Transcript Environmental Transmission of Pathogenic Microbes

Environmental Transmission of
Pathogenic Microbes –
why they are where they are when
they are
Part 2
Dr. Julie Ann Kase
Public Health Scientist – Bioterrorism and
Emerging Pathogens Unit
NC State Laboratory of Public Health
[email protected]
Environmental Monitoring of Pathogenic
Microbes : Water, Soil, Air
• Improve microbiological water quality,
reduce diarrhea morbidity and mortality
associated with waterborne disease
• Standards for water quality
– EPA
– World Health Organization (WHO)
• Total and fecal coliforms
Environmental Monitoring of Pathogenic
Microbes : Water, Soil, Air
Methods to measure water quality
– Accurate and reproducible
– Rapid
– Relatively simple techniques, applicable to
most laboratories
– Common reagents, inexpensive
Environmental Monitoring of Pathogenic
Microbes : Water, Soil, Air
Detection of infectious agents in water
– Many are difficult to detect/quantify
• May require expensive equipment
• Complex techniques – specialized reference
laboratories
– Newly recognized agents, methods are still
being developed
– Pathogen occurrence surveys and special
studies
Environmental Monitoring of Pathogenic
Microbes : Water, Soil, Air
Detection of infectious agents in water
– Laboratory investigations of disease outbreaks
often never detect the etiologic agent
• Contamination was temporary (e.g. problem was
discovered and fixed before investigation)
• Microbe died off or flushed away
• Sensitivity/specificity of methods
• Size of event
Environmental Monitoring of Pathogenic
Microbes : Water, Soil, Air
Detection of infectious agents in water
– Microbial Indicator Organism
• Traditional approach to protect/assess the "sanitary"
quality of water (food) with respect to fecal
contamination
• Quantify bacteria commonly present in intestines of
warm blooded animals; surrogates for pathogens,
especially bacterial
• May not be reliable indicators of viruses and
parasites
Environmental Monitoring of Pathogenic
Microbes : Water, Soil, Air
Criteria for an Ideal Indicator of Fecal Contamination
• Applicable to all types of water (and other relevant samples)
• Present in feces, sewage and fecally contaminated samples when
pathogens are present; numbers correlate with amount of fecal
contamination; outnumber pathogens
• No "after growth" or "regrowth" in the environment
• Survive/persist > than or = to pathogens
• Easily detected/quantified by simple lab tests in a short time
• Constant characteristics
• Harmless to humans and other animals
• Numbers in water are associated with risks of enteric illness in
consumers (dose-response relationship)
Environmental Monitoring of Pathogenic
Microbes : Water, Soil, Air
The Quest for The Ideal Indicator(s)
• No single indicator (so far discovered) meets all of
the criteria of an ideal indicator
• It is unlikely that a single organism or (taxonomic)
group will meet all of the indicator criteria when
applied to viruses, bacteria and parasites
• Current microbial indicator criteria do not address
those pathogens that are not associated with fecal
contamination
Environmental Monitoring of Pathogenic
Microbes : Water, Soil, Air
Current and Candidate Bacterial Indicators of Fecal
Contamination
• Total coliforms: standards for drinking, bathing and shellfish
harvesting waters; not feces-specific (environmental sources)
• Fecal ("thermotolerant") coliforms: ditto for total coliforms
• E. coli: the "fecal" coliform; may occur naturally in tropics
• Fecal streptococci: another group of enteric, fecally excreted bacteria;
not feces-specific (environmental sources)
• Enterococci: Streptococcus faecalis and S. faecium; a sub-set of the
fecal streptococci considered more feces-specific; EPA guide-line for
bathing water quality used as standards in some states
• Clostridium perfringens: anaerobe; ?feces-specific?; very (too?)
