Brief summary regarding water borne diseases, particularly bacterial causes

1. Water-Borne Diseases
(Bacterial)
Bachelor of Public health
Classroom Lecture
Dr. Tanveer Rehman
Dr. Yogesh Arora 19-02-2021 1

2. Introduction
• Water is an essential component of human body and life. Both quality and
quantity are important, but without enough quantity, quality cannot be
assured
• Water is related with development of diseases in various ways. Various ways
by which water can transmit disease to humans are: -
Water-borne, Water-based, Water-washed, Water-related
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3. Category Transmission Disease Example
Water-borne Ingestion of water contaminated by human
or animal feces or urine containing
pathogenic bacteria, viruses or parasites
Diarrhoeal diseases (gastroenteritis), amoebic &
bacillary dysentery, cholera, poliomyelitis,
typhoid/paratyphoid fever
Water-washed Skin, ear or eye contact with contaminated
water & poor personal hygiene
Conjunctivitis, trachoma, intestinal helminth
infections, leprosy, scabies
Water-based Parasitical worm infections (parasites found
in intermediate organisms living in water)
Dracunculiasis, schistosomiasis, bilharziasis
Water-related Insect vectors breeding in water or biting
near water
Dengue, lymphatic filariasis, malaria,
onchocerciasis, trypanosomiasis, yellow fever
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4. Biological
• Those caused by the presence of an
infective agent.
a) Viral b) Bacterial c) Protozoal d)
Helminthic e) Fungal
• Those due to the presence of an
aquatic host
a) Snail b) Cyclops
Chemical
Chemical pollutants of diverse nature,
derived from industrial and
agricultural wastes, are increasingly
finding their way into public water
supplies. Theses pollutants include:
a) Detergent solvents, b) cyanides, c)
heavy metals, d) minerals and organic
acids, e) biocidal organic compounds
etc.
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5. Water-borne diseases
• Diarrhoeal: Infect the gastrointestinal tract – Rotavirus, pathogenic E.coli,
Campylobacter, Entamoeba, Giardia
• Epidemic diarrhoea: Shigella, Vibrio cholera are particularly infectious – potential to
cause severe epidemics
• Non-diarrhoeal: Affecting other parts of the body – Hepatitis, Poliomyelitis,
Legionellosis, Leptospirosis
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6. Burden of diarrhoea
• World-wide 1.8 million deaths, 4 million cases reported in 2004
• 88% of those deaths are due to unsafe water & poor sanitation
• 99% of those deaths occur in developing nations
• One in nine people lack access to an improved water source
• More people have a mobile phone than a toilet
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7. Water-borne diseases
• It is transmission of fecal-orally transmitted infectious diseases through
ingestion of water contaminated by human or animal feces or urine
containing pathogenic bacteria, viruses or protozoa.
• Pathogenic bacteria, viruses or protozoa can cause disease when ingested
• Human feces are generally the most dangerous
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8. Effects of climate on water-borne diseases
• Flooding: - a) Sewage treatment plant overflow, b) Contamination of water
resources, c) Shortage of drinking water supply.
• Drought:- Higher concentrations of pathogens, impedes hygiene
• Global warming: -Higher temperatures increases growth and prolongs
survival of infectious agents.
• Rainfall: -Dissemination of infectious agent from one place to another.
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9. Infection depends on
• Amount of faecal contamination of water
• Concentration of pathogens in faecal contamination
• Survival of the pathogenic organism
• Infectivity of the organism
• Individual health status
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10. Water-borne Pathogens
• Bacteria:- Vibrio sp, E. Coli, Camplylobacter, Salmonella,
Leptospira, Legionella
• Protozoa: -Giardia, Cryptosporidium, Cyclospora, Toxoplasma,
Naegleria.
• Virus: -Hepatitis A, E, Enterovirus (polio), Norovirus
• Fungi: -Cryptococcus, Aspergillus
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11. Bacterial Diseases
1. Pathogenic E.coli:-
• Strain O157: H7 may cause bloody diarrhoea, vomiting, and may cause death
in individuals.
• Source: - From contaminated food and water.
2. Campylobacter: -
• Common cause of food poisoning from contaminated water, meats and
unpasteurized dairy products – complication causes Guillain-Barre Syndrome
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12. Bacterial Diseases
3. Salmonella: -
• Typhoid fever: Common cause of food poisoning
4. Leptospira: -
• Causes Weil’s disease – high fever, headaches, kidney and liver dysfunction
• Spread through the infected urine of animals (rodents).
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13. Bacterial Diseases
5. Vibrio: -
• Causes cholera, a highly infectious disease that causes severe watery diarrhea, which
can lead to dehydration and even death if untreated.
• Climate warming can increase its survival and transmission rate
6. Legionella: -
• Causes Legionnaires' disease, a form of respiratory illness transmitted by water.
Signs and symptoms include cough, shortness of breath, high fever, muscle pain,
and headaches.
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15. Prevention & Control
• Improve quality – at source – tap, storage vessel
• Interrupt routes of transmission – empty accumulated water sources
• Chlorination
• Hygiene behaviour – handwashing
• Exclusive Breastfeeding
• Careful disposal of all waste products
• Maintenance of sanitation system, pumps & wells
• Immunization – rotavirus
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17. Thank You
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18. Bibliography
• Park’s Textbook of Preventive and Social Medicine. 24th Edition
• World Health Organization: Documents on diarrhoea
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