Sanitary MicrobiologySanitary MicrobiologyCurrent issues facing the developed and developing worldCurrent issues facing the developed and developing world
3rd MICROBIOLOGYSEMINAR
Dr Gavin CollinsMicrobial Ecology Lab (3783)Environmental Change Institute (5047)
… … is responsible for, is responsible for, by some estimates, approximatelyby some estimates, approximately
Sanitary MicrobiologySanitary Microbiology
WATER…WATER…
80%80% of all infectious disease - of all infectious disease - not just waterborne diseases, not just waterborne diseases, but but any disease any disease where water plays a role… WATER where water plays a role… WATER ASSOCIATED DISEASESASSOCIATED DISEASES
Water-washedWater-washed diseases,diseases, such as such as trachoma, scabies, dysentery, louse-trachoma, scabies, dysentery, louse-borne fever;borne fever;
1
2
There are There are waterborne diseases,waterborne diseases, such as such as cholera, typhoid, bacillary dysentery, cholera, typhoid, bacillary dysentery, infectious hepatitis;infectious hepatitis;
4
3 Water-based diseases,Water-based diseases, such as such as schistosomiasis, and Guinea worm;schistosomiasis, and Guinea worm;
And And water-related diseaseswater-related diseases (involving (involving an insect vector) such as malaria, an insect vector) such as malaria, sleeping sickness, or onchocerciasis.sleeping sickness, or onchocerciasis.
40% of 40% of annual annual
worldwide worldwide deaths deaths
attributed to attributed to these these
diseasesdiseases
HH22O can act as a vector for the transmission of O can act as a vector for the transmission of bacterial, viral and protozoan agents which bacterial, viral and protozoan agents which
cause a variety of diseases (mainly intestinal)cause a variety of diseases (mainly intestinal)
It can also be linked to worm invasions and It can also be linked to worm invasions and viral/protozoan diseases transmitted by insects viral/protozoan diseases transmitted by insects
(aquatic hosts or insect breeding in H(aquatic hosts or insect breeding in H22O - O - indirect)indirect)
Water-associated diseases can be classified Water-associated diseases can be classified under 4 different categories: -under 4 different categories: -
1. Water-borne diseases1. Water-borne diseases
Mainly enteric diseases resulting from the ingestion Mainly enteric diseases resulting from the ingestion of faecally-contaminated Hof faecally-contaminated H22O (man, animal and O (man, animal and bird excreta)bird excreta)
In developed countries, classical HIn developed countries, classical H22O -borne diseases O -borne diseases are mostly are mostly lowlow infective dose infections - cholera infective dose infections - cholera and typhoid fever (rare), leptospirosis (rare); viral and typhoid fever (rare), leptospirosis (rare); viral infections; infections; CampylobacterCampylobacter (bacterium) and (bacterium) and GiardiaGiardia and and CryptosporidiumCryptosporidium (protozoa) infections - (protozoa) infections - becoming more common in Irelandbecoming more common in Ireland
In developing countries (or as a result of the In developing countries (or as a result of the breakdown of sanitary services in developed breakdown of sanitary services in developed countries - earthquakes, war etc.), a variety of countries - earthquakes, war etc.), a variety of other, high-infective dose diseases can be other, high-infective dose diseases can be transmitted via Htransmitted via H22O - infectious hepatitis, O - infectious hepatitis, VibrioVibrio (bacterial) infections; bacillary dysentery; other (bacterial) infections; bacillary dysentery; other viral infections etc. (human and/or animal originviral infections etc. (human and/or animal origin
All water borne diseases can also be transmitted by All water borne diseases can also be transmitted by other routes that permit ingestion of faecal matter other routes that permit ingestion of faecal matter - e.g. contaminated food- e.g. contaminated food
2. Water-washed 2. Water-washed diseasesdiseases
Diseases linked to HDiseases linked to H220 scarcity and resultant poor 0 scarcity and resultant poor personal hygienepersonal hygiene
Obviously more common in tropical, 3rd world Obviously more common in tropical, 3rd world countries where Hcountries where H22O supplies may be scarceO supplies may be scarce
Intestinal and non-intestinal infectionsIntestinal and non-intestinal infections
Intestinal: Intestinal: ShigellaShigella (dysentery); typhoid; cholera; (dysentery); typhoid; cholera; CampylobacterCampylobacter; Giardia; Cryptosporidium; viruses; Giardia; Cryptosporidium; viruses
Non-intestinal: Infections of the skin and Non-intestinal: Infections of the skin and mucous membranes - bacterial skin sepsis; mucous membranes - bacterial skin sepsis; scabies; fungal infections such as ring-scabies; fungal infections such as ring-worm; fungal mouth ulcers etc.worm; fungal mouth ulcers etc.
