PART 5Emerging Issue in Water and Waterborne Disease

Dr. Norhafizah AbdullahEnvironmental Health Engineering

(ECH 4102)

• Water-related diseases include those due to micro-organisms and chemicals in water people drink;

• diseases like schistosomiasis which have part of their lifecycle in water

• diseases like malaria with water-related vectors

• drowning and some injuries

• others such as legionellosis carried by aerosols containing certain micro-organisms.

Purification of Drinking WaterPurification of Drinking Water

goals:• remove potentially

pathogenic microoganisms• decrease turbidity (amount

of suspended particles)• eliminate taste and odour• reduce nuisance chemicals

(Fe, Mn)

add anionic polymers, alum, Cl2

flocculation:• alum (aluminum sulfate), anionic polymers interact with small suspended

particles and colloids (coagulation) to form larger flocs (flocculation)• flocs settle by gravity, trapping and removing microorganisms, adsorbing

organic matter, sediment

filtration:• removes remaining suspended particles, microorganisms• critical to removal of disinfectant-resistant microbes (Giardia, Cryptosporidium)• slow sand filtration; use of rapid filters (sand, ionic media)• filtered water is particulate-free, low in most organic, inorganic chemicals,

microorganisms

disinfection:• chlorination (Cl2 or Na or Ca hypochlorite) to provide residual of 0.2-0.6 μg/mL• most microorganisms killed within 30 min; organic compounds oxidized

(improved taste and odour)• chloramination: HOCl + NH3 → NH2Cl + H2O; to ensure residual chlorine levels

maintained through distribution system• ozonation, UV irradiation are alternate technologies to avoid production of

disinfection byproducts (e.g., trihalomethanestrihalomethanes)

Reduction of typhoid fever (caused by Salmonella typhi) in Philadelphia following introduction of filtration and chlorination to treat drinking water. Similar reductions in other waterborne diseases were seen.

H2O16

Water related Infections

Related to water or impurities in water

Transmission by 4 mechanism :

1) Water- borne

2) Water-washed

3) Water-based

4) Insect vector

1. WATER-BORNED MECHANISM

• Pathogen in water taken by human/animal • Disease eg. Cholera, typhoid, diarrhoeas and dysenteries• These disease also can be transmitted by any route which allow

faecal-mouth contact• Preventive strategy- improve drink water quality, prevent casual

used of unimproved sources

cholera patient showing evidence of extensive fluid loss (hand, cheeks)(CDC Public Health Image Library)

disease agent outbreaks cases

Salmonellosis Salmonella species 2 208

Giardiasis Giardia lamblia 6 52

Cryptosporidiosis Cryptosporidium parvum 1 5

Acute gastrointestinal illness Escherichia coli O157:H7Campylobacter jejuniE. coli O157:H7 & C. jejunismall round virusnorwalk-like virusesunknown

4211317

6011778170356416

Waterborne infectious disease outbreaks associated with drinking water in USA (1999-2000) (after Table 28.1, Madigan & Martinko)

“Water-related diseasesDiarrheaDiarrhea occurs world-wide and causes 4% of all deaths and 5% of health loss to disability. It is most commonly caused by gastrointestinal infections which kill around 2.2 million people globally each year, mostly children in developing countries. The use of water in hygiene is an important preventative measure but contaminated water is also an important cause of diarrhea. Cholera and dysentery cause severe, sometimes life threatening forms of diarrhoea.”World Health Organization http://www.who.int/water_sanitation_health/diseases/diarrhoea

disease number of outbreaks percent

gastroenteritis 74 46.8

dermatitis/keratinitis 50 31.6

meningoencephalitis 22 13.9

other 12 7.6

Recreational waterborne disease outbreaks in USA (1989-00) (Table 28.2, Madigan & Martinko)

• gastroenteritis mostly due to Cryptosporidium parvum (protozoa), E. coli O157:H7 or Norwalk-like virus

• dermatitis mostly due to Pseudomonas aeruginosa• meningoencephalitis agent was Naegleria fowleri (amoeba)• cases of leptospirosis (Leptospira) and Pontiac fever (Legionella) also recorded

USEPA guidelines for fresh recreational water, based on monthly geometric mean:enterococci ≤33/100 mL or E. coli ≤126/100 mL

Waterborne microbial diseases:Waterborne microbial diseases:

• epidemics of waterborne disease often show a pattern of cases consistent with a common source of infection (i.e., the water supply)• a treatment plant malfunction, an undetected break in the distribution system, or disruption of treatment by a natural disaster (earthquake, flood) are possible causes