resistant spores; candidate indicator for protozoan cysts
Environmental Monitoring of Pathogenic
Microbes : Water, Soil, Air
Microbial Indicators of Fecal Contamination and Treatment
Efficacy for Enteric Protozoan Pathogens
• Clostridium perfringens spores may be useful indicators of enteric
protozoan parasites
– Plentiful in feces, raw sewage, treated effluents and receiving
waters and soils
– Spores of aerobic bacilli (Bacillus spp.) may be useful indicators of
water treatment efficacy
– Plentiful in water and other environmental media
– But, not feces-specific
– Spores are reduced less than are conventional vegetative indicator
bacteria by water and sewage treatment processes
– Spores of C. perfringens and Bacillus spp. superficially resemble
enteric protozoan parasite cysts and oocysts
Environmental Monitoring of Pathogenic
Microbes : Water, Soil, Air
CANDIDATE VIRAL INDICATORS OF FECAL CONTAMINATION
OF WATER
Coliphages: viruses (bacteriophages) infecting E. coli and perhaps other
coliforms; attach directly to cell wall (somatic) heterogeneous group;
may not be feces-specific; host-dependent detection.
Male-specific (F+) coliphages: coliphages infecting "male" strains of E.
coli (posses pili); may be feces-specific.
May distinguish human from animal fecal contamination by group
classification (II & III human; I & IV animal);
but, pigs may harbor groups II & III, too.
Bacteroides fragilis phages: may be human feces specific; USA studies
do not show human-specificity; concentrations too low.
Salmonella phages: in human and animal feces; may indicate presence of
Salmonella bacteria; concentrations too low.
Cary residents told to boil water (Aug 18, 2006)
http://rdu.news14.com/content/story_links/?ArID=89457&SecID=231
Town of Cary Press Release
CARY, N.C. -- Officials told the approximately 100,000 residents of the
Wake County town of Cary to boil their water and they closed restaurants
because fecal coliform was found Friday in a sample from one home.
Results of the Town of Cary’s routine sampling and testing of its water
supply has revealed the presence of E. coli on Coronado Way in the
Coronado Village subdivision in central Cary.
Water Contamination In Cary Costs Restaurants Millions
August 22, 2006
http://www.wral.com/apncnews/9718848/detail.html
CARY, N.C. -- The restaurant shutdown ordered here over the weekend after
E. coli was found in the water supply may have cost owners and
employees some $6 million. Health officials ordered the town's 115,000 residents
To boil tap water and forced restaurants to close Friday night
after the bacteria was detected.
Cary has 'weird' water mix-up
News and Observer July 25 2007
"In a place like Cary, it never even occurred to me that this might even be a possibility,"
Vinay Jain said Tuesday as Cary workers walked through his house testing taps.
"This gives the impression of a Third World country.
At least in India, we knew the water was bad, and we boiled it."
Cary Families' Faucets Delivered Treated Wastewater
www.wral.com July 25 2007
N.C. family drinks lawn water for 5 months
www.sciencedaily.com July 26 2007
Environmental Monitoring of Pathogenic
Microbes : Water, Soil, Air
Sources of drinking water
• Surface water
– Widely used as a supply for municipal DW
– Need to protect from sources of contamination (land
run-off, wildlife, recreational activities)
• Ground water
– Comprises 95% of water serving rural populations in
US (>100 million people)
– Assumed that soil will filter out most microbes
– Rarely are private wells treated, also public H2O supply
Environmental Monitoring of Pathogenic
Microbes : Water, Soil, Air
• Traditionally, more than half waterborne
disease outbreaks – groundwater responsible
– From 1997-98 15/17 (88%) reported outbreaks
- groundwater responsible
– Most common pathogens identified = Shigella
spp. and Hepatitis A virus
– 2/3 of the time no etiologic agent identified
Environmental Transmission of Pathogenic
Microbes : Water, Soil, Air
• Soil microbial communities
– Complex set of natural communities
– 10,000 species per gram of soil
• Traditionally soil microbiology has focused on
metabolic activities of microbes (e.g.
