Malaria Atlas Project Flashcards
Malaria
» Mosquito-borne disease, endemic in only some parts
of the world
» Symptoms can be mild or life-threatening
- Mild symptoms include fever, chills, and headache
- Severe symptoms include fatigue, confusion, seizures,
and difculty breathing
» Some people are at higher risk of severe infection:
children under 5 years, pregnant women, travelers,
and people living with HIV
- Children under 5 are at greatest risk of dying from
malaria, representing around 60-80% of all deaths
Malaria transmission
» Spread through bites of infected
Anopheles mosquitoes - Not directly person to person
» Micro-organism = Plasmodium - P. falciparum - P. vivax » Life-cycle: after infection the
parasite spreads to a person’s
liver, then to their blood, then to
another mosquito
Burden of disease due to malaria
Globally, 1.1% of all deaths due to malaria In Nigeria, 12.5% of all deaths due to malaria
Key points
» Malaria is a mosquito-borne disease that is endemic in only some parts of the world.
» The two most common types of malaria are Plasmodium falciparum and Plasmodium vivax.
» In some countries, malaria is one of the biggest causes of death (e.g. 12% of all deaths in
Nigeria), and one of the top three causes of death in children under fve.
» Multiple methods of prevention (insecticide treated bed nets, indoor residual spraying,
seasonal malaria chemoprevention, vaccine) and treatment (artemisinin-based
combination therapy).
» Global programs have been efective in controlling malaria, though progress has stalled over
the past ten years.
Artemisinin-based combination therapy (ACT)
» Relatively quick and efective treatment for mild
cases of malaria
- Three-day course of tablets
» In some countries, community case management
of malaria through volunteer/paid community
health workers
- Children with fever given ACTs and referred to the
nearest health centre
» For severe malaria, patients need intravenous or
intramuscular treatment
Malaria prevention and treatment
» Malaria can be prevented by avoiding mosquito
bites and with medicines.
- Vector control
* Indoor residual spraying (IRS)
* Insecticide treated bed nets (ITNs, LLINs)
- Pharmaceuticals
* Seasonal malaria chemoprevention (SMC)
* Malaria vaccine
» Treatments can stop mild cases from getting worse.
- Artemisinin-based combination therapy (ACT)
Insecticide treated bed nets (ITNs)
» Highly efective and responsible for a
large part of the global reduction in
malaria cases since 2000
» Requires people to have a net (access)
and to sleep under it (use)
» Net quality and insecticide
efectiveness can deteriorate over time
- Regular ITN distribution campaigns
are needed
Malaria
- Malaria is a major global disease
- Caused by the Plasmodium parasite (Plasmodium falciparum, plasmodium vivax, etc.)
- Spread by the Anopheles mosquito
- Accounts for approximately 600 thousand deaths a year (>1 per minute)
The global fight against malaria
Malaria funding saw a major increase from 2000 to 2010 (MDGs)
* Substantial reductions were achieved but we remain far from global eradication, and the
funds are still not enough (it is estimated around $7.8 bn USD was required in 2022).
The global fight against malaria
How can we make progress?
* Needs more resources
* Resources need to be used more effectively
How do we achieve this?
Improved situational awareness:
* Malaria risk is very variable across space & time
* So where do we target resources?
The Malaria Atlas Project (MAP) was founded in 2005 with the aim to develop
a quantitative evidence base on the global distribution of malaria risk
Geospatial Statistics
Decision making under uncertainty
we can’t know exactly the nature of malaria risk throughout a country but we can be rigorous in describing our
uncertainties: this allows assumptions and sensitivities to be tested
Statistical Models
Malaria-metric data is ‘noisy’ and incomplete (only a small fraction of children in a small
fraction of villages are surveyed at any given time): we need statistical models to make
useable maps
MAP: History
2005 – 2019: Oxford
* Three pillars of activity:
* Data - ongoing assembly and curation of all available (georeferenced) malaria data + climatic & environmental
information
* Analysis - development of wide range of statistical models to
use these data to address policy relevant questions
* Engagement and dissemination – Passive (MAP
website); Active via policy engagement, collaboration
* Progressive growth in funding, team, scope, impact over the years
But why do we need a model?
Data is sparse
In space… And in time….
Geospatial Statistics
Concerned with statistical inference using geographical data
* Emerged from the field of mining: ‘kriging’ method to estimate
ore body volumes (esp. Georges Matheron: 1930-2000)
* A new era thanks in part to increasing computational power (esp.
Peter Diggle: ‘model based geostatistics’; Sylvia Richardson &
Nicky Best)
MAP: History
Since Sept 2019: Curtin and The Kids Research Institute Australia
* (Gradual) relocation of entire program: Team of 30 in Perth
* Primarily BMGF funding - portfolio approx $15M
Challenges facing MAP
- Inaccurate/incomplete data
- Lack of adequate information on contextual factors
Routine surveillance data offers the possibility of continuous risk monitoring, but there remain issues with accuracy of
data capture and missingness from non-attendance
Tobler’s first law of geography:
“everything is related to everything
else, but near things are more
related than distant things”
A model allows us to
- Fill in the gaps
- Standardise observations between locations, timepoints, and methodologies
- Inform policy-making, funding decision, and to track our progress against malaria
Challenges facing MAP
Human geography:
* people’s movements through the risk and
treatment landscape complicate data
interpretation and modelling
e.g. place of residence not necessarily place of infection
* data on behavioural factors such as time spent
outside during peak mosquito feeding hours is
scarce