H2O23

Virulence Factor

Enterotoxigenicity of E.coli infection

Rotavirus Infection

Shigella Infection

2.WATER-WASHED MECHANISM

• Infections of intestinal tract and skin• Poor hygiene and limited availability of water• 3 types:

– Infection of intestinal tract –diarrhoeal, cholera, dysentery

– Infection of skin and eyes-skin sepsis, scabies and fungal infection due to poor hygiene

– Infection due to lice and mites• Prevention-increase water quality, improve accessibility

and reliability of domestic water supply, improve hygiene

• transmitted almost exclusively via contaminated water (fecal-oral route); also raw shellfish, vegetables (Americas)• 7 or 8 world-wide pandemics since 1817 • endemic in Africa, parts of Asia, Indian subcontinent, Central & South America• controlled by applying appropriate water treatment, sanitation measures

V. cholerae: gram negative, curved rod; free-living in coastal waters, adhering to normal microbiota

disease: initiated when ingested bacteria attach to epithelial cells of small intestine, begin to grow and release enterotoxin (toxin affecting GI tract)• characterized by copious watery diarrhea – “rice water stools”• fluid losses may exceed 20 L per day• untreated, mortality rate can reach 60%

treatment: intravenous or oral liquid and electrolyte replacement therapy(20 g glucose, 4.2 g NaCl, 4.0 g NaHCO3, 1.8 g KCl in 1 L H2O)

Cholera

V. cholerae is an aquatic bacterium that often lives in association with other aquatic microbiota, e.g., the alga Volvox

• the micrograph was taken with an epifluorescence microscope• the bacteria are stained green by a monoclonal antibody-fluorescent tag system• the red algal colour is due to natural fluorescence of chlorophyll a

Volvox

Vibrio choleraebacteria

Cholera

Infectious cycle of V.cholerae

Infectious cycle of V.cholerae

Cholera toxin

Cholera toxin

Cholera Treatment

Virulence

Virulence determinant

3.WATER BASED MECHANISM

• Pathogen spends a part of its life cycle in a water snail or other aquatic animal

• Infection of parasitic worms (helmith)• Eg: Guinea worm, larvae escape man through blister

and into small aquatic animal, then man drink water containing these larvae

• Acquire by eating insufficiently cooked fish• Prevention: reduce contact with infected water, control

snail population

4. INSECT VECTOR MECHANISM

• Spread by insect which either breed in water or bite near water

• Eg. Malaria, yellow fever, dengue, river blindness and sleeping sickness

• Prevention-improve surface water management, destroy breeding sites, decrease visit to breeding sites, use mosquito netting

EXCRETA-RELATED INFECTIONS

• All disease in the faecal-oral route, most water-based diseases are caused by pathogen transmitted in human excreta (normally in faeces)

• This can be controlled by improvement of water supply and hygiene, excreta disposal, toilet, final disposal or re-use

a). Faecal-oral disease (non-bacterial)

• Cause by virus, protozoa and helmiths• Spread easily from person due to bad hygiene• Improve excreta disposal unlikely to reduce their

incidence. Health education

b). Faecal-oral disease (Bacterial)

• Person-to-person transmitted,• Also contaminated food crops, water source with faecal

material• Eg. Salmonella passed in the faces of bird

c). Soil-transmitted Helmiths

• Parasitic worms whose eggs are passed in faeces

• This route require period of development in favourable of their growth- usually moist soil

• Reach to human via ingestion • Latrine help to avoid faecal

contamination of the floor hep to limit transmission

• Eggs survive for months between host

• Eliminate eggs by sedimentation in stabilisation ponds, heat or prolonged storage

d). Beef and Pork Tapeworms (Taenia)

• Require period in body of host before infecting human

• When meat eaten without sufficient cooking

• Prevent untreated excreta eaten by pig/cattle help prevent transmission of parasite

e). Water-based Helminths

• Passed in excreta and then to snail (aquatic host)

• Re-infect man through skin or eating uncooked fish

• One egg can multiply in snail to produce thousand larvae

f). Excreta-related insect Vectors

• 2 kinds:

1.Culex pipens group of mosquitoes, breed in highly polluted water and transmits filariasis

2. Flies and cockroaches, breed where faeces exposed, they carry pathogen on their bodies and intestinal tract.

Forms of Infection

1. Anthroponosis = infection affect only man and transmision route is man-to-man

2. Zoonoses= infection affect other vertebrates and may be transmitted from man-to-animal and vice-versa

ZOONOSES

• Disease that occur primarily in animal, but occasionally transmitted to human.

• Since public health for animal is less, infection rate for these disease in animal is very high.

