Water is a gift of nature. The total amount
of water on the earth is finite, while man's capacity for
pollution is accelerating fast with the growth of population,
agriculture and industry across the globe. Local water bodies
may very quickly be exhausted and become polluted due to greed
and ignorance; water can become a source of death and disease
rather than life.
Today, at least one-fifth of all people
worldwide lack access to safe drinking water. In developing
countries, most cities discharge 80 to 90 % of the untreated
sewage directly into rivers and streams, which are used for
drinking, bathing and washing. This lack of sewage treatment
has allowed dangerous microorganisms to spread water-borne
diseases; particularly diseases transmitted by vectors which
live in the water environment account for about a third of
all deaths in the world.
The growing pollution of our rivers constitutes
the biggest threat to public health. Polluted waters lead
to various gastrointestinal problems, liver infections, cancer,
etc. Children are often the worst affected, dying in large
numbers because of diarrhea. Even in the 1990s more than
1 million children died due to diarrhea and other gastrointestinal
Distribution of the earth's
Oceans and seas 97.29%
Ice caps and glaciers 2.09%
Underground aquifers 0.61%
Lakes and rivers 0.01%
The need is great in the
1 billion people do not have access
to safe drinking water
2.9 billion people do not have adequate sanitation facilities
11,000 children die each day of water-related diseases
The water-related infections of man are
extremely numerous and diverse. In general the following are
the ways in which diseases may be carried by water.
- Pathogenic organisms are transmitted from one person to
another through their domestic water supply.
(e.g.) cholera, typhoid and hepatitis.
- Inadequate water supply, lack of personal cleanliness
(e.g.) trachoma and skin infection
- Infection transmitted by organisms which live in water.
(e.g.) helminths (parasitic flukes) that spend part of their
life cycle in water.
- Insect vectors which are related in some way to water
(e.g.) yellow fever, malaria etc.
Sources of water pollutants
- Discharge of domestic, industrial or agricultural effluents.
- Direct application of herbicides to control water plants
that interfere with man's use of freshwaters.
- Direct application of insecticides to fresh waters to
destroy larvae of mosquitoes, the vector of malaria.
- Molluscicides widely used in the tropics to control the
snail vectors of schistosomiasis.
- Run-off of insecticides and herbicides applied to the
- Carelessly dumped waste pesticides and their empty containers
in pools or streams.
- Land fill sites and toxic waste dumps contaminate ground
Types of pollutants found in water
- Organic pollutants
- Inorganic pollutants
- Thermal pollutants
- Radioactive materials
- Domestic sewage (major source)
- Urban run-off (from houses, factories and roads)
- Industrial effluents
- Depletion of dissolved oxygen (the recommended DO level
for natural water is 4 to 6 ppm)
Faecal contamination of water can introduce a variety of
pathogens into waterways, including
- Parasitic worms
Water for life
Life originated in water and it is
water that makes life possible. Water makes up 60 percent
of body weight, blood plasma contains more than 90 percent
of water, cell cytoplasm contains about 70 percent of
the water. Even bone is 20 percent water. Water is needed
- Transporting nutrients and oxygen
to all parts of the body via blood
- Maintaining blood volume
- Removing body waste materials
- Helping maintain body temperature
- Plants which use water to convert
the nutrients in the soil into food, which keeps them
alive and helps them to grow
SOME WATER-RELATED DISEASES AND THEIR CAUSATIVE ORGANISMS
Mode of Spread
||Ingestion of contaminated food, water,
milk, unwashed raw vegetables and flies
||Continuous fever which progressively
increases day by day, the temperature being higher in
the evening than in the morning accompanied by body aches,
headache and constipation, Hemorrhage from an ulceration
in the small intestine
||Ingestion of water or food contaminated
by the bacteria from the stool of a cholera patient
||Painless diarrhea followed by vomiting;
patient may pass 30 to 40 stools per day which soon becomes
typically watery and colourless with flakes of mucous
floating in them
||Through contaminated food, water and
by direct personal contact
||Diarrhea, with the presence of blood
and mucous in the stools accompanied by severe gripping
pain in the abdomen. Stools are not too frequent (4-10
per day) and the fecal matter is scanty. Patient looks
||Primary hosts are rodents, which carry
the organisms in their kidneys and the patient may become
infected by wading or swimming in water contaminated with
the rodents urine
||Fever, pain in legs, nausea, vomiting
are common, congestion of the conjunctival blood vessels
around the corneas of the eyes
||Stools that contain virus contaminating
the water and food
||Loss of appetite, nausea, vomiting
and diarrhea accompanied by fever. The urine is dark
coloured. Eye and skin have yellow coloration
||Ingestion of cysts in food and water
||Abdominal discomfort to diarrhea,
with or without the presence of blood or mucus in the
stools, accompanied by fever, chills and gripping pain
in the abdomen
||Cysts which are voided with the feces
and enter the new hosts in food or water
||Intestinal disorders leading to epigastric
pain, abdominal discomfort, loss of appetite, headache
and loose bowels
||Eggs of the flukes pass out with human
feces or urine and if they reach fresh water, develop
into miracidia larvae which infect snails. The cercaria
stage develops in the snails and on leaving the host,
cercaria penetrate the skin of humans wading in the water.
