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Soil Type and Short-Term Survival of Porcine Epidemic Diarrhea Virus

Manure management practices recycle nutrients in animal manures for crop production.  Harmful microbes and viruses in the manure are generally reduced in the soil environment over time.  The soil properties influencing how long animal virus persistence are poorly understood and may be specific even down to the type of microbe present.  Recently, porcine epidemic diarrhea virus (PEDV), which causes nearly 100% mortality in newborn piglets, has become a serious challenge for swine production.  An important concern is whether PEDV in manure applied to nearby farmland may be a source for herd reinfection. How long will PEDV persist in the soil and still be infectious?  Are some soils better suited to reduce PEDV risk?

What did we do?

A laboratory study was conducted to mimic a standard manure application practice (manure slurry application into soil) to determine if it reduced the potential for PEDV reinfection.  In our study, we tested a range of soil types spiked with PEDV-positive manure slurry and evaluated how PEDV detection and potential infectious risk was affected by soil type. Quantitative PCR and live swine bioassays were used to enumerate PEDV and to determine whether manure and soil samples contained infectious PEDV (Stevens et al., 2018).

What have we learned?

Manure Slurry/Soil Incubations.  PEDV genomes declined at different rates depending upon the type of soil tested (Figure 1).  While PEDV declined rapidly and was not detected by PCR in Soil #1, #2, and #5 in just 24 hours, PEDV genomes in Soil #6 and #7 decreased more slowly the other soils.  Soils #3 and #4 displayed an intermediate rate of decline and reached our detection limit at 48 hours. Soil is an important factor on PEDV persistence.

Figure 1. Porcine epidemic diarrhea virus genomes in the manure slurry/soil incubation determined by reverse-transcriptase quantitative polymerase chain reaction.
Figure 1. Porcine epidemic diarrhea virus genomes in the manure slurry/soil incubation determined by reverse-transcriptase quantitative polymerase chain reaction.

 

Swine Bioassay.  Several of the samples tested positive for infections PEDV (Table 2) even when PCR indicated no virus was present; PCR molecular detection of the virus did not produce a complete picture of PEDV survival.  For instance, the PCR method indicated no virus in soil #1 or #2 at 24 hours, yet the soil-manure mixture caused disease in a swine bioassay test—the gold standard test for infectious PEDV.

 

Table 2. Outcome of Swine Bioassay
Manure-slurry Soil Composite
Time (hours) #1 #2 #3 #4 #5 #6 #6
24 Pos Pos Neg Pos Neg Neg Pos
48 Pos Neg Neg Neg Pos Neg Pos

†Animals inoculated by oral gavage of 10 mL of phosphate buffer-diluted sample.  A porcine epidemic diarrhea virus positive (Pos) or negative (Neg) score is based on fecal swab molecular diagnostic test (reverse transcriptase quantitative polymerase chain reaction).

Are there any soil environmental factors that can help predict whether/how long infectious PEDV lasts in soils?  Anything that would damage or disrupt the membrane or proteins on the outside of PEDV would render the virus non-infectious.  Theoretically moist soils with lots of active bacteria would release enzymes to chew up PEDV proteins or alkaline (high pH) soils may denature PEDV proteins and damage membranes to inactivate PEDV.  On the other hand, soils where manure rapidly dries would help preserve PEDV. None of these hypotheses could explain the PCR or swine bioassay results. Only one factor seemed related to PEDV persistence—high soil phosphorous seemed to protect the virus.  No single factor seemed to destroy the virus.

Future Plans

Additional studies are underway determining where PEDV is found within three production sites and the surrounding environment immediately after an outbreak of PEDV.  The sites will be monitored over 18 months to signs of PEDV re-emergence.

Authors

Corresponding author:  Dan Miller, Research Microbiologist, USDA Agriculture Research Service; email: Dan.miller@ars.usda.gov

Other authors:  Erin Stevens (Department of Animal Science, University of Nebraska – Lincoln); Amy Schmidt (Department of Biological Systems Engineering, University of Nebraska – Lincoln); Sarah Vitosh-Sillman and J. Dustin Loy (School of Veterinary Medicine and Biomedical Sciences, University of Nebraska – Lincoln).

