Pathogens

1. Pathogens • Ways livestock agriculture may increase pathogens in the environment • Indirect effects on water • Direct contamination in water • Drinking • Irrigation • Antibiotic resistance in microorganisms • Direct contamination in air

2. Indirect effects on pathogens in water • Effect Blooms of toxic algae Excess N Pfiesteria piscidida Toxins or P (Red tides in marine Contact causes environments) confusion, memory loss and gastrointestinal problems Cyanobacteria Toxins (called blue-green algae Can kill livestock in fresh water) • Control • Reduction of N and P excretion and losses during storage and application

3. Direct pathogen contamination of water • Major microorganisms of concern Effects (Particularly severe in very young, elderly, or individuals with compromised immunity) • Protozoa Cryptosporidium parvum Severe diarrhea, vomiting Giardia fatigue, dehydration • Bacteria E. Coli O157:H7 Bloody diarrhea, dehydration, kidney failure • Viruses Bovine rotavirus Diarrhea Bovine coronavirus • Number of cases US Outbreaks (1989-96) Drinking waterRecreational water SurfaceGroundNaturalPool Cryptosporidium parvum 4 4 2 11 Giardia 12 6 4 5 E. Coli O157:H7 0 3 7 1

4. Reasons for problems these organisms • The organisms or their reproductive forms are shed by infected animals in large numbers • The organisms survive and remain infectious in the environment for long periods • Some are resistant to water treatment • E. Coli O157:H7 can multiply outside the host if adequate nutrition • Low dose needed for infection • Wide range of animal hosts • Other potentially harmful bacteria in the environment • Campylobacter • Listeria monocytogenes • Salmonella • Mycobacterium paratuberculosis • Causes Johne’s Disease • Association with Crohn’s disease in humans

5. Risk is largely unknown • Most studies on water quality have demonstrated that poor manure management increases fecal coliforms in water supplies • Relationship between fecal coliforms and pathogens has not been established • Difficult to separate contamination from humans, domestic animals and wild animals

6. Pathogenic organisms • Cryptosporidium parvum • Life cycle (1 – 8 days) Oocysts consumed by host animal (Contain 4 sporozoites) Sporozoites released in intestine Sporozoites invade intestinal cells and reproduce in cells New sporozoites invade new cells Oocysts released in feces Damage intestinal cells Severe diarrhea • Oocysts in 39 to 87% of US surface waters

7. Hosts • Species • Humans • Domestic livestock (Cattle, sheep, goats, swine, horses) • Companion animals (Dogs, cats) • Wildlife (Mice, Raccoons) • Age • Calves 50% of calves shed oocysts between 1-3 weeks Few shed in cattle > 6 months • Swine Shed oocysts during nursing and weanling stages • Foals Shed oocysts up to 19 weeks • Sheep Adult ewes will shed oocysts around lambing

8. Viability characteristics • Resistant to most public water treatments • Very susceptible to drying • 2 hours of dryness is lethal • Very susceptible to high temperatures • >100oF • Susceptible to freezing temperatures • Freezing for 10 days reduced viability by 90% • Susceptible to pH>9.0 • Public water treatment plants often treat water to pH 12.0 • Oocysts remain in upper soil unless transported to ground water with macropore flow

9. Giardia • Life cycle (7-9 days) Cysts ingested (Contain trophozoites) Trophozoites attach to Severe upper small intestine diarrhea Produce cysts Cysts released Cysts release more in feces trophozoites • Cysts are present in most surface waters • Hosts • Species • All mammals, some birds, reptiles, and amphibians • Age • Occurs at all ages, but most common in animals that are less than 6 months • Viability characteristics • Similar to Cryptosporidium • No evidence of human infection from domestic livestock

10. Escherichia Coli O157:H7 • A potentially deadly bacteria • Causes bloody disease, dehydration and kidney failure • Particularly hazardous to young, elderly, and compromised immune systems • Infection can occur with as few as 10 cells • Life cycle • E. Coli O157 is consumed from water troughs or moist rations • Can survive in water trough for 4 months • E. Coli only present in cattle for 1 to 2 months • More frequent in cattle fed high grain diets Feeding forage at the end of finishing will decrease numbers Role of distillers grains??? • More common in summer than winter • More frequent in cattle that are 3 – 18 months old than mature cows • More frequent in large herds • Excreted in feces as viable bacteria • Capable of multiplying in the environment • Dependent on nutrients • Usually decrease over time

11. Viability • E. Coli O157:H7 are killed by chlorine, high temperature, drying, aerobic storage • At this time, few cases of direct human infection through water • Contamination of spinach believed to occur from irrigation water with a feedlot ½ mile away • E. Coli may be transported by flow, adhesion of soil particles or motility.