3. Water-based diseases3. Water-based diseases
Diseases caused by pathogens that have a complex Diseases caused by pathogens that have a complex life-cycle which involves an intermediate aquatic life-cycle which involves an intermediate aquatic hosthost
All of these diseases are caused by worms, e.g. All of these diseases are caused by worms, e.g. SchistosomiasisSchistosomiasis caused by the Schistosoma worm caused by the Schistosoma worm which uses aquatic snails as an intermediate host, which uses aquatic snails as an intermediate host, also the Guinea worm (also the Guinea worm (Dracunculus medimensisDracunculus medimensis) ) which uses a small crustacean as an intermediate which uses a small crustacean as an intermediate hosthost
SchistosomiasisSchistosomiasis affects affects 200 million people 200 million people worldwide per annumworldwide per annum
4. Water-related 4. Water-related diseasesdiseases
Diseases caused by pathogens carried by Diseases caused by pathogens carried by
insects that live near Hinsects that live near H22O and act as O and act as
mechanical vectorsmechanical vectors
Very difficult to control and diseases are very Very difficult to control and diseases are very
severesevere
Examples: Examples: Yellow feverYellow fever (viral disease) is transmitted by the (viral disease) is transmitted by the
mosquito mosquito AedesAedes spp.; spp.; Dengue (viral) carried by the mosquito Dengue (viral) carried by the mosquito Aedes Aedes
aegyptiaegypti (breeds in water); (breeds in water); Malaria is caused by a protozoan (Malaria is caused by a protozoan (PlasmodiumPlasmodium
spp.) and is also spread by a mosquito spp.) and is also spread by a mosquito ((AnophelesAnopheles spp.); spp.);
Trypanosomiasis (Gambian sleeping sickness) is Trypanosomiasis (Gambian sleeping sickness) is also caused by a protozoan transmitted by the also caused by a protozoan transmitted by the riverine Tetse fly (riverine Tetse fly (GlossinaGlossina spp.) spp.)
(increasing numbers of elderly & (increasing numbers of elderly & immuno-suppressed people)immuno-suppressed people)
(such as water treatment and (such as water treatment and distribution systems)distribution systems)
with increased flooding leads towith increased flooding leads to breakdown of sanitary breakdown of sanitary
infrastructure and further spread of infrastructure and further spread of diseasedisease
Increasing Crises Increasing Crises WorldwideWorldwide
Population growthPopulation growth
PollutionPollution
Climate changeClimate change
Engineered systemsEngineered systems
Population Population susceptibilitysusceptibility
Simpler moleculesBiogas (CH4 & CO2)
Complex molecules
ANAEROBIC DIGESTIONANAEROBIC DIGESTION
Greenhouse Greenhouse effecteffect
Methane (CH4) from anaerobic digestion
Bovine generated CH4
CO2 from industry
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Urbanisation
Globalisation
Celtic Tiger economy
Wealth & Wastefulness
Kyoto treaty
The diseases that result from flooding vary according to geographic region.
Typical ones include cholera, typhoid, dengue, Rift Valley fever, malaria, hepatitis A, AGI [acute gastro-intestinal illness], and ARI [acute respiratory illness].
Flooding
Problems involved in getting clean, Problems involved in getting clean, safe water to people in the safe water to people in the
developing worlddeveloping world
Water supplies in communities Water supplies in communities highly susceptible to municipal, highly susceptible to municipal, agricultural, and industrial agricultural, and industrial contamination.contamination.
e.g., in India, huge e.g., in India, huge numbers of people live in numbers of people live in slums sited in low-lying slums sited in low-lying points, and at end-of-pipe points, and at end-of-pipe sites.sites.
Water has maximum "residence time" in Water has maximum "residence time" in deteriorating distribution systems. Uses deteriorating distribution systems. Uses antiquated British water treatment technology antiquated British water treatment technology designed for a much smaller population, only designed for a much smaller population, only supplies water for 2 hours per day.supplies water for 2 hours per day.