Additional information

Stevens EE, Miller DN, Brittenham BA, Vitosh-Sillman SJ, Brodersen BW, Jin VL, et al. Alkaline stabilization of manure slurry inactivates porcine epidemic diarrhea virus. Journal of Swine Health and Production. 2018;26(2):95-100.

Acknowledgements

Funding for this research was provided by the National Pork Board and USDA Agriculture Research Service operational funds. USDA is an equal opportunity provider and employer.

 

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2019. Title of presentation. Waste to Worth. Minneapolis, MN. April 22-26, 2019. URL of this page. Accessed on: today’s date.

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Manure Treatment and Natural Inactivation of Porcine Epidemic Diarrhea Virus in Soils

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Purpose

The porcine epidemic diarrhea virus (PEDv) outbreak in North America has substantially impacted swine production, causing nearly 100% mortality in infected newborn piglets. Because manure may remain a source of reinfection, proper manure management practices to limit outbreaks need to be developed and evaluated. Two laboratory studies simulating manure pit treatment with increasing amounts of quicklime were conducted to determine PEDv susceptibility to increasing pH. Additionally, two laboratory soil incubation studies contrasting manure liming, multiple soil types, and two antecedent soil moistures were conducted over several months with incubation conditions mimicking the climates in Minnesota, Missouri, and Oklahoma to determine whether current manure application practices reduce the potential for PEDv reinfection via manure-amended soil. Quantitative PCR and live swine bioassays were used to enumerate PED virus and to determine whether manure and soil samples contained infectious PEDv.

What did we do?

Quicklime-Manure Slurry Incubations: An initial short-term manure slurry study was conducted on fresh PEDv-positive manure slurry collected in 2015 from the shallow pit of a commercial swine facility in southeast Nebraska. Manure was sampled prior to treatment (0 h) and then distributed among glass beakers (250 mL) to accommodate triplicates of three treatments: liming to pH 10, liming to pH 12, and unlimed manure. Following pH adjustment, aliquots of each sample were collected at 1 and 10 h, immediately neutralized with 10 mM HCl and stored at -80°C for subsequent analysis. In a second manure slurry incubation, triplicate PEDv-positive manure samples collected from a commercial swine operation in south central Nebraska site in December 2016 were mixed in equal portion (w:v) with distilled water to mimic manure slurry consistency observed in swine production pit storages. Quicklime was added stepwise (0.25 g addition) to each manure slurr! y sample with continuous stirring to gradually increase manure slurry pH. After each addition of quicklime, pH was measured and an aliquot of manure slurry was collected for subsequent quantitative PCR PEDv enumeration and infectivity in a pig bioassay.

Long-term manure and soil incubation. Initial tests determined appropriate initial soil moisture contents (representing a ‘dry’ and ‘moist’ soil condition) and manure:soil ratios (1 g slurry:3 g soil) to best represent the manure:soil within an injection furrow when slurry is injected into soil, and appropriate liming source (ag lime vs. quicklime). PEDv-positive manure slurry collected from a commercial swine operation in southeast Nebraska was divided between two 3-L containers, one for limed treatment (LIME) and the other for the control, or no-lime, treatment (CNL). Quicklime (30 g) was added to one 3 L portion (equivalent to an application of 80 lbs. quicklime per 1000 gallons of slurry) to achieve a final pH of 12. Both treated and untreated slurry stocks were incubated at room temperature for 24 hours. Distilled water was added to two soils, a silty clay loam (pH 7.0) and a loamy fine sand (pH 6.9), to attain 10% and 30% water holding capacity! (dry and moist soil condition). Thirty grams (dry weight) of soil was apportioned to multiple 50 mL screw top conical tubes and a cavity was made in the center of the soil by pressing a 10 mL pipet tip into the soil. Ten mL of slurry (LIME or CNL) were then added to each soil tube via pipet. Four replicate tubes were immediately frozen at -80°C for each combination of soil, moisture, and manure treatment to represent initial soil application (day 0). The tubes were loosely capped and placed into one of three incubators operated independently throughout the trial to simulate soil temperatures between November 1 and May 1 at one of three geographic locations: southern Minnesota, northern Missouri, and central Oklahoma (Figure 1). Twenty replicate tubes were created for each combination of soil, moisture, incubation, and manure treatment, and a set of four tubes were collected for each treatment combination on days 30, 60, 90, 120 and 150 of the incubation and immediately transfer! red to a -80°C freezer for storage.

