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Introductory Global Health Flashcards > Malaria Atlas Project > Flashcards

Malaria Atlas Project Flashcards

1
Q

Malaria

A

» 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

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1
Q

Malaria transmission

A

» 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

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2
Q

Burden of disease due to malaria

A

Globally, 1.1% of all deaths due to malaria In Nigeria, 12.5% of all deaths due to malaria

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3
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3
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4
Q

Key points

A

» 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.

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4
Q

Artemisinin-based combination therapy (ACT)

A

» 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

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4
Q

Malaria prevention and treatment

A

» 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)

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4
Q

Insecticide treated bed nets (ITNs)

A

» 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

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5
Q

Malaria

A
  • 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)
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6
Q

The global fight against malaria

A

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).

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7
Q

The global fight against malaria

A

How can we make progress?
* Needs more resources
* Resources need to be used more effectively

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7
Q
A

How do we achieve this?
Improved situational awareness:
* Malaria risk is very variable across space & time
* So where do we target resources?

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8
Q
A

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

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9
Q

Geospatial Statistics

A

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

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9
Q

Statistical Models

A

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

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10
Q

MAP: History

A

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

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10
Q

But why do we need a model?

A

Data is sparse
In space… And in time….

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10
Q

Geospatial Statistics

A

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)

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10
Q

MAP: History

A

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

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11
Q

Challenges facing MAP

A
  • 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
12
Q
A

Tobler’s first law of geography:
“everything is related to everything
else, but near things are more
related than distant things”

13
Q

A model allows us to

A
  • Fill in the gaps
  • Standardise observations between locations, timepoints, and methodologies
  • Inform policy-making, funding decision, and to track our progress against malaria
14
Q

Challenges facing MAP

A

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

14
Q
A
  • point data: observations from a single location (has GPS coordinates, village/school name):
    e.g. survey of patent parasitaemia amongst children from a given village
14
Q

Challenges facing MAP

A

Updating and innovating our methods whilst maintaining a consistent historical view to
track progress in malaria fight
MAP provides estimates for the World Malaria Report and Global Burden of Diseases
studies: consistency of method is very important for continuity

14
Q

Challenges facing MAP

A

Decolonising global health: how to be an effective ally for emerging scientists from LMICs
* opening of new MAP office in Tanzania (Susan Rumisha; Punam Amratia)
* taking training and workshops to endemic countries; focus on NMCPs and stakeholders
* collaborations and sub-awards/consulting to local researchers (e.g. Ezra Gayawan; FUTA)

15
Q
A
16
Q

Geographical data for the geography of malaria

A

geographical (γῆ-γραφω) data: data on people, environment, climate etc. tied to location
(and time)

17
Q
A
  • geographical image data: a pixel-grid of observations (has a coordinate system):
    e.g. satellite-based radar elevation measurements
18
Q
A
  • areal data: observations covering an extended region (has a described boundary):
    e.g. counts of reported malaria cases in a local government area
19
Q

MAP: Data

A
  • Environmental/climatic covariates
    (geographical image data) coordinate system, time, measurement
    there is a lot of work to process the original satellite-based products into useable covariates (gap-filling for cloud cover,
    bad pixels, etc)
20
Q

MAP: Data

A
  • Infection surveys (roughly 50,000 datapoints)
    (point data): location, time, number positive, number tested
21
Q

MAP: Data

A
  • Case reporting (~90,000 admin units)
    (areal data) area, time, number of cases
    primarily passive surveillance: relies on cases reaching a health clinic and being captured in reporting systems
22
Q
A
23
Q

Malaria

A
  • Clinical malaria (uncomplicated):
    fever, chills, headache, sweating, nausea
    (249 million clinical cases globally in 2022)
23
Q

Malaria

A
  • Severe malaria: loss of consciousness,
    seizure, severe anemia, difficulty breathing
    (608k deaths globally; mostly children)
24
Q

Malaria

A
  • Economic costs: loss of productive work
    days / school days; cost of medicine and
    care seeking
25
Q

