Lecture 15: Malaria

Question 1

Basics of disease transmission

Answer 1

Vector transmission
Direct (contact) transmission
Indirect transmission

Question 2

Malaria is caused by

Answer 2

Protozoan parasites of the genus Plasmodium.
Five species of Plasmodium can produce the disease in its various forms
P. falciparum is the most widespread and dangerous of the four: untreated it can lead to fatality.

Question 3

Malaria types

Plasmodium falciparum

Answer 3

Most dangerous form of malaria (highest mortality rate)

More prevalent in sub-Saharan Africa

Question 4

Malaria types

Plasmodium vivax

Answer 4

Most widely spread form of malaria

Question 5

Malaria types

Plasmodium malariae, ovale, knowlesi

Answer 5

All rare compared to falciparum and vivax

Generally not as dangerous as falciparum and vivax

Question 6

Background: malaria today

Answer 6

350-550 million episodes of clinical P. falciparum malaria
Around 650,000 deaths in 2014, mostly children <5 years old
Pregnant women also at increased risk of complications and death
48% of global population live in malarious regions

Question 7

Impacts of malaria

Viscous cycle

Answer 7

Malaria affects those living in poverty Having malaria causes poverty

Question 8

Health impacts (of many…)

Answer 8

Jaundice
Kidney failure
Respiratory distress
Anaemia
Pneumonia
Stillbirths/infant mortality
Coma
Death

Question 9

Socio-economic impacts

Answer 9

Inability to work/attend school
Need family members to care for them
High costs of accessing treatment – travel, time of work, medications
High costs of providing treatment
High costs of control programs

Question 10

Controlling malaria

Answer 10

Significant investment in control and research over the last decade, and progress is being seen
Key: Break the parasite lifecycle – generally by reducing contact between humans and mosquitoes

Question 11

How can we control malaria?

Answer 11

Insecticide-Treated Bednets (ITNs)
Drugs 
Indoor spraying
Larval source management
Education
Landscape modifications
Housing improvements
Vaccines in development….

Question 12

Control programs

Answer 12

The Global Malaria Eradication Program (1955-69) of the WHO
Ultimately unsuccessful globally, but helped free many countries from malaria
Largely DDT-based
Since then, national programs have been successful – e.g. UAE, Morocco

Question 13

Land use changes

Answer 13

Marsh drainage
Urbanization
Livestock increases – e.g. dairy farming
Deforestation

Question 14

Housing improvements

Answer 14

Windows
Doors
Sealed roof eaves
Screens
Air conditioning

Question 15

Wealth

Answer 15

Health system improvements
Infrastructure improvements = access to treatment
Extensive control methods

Question 16

Medical/engineering advancements

Answer 16

Sanitation
Drug efficiency
Case management
Access to treatment
Control method improvements

Question 17

Why measure malaria?

Answer 17

Understanding epidemiology
Clinical outcomes
Control methods: testing, efficiency, demand
Drugs: testing, efficiency, demand
Socioeconomic burden
Inherited blood disorders
Travel risks

Question 18

What do you want to know???

Answer 18

Traveller’s need for drugs?
Maps of where malaria is/isn’t
Underlying population prevalence?
Parasite prevalence, or rate (PR)
Risk of infection acquisition?
Entomological Innoculation Rate (EIR)
Ability to control and eliminate malaria from an area?
Basic reproductive number (R0)
Expected health system burden?
Number of clinical cases per year

Question 19

Parasite Rate

Answer 19

The proportion of the population found to carry asexual blood-stage parasites.

Question 20

Where malaria is/isn’t

Answer 20

Sub-Saharan Africa and South Asia

Not USA/Europe