Molecular detection and quantification of PEDv. Prior to analysis, soil and manure samples were removed from -80°C storage and allowed to thaw at room temperature. The RNA in each sample was extracted using the RNA PowerSoil Total RNA Isolation kit (Mo Bio, Carlsbad, CA). PEDv was detected in samples by reverse transcription and quantitative polymerase chain reaction (RT-qPCR).

Swine bioassay. To confirm that conditions yielding a PCR negative result actually inactivated the PED virus and rendered the manure non-infectious, a live pig bioassay was conducted with the limed and non-limed manure slurry samples from the initial short-term manure slurry incubation (quicklime addition). Fifteen pigs, approximately 21 days old, were sourced from a high-health facility whose dams tested negative for PEDv antibodies and virus by PCR. Piglets were tested for PEDv upon arrival and confirmed negative. Piglets were randomly assigned to individual housing in BSL-2 rooms at the University of Nebraska-Lincoln Life Sciences Annex as follows: control (3 piglets), pH 10 (6 piglets), and pH 12 (6 piglets), and allowed to acclimate for three days. Each pig was then administered a 10-mL oral gavage of manure slurry: three piglets in the control room received one of the three un-limed slurry samples; six piglets in the pH 10 room received one of the six limed (pH 10) sl! urry samp les (three limed for 1 h and three limed for 10 h); and six pigs in the pH 12 room received one of the six limed (pH 12) slurry samples (three limed for 1 h and three limed for 10 h). Piglets were monitored for fecal shedding of PEDv for four days until control animals began to demonstrate clinical signs of PEDv infection, at which time all piglets were humanely euthanized. Fecal swabs, and duodenum, ileum, jejunum, and cecum samples were collected from each animal and fixed in formalin. All fecal and tissue samples were analyzed for the presence of detectable PED virus by immunohistochemistry and PCR.

PEDv, log # g soil

What have we learned?

Manure Slurry Incubation: Manure limed to pH 10 and pH 12 for 1 and 10 h yielded no detectable PEDv RNA. Live swine bioassay results confirmed that these samples were not infective while control samples resulted in PEDv infection of piglets. These results indicate that a final manure slurry pH of 10 (equivalent to 50 lbs. of quicklime added to 1000 gallons manure slurry) is sufficient to reduce PEDv RNA to an undetectable concentration after 1 hour of contact time. All pigs receiving limed manure (pH 10 or 12 maintained for 1 or 10 h) during the live swine bioassay tested negative for PEDv infection while control pigs (un-limed treatment) all tested positive for PEDv infection (Figure 1). The pig bioassay results confirmed that the PCR assay is a reliable predictor for the presence of infectious PEDv in these matrices and that lime addition to achieve pH 10 for just one hour is sufficient to deactivate the virus in stored manure.

Soil Incubations: At the completion of the long-term (150-day) soil incubation, a subset of the frozen samples (LIME and CON soil samples collected on day 0 and 30) was selected for RNA extraction and qPCR analysis. The qPCR results from days 0 and 30 yielded no detectable PEDv RNA in either the limed or un-limed manure-amended soils (Figure 1). Furthermore, manure-amended soils did not differ from soil-only controls even though PEDv RNA was still detectable in the original manure slurry at high concentrations. No differences in PEDv abundance were detected on either day when initial soil moisture (10% vs 30% water holding capacity), incubation condition (MN vs. MO vs. OK), or soil type (silty clay loam and loamy fine sand) were varied. For these soils, the concentration of PEDv in limed or un-limed manure decreased immediately to a non-detectable level. These results indicate that manure-amended soil with pH 6.9 or greater is not a vector for transmission of the PED virus.