12. Factors affecting extent of pathogen problem • Size of loading dose • Percentage of herd infected • Frequency on manure addition to storage • Amount of dilution • Length of storage • Manure treatment • Anerobic > Aerobic > Compost • Storage characteristics • Aerobic/anerobic • Drying • Temperature • Freeze/thaw • pH • Nutrients • Inhibitors • Form of organisms excreted • Cysts or oocysts > vegetative forms • Routes of pathogen contamination • Run-off from bare lots • Direct deposit in pastures or lots • Run-off from manure application

13. Vegetation on land application • Tall forage reduces run-off • Prevents microorganisms from reaching water sources • Tall forage provides shade and moisture • Increases survivability • Soil of land application area • Organic or clay soils trap protozoa and bacteria • E. Coli can move rapidly through saturated soils or soils with macropores

14. Control of pathogen transport from livestock units • Prevent import of pathogen onto farm • Feed feedstuffs not contaminated with feces from rodents or other livestock • Prevent infestation of rodents or other wild or domestic animals in feed storage areas • Purchase feeds from sources that prevent fecal contamination of feedstuffs • Provide water sources with low risk of pathogen contamination • Keep livestock out of streams and ponds • Provide alternate water sources • Divert precipitation run-off from livestock facilities • Purchase livestock from sources with good health management • Avoid purchases from sales barns • Separate and quarantine new animals • Avoid transport of manure onto farm • Have visitors wear plastic boots • Thoroughly clean tires on vehicles

15. Prevent amplification and proliferation of organisms on farm • Frequent cleaning and drying of housing units • Particularly maternity areas • Use separate implements for feeding and cleaning • Frequent cleaning of equipment • Tires and blades • Provide feed and water free of fecal contamination from livestock, pets, rodents, wildlife, and humans • No feeding of wasted adult feed to young livestock • Segregate calves by age • Prevent contact of calves < 3 months with older cattle • Prevent run-off from entering or leaving areas housing young animals • Limiting pathogen proliferation during manure storage • Store manure from animals less than 6 months separate from mature animals and spread on non-hydrologically sensitive areas • If calf manure can’t be stored in area that restricts leaching or run-off, mix it with manure from mature cattle and apply by Best Management Practices (Dilutes organisms) • Composting at 140oF will kill most pathogenic organisms and cysts

16. Prevention of pathogen contamination by manure application • Application methods • Incorporation into the soil • Particularly effective during wet weather • Reduces risk of contamination of water sources by: Adsorption of organisms to soil particles Filtration of organisms Attack by predator organisms Freeze-thaw activity • Surface application • Effective in dry weather • Reduces risk by: Drying UV light • Hydrologic considerations • Avoid manure application in major water flow paths • Should consider: • Soil permeability • Slope steepness • Flood plains • Flow paths

17. Grassland manure application considerations • Manure should be stored for at least 60 days • Manure should be applied at least 30 days before grazing • Grass should be short when manure is applied • Pastures fertilized with manure should only be grazed by mature animals • Preventing export of pathogens from farm • Control run-off from livestock facilities • Particularly facilities housing young animals • Place cow winter feeding areas away from streams • Utilize buffer strips • Grass strips lining sides of streams or ponds • Width • > 4.5 m from field with manure application • > 10 – 20 m from animal feeding operations • Effective as part of a group of Best Management Practices • Should not be relied on as only practice • Proper grazing management • Use of rotational grazing • More uniform distribution of manure • Avoid over-grazing • Limit or prevent access of water bodies to animals

18. Release of antibiotic resistant microorganisms into the environment • Numerous antibiotics fed at subtherapeutic levels to promote growth and feed efficiency • Chlortetracycline, Oxytetracycline, Penicillin, Bacitracin, Tylosin • Actions • Prevent subclinical disease • Increases nutrient absorption • Improves metabolic processes • Increases rate of protein synthesis • Problem • Selection of organisms that are resistant to antibiotics • Concern for penicillin, tetracyclines, and erythromycin • Organisms released from non-sealed lagoons and from surface-applied manure

19. Recommend • Proper use of antibiotics • Don’t use antibiotics as a substitute for good management • Rotate antibiotics used on operation • Proper manure storage • No run-off or leakage • Proper manure application • Minimize run-off

20. Direct contamination of the air • Endotoxin • Lipopolysaccharide component of the cell wall of gram-negative bacteria • Problem in confinements, not in outside environment • Health effects on works in confinement buildings • Cough • Chest tightness • Headache • Fever • Flu-like symptoms • Control dust control measures