biogeochemical cycles – nitrogen fixation)
• Concern when pathogens on/in soil reach
surface/ground waters or are disturbed
(transmitted via air)
Environmental Transmission of Pathogenic
Microbes : Water, Soil, Air
• Sources of pathogenic soil microbes
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Domestic drainage/septic systems
Land applied municipal sewage
Land applied agricultural waste
Landfills
• Disposable diapers and animal waste– untreated
waste penetrating subsurface
– Naturally occurring
Environmental Transmission of Pathogenic
Microbes : Water, Soil, Air
• Although most of us don’t routinely ingest soil…
– Infiltrated ground water
– Surface of raw fruits & vegetables
• Sampling
– Surface soils
– Subsurface soils
• Horizontal and vertical variations
• Perturbation of site, contamination
• Specialized technologies for drilling and coring
– Cost and expertise
Environmental Transmission of Pathogenic
Microbes : Water, Soil, Air
Survival and persistence of soil microbes
• Some things to consider …
– Soil type
• Texture: sand>silt>clay
• Moisture content: below 10% is biocidal
– Adsorption to soil (esp. viruses)
– Migration of microbes thru soil layers
• Type and species of microbe (physiological & morphological
characteristics)
– Smaller microbes penetrate soil better
– Virus>bacteria>protozoa
Environmental Transmission of Pathogenic
Microbes : Water, Soil, Air
Ground water recharge• Lack of water in arid SW US has prompted actions such as
the land application or injection of treated wastewater to
recharge subsurface aquifers
• Movement of viruses (small size=greatest potential to be
transported) thru soil mostly studied
– In one study, indigenous enteroviruses were found in 9m deep
well, 14m from recharge basin
– Movement of larger microbes (bacteria and protozoans)
theoretically less
Environmental Transmission of Pathogenic
Microbes : Water, Soil, Air
Airborne transmission
• Bioaerosol –
– “collection of airborne biological particles”
– Droplets or particles 0.5 to 30 μm diameter
– Composition will vary with source &
environmental conditions
• Airplane
Environmental Transmission of Pathogenic
Microbes : Water, Soil, Air
Sources: any object that can produce droplets or aerosols
– Humans and other animals (cough, sneezes)
– Mechanical ventilation system
– Fresh and marine surface waters, showers, whirlpool
baths, toilets
• Splash/wave action : microbes enclosed within droplet
– Soil, plants
• associated with particles, dust; act as “raft”
• spores
– US postal letters – mail-borne attack Oct. 2001
Environmental Transmission of Pathogenic
Microbes : Water, Soil, Air
Type of microbes found in bioaerosols:
– Viruses, bacteria, fungi (spores & hyphae)
– Generally protozoans are too large to remain
airborne
Some Examples of Bioaerosols
Living Source
Examples
Microorganisms (microbes):
• Bacteria
Legionella, Anthrax, endotoxins
• Fungi
Histoplasma,Cyptococcus, Pencillium,
Aspergillus, Stachybotrys aflatoxins,
• Protozoa
Naegleria, Acanthamoeba
• Viruses
Rhinoviruses (colds), Influenza (flu),
Coronaviruses (SARS), Hantavirus
• Algae
Chlorococus
• Green plants
Ambrosia (ragweed) pollen
• Arthropods
Dermatophagoides (dust mites)
• Mammals
Horse or cat dander
Environmental Transmission of Pathogenic
Microbes : Water, Soil, Air
Airborne Microbes and their Reservoirs – Bacteria
Legionella pneumophila
• Reservoirs and amplifiers:
– Hot water systems, circulating water ventilation systems (cooling
towers), plumbing (e.g., shower heads), hot tubs, whirlpools,
produce fresheners
• Legionnaire's disease:
– A bacterial pneumonia that affects the lungs and may also affect the
stomach and intestines, kidneys, and central nervous system
– Frequently requires hospitalization
Environmental Transmission of Pathogenic
Microbes : Water, Soil, Air
Airborne Microbes and their Reservoirs – Bacteria
Bacillus anthracis
•
Reservoirs and amplifiers:
– Herbivores (e.g., cattle, sheep, goats ) may become infected by ingesting spores
while grazing in areas of high soil contamination
– Anthrax can be found globally
– Endemic to the parts of US (Dakotas, OK, TX)
– Spores are extremely resistant, 50 years or more in soil
– Animal carcass – vegetative cells will sporolate when exposed to air
– Person-person spread unlikely
– 2005: South Dakota: 11 counties: 39 outbreaks, 330 head; North Dakota: 13
counties, 86 cases
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Anthrax:
– Cutaneous: skin lesions from contact with spores or contaminated meat
– Gastrointestinal: ingestion of spores or contaminated foods
– Inhalation: often fatal, especially with inhalation of weapons-grade spores,
symptoms resemble common cold, severe breathing problems, shock
Inhalation Anthrax Associated with Dried
Animal Hides --- Pennsylvania and New York
City, 2006 (Feb)
March 17, 2006 / 55(10);280-282
•This report describes the first case of naturally acquired inhalation anthrax
in the United States since 1976
•The patient made traditional African drums by using hard-dried animal
hides (e.g., air-dried until brittle enough to crack) obtained in NYC from
importers who primarily sold African goat and cow hides.