A consistent finding from all of the studies is that pH of media (slurry or soil) strongly influences PED virus survival.

Future Plans

Additional studies are underway to identify the lowest pH at which the PED virus is rendered non-infectious in slurry manure.

Corresponding author, title, and affiliation

Amy Millmier Schmidt, Assistant Professor, Departments of Biological Systems Engineering and Animal Science, University of Nebraska – Lincoln

Corresponding author email

aschmidt@unl.edu

Other authors

Stevens, E., A. Schmidt, D. Miller, J.D. Loy and V. Jin

Additional information

Dr. Amy Millmier Schmidt, corresponding author, can also be reach at (402) 472-0877.

Acknowledgements

Funding for this research was provided by the National Pork Board. Gratitude is extended to Ashley Schmit for assistance with laboratory activities and animal care. Special thanks to the Nebraska pork producers who granted access to their farms for collection of PEDv-positive manure.

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Time-Temperature Combinations for Destruction of PEDv During Composting


*Purpose

The purpose of this project was to determine the appropriate time-temperature combinations required for inactivation of the porcine epidemic diarrhea virus (PEDv) in composting material as a basis for evaluation of composting for disposal of swine mortalities and/or other PEDv-positive biological material.

What did we do?

In vitro propagation of PEDv for laboratory survivability assays was conducted using a cell culture-adapted isolate received from APHIS-NVSL (Ames, IA) that was free of extraneous agents (5th passage Colorado 2013 PEDv 1303). Propagation was conducted by infection of confluent VERO cell monolayers at a multiplicity of infection (MOI) of 0.1 with a concentration of 5 µg/mL TPCK trypsin. Virus stocks were be amplified following a 2-4 day incubation period on cell monolayers, frozen and thawed, centrifuged, and culture supernatants containing virus were harvested. Virus concentration was calculated and standardized to 1×105-1×106 TCID50/mL using immunocytochemistry and indirect fluorescent antibody assay (IFA) using a PEDV specific mouse monoclonal antibody (MedGene Labs).

The effect of temperature on survivability of PEDv in compost material was evaluated by inoculating compost material and subjecting the material to temperatures of 50°C (122°F), 55°C (131°F), 60°C (140°F), 65°C (149°F), and 70°C (158°F) for 0, 24, 48, 72, 96 h, and 120 h. Sawdust was acquired from a commercial source, autoclaved to eliminate existing microbes, oven dried and used to simulate compost material. One gram of prepared sawdust was placed in each of 140 1-mL centrifuge tubes. Cell culture supernatant containing infectious PEDv was added to phosphate buffered saline and added to each tube achieve a moisture content of 50% w.b. Tubes were randomly assigned to laboratory incubators at the five temperature treatment levels. At each sampling point, four tubes were removed from each incubator and tested to determine virus survivability.

PEDv survivability was determined via two independent assay methods. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) is a rapid and sensitive method that was used by the Nebraska Veterinary Diagnostic Center to quantify the amount of virus RNA genome in the samples. To validate results from the RT-qPCR in laboratory assays, sawdust simulated compost matrix was spiked with known concentrations of PEDv target RNA and compared to known standards to ensure no inhibition was present and that proper extraction methods were being used. An alternative method using virus isolation was also conducted to determine whether viable virus was present in tubes at a smaller subset of time points. To do this, Vero cell monolayers were infected with filter sterilized aliquots of compost exudate, blindly passaged once after seven days, and examined for virus presence using IFA with a PED specific monoclonal antibody. At specific time points, RT-qPCR Ct values and Virus Isolation were run in parallel to ensure sensitivity of testing and to evaluate correlation of the testing modalities under the simulated testing conditions and matrices.

What have we learned?

At the time of proceedings submission, results were not available for inclusion in this report. Results will be presented during the scheduled oral seminar at the conference.