CASE STUDY
Hyderabad, IndiaHyderabad, India
The remaining time, The remaining time, 22 hours per day,22 hours per day, water sits water sits stagnantstagnant in the distribution in the distribution system. In addition to pathogens in system. In addition to pathogens in drinking water, slums tend to be sited drinking water, slums tend to be sited near standing water.near standing water.
Standing waterStanding water is a major problem in malaria is a major problem in malaria and other vector-borne diseases.and other vector-borne diseases.
Moreover, children routinely play in this Moreover, children routinely play in this water - both fouling it and further water - both fouling it and further exposing themselves to disease.exposing themselves to disease.
Cholera, giardiasis, hepatitis, shigellosis, Cholera, giardiasis, hepatitis, shigellosis, typhoid, and AGItyphoid, and AGI
Other infections such as legionellosis, Other infections such as legionellosis, cryptosporidiosis, and mycobacterial cryptosporidiosis, and mycobacterial infections occur, but are seldom infections occur, but are seldom diagnoseddiagnosed..
Absence of Sanitary Absence of Sanitary InfrastructureInfrastructure
Often in the developing world gastroenteritis Often in the developing world gastroenteritis and other infections cause unnecessary and other infections cause unnecessary mortalitymortality
e.g. Massai in Kenya each e.g. Massai in Kenya each year the current infant year the current infant mortality rate is mortality rate is 20%20% for for children < 5 years old from children < 5 years old from diarrhoeal infections - diarrhoeal infections - Campylobacter/E. coliCampylobacter/E. coli
Treatment for these infections does not need Treatment for these infections does not need expensive drugs or antibiotics (self-limiting expensive drugs or antibiotics (self-limiting infections)infections)
Needs only water and salt to balance loss - Needs only water and salt to balance loss - but if available water is contaminated??but if available water is contaminated??
Diarrhoea kills 15000 < 5 year olds every day, Diarrhoea kills 15000 < 5 year olds every day, 5.5m/annum5.5m/annum
Treatable at the cost of <10 cent per childTreatable at the cost of <10 cent per child
HOWEVER, NOT JUST A HOWEVER, NOT JUST A PROBLEM OF THE PROBLEM OF THE
DEVELOPING WORLDDEVELOPING WORLD
WBD’s in a developed world WBD’s in a developed world contextcontext
Growing problem in Ireland primarily due to Growing problem in Ireland primarily due to deterioration of ground and surface water deterioration of ground and surface water quality quality
Massive volume of wastes produced in Massive volume of wastes produced in intensive agriculture can contaminate a intensive agriculture can contaminate a water supply if not managed correctlywater supply if not managed correctly
General causes of WBDOs include:General causes of WBDOs include:
1) No treatment1) No treatment
2) Breakthrough at treatment plant2) Breakthrough at treatment plant
3) No disinfectant residual3) No disinfectant residual
4) Direct sewage contamination through pipe 4) Direct sewage contamination through pipe
leakage, breakage, back-siphoning, and leakage, breakage, back-siphoning, and
cross-connectionscross-connections
30%30% of rivers polluted; of rivers polluted;
50%50% of group water supplies of group water supplies contaminated with contaminated with E. coliE. coli
Where the problems ariseWhere the problems ariseCorrosion of pipe networks allowing Corrosion of pipe networks allowing contamination during distributioncontamination during distribution
biofouling; biofouling; foul odour, smell, colour, and the general foul odour, smell, colour, and the general impression of "dirty water”; impression of "dirty water”; biocorrosion; biocorrosion; survival and proliferation of pathogens; survival and proliferation of pathogens; disinfection resistance; disinfection resistance; transfer of antibiotic and virulence factorstransfer of antibiotic and virulence factors
BiofilmBiofilm formation leads to:formation leads to:
The presence of coliforms in water only The presence of coliforms in water only reflects sewage contamination - not potential reflects sewage contamination - not potential pathogens likepathogens like Legionella Legionella
Coliform behaviour and die-off is not Coliform behaviour and die-off is not comparable to the behaviour of viruses and comparable to the behaviour of viruses and protozoaprotozoa
Die-off rates of faecal coliforms have been Die-off rates of faecal coliforms have been demonstrated to vary enormouslydemonstrated to vary enormously
Problems with Problems with Microbiological MonitoringMicrobiological Monitoring
Current Current indicator organismsindicator organisms may not be may not be adequate for the following reasons:adequate for the following reasons:
Problems with Microbiological Problems with Microbiological Methods (cont’d)Methods (cont’d)
Techniques used to identify indicators Techniques used to identify indicators rely on growth and culture - many rely on growth and culture - many organisms can be viable in the organisms can be viable in the environment but unculturable using environment but unculturable using current methodscurrent methods (‘Plate-count anomaly’)(‘Plate-count anomaly’)
Molecular methods based on DNA Molecular methods based on DNA probes and PCR still not adequateprobes and PCR still not adequate
Challenges for the future: controlling Challenges for the future: controlling LegionellaLegionella and other organisms and other organisms
Legionella pneumophilaLegionella pneumophila an emerging an emerging pathogen - first recognized in the 1970spathogen - first recognized in the 1970s
Example of how creation of a unique Example of how creation of a unique environment in our water systems that has environment in our water systems that has lead to a "new" or newly recognized disease. lead to a "new" or newly recognized disease.
