Environmental Transmission of Pathogenic Microbes – why they are, where they are, when they are Dr. Julie Ann Kase Public Health Scientist – Bioterrorism

Environmental Transmission of Pathogenic Microbes – why they

are, where they are, when they are

Dr. Julie Ann Kase

Public Health Scientist – Bioterrorism and Emerging Pathogens Unit

NC State Laboratory of Public Health

[email protected]

• 1976 Legionnaires' disease – Outbreak of pneumonia occurred among persons attending a convention of the

American Legion in Philadelphia– ~ 8,000 to 18,000 cases in the US each year; 5% to 30% die

• 1981 AIDS– report in MMWR of 5 CA men with severe immunodeficency (1983 HIV recovered

from lymph node)• 1993 Cryptosporidiosis

– 400,000 people sick and killed more than 100– worst waterborne disease outbreak in the United States

• 1995 Ebola Hemorrhagic Fever

– Ebola Virus initial recognition in 1976 – Occurred in Kikwit and surrounding area – 315 cases 81% death of cases

• 2002 (November) Severe acute respiratory syndrome (SARS) – Viral respiratory illness that was recognized as a global threat in March 2003– first appearing in Southern China in November– November 2002 - July 2003, a total of 8,098 people worldwide became sick; 774

died– By late July 2003, no new cases, and WHO declared the global outbreak to be over

• Late 2003 and Early 2004 Avian influenza– Outbreaks of influenza H5N1 occurred among poultry in eight countries in Asia

(Cambodia, China, Indonesia, Japan, Laos, South Korea, Thailand, and Vietnam) – By March 2004, the outbreak was reported to be under control until late June 2004– Human infections (H5N1) have been reported in Thailand, Vietnam and Cambodia

E. coli O157:H7 Outbreak Case Counts by State

(As of October 6, 2006)

www.cdc.gov

Cases infected with the outbreak strain of Salmonella Saintpaul, United States, by state,

as of August 25, 2008 9pm EDT

www.cdc.gov

Seek and Ye Shall Find

• Environmental Transmission– Presence

• Cover our planet– Several 100m deep in glacial ice sheets– Deep-ocean thermal vents

– Survival and transport• Media

– Water– Soil– Air

• Natural fate + influence of man’s actions

Microbial Survival in the Environment

Pathogen survival• Differs widely among microbes:

– Bacteria: • Spores survive better than vegetative cell

– Viruses: • non-enveloped viruses survive better than enveloped viruses under

most environmental conditions– Envelopes are relatively fragile compared to outer capsids (protein

coats)

– Parasites: • protozoan (oo)cysts and spores and helminth ova survive better than

active life stages of these parasites or than those with no resting or special environmental forms

– Fungi: • spores survive better than other forms

Environmental Factors Influencing Survival or Proliferation of Infectious Agents

• Temperature– Greater inactivation/death rates at higher temps– Environmental temperatures influence pathogen spread by insect

vectors

• pH– Extreme pH inactivates microbes– Important exceptions: enteric pathogens survive pH 3.0

• Moisture content– Drying or low moisture inactivates /kills some microbes– Ex. Preserving food by desiccation

• Sunlight (UV)– Nucleic acids absorb the UV energy and is damaged

Environmental Factors Influencing Survival or Proliferation of Infectious Agents

• Pressure (atmospheric & hydrostatic)– Typical atmospheric pressure– Use of high hydrostatic pressure in shellfish

• Weather– Microbes levels may increase or decrease– Warmer weather increases some microbes (ex. Vibrio bacteria in NC

coastal waters during warmer months) and vectors, like mosquitoes– Wet weather carries microbes also resuspension in water resources

• Chemicals & nutrients– Levels influence microbe survival– Ex. Lack of nutrients (e.g. carbon, nitrogen) will limit proliferation

• Biological factors– Predation, vectors, reservoirs (animals), microbe species/type