Malaria treatment and prevention

A
  • Chemoprevention treatments: mass coordinated distribution
    to vulnerable populations including children and pregnant women to
    clear infections and interrupt transmission. This includes

o Seasonal malaria chemoprevention (SMC) - for children 6mnth – 5yrs

o Intermittent preventive treatment for pregnant women (IPTp)

o Perennial malaria chemoprevention (PMC) - for children below 2 yrs

o Mass drug administration (MDA) - for populations in low malaria settings

25
Q

Malaria treatment and prevention

A
  • Artemisinin-based combination therapy (ACT): quick reduction in
    parasite load from artemisinin then longer acting partner drug takes
    care of remainder
  • Insecticide-treated bed nets (ITN): prevent infection (kill mosquitos +
    physical barrier)
  • Indoor residual spraying (IRS): insecticide coating on walls kills resting mosquitoes
26
Q

Three main streams of work

A
27
Q

Skills, Backgrounds and Experiences

A
27
Q

Our goals

A
  • We assemble global databases on malaria risk and
    intervention coverage, and develop innovative analysis
    methods that use those data to address critical questions.
28
Q

Our goals

A
  • These include better understanding the global landscape of
    malaria risk, how this is changing, and the impact of malaria
    interventions.
29
Q

Our goals

A
  • By modelling burden, trends, and impact at a fine
    geographical scale we support informed decision making for
    malaria control at international, regional and national scales.
30
Q

Why do some countries have more cases of malaria
than other countries?

A

● Different country population size – more people in a country means more possible cases of malaria (or of
any disease)

● Different mosquito populations (specifically, Anopheles mosquitoes)

● Different capacities to prevent and treat malaria (i.e. stronger/weaker health systems)

● Different baseline prevalance of the disease - more humans with malaria makes it more likely that mosquitoes will pick it up and transmit it

30
Q

Describe three different malaria prevention strategies

A

● Malaria can be prevented by avoiding mosquito bites and with medicines.

○ Vector control

○ Insecticide treated bed nets (ITNs, LLINs)

○ Indoor residual spraying (IRS)

○ Reducing/treating stagnant water

Pharmaceuticals

○ Seasonal malaria chemoprevention (SMC)

○ Malaria vaccine

30
Q

Insecticide Treated Bed Nets (ITNs) are an effective way to prevent malaria.

If you were going to run an ITN distribution campaign, how would you design it?

A

● Needs to include components for BOTH “access” and “use”

● ACCESS - making sure every household has an ITN - ideally, at least 1 ITN for every 2 people

○ Can distribute via health facilities, schools, central pick-up points

○ Priortise families with children, pregnant women

● USE - making sure people are actually sleeping under the nets (through awareness-raising, education, behaviour change programs)

● Frequency = campaigns every 2 to 3 years, because ITNs degrade in quality and effectiveness over time

31
Q

● Why do we need data on malaria?

● What is the difference between
“empirical data” and “modelled data”?

● Why, specifically, do we need
“modelled data” on malaria?

A
31
Q

Should a country prioritise prevention, treatment, or both if they experience:

  1. A high number of cases, but few deaths
  2. A low number of cases, where most result in death
  3. A high number of cases, where most result in death
A

● Need to determine whether to focus on prevention or treatment

○ If high number of cases, but few deaths, priority would be prevention (i.e., to reduce malaria cases and therefore malaria MORBIDITY)

○ Can do this through ITN campaigns, indoor residual spraying, seasonal chemoprevention, malaria vaccine

○ If low number of cases AND same number of deaths, you should likely focus on treatment (i.e., to reduce those few cases from progressing to severe/life-threatening malaria)

○ Can do this through increasing access to artemisinin-based combination therapy (ACTs); for example, through
community health workers

○ If high number of cases AND high number of deaths, you could arguably focus on both prevention and treatment -whichever is likely to be most effective

● Key point - it can depend, but in all scenarios, if there are any cases and any deaths, both prevention and
treatment are likely to have some effect

Introductory Global Health Flashcards (12 decks)

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