Incidence of Legionnaires' disease in the U.S.: Incidence of Legionnaires' disease in the U.S.: approximately 1,000 cases annuallyapproximately 1,000 cases annually
Estimated that over 25,000 cases of the illness Estimated that over 25,000 cases of the illness occur each year, causing more than 4,000 deathsoccur each year, causing more than 4,000 deaths..
LegionellaLegionella is one of the top three causes of sporadic, is one of the top three causes of sporadic,
community-acquired pneumonia. Difficult to community-acquired pneumonia. Difficult to
distinguish, many cases go unreported.distinguish, many cases go unreported.
For growth For growth LegionellaLegionella requires the following: requires the following:
stagnation; temps between 20° and 50°C (optimal stagnation; temps between 20° and 50°C (optimal
growth range is 35° - 46°C);growth range is 35° - 46°C);
pH between 5.0 and 8.5;pH between 5.0 and 8.5;
Microbes incl algae, flavobacteria, and Microbes incl algae, flavobacteria, and PseudomonasPseudomonas, ,
which supply essential nutrients or harbor the which supply essential nutrients or harbor the
organism (protozoa)organism (protozoa)
Optimal conditions created for Optimal conditions created for LegionellaLegionella growth in many modern buildings:growth in many modern buildings:
Domestic hot-water systems with water Domestic hot-water systems with water heaters that operate below 60°C; centralized heaters that operate below 60°C; centralized hot water systems [common in eastern hot water systems [common in eastern European countries]European countries]
Cooling towers, and fluid coolers that use Cooling towers, and fluid coolers that use evaporation; humidifiers and decorative evaporation; humidifiers and decorative fountains that create a water spray; spas fountains that create a water spray; spas and whirlpools.and whirlpools.
GiardiaGiardia and and CryptosporidiumCryptosporidium
Protozoa and common causes of GI infectionsProtozoa and common causes of GI infections
Used to be rare in Ireland, incidence nowUsed to be rare in Ireland, incidence nowincreasingincreasing
Form oocysts as part of the life-cycleForm oocysts as part of the life-cycle
These oocysts are resistant to chlorination These oocysts are resistant to chlorination which is the only method used to disinfect which is the only method used to disinfect water in Irelandwater in Ireland
How many of the How many of the 350,000350,000 cases cases of food/water borne illnesses in of food/water borne illnesses in Ireland last year caused by Ireland last year caused by these organisms??these organisms??
No detection methods for these No detection methods for these organisms at the momentorganisms at the moment
Use of conventional indicators Use of conventional indicators meaninglessmeaningless
ConclusionsConclusions
Partial solutions to the problems of Partial solutions to the problems of maintaining clean safe water for all include:maintaining clean safe water for all include:
1. Active surveillance1. Active surveillance
2. Population surveys2. Population surveys
3. Low-cost solutions to treatment3. Low-cost solutions to treatment
4. Waste-water reclamation4. Waste-water reclamation
5.5. Appropriate valuation of the resourceAppropriate valuation of the resource
6.6. Assessments of impacts of engineered Assessments of impacts of engineered "ecosystems”"ecosystems”
7.7. Monitoring of antibiotic resistance and Monitoring of antibiotic resistance and changing virulencechanging virulence
8.8. Tighter regulation guided by precautionary Tighter regulation guided by precautionary principlesprinciples
www.nuigalway.ie/microbiology/mel
Further Info
http://www.doh.ie/
http://www.who.int
http://www.cdc.gov/health/
http://www.cfsan.fda.gov/~mow/intro.html
http://www.epa.ie/
http://www.aem.org
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