Environmental Transmission of Pathogenic Microbes : Water, Soil, Air

• Microbes can be found anywhere in which water is maintained in a liquid state

• Human illness associated with water – usually acute in nature but some have chronic sequelae (e.g. stomach cancer (Helicobacter pylori), myocarditis & diabetes (coxsackieviruses))

• Highly effective means of introducing an infectious microbe to a large population– Person-to-person not efficient in reaching a large

population


Reservoirs for pathogenic microbes found in water: humans, animals, environment

– Source tracking

– Human sources – important contributor of pathogens in water

• Recreational activities (e.g. water theme parks)• Domestic wastewater

– Discharge of wastewater into surface waters

– Aquifer contamination

Infectious Disease Water Transmission Model


Microbial agents associated with waterborne diseases

– Enteric, non-enteric,and aquatic bacteria

– Enteric viruses

– Enteric protozoa


Enteric bacteria– Shigellosis: Shigella spp. (classical bacillary dysentery)

• occur around the world, with most victims being children in developing countries

• 300,000 cases of shigellosis are reported in the United States (not all confirmed)

• Shigella dysenteriae type 1 – deadly epidemics in dev. world• Spread can be via vector, food, water, and fomites

– Cholera: Vibrio cholerae serogroup O1 or O139 (1992) that produces toxin

• Endemic poverty, summer rains, poor health & living conditions• 56 countries, 101,383 cases (2345 deaths) in 2004• Africa - 94% cases in 2004• No major outbreaks of this disease have occurred in the United States

since 1911 • Easily treatable

– Infectious dose variable: 10 - 500 orgshttp://www.cfsan.fda.gov


Aeromonas hydrophila• Commonly found in water but recently implicated as a cause of GI

illness, also wound infection• Potential to grow in water distribution systems, especially in

biofilms, where it may be resistant to chlorination• EPA list (candidate contaminant list) for drinking water

Legionella pneumophila • Ubiquitous in water, aerosol transmission• Proliferate at high temperatures (hot water systems, cooling towers

and evaporative condensers)• Etiologic agent of Legionnaires’disease, Pontiac fever

Leptospira spp.• Species not enteric or aquatic - Urine from dom. & wild animals• Outbreak during Eco-Challenge - grueling 2-week contest in late

Aug and early Sept [2000] island of Borneo • http://www.youtube.com/watch?v=RMIFu5qWjSU&feature=related

Leptospirosis

• Reports of outbreaks occurring following flooding, tropical storms, hurricanes – all can increase the exposure to contaminated water

• Asymptomatic, high fever, severe headache, muscle aches

• LA- found in cattle, skunks, rodents

• Most common in tropic climates

• Recent outbreaks of leptospirosis in the US have occurred in Illinois and Florida (CDC, unpublished data), while leptospirosis is endemic to Hawaii

• According to the Centers for Disease Control and Prevention (CDC), between 100 and 200 cases of leptospirosis are reported in the United States each year as of the early 2000s.

http://www.cdc.gov/ncidod/dbmd/diseaseinfo/leptospirosis_t.htm


Enteric viruses– Generally more persistent than enteric bacteria but can

not multiply in environment– Survival influenced by physical, chemical, and

microbial factors as well as virus type• Non-enveloped viruses most persistent – protein coat offers

stability and resistant barrier to stressors• Majority of enteric viruses are non-enveloped

– Require more sophisticated detection methods• Tissue cultivation, electron microscopy, molecular techniques

(e.g. PCR, nucleic acid hybridization)• Limit microbe ID from clinical & environmental samples• Distinguish between infectious/non-infectious - MAYBE


Implicated in majority of AGI outbreaks in US based upon clinical & epidemiological evidence

• Rotavirus –

– the virus is stable in the environment, transmission can occur through ingestion of contaminated water, global problem

– Rotavirus is the most common cause of severe diarrhea among children, resulting in the hospitalization of approximately 55,000 children each year in the United States and the death of over 600,000 children annually worldwide

• Norovirus –

– Among the 232 outbreaks of illness reported to CDC from July 1997 to June 2000, 3% were waterborne; in 23% of outbreaks, the cause of transmission was not determined

– Waterborne outbreaks of norovirus disease in community settings have often been caused by sewage contamination of wells and recreational water.