Results of this laboratory study will be used to evaluate appropriate time-temperature combinations necessary during swine mortality composting to inactivate the PEDv virus and determine the feasibility of on-farm mortality composting as a biosecure disposal method for PEDv-infected pigs. Following this laboratory study, mortality composting was initiated using PEDv-positive piglets to confirm the inactivation of PEDv during composting.

Future Plans

Results of this and the full-scale composting study will be used to recommend appropriate swine mortality disposal methods for swine producers with losses due to PEDv as part of their farm biosecurity plan. Additional swine enteric corornaviruses will likely be studied to confirm similar requirements for disposal of mortalities caused by these viruses.

Authors

Amy Millmier Schmidt, Assistant Professor and Livestock Bioenvironmental Engineer, University of Nebraska – Lincoln aschmidt@unl.edu

J. Dustin Loy, Assistant Professor, Clayton Kelling, Professor, Judith Galeota, Virology Laboratory Manager, and Sarah Vitosh, Graduate Research Assistant, Veterinary & Biomedical Sciences, University of Nebraska – Lincoln

Additional information

Dr. Amy Millmier Schmidt
(402) 472-0877
aschmidt@unl.edu

Acknowledgements

The authors would like to acknowledge the Nebraska Pork Producers Association and the National Pork Board for providing funding for this research. Special thanks to Jared Korth for helping with laboratory activities on this project.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2015. Title of presentation. Waste to Worth: Spreading Science and Solutions. Seattle, WA. March 31-April 3, 2015. URL of this page. Accessed on: today’s date.

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PEDV Survivability in Swine Mortality Compost Piles


*Purpose

PEDv has caused significant losses in the Nebraska pork industry and mortality can approach 100%. Disposal of these carcasses is a challenge as they serve as a source of tremendous amounts of infectious virus. Current alternative methods of disposal include rendering, incineration and burial. Rendering trucks may serve as a farm-to-farm vector. Incineration is not feasible for the significant number of mortalities and burial may enable long-term survival of virus in soil and may cause re-infection after disease elimination. Therefore, composting may serve as an ideal solution for disposal and mortalities this would provide a biosecure, safe, and cost-effective method to mitigate on-farm sources of virus. The overall objective of this study was to determine the efficacy of composting as a mortality disposal method following death loss from the porcine epidemic diarrhea virus (PEDv). Validation of time-temperature combinations for PEDv inactivation in mortality compost piles was the primary intended outcome of this project.

What did we do?

PEDv virus challenge protocol modeled one that has shown previous success using weanling pigs (Hesse et al., 2013). Twenty-seven animals (approximately 21-day-old weaned piglets) were sourced from a high-health commercial source that had no history of PEDv and with dams that tested negative for the presence of PEDv-specific antibodies and were negative for fecal virus shedding as determined by PCR. Experimental groups were housed in pens and maintained at appropriate temperature and in accordance with national animal care space requirements. Pigs were given five days of acclimation and maintained on commercial nursery pig diets. Following acclimation, each pig was inoculated orally with 5 mL of virus inoculum (NE 9282) supplemented with gentamicin that had been diluted to a real time PCR assay cycle threshold (Ct) 22. Inocula (feces/intestinal contents) from a natural outbreak of PEDv were used. Pigs were evaluated twice daily for evidence of infection: temperature, pulse, respiration, dehydration, and diarrhea. Fecal samples were collected daily for evaluation of fecal shedding of PEDv. When significant clinical signs of enteric disease were present or pigs became sufficiently ill that the attending veterinarian determined euthanasia was appropriate, animals were humanely euthanized and samples taken for necropsy.