ZOONOSES

• Latency- they can’t infect man immediately after they’ve been excreted, but must undergo a period of development in soil, pigs or aquatic animal

• Persistence- how long it can survive in the environment

• The latent and persistent organism have longer transmission cycle

Zoonoses Control

• Primal transmission is animal to animal. • Occasionally animal to human. Thus, to control zoonosis

in human is not good approach to eradicate it from animal reservoir.

• Success case for zoonosis control are bovine TB and brucellosis via pasteurisation of milk.

• Some have more complex life cycle. Eg. Protozoa (malaria) and metazoans (tapeworms). So, control in human or in the alternative animal host.

REFUSE-RELATED INFECTION

• Poor refuse disposal encourage fly breeding• Promote disease associated with rats, such as plague,

salmonellosis, endemic typhus• Uncollected refuse can obstruct streets and drainage

channel• Refuse is potential source for composting, food source of

animal

HOUSE-RELATED INFECTION

• Interaction between housing and human health are numerous

• Location affect the health of inhabitant• In manner promote airborne disease- overcrowding,

ventilation, air, temp, humidity• In manner promote population of rats, fleas, mites, lice-

share with animals, poultry, pets.

Water coursesWater courses = sources of raw water for drinking

• necessary to monitor for presence of potential disease-causing agents

• many waterborne pathogens cause gastrointestinal upset (gastritis, diarrhea, colitis)

• transmitted by the fecal-oral routefecal-oral route (cycle)(cycle)• acquired from physical contact or ingestion of water contaminated by the disease-causing agent

potential pathogens include:potential pathogens include:

bacteriabacteria:Salmonella, Shigella, Vibrio cholerae, Escherichia coli (incl O157:H7O157:H7), Yersinia, CampylobacterCampylobacter, Leptospira, Legionella, Bacteroides)

virusesviruses:: hepatitis viruses, rotaviruses, Norwalk-like agents

protozoaprotozoa:: Giardia, Cryptosporidium, Entamoeba, Balantidium, Naegleria

(Walkerton outbreak)(Walkerton outbreak)

Monitoring of water quality:Monitoring of water quality:

monitor for pathogens?

• too many possible pathogens• numbers vary markedly depending on prevalence of disease, its causative

agent in human community• numbers often low in test waters• technical issues (and time, $$)

→ use indicator organisms for monitoring purposes• choice depends on goal

• occurrence of fecal contamination• treatment efficiency (water purification, wastewater)• post-treatment contamination in water distribution systems

ideal indicator should be:• member of intestinal microbiota of warm-blooded animals• at least equally resistant as pathogen to environmental insults, disinfection in

water & wastewater treatment plants• present in greater numbers than pathogen• detectable via easy, rapid, cheap methods• non-pathogenic• should not multiply in the environment

indicatorindicator organismsorganisms:

coliform group: aerobic and facultatively aerobic, gram negative, nonspore-forming, rod-shaped bacteria that ferment lactose with gas formation within 48 h at 35°C• growth-based, operational definition, rather than taxonomic• includes E. coli, (intestinal inhabitant), Enterobacter aerogenes (not an intestinal inhabitant), Klebsiella pneumoniae (sometimes intestinal)

• classic coliform test is conducted by most probable number (MPN) procedure (presumptive, confirmed, completed steps) (lab – expt 5)• widely-used alternate is membrane filtration (MF) procedure (lab - expt 6)

coliform colonies on EMB

fecal (or thermotolerant) coliforms: all coliforms that can ferment lactose at 44.5C

• MF procedure using mFC medium (lab)• sometimes not intestinal• may grow under environmental conditions• current movement toward abolishing this technical designation

Escherichia coli: is not perfect indicator, but not bad for enteric bacterial pathogens• in the past, drawback was lack of simple growth-based assay

alternate operational definitions (based on enzymes, defined substrate technology):

coliforms: will convert chromogenic substrate ONPG to o-nitrophenol (yellow) within 24 h at 35C (due to possessing gene for -galactosidase)

E. coli: will convert fluorogenic/chromogenic substrate within 24 h (due to possessing gene for -glucuronidase) • MUG (4-methylumbelliferyl--D-glucuronide) fluorescent product• BCIG (5-bromo-6-chloro-3-indoyl--D-glucuronide) insoluble blue compound

NOTE: unfortunately….

