Malaria What do I need to know? The physical and human causes of malaria The impact of malaria on individuals, communities and countries Methods of controlling.

MalariaWhat do I need to know?

•The physical and human causes of malaria

•The impact of malaria on individuals, communities and countries

•Methods of controlling malaria

•How effective these methods are•http://blip.tv/file/110655

Distribution of Malaria

Malaria Distribution and Resistance

Facts• 300-500m clinical cases p.a. worldwide

• Up to 3m deaths worldwide p.a.

• 90% of all deaths are in sub-Saharan Africa

A child dies of malaria every 25 seconds Malaria is on the increase for the first time

in 20 years due to drug resistance

Eggs hatch Mosquito

lays eggs in stagnant

water

Parasites attack the

liver, mature and

reproduce

Mosquito bites another person and transfers the parasite

Parasites are released into

the bloodstream

Malaria parasites develop

within the mosquito

Female sucks blood from an

infected person

becoming a vector or carrier

Mosquito must feed

on blood to survive

Causes

• Female anopheles mosquito• Stagnant water – puddles• Moderate to high rainfall• Temperatures 15-40oc• High population density• Shade for mosquito to rest• Altitude below 3000m• Humidity over 60%

Human Causes

• Stagnant water – padi fields, bomb craters, irrigation canals

• Shade created by urbanisation

• Increased travel, trade and tourism

Impact on individuals

• Fever, shivering, anaemia, enlarged spleen, can be fatal especially if immune system is weakened by malnutrition or other illness.

• Lose 8-10 days work per attack• Income 60% lower than non-malarial

areas• Risk of infection highest in rainy season –

coinciding with agricultural peak

Impact on communities

• More likely to focus on subsistence cropping which is less risky than cash cropping

• Chronic absenteeism in school children

Impact on countries

• Loss of income due to illness

• Growth of GDP is lowered by 1-3% per year

• Accounts for 30-50% of all hospital admissions

• Costs up to 40% of public health expenditure

Controlling Malaria

Method Advantages Disadvantages

Drain breeding sites by filling depressions and planting eucalyptus trees

Removes the breeding sites

•Impossible to implement as the mosquito can breed in a muddy footprint•Canals need to be flushed every 5-7 days to disrupt breeding cycle – clean water is too valuable

Method Advantages Disadvantages

Introduce natural enemies•Spores•Carp – eat larvae•Mustard seeds – sticky – drown larvae•Egg white – suffocate larvae•Parasitic wasps – eat larvae

Natural

Carp add protein to diet

Carp are self sustaining

No risk to human health

Wasteful

Expensive

Risk to indigenous wildlife

DDT Cheap

Easy to apply

effective

Due to be banned in 2007

Damaging to environment

Risk to human health

Mosquitoes build up resistance

Malathion Less risky than DDT

Expensive

Needs to be re-applied more often

Unpleasant smell

Insecticide treated bed nets

•Lasts up to 1 year•Reduced incidence in Tanzania by 35%

•3x as expensive as DDT•$4 per net, 25 cents for insecticide•Some countries (Ethiopia) tax bed nets

Bti bacteria grown on coconuts – thrown into stagnant water

Destroy stomach lining of larvae

•Cheap

•No risk to environment

•Coconuts are plentiful and often grow near stagnant water

•Last up to 45 days

Need coconuts

Only suitable for larger areas of water i.e. not puddles

Anti-malarial drugs

Chloroquine •Cheap•Easy to use

•Mosquitoes developed resistance

Laruim •More powerful •Side effects•Mosquitoes will be resistant in 10 years

Malarone •98% effective•Few side effects

•expensive

Drugs

continued

•Quinghaosu – developed from chinese herbal medicine

or•Artemissinin (commercial name)

•Fast acting

•Mosquitoes NOT becoming resistant so far

•Easy to take

•Very expensive

Vaccine    

 Currently being researchedBill & Melinda Gates Foundation 

 None currently available – 10 years away

Genetic engineering     

Aim to make mosquito unable to carry parasite  

Very expensive

Difficult to apply to all mosquitoes 

Primary Health Care      

AffordableFocus on education•removing breeding sites•using bed nets•Covering skin at dusk     

Relies on public finding

Usually small scale projects