– Infectious dose: typically low, maybe 1 to 10 infectious units

– Developing countries: Hepatitis A virus, Hepatitis E virus


Proposed EPA drinking water contaminant list• The Safe Drinking Water Act directs that periodically publish a CCL

• 2003 - regulatory determinations for nine contaminants from the first CCL (60 contaminants in March 1998)

• Summer of 2005 - second cycle of preliminary regulatory determinations - continue research on the list of contaminants on the first CCL

– Adenoviruses Helicobacter pylori– Noroviruses Aeromonas hydrophila

– Coxsackieviruses Cyanobacteria – Echoviruses

• February 2008 = Draft CCL 3 efforts to expand and strengthen the CCL listing process

– Caliciviruses

– Campylobacter jejuni

– Entamoeba histolytica

– Escherichia coli (0157)

– Helicobacter pylori

– Hepatitis A virus

– Legionella pneumophila

– Naegleria fowleri

– Salmonella enterica

– Shigella sonnei

– Vibrio cholerae

“Payment Intervention Studies”: References

• Payment P., et al, (1991). A Randomized Trial to Evaluate the Risk of Gastrointestinal Disease due to Consumption of Drinking Water Meeting Current Microbiological Standards. American Journal of Public Health 81 (6) 703-708.

• Payment P., et al (1997). A prospective epidemiological study of gastrointestinal health effects due to the consumption of drinking water. International Journal of Environmental Health Research. 7(1). 1997. 5-31


Payment et al. intervention studies Wanted to know risk of GI illness associated

w/consumption of municipal drinking H2O– Municipal H2O source = river polluted with human

sewage– 1st study: 606 households; ~half had RO filters, others

no intervention; 15mo• 35% higher rate of GI symptoms households w/o intervention;

symptoms & serologic evidence pointed to enteric viruses

– 2nd study: 1400 households; 3 groups w/tap H2O, 1 group purified bottle H2O; 16 mo

• ~20% more GI illness in tap H2O consumers


Enteric protozoa– Recently recognized as water borne pathogens

– Thick-walled protozoan cysts and oocysts are environmentally resistant

– Recovery and detection technically challenging• Filtering liters of water

• Immunofluorescence microscopy

• May not distinguish between nonviable/viable orgs

– Infectious dose is low• C. parvum ~ 100 oocysts


Enteric protozoa (cont.)– Ex. Cryptosporidium, Giardia

• Size: Cryptosporidium oocysts (4-6 µm) Giardia cysts (7-14 µm)• Animal reservoirs • Size limits movement thru soil, thus surface waters contamination

mostly (esp. unfiltered)• Greater than half of 300 surface water supplies in US contained

Cryptosporidium oocysts – Ex. Toxoplasma gondii

– Matures only inside cats and spreads through their feces – Lethal parasite that has infected or killed hundreds of California sea

otters – Parasite can concentrate inside clams and other bivalves, favorite of

otters – Flushable cat litter runoff from land, affecting the ecosystem, including

the clams that otters eat


Other aquatic microbes• Cyanobacteria – algal blooms, dermatitis• Naegleria fowleri – meningoencephalitis, usually fatal

– small, free-living amoeba – occ. infects humans & other mammalsN. fowleri can invade the CNS via the nose & nasal tissues

– 2003 case in North Carolina– In August 2008, a 9-year-old boy was killed after having been exposed to the amoeba while swimming several times in Lake Elsinore in CA

• Acanthamoeba species – subcutaneous abscesses, conjunctivitis– Contact lens wearers, EPA published warning: Acanthamoeba Guidance

Document EPA-822-B-04-001 – Amoebae invades the cornea of the eye – EPA determined not to regulate because “regulation would not present a

meaningful opportunity for health risk reduction”