E. coli not the ideal indicator for some enteroviruses, Cryptosporidium, Giardia

unknown sample

membrane filtration

vacuum filtration flask

filter(0.45 µm)

transfer filter to plate of BCIG-containing medium, incubate

sample processing:

P-A test (e.g., Colilert)

100 mL incubate

ONPG & MUG-containing medium

under UV

unknown sample

+ TC + EC

+ EC

_

_

Typhoid (Salmonella typhi)

• most common route of transmission is via water; may also be foodborne, by direct contact with infected individuals• virtually eliminated in developed countries as a result of water treatment practices• carrier state can be important (carrier: individual that harbours organism but shows no disease symptoms)• story of “Typhoid Mary” – see p. 823 (11th ed) or p. 853 (10th ed) of Madigan

S. typhi: gram negative rod, one of the “Enterobacteriaceae”

disease: systemic infection with sustained bacteremia (bacteria in blood), characterized by high fever (several weeks)• also initial headache, often constipation, then diarrhea• complications may include perforation of intestinal wall• mortality may approach 15% in untreated typhoid; reduced to less than 1% with antibiotic therapy (e.g., chloramphenicol, ampicillin, cephalosporins)

Cryptosporidiosis and Giardiasis• common waterborne diseases in areas with regulated water supplies• cysts or oocysts of these parasitic protozoa found in most surface waters

• chlorine-resistant; dose rates can be low• cryptosporidiosis in Milwaukee, WI affected over 400,000 people (spring 1993)

• outbreak attributed to overburdened water supply system + spring rains and runoff from surrounding farmland into L. Michigan (source for supply system)

Giardia lamblia: flagellate; infects animals (e.g., beaver), humans• environmentally resistant cyst (~10 μm dia) is infective agent• ingested cysts germinate in intestine, resultant trophozoites grow on intestinal wall• explosive, foul-smelling, watery diarrhea, cramps, flatulence, nausea, weight loss

Cryptosporidium parvum: infects variety of warm-blooded animals• resistant oocysts transmitted to new host via feces-contaminated water• oocysts (~2-5 μm) smaller than Giardia, more chlorine-resistant• ingested oocysts germinate, trophozoites growth within epithelial cells of stomach,

intestine• mild, self-limiting diarrhea in healthy individuals• chronic diarrhea in individuals with impaired immunity (+ possible

complications)

(M. Johnson, Mesa Community College, Mesa, Az)

(Biol 447)

trophozoites

cyst stainedwith iodine

Giardia lamblia life cycle (US CDC)

Legionellosis (Legionella pneumophila)

severity of infection varies:• may be asymptomatic• Pontiac fever: mild cough, mild sore throat, mild headache, self-limiting • Legionellosis: a type of pneumonia, more likely to affect elderly, immune-

impaired, associated with certain L. pneumophila serotypes• intestinal disorder. then high fever, chills, muscle aches, followed by dry

cough, chest and abdominal pain

Legionella: discovered in late 1970s, probably a recent human pathogen

• present in small numbers in natural waters and soil, may live inside free-living protozoa, heat- and chlorine-resistant

→ lives happily in cooling towers, air conditioning systems, hot water tanks, whirlpool spas, etc.

• bacteria disseminated in humidified aerosols, human infection is via airborne droplets (showering, water-dependent heating/cooling systems)

• no person-person transmission

→ entirely different than other pathogens involved in respiratory infections→ a “newly emergent” disease resulting from changing human behaviour

Waterborne viral diseases:• many cause gastroenteritis (e.g., rotaviruses, Norwalk-like)• may cause eye throat infections (e.g., adenoviruses)• hepatitis (liver disease): hepatitis A, hepatitis E viruses• polio: wild poliovirus been eliminated from western hemisphere

• most are neutralized by chlorination

Amebiasis:

Entamoeba histolytica is transmitted primarily by water (cysts)• excysted trophozoites grow on/in intestinal mucosal cells • amebic dysentery is invasive version (intestinal inflammation and ulceration,

fever, blood and mucus in feces)• invasion of liver, lung or brain may result → abscessing, death

• common in tropics, subtropics; in USA: several 100 cases/yr

Naegleria fowleri: free-living amoeba (soil, water runoff)• may enter through nose, burrow into brain → multiples• meningoencephalitis (extensive hemorrhage, brain damage) → death

unless quickly diagnosed and treated (amphotericin B)

MALARIA

Pathology of MALARIA

Malaria

MALARIA CONTROL: VECTOR

• Control of breeding sites (water)• Insecticide use (residual sprays in/around houses)• Reduction in exposure (bed nets, screens, repellants)

MALARIA CONTROL: VECTOR

MALARIA CONTROL: DRUG

MALARIA CONTROL: VACCINATION

MALARIA: SUMMARY

Assignment topic: Dengue

• What are the obstacles to control dengue in Malaysia?