Following necropsy, carcasses from infected and euthanized pigs were composted inside biosecure rooms in the Veterinary and Biomedical Sciences Research Facility at the University of Nebraska – Lincoln. Three compost piles were constructed using commercial sawdust and wood shavings at a target moisture content of 50% w.b. For each pile, an insulated platform with internal dimensions of 121.92 cm (W) x 152.4 cm (L) (48 in x 60 in) was used to contain piles. Platforms were constructed of an outer layer of plywood and an inner layer of PolyBoard sheeting with foam board insulation in between to simulate the linear continuation of the pile and the insulative properties of a compacted soil base. Compost piles were constructed by placing a layer of wood shavings on each base to a depth of 60 cm (24 in), followed by placement of five carcasses in a single layer in the center of the pile followed by a 15 cm (6 in) layer of pile material and a second layer of four carcasses in a single layer. Additional sawdust was placed over and around the carcasses to achieve 60 cm of coverage on the top of the pile. Rooms were maintained at approximately 21°C (70°F) and 25% RH throughout the duration of the project.

Temperature was monitored at ten locations within each pile using Apresys in-transit digital temperature recorders (Apresys, Inc., Duluth, GA) beginning at establishment of the piles and continuing at a 20-min sampling frequency (duration of primary compost cycle not established at time of proceedings submission). Temperature within each pile was also monitored manually using a thermometer at 0, 24, 48, 96 h, and 168 h, and then weekly for the duration of the compost cycle to confirm success of the heating process.

Following completion of the primary compost cycle, temperature loggers will be recovered and each pile will be mixed, sampled for analysis of survivability of PEDv at five locations, moisture will be added, and piles will be re-established for a secondary composting cycle with temperature loggers placed as previously described. At the completion of the secondary composting cycle, piles will again be sampled for analysis of survivability of PEDv (5 samples per pile) and temperature loggers will be recovered.

PEDv survivability will be determined via two independent assay methods. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) is a rapid and sensitive method that will be used to quantify the amount of virus RNA genome in the samples. The Nebraska Veterinary Diagnostic Center currently has a validated RT-qPCR test to assay for the presence of PEDv in manure sample matrices. To validate results from the RT-qPCR in laboratory assays, sawdust simulated compost matrix will be spiked with known concentrations of PEDv target RNA and compared to known standards to ensure no inhibition is present and that proper extraction methods are being used. An alternative method using virus isolation will also be conducted to determine whether viable virus is present in flasks at a smaller subset of time points. To do this, Vero cell monolayers will be infected with filter sterilized aliquots of compost exudate, blindly passaged once after seven days, and examined for virus p resence using IFA with a PED specific monoclonal antibody. At specific time points, RT-qPCR Ct values and Virus Isolation will be run in parallel to ensure sensitivity of testing and to evaluate correlation of the testing modalities under the simulated testing conditions and matrices. If these testing methods show agreement, and/or no virus is isolated, RT-qPCR testing will be utilized to facilitate rapid and consistent assessment of virus persistence during the majority of experimental time points.

What have we learned?

Biosecurity is essential to controlling the spread of PEDv and any facility that is currently positive for PEDv should work diligently to prevent contamination of neighboring facilities. Vehicle transport has been shown as a high-risk activity that may facilitate spread of PEDv (Lowe 2014) and mortalities that are positive for PEDv may be rejected by renderers to protect them from liability for transmitting the disease. Burial of mortalities can be detrimental to water quality (Bartelt-Hunt et al., 2013) and it is unknown how long the PEDv can remain active in the cool, dark, moist environment that accompanies land burial of carcasses, but extrapolation of available data suggests virus may persist for months. Therefore, we believe composting is likely to provide an effective, biosecure, economically viable and environmentally compatible option for disposal of PEDv mortalities. This research will validate the effectiveness of composting through controlled mortality composting trials subsequent to experimental infections. With the completion of this research, our expectation is that we will know what operating parameters are required to ensure inactivation of PEDv during composting of PEDv mortalities.

Future Plans

Using the information generated from this research, we will deliver extension programming and outreach materials to swine producers, veterinarians, and stakeholders within and beyond Nebraska to promote biosecure disposal of PEDv-infected mortalities.