•Making the drums involved soaking hides for 1 hour in water and then
scraping hair from the hides with a razor, which reportedly generated a large
amount of aerosolized dust in the patient's workspace as the hides dried.
•The man did not wear any personal protective equipment (e.g., mask or
gloves) while working.
Cutaneous Anthrax Associated with Dried
Animal Hides (Sept 2007)
• Two family members in Danbury, CT; on antibiotics and
recovering
• Goat and cattle hides imported from Africa used in drum
making
• Wore masks while working
• Traffic rerouted around location; FBI, EPA, and other state
officials notified
• Neighbors evacuated
• Samples taken from house, shed and soil
• Positive samples from shed, door to shed, and rear
entrance of home
Environmental Transmission of Pathogenic
Microbes : Water, Soil, Air
• Biohazard Detection System (BDS)
– Combined automated air sampling w/internal automated testing
system
– Sampling interval 1.5 hrs, 30 min analysis
– Currently only set-up for B. anthracis spores
– Used across the US in USPS PDC
• BioWatch Program
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Air monitors set up since 2003; >30 metro areas
Goal: detect w/in 36 hrs release of anthrax, sm pox, plague (20)
~10 sensors per city, tested once a day
15 positives
Not intended to prevent attack, hundreds of thousands of victims,
instead start mass treatment
Environmental Transmission of Pathogenic
Microbes : Water, Soil, Air
Airborne Microbes and their Reservoirs – Viruses
Coronaviruses (SARS)
• Reservoirs and amplifiers:
– First reported in Asia 2003, global outbreak-few months spread to
two dozen countries
– Person-person spread – respiratory droplets travel short distances
(~ 3ft)
– Knowledge is still evolving
• Morbidity/Mortality:
– Flu-like symptoms, most develop pneumonia
– 8,437 people worldwide w/ 813 deaths
– US: 192 cases, none died, very little transmission among close
contacts and generally did not spread thru community!!??
Environmental Transmission of Pathogenic
Microbes : Water, Soil, Air
Airborne Microbes and their Reservoirs – Viruses
Hantaviruses
• Reservoirs and amplifiers:
– Wild rodents - pass it in their droppings, urine, or saliva. The
common house mouse does not carry hantavirus.
– Human exposure - touch rodent urine, droppings, or places where
these animals have nested. Most exposed (by inhalation) when
sweeping areas with dried droppings or urine
• Hantavirus pulmonary syndrome:
– Flu-like symptoms, most develop cough and shortness of breath
– Person-to-person spread unlikely
– Around in US since 1950s, took outbreak in “four corners” area of
US to be recognized
Environmental Transmission of Pathogenic
Microbes : Water, Soil, Air
Airborne Microbes and their Reservoirs – Fungi
Cryptococcus neoformans
• Reservoirs and amplifiers:
– Fungal Pathogen
– Isolated from the soil worldwide, usually in association with bird
droppings
– Inhalation of airborne cells and/or spores
• Cryptococcosis:
– Initial pulmonary infection - usually asymptomatic
– Disseminated infection, especially meningoencephalitis
– one of the most common life-threatening fungal infections in AIDS
patients
– In the United States, 85% of cases occur in HIV-infected persons