Manure-borne Pathogens:Impact of Animal Agriculture on Microbial Water Quality

Jeanette A. Thurston-Enriquez

USDA-ARS

• Increase in CAFOs• 500 million

tons/year in U.S.• 26 million tons/yr

in NE

Livestock Manure

Public Health and Animal Waste

• Animal waste agents – Infectious

• bacteria, viruses, protozoa

– Chemical • nutrients, endocrine disrupters, antimicrobials

Manure-borne Pathogens of Concern

Antibiotic Resistant Bacteria

Protozoan Parasites Pathogenic Bacteria

Viruses

Fungi

In order to determine the human health impact of

manure-borne pathogens we need to evaluate:

• Occurrence• Survival/Persistence• Dissemination/

Transport

Manure, Manure Management Systems, & Surrounding

Environment: Water, Air, Soil

Other Health-Related Microorganisms

• Fecal Indicator Microorganisms– What?

• Traditionally, bacteria of fecal origin

– Total and fecal coliforms– Escherichia coli

– Why?• Indicators of fecal contamination• Recreational and drinking water

quality regulations• Faster, cheaper, easier detection

Waterborne Disease in the U.S.

• 12-20 outbreaks/yr– 10-100 x higher

• ~900,000 cases of waterborne microbial infections

• Up to 900 deaths• >70% in >55 yrs

Recreational

Foodborne

DrinkingIrrigation

Water Sources Affecting Public Health

RUNOFF RUNOFF

Contamination Routes

Well head impacts

Urban and storm waterWWTP

overflowSeptic tankleakage

Agriculture

Recreation

Wildlife

Groundwater

Infiltrationpercolation Discharge

Manure Dissemination

• Land application• Aerosol generation• Leakage or overflow from storage

lagoons or treatment ponds• Runoff from feed yards, manure-

applied land, pasture land, etc.

Holding Pond

Surface Water

Groundwater

Runoff and Aerosol Deposition

Manure storage

Manure Land Application

Well head impacts

Outbreak Source: Animal Ag.

Walkerton, 2001– Land-applied cattle manure– Agricultural runoff to groundwater

supply– Escherichia coli O157:H7 &

Campylobacter– >2000 cases– 7 fatalities

Contributing Factors for Environmental Persistence and

Transmission ofEnteric Pathogens

• High numbers shed in feces• Increased survival• Low infectious dose• Increased resistance to

disinfection/treatment• Multiple routes of

transmission• Animal and human infections

Potential Routes of Human Exposure to

Pathogens– Waterborne

• Drinking and recreational water– Foodborne (can be related to waterborne)

• Direct contact, irrigation water, ingestion of contaminated produce

– Direct Contact– Aerosol Transmission

• Transport to water supplies or food crops• Inhalation of aerosols • Contact

Possible Pathogen Transmission by

Aerosols• Direct transmission or deposition

onto food crops, fomites, or water

Livestock Spray IrrigationBiosolids Land

Application

Barriers Against Waterborne Disease• Drinking water and wastewater

treatment– Disinfection & Filtration

• Surface water monitoring/Source water protection

• Point-of-use devices—disinfect/filter

• Protection of recreational waters•Contaminant monitoring•Designation of specific uses

Agriculture: Limiting Microbial

Transport

Limiting Microbial Transport:Manure Storage & Treatment

Compost Holding Ponds & Lagoons

Limiting Microbial Transport:Aerosols

• Top spray vs. drop spray• Keep tractor speed low; scrape moist soil• Low wind speed • Wind direction

Pen scrapingLand application

Limiting Microbial Transport:Vegetated Filter Strips

Microbial Reduction Prior to Land Application:

Constructed Wetlands

• Alternative waste management and treatment technology• Bacterial reduction: >80 % (prior to plant establishment)• Protozoan parasite reduction: >60 % (prior to plant

establishment)

Manure-borne Pathogen Information Gaps

• Environmental Loading

• Environmental Fate

• Treatment Effectiveness

• Alternative Treatments/Tech.

• Detection Methods– Viability– Sensitivity– Specificity

• Emerging Pathogens• **Risk Assessments

– Requires above information

Questions/Comments?