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 What I am going to cover will be an overview of the topic and keep in mind that this topic could be expanded into a semester long course

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 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: 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 is to suspect an old forgotten anthrax grave on the primary ranch. With the heavy rains, spores might have been forced to the surface, unless the rancher had been earth moving (clearing ditches, trenching, bulldozing, scrub clearing

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 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 PDC = process and distribution centers

Environmental Transmission of Pathogenic Microbes : Water, Soil, Air 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 (~ 3ft) 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, 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: 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