really important to help interpret the impact of vector control interventions on the mosquito populations.

We know that there are key mosquito indicators that we can use, density, seasonalities, survival rates, age, structure of the population, abundance. All of these things are really key parameters. So we know if we can keep, for example, daily survival rates down, keep the life expectancy of mosquitoes below the period it takes for the parasite to develop in the mosquito, then we're onto a winning formula. But we also know that there are massive impacts of climate on all of these indicators, not just mosquito parameters, but also the parasite. So the length of development of the parasite in the mosquito is dependent on temperature. The survival of the mosquito, reproduction of mosquitoes, the period in between taking blood meals and mosquitoes, all of these things are affected by temperatures and obviously, very critically, rainfall because mosquitoes are aquatic. They have an aquatic larval stage. They are very much limited by, and strongly associated with, rainfall patterns. And that can work in two ways. So we obviously need some rainfall in order to develop breeding sites for these mosquitoes. But if we have these catastrophic events or some flooding, we can actually wash out those habitats, and that can have the opposite effect on density. So all of these parameters that we're trying to recall with our mosquito monitoring have links to climate change and also impact on our ability to interpret the effectiveness of the interventions we're using.

Eric: Great, thanks. And that would seem to track back, then, to what Caroline was talking about in terms of gathering data on climate impacts. You guys want to talk about that a little bit? Caroline, maybe the data that you're collecting; Matt, the data you’d like to be seeing. How can we connect those dots?

Caroline: Sure, I think what might help discuss or answer this particular question is first understanding how weather extremes are affecting operational decisions, how changing seasons are affecting decisions in planning, and then we can talk about the types of data. What do you think?

Matt: Yeah, I agree. I guess one of the critical indicators that we use is, or one of the key timings that we have is, when to spray insecticide.

Caroline: Yeah.

Matt: We have to spray before the rains. So that's, for several reasons, it's operationally easier to be conducting those campaigns in the dry season, but we also have to implement the insecticide spraying before mosquito densities increase. And we need to maximize the period of effectiveness. These insecticides decay over time, so we have to make sure that we spray at a time that that insecticide will then provide protection throughout.

Caroline: Right, in Uganda, for example, two distinct rainfall seasons have now merged into one very long season. And that, like Matt was saying, is affecting the effectiveness of the spray campaigns and making  them more costly. It's also interesting to think about the operation side. So on the day-to-day basis, extreme weather events are causing people to migrate to new areas, which means making things very difficult to plan in health-related interventions. We're looking at heat waves that are affecting operations as well, causing health officers to suffer from fatigue, from dehydration, and then thinking about torrential rain, which damages health centers and infrastructure. So roads needed to deliver goods and services become unusable.

Matt: Yeah, and it's a really good point you raise, actually, about, there's not just the impact on the mosquitoes and on malaria transmission, but also we mustn't forget the human element in that equation. If populations are displaced by extreme events, they are less likely to be reached by vector control, or they might not be living in accommodation that can be sprayed within insecticide or are suitable for hanging a bed net. So that's obviously another impact there that climate change can have more, I guess, more indirectly on the ability of vector control to protect people.

But yeah, just coming back to your example for Uganda, so in several countries, we've shifted IRS campaign periods and start dates in response to changing rain patterns and malaria transmission seasons. So in Uganda, under an Abt-led bilateral project, the spraying was done in May to August, but under VectorLink, we've now moved back to March. And in a similar example in Tanzania, in the Lake Victoria region, we were implementing spray campaigns in late January and early February. But by last year, we started shifting those campaigns by seven months to October and November. And that's really absolutely forced changes we've had to make to adjust our programs to maximize their impact because of climate change and that impact on seasonality and mosquitoes and malaria.

Eric: So getting back to Caroline's comments really about gathering data, Matt, what can Caroline's side of the house be doing to help your side of the house?

Matt: Yeah, so one of the tools that we use is called the Race to the Start Line. The IRS program is a massive operation, so there's planning that goes on several weeks, I think at least nine weeks before we start our campaigns to make sure that we begin on time. And that tool, it reflects the checklist of criteria we need to meet to ensure a successful campaign. And the tool sends reminders. It's an electronic-based tool, and it really ensures that our activities are completed successfully on time and follow along a critical path. So tied to that Race to the Start Line tool, the use of seasonal weather forecasts that might be able to give us a three-month advance warning of above or below average rainfalls or extreme or changes in temperatures at a regional level, that could really help potentially to trigger operational decisions. And then we can adjust our supplies, procurement, and prepositioning accordingly.