||Allergy-like itch, rash, aches, fever,
eosinophilia, etc. When infection is heavy, the eggs may
be deposited in the arterioles of the lungs causing cardio-pulmonary
schistosomiasis or corpulmonale or ayerza disease, which
may lead to congestive heart failure
||Unfiltered water containing the infected
||Blister near the ankle, burns around
the blister, allergy and aches
Protection against water-borne diseases
is necessary to be careful about the water you drink and the
water you bathe in, since water is a carrier for a number
- Filter water with a good quality purifier (ultraviolet
or reverse osmosis)
- Boil un-treated water to 100°C for 10 to 15 minutes
- All fruit and vegetables that will not be cooked must
be peeled after soaking them in treated water
- Do not eat ice-creams, drinks, etc., sold by street vendors
- Clean your teeth preferably with treated water
Bathing can expose the body to several diseases, notablybilharzia,
leptospirosis and diarrheic diseases. Mud and sand can contain
with bare feet
- Bathing in untreated water
Safe water supply
This is very essential. In rural areas this can be achieved
by chlorination of water and replacement of shallow wells
by sanitary wells.
This implies the proper disposal of excreta so that infection
does not reach water, soil, milk, food or flies.
It is essential to educate people for improvement in sanitation
and personal hygiene.
Bottled water- is it your
Recent studies show that many brands of bottled water
contain high levels of contaminants. Surveys reveal
that most of what is promoted as pure is just municipal
water that has been refiltered and repackaged with slick
If you do drink bottled water regularly, make sure
that the bottle is
- properly sealed
- opened in front of your eyes
- crushed and properly disposed off to avoid reuse
and adulteration (bottles are made up of PVC)
Source: - Health and Nutrition, Vol.12, No. 6, September
MOSQUITO BORNE DISEASES
||Female Anopheles (primary or final
||Man (Intermediate hosts)
||Shaking chills and sweating. As chills
subside, the body temperature rises as high as 106°F.
As temperature lowers down, the patient sweats profusely
and finally becomes comfortable until the next attack,
which takes place at regular intervals of 48 hrs.
|Culex fatigans (Intermediate hosts)
||Man (final hosts)
||Enlargement of limbs, scrotum or mammage
||Barbo - virus
||Sudden onset of moderately high fever,
excruciating joint pain, intense pain behind the eyes,
a second rise in temperature following the brief remission
and particularly the type of rash and decided reduction
in neutrophilic white blood cells.
Elimination of breeding places
The mosquito larvae and pupae develop in water; therefore,
Swampy areas and stagnant water should be drained out.
- Water should be prevented from stagnating in gutters,
drains and depressions.
- The domestic species can be largely controlled by eliminating
receptacles that hold water such as tin-cans, buckets, cisterns,
barrels, open tanks, etc.
- If possible, the breeding grounds may be filled up.
Destruction of larvae and pupae
- Larvicidal fish like sticklebacks, minnows, trout, etc.
should be introduced in the ornamental fountains, ditches,
ponds, lakes, canals, tanks, etc.
- Keeping lakes, reservoirs and streams free of aquatic
vegetation and other floating material provides the top-
feeding minnows (gambusia) better opportunities to search
out and feed upon the larvae and pupae.
- Aquatic nymphs and adult insects (dragonflies), which
are natural enemies of mosquitoes, should be encouraged.
Protection against mosquito bite
- Houses in mosquito-infested areas should be made mosquito
proof by screening all the doors and windows.
- While sleeping, mosquito nets should be used to keep away
- The exposed parts of the body may be protected by the
use of veils, gloves and boots or by the application of
repellents, such as herbal anti mosquito creams, neem oil,
mustard oil, oil of java citronella and eucalyptus oil,
- If you do not have mosquito proofing keep doors and windows
shut during sunrise and sunset. Mosquitoes are on the move
at these times in search of prey and of a more pleasant
||IN SPITE OF
ANY OR ALL OF
COULD BE FATAL
KEEP YOUR WATER CLEAN