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