And then as Caroline was alluding to, we use these spray calendars to ensure we’re cost effective when still maximizing the IRS coverage. So those calendars give the teams a daily itinerary throughout the spray period, so we're making sure we're getting to all of the households in an effective way. And this is a costly operation, so daily transportation is one of the biggest contributors to the cost of those operations. So if we're able to anticipate events that could disrupt that calendar or those operations, we can plan around those again in advance and make sure that, for example, we're only renting or fueling vehicles on days when they're absolutely required.

Eric: Caroline, and how about you? Hearing that, are you seeing ways in which you feel like your side of the house can support? Are you thinking of other things that might be helpful or, then conversely, anything from that side that could be helping you in your work?

Caroline: Yeah, I think Matt laid it out really well. Vector-borne diseases, when we're talking about adaptation options, we're really talking about a variety of solutions. We're talking about surveillance, we're talking about vaccine development, we're talking about early warning systems, and Matt alluded to the latter. And what's encouraging is that many studies have shown now, for example studies by Thompson and her colleagues, are showing that accurate and timely climate information can help predict the timing of peak malaria transmission every year. It can improve the efficiency of resource use. It can reduce caseloads, particularly in areas that are prone to epidemics and where transmission is seasonal. 

I think what's important to, I guess, appreciate is that climate information is used together with parasitological and entomological variables. They can be used to map areas and time periods that are becoming more suitable for malaria transmission and also help predict those in the future. We call them climate smart health services, and they've been used now in vector control for many years. In Ethiopia and Madagascar, climate and health experts started collaborating on data sharing and technical support for over 20 years now. They organize trainings for malaria control professionals at various levels. The National Meteorological Agency tailored its service and its data toward supporting decisionmaking by making forecasting disease transmission, using proven evidence-based tools, so those decision tools can help establish an association between rainfall and temperature on the one hand, and the biology of malaria, parasites, and mosquitoes on the other hand, which they then use to forecast the probability of outbreaks.

Matt: So, one of the examples where we already have this interface between the activities of VectorLink and some climate-related data is the use of ground-based observations from met stations to help with interpretation of some of the outcomes that we find. What we're expecting to see with our IRS, with our spraying, is an almost immediate impact on mosquito densities. So in events where we don't see that, or we're hitting some anomalies, being able to correctly attribute changes in densities in mosquitoes, or seasonality, is really important. It becomes even more important. And climate obviously is something that also has an impact on densities and on seasonalities.

So one example of this is again, back in Uganda, we had an actual increase in density soon after spraying. So we thought, "What going on?" We were able to look at the rainfall in that one particular district where we saw this anomaly, and we found that the rainfall was three times higher in that month than all of our other sentinel districts. It was also the highest in that one district for five years.

Eric: Wow.

Matt: So it gives a good example that we need to be interpreting our data in the right context, and having climate data in our database systems, having that integrated approach, would really help to consolidate that approach.

Caroline: Yes, no, that's a great point. I think there's a lot to be said about just bringing the climate and health communities together and encouraging collaboration on data sharing and technical support, organizing trainings for malaria control professionals at various levels. There's a lot of opportunity to further the use of climate-informed surveillance and early warning systems for vector control.

Matt: Definitely that training piece is really important, because VectorLink, we have surveillance in it. We have a limited surveillance. There's only so much we can do, but national programs have surveillance nationwide. And so, really training their teams to be adding this component into what they're doing is critical, yeah.

Eric: Great. Well, of course we call this podcast The Intersect because we want to bring together those sectors within Abt to help deliver more thorough and more efficient and broader solutions. So it's good to have you guys talking and recognizing that there's that opportunity for greater partnership within Abt to help our clients. Thank you both for joining me.

Caroline: Thanks very much. Thanks for having me.

Matt: Thank you so much.

Eric: And thank you for joining us at The Intersect.

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