• Schistosoma species – dermatitis, swimmer’s itch– Debilitating (liver and intestinal damage) illness that results from infection of the blood

with a parasitic flatworm (schistosome)– Found in Asia, Africa, and South America, especially in areas with water that is

contaminated with fresh water snails, which contain the parasite

http://upload.wikimedia.org/wikipedia/commons/3/33/Naegleria_%28formes%29.png


Categories of water-related infectious hazards

– Waterborne

– Water contact

– Water related

– Water washed


Waterborne– Physical contact w/microbially contaminated

H2O

– Bathing, recreational activities, ingesting water (also ice)

– Example: cholera


Water Contact– Infections caused by

aquatic organisms• Pathogenic

microorganisms or macroorganisms (worms)

• Naturally spend part of life cycle in aquatic envr or within a host that resides in water

– Ingestion or immersion in water

– Example: Schistosomiasis


Water Related– Disease as a consequence of

being bitten by an invertebrate vector whose life cycle requires access to H2O

– Influences of season, rain events (monsoon, flooding)

– Example: Malaria (parasite) and yellow fever, west nile infection (viruses)


Water Washed– Infections associated

with inadequate hygiene

– Eliminate hazard by using microbe-free water for cleaning of eating and cooking utensils, plates, self, etc.

– Example: Shigellosis

Environmental Transmission of Pathogenic Microbes –

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


Methods to measure water quality– Accurate and reproducible– Rapid– Relatively simple techniques, applicable to

most laboratories– Common reagents, inexpensive


Detection of specific 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


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


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


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)


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


Current and Candidate Bacterial Indicators of Fecal Contamination

• Total coliforms: standards for drinking, bathing and shellfishharvesting 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


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


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.

Water Contamination In Cary Costs Restaurants MillionsAugust 22, 2006

http://www.wral.com/apncnews/9718848/detail.htmlCARY, 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 residents told to boil water (Aug 18, 2006)

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.

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.

http://rdu.news14.com/content/story_links/?ArID=89457&SecID=231Town of Cary Press Release

http://rdu.news14.com/content/story_links/?ArID=89457&SecID=231

Cary has 'weird' water mix-upNews and Observer July 25 2007

Cary Families' Faucets Delivered Treated Wastewaterwww.wral.com 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."

N.C. family drinks lawn water for 5 monthswww.sciencedaily.com July 26 2007

http://www.wral.com/

http://www.sciencedaily.com/


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


• 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

– EPA estimates: 185,000 viral illnesses/yr from ground water


• 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)


• Sources of pathogenic soil microbes– Domestic drainage/septic systems– Land applied municipal sewage– Land applied agricultural waste– Landfills

• Disposable diapers and animal waste– untreated waste penetrating subsurface

– Naturally occurring


• 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


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


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 thru soil mostly studied– Small size = greatest potential to be transported

– In one study, enteroviruses were found in 9m deep well, 14m from recharge basin


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


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


Type of microbes found in bioaerosols:

– Viruses, bacteria, fungi (spores & hyphae)

– Generally protozoans are too large to remain airborne

Some Examples of BioaerosolsLiving Source Examples • 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


Airborne Microbes and their Reservoirs – BacteriaLegionella 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– Aug 2008 – Elmira (NY) Housing Authority said they suspended the use of hot water in

the senior housing complex. Tests revealed Legionella pneumophila in the hot water system

– 10 cases & health officials have been advising residents to take sponge baths instead of showers to avoid breathing in water vapor


Airborne Microbes and their Reservoirs – BacteriaBacillus 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 • 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)

•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.

March 17, 2006 / 55(10);280-282

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


• 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– 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


Airborne Microbes and their Reservoirs – VirusesCoronaviruses (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!!??


Airborne Microbes and their Reservoirs – VirusesHantaviruses• 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– 15 Aug 2008: A policeman, 34, died at Yakima Valley Memorial

Hospital Wa, barely 48 hours after suffering symptoms


Airborne Microbes and their Reservoirs – FungiCryptococcus 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

Documents

Environmental Transmission of Pathogenic Microbes – why they are, where they are, when they are Dr. Julie Ann Kase Public Health Scientist – Bioterrorism