Environmental Transmission of Pathogenic Microbes why they

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 Julie. Kase@ncmail. net

• 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 H 5 N 1 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 (H 5 N 1) have been reported in Thailand, Vietnam and Cambodia

E. coli O 157: H 7 Outbreak Case Counts by State (As of October 6, 2006) www. cdc. gov

Seek and Ye Shall Find • Environmental Transmission – Presence • Cover our planet – Several 100 m 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 • p. H – Extreme p. H inactivates microbes – Important exceptions: enteric pathogens survive p. H 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 • Most human illness associated with water – infectious, 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

Environmental Transmission of Pathogenic Microbes : Water, Soil, Air 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

Environmental Transmission of Pathogenic Microbes : Water, Soil, Air Microbial agents associated with waterborne diseases – Enteric, non-enteric, and aquatic bacteria – Enteric viruses – Enteric protozoa

Environmental Transmission of Pathogenic Microbes : Water, Soil, Air Enteric bacteria – Shigellosis: Shigella spp. (classical bacillary dysentery) • occur around the world, with most victims being children in developing countries • 18, 000 cases of shigellosis are reported in the United States • Shigella dysenteriae type 1 – deadly epidemics in dev. world • Spread can be via vector, food, water, and fomites – Cholera: Vibrio cholerae serogroup O 1 or O 139 (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 Easily treatable – Infectious dose variable: usually high - 102 to 108 orgs

Environmental Transmission of Pathogenic Microbes : Water, Soil, Air 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]

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 • 1965 -1993 incidence rate in LA = 1 -14/100, 000 people per year

Environmental Transmission of Pathogenic Microbes : Water, Soil, Air 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

Environmental Transmission of Pathogenic Microbes : Water, Soil, Air – 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 • 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 – Infectious dose: typically low, maybe 1 to 10 infectious units – Developing countries: Rotaviruses, Hepatitis A virus, Hepatitis E virus

Environmental Transmission of Pathogenic Microbes : Water, Soil, Air 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 • Make final regulatory determinations – Adenoviruses – Noroviruses – Coxsackieviruses – Echoviruses

“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

Environmental Transmission of Pathogenic Microbes : Water, Soil, Air Payment et al. intervention studies Wanted to know risk of GI illness associated w/consumption of municipal drinking H 2 O – Municipal H 2 O source = river polluted with human sewage – 1 st study: 606 households; ~half had RO filters, others no intervention; 15 mo • 35% higher rate of GI symptoms households w/o intervention; symptoms & serologic evidence pointed to enteric viruses – 2 nd study: 1400 households; 3 groups w/tap H 2 O, 1 group purified bottle H 2 O; 16 mo • ~20% more GI illness in tap H 2 O consumers

Environmental Transmission of Pathogenic Microbes : Water, Soil, Air 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

Environmental Transmission of Pathogenic Microbes : Water, Soil, Air 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, affecting the ecosystem, including the clams that otters eat

Environmental Transmission of Pathogenic Microbes : Water, Soil, Air Other aquatic microbes • Cyanobacteria – algal blooms, dermatitis • Naegleria fowleri – meningoencephalitis, usually fatal – small, free-living ameba that occasionally infects humans and other mammals – 2003 case in North Carolina • Acanthamoeba species – subcutaneous abscesses, conjunctivitis – Contact lens wearers, EPA published warning: Acanthamoeba Guidance Document EPA-822 -B-04 -001 – 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

Environmental Transmission of Pathogenic Microbes : Water, Soil, Air Categories of water-related infectious hazards – Waterborne – Water contact – Water related – Water washed

Environmental Transmission of Pathogenic Microbes : Water, Soil, Air Waterborne – Physical contact w/microbially contaminated H 2 O – Bathing, recreational activities, ingesting water (also ice) – Example: cholera

Environmental Transmission of Pathogenic Microbes : Water, Soil, Air 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

Environmental Transmission of Pathogenic Microbes : Water, Soil, Air Water Related – Disease as a consequence of being bitten by an invertebrate vector whose life cycle requires access to H 2 O – Influences of season, rain events (monsoon, flooding) – Example: Malaria (parasite) and yellow fever, west nile infection (viruses)

Environmental Transmission of Pathogenic Microbes : Water, Soil, Air 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 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

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. news 14. com/content/story_links/? Ar. ID=89457&Sec. ID=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 H 2 O 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 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 9 m deep well, 14 m from recharge basin – Movement of larger microbes (bacteria and protozoans) theoretically less