DDT 25 - Water, Sanitation and Hygiene (WASH) Intervention and Against Waterborne Disease Flashcards
in developing countries what % of al illnesses are caused by water borne diseases
80%
what would be considered water related disease
those due to micro-organisms and chemicals in water that people drink
examples of water related disease
diseases like schistosomiasis which have part of their lifecycle in water;
diseases like malaria with water-related vectors;
others such as legionellosis carried by aerosols containing certain micro-organisms
disability-adjusted life year (DALY)
is a measure of overall disease burden, expressed as the number of years lost due to ill-health, disability or early death
what % of DALY global burden of disease are from diarrhoeal disease and how many peoples death are from diarrhoeal disease
Diarrhoeal disease alone amounts to an estimated 4.1 % of the total DALY global burden of disease and is responsible for the deaths of 1.8 million people every year (WHO, 2004
types of waterborne disease
biological waterborne disease chemical waterborne disease water-washed disease water-based disease water related
chemical waterborne
Caused by the pollution of water with chemicals that have an adverse effect on health:
biological waterborne
Caused by ingestion of water contaminated by human or animal excrement, which contain pathogenic microorganisms:
examples of biological waterborne disease
cholera, typhoid, amoebic and bacillary dysentery
examples of chemical waterborne disease
Arsenic, Fluoride, Nitrates from fertilizers,
water-washed disease
Diseases caused by poor personal hygiene and skin and eye contact with contaminated water
examples of water washed disease
scabies,
trachoma,
typhus,
flea
water-based disease
Diseases caused by parasites found in intermediate organisms living in contaminated water
examples of water based disease
Schistosomiasis and Dracunculiasis (Guinea worm)
water related disease
caused by insect vectors, especially mosquitoes, that breed or feed near contaminated water. They are not typically associated with lack of access to clean drinking water or sanitation services:
example of water relate disease
dengue, filariasis, malaria, onchocerciasis, trypanosomiasis
economic consequences of water borne disease
Cost of treatment at clinic.
Cost of transport of patient to clinic.
Cost of medicines.
Loss of income generating opportunities due to time required for parent/caregiver to look after sick family member.
WASH programmes
Programmes designed to reduce incidence of waterborne disease in the developing world must adopt a combined approach to educate and introduce interventions that address the inter-linked problems associated with:
Water
Sanitation
Hygiene
sanitation
the hygienic means of promoting health through prevention of human contact with the hazards of wastes as well as the treatment and proper disposal of sewage wastewater.
how many viruses and bacteria and oarasitic cysts and eggs are in 1g of human faeces
10,000,000 viruses
1,000,000 bacteria
1,000 parasitic cysts
100 parasitic eggs
what % of feces is microbe fauna
60%
slit trench
wide and shallow trench for feet and smaller narrower trench is made to deposit where it is covered in soil
Relies on microbial fauna in the soil to inactivate the pathogens in the faeces.
latrines
In absence of a municipal distributed water system the simplest form of sanitation is a Pit Latrine, also known as “the long drop
must be located away from source of water
Ventilated improved pit
The VIP latrine is a brick-lined permanent toilet that does not require emptying.
When the bricks are laid, it is important to only use mortar between the layers and not on the vertical joints. This allows the contents to slowly seep into the soil as it decomposes and keeps the pit from filling up too soon.
allows for aerobic digestion and faeces does not need to be emptied
ways to improve drinking water
piped water into dwelling, yard or plot public tap or standpie tubewell or borehole protected dug well protected spring rainwater collection
examples of unimproved drinking water
unprotect dug well
unprotected spring
tanker truck
surface water - dam, river
issues with stand pipes
distributing municipally treated water are often locked by land owners. Residents/tenants have to pay for access
problems with municiple supply
Intermittent electricity supply often means that water pumped through municipal supplies lies stagnant for extended periods while residual chlorine concentration drops to ineffective levels.
issue with harvested rain water
Harvested rain water is typically contaminated with faecal bacteria from birds, reptiles and mammals who have access to the roof from which the rain has been collected.
household water treatment and storage (HWTS)
Point of use (PoU) treatment within the household thus provides a more effective method of ensuring safe water within the household.
There are several effective “household water treatment & storage (HWTS) interventions.
HWTS must be…
Seen to solve a problem. Effective. Easy to use (requires minimal training) Cost effective. Not expensive.
methods of HWTS
Boiling
filtration - life-straw filter
chlorine
flocculation - flocculant binds to suspended solids and clear water is decanted off
issue with chlorination
some pathogens e.g. vibrio cholerae and oocysts of cryptosporidium spp become resistant
