Environmental Transmission of Pathogenic Microbes why they

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 Julie. Kase@ncmail. net

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 – 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 9 m deep well, 14 m from recharge basin – Movement of larger microbes (bacteria and protozoans) theoretically less

Environmental Transmission of Pathogenic Microbes : Water, Soil, 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)

Environmental Transmission of Pathogenic Microbes : Water, Soil, 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, Airborne Microbes and their Reservoirs – Bacteria Bacillus anthracis • Reservoirs and amplifiers: – – 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

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 • Bio. Watch Program – – Air monitors set up in last 3 yrs; 30 metro areas Goal: detect w/in 36 hrs release of anthrax, sm pox, plague ~10 sensors per city, tested once a day Not intended to prevent attack, hundreds of thousands of victims, instead start mass treatment

Environmental Transmission of Pathogenic Microbes : Water, Soil, Airborne Microbes and their Reservoirs – Viruses Coronaviruses • 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 (~ 3 ft) – Knowledge is still evolving • SARS: – 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, 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 1950 s, took outbreak in “four corners” area of US to be recognized

Environmental Transmission of Pathogenic Microbes : Water, Soil, Airborne Microbes and their Reservoirs – Fungi Cryptococcus neoformans • Reservoirs and amplifiers: – 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 – In the United States, 85% of cases occur in HIV-infected persons