Authors

Amy Millmier Schmidt, Assistant Professor and Livestock Bioenvironmental Engineer, University of Nebraska – Lincoln aschmidt@unl.edu

J. Dustin Loy, Assistant Professor, Veterinary & Biomedical Sciences, University of Nebraska – Lincoln

Additional information

Dr. Amy Millmier Schmidt
(402) 472-0877
aschmidt@unl.edu

Acknowledgements

The authors would like to acknowledge the Nebraska Pork Producers Association and the National Pork Board for providing funding for this research. Special thanks to Jared Korth for helping with laboratory activities on this project and construction of mortality composting platforms.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2015. Title of presentation. Waste to Worth: Spreading Science and Solutions. Seattle, WA. March 31-April 3, 2015. URL of this page. Accessed on: today’s date.

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Biosecurity for Livestock and Poultry Manure Management

Most biosecurity plans are meant to protect animal and human health by preventing the spread of bacteria or other pathogens. Indirectly, effective biosecurity practices can reduce the likelihood of multiple or catastrophic mortalities which is an issue of environmental concern. While not usually discussed under the umbrella of “biosecurity”, manure handling should not be ignored when considering your plan. Related: Manure Pathogens

Avian Influenza | Swine PEDv | Pumping & Land Application | Inspectors | Mortalities | Recommendations by Species

Avian Influenza Resources

In 2015, millions of birds either died or had to be euthanized because of highly pathogenic avian influenza (HPAI). The approved methods of disposal for large-scale (catastrophic) mortalities include: burial, incineration, and composting.

PEDv (Porcine Epidemic Diarrhea virus) Resources

The swine industry has experienced significant losses as a result of PEDv, which can be transmitted through contact with manure of infected pigs. It is possible to move the virus between farms on vehicles, pumps, manure handling equipment, clothing, or any other item that comes in contact with manure and is not thoroughly disinfected between farms/fields. The low amount of viral exposure required to cause illness means that even tiny amounts of residual manure pose significant biosecurity risks.

Preventing Manure Pathogen Dispersal Between Farms or Field

Restricting access of off-farm equipment and personnel involved in manure pumping or manure application and thorough cleaning of equipment between farms are among the recommendations to follow to reduce risks of spreading manure-borne pathogens.

  • North Dakota State Biosecure Nutrient Management. This fact sheet does an especially nice job describing how to manage and clean equipment used in manure handling around the farm.
  • The National Pork Board released fact sheets on Biosecure Manure Pumping Procedures for farmers (pg 20), commercial manure haulers (pg 22), and land owners (pg 20).
  • The Maryland Department of Agriculture developed a brochure related to transporting manure and set out some guidelines to prevent the spread of pathogens.

Biosecurity for Inspectors or Technical Service Providers

What should regulatory inspectors do when traveling between farms to prevent the spread of disease? What requests can farmers make of inspectors to protect their farm biosecurity?

Biosecure Mortality Management

One of the best collections on composting animal mortalities comes from the Cornell Waste Management Institute. Check out their sections on health and safety and animal mortality composting for research on pathogen destruction and other safety considerations.

The following fact sheet was developed in response to the PEDv (porcine epidemic diarrhea virus), although these guidelines should be effective for reducing the risks related to other pathogens. It focuses on the use of rendering as the main mortality disposal method. Biosecure Mortalities Removal (pg 10)

Farmer & Farm Worker Biosecurity Resources

The following resources are not focused on managing manure but give a great overview of the larger biosecurity issue and practices on livestock and poultry farms.

farm worker in a confined swine barn

This farm worker follows the farm biosecurity protocol and is wearing coveralls and boots that are cleaned and laundered on-site.

Swine

Poultry

Dairy

Beef Cattle

Goats and Sheep

Page Managers: Jill Heemstra, University of Nebraska and John Lawrence, Iowa State University

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Managing Biosecurity to Control Porcine Epidemic Diarrhea virus (PEDv)

The appearance of the Porcine Epidemic Diarrhea Virus (PED) in North America presents significant challenges for manure applicators. Since the virus is primarily spread by fecal-oral contact and can survive in manure for extended periods of time, it is possible for the disease to be spread by any object that becomes contaminated with infected pig manure. Biosecurity is an important part of preventing its spread. This presentation was originally broadcast on July 18, 2014. More… Continue reading “Managing Biosecurity to Control Porcine Epidemic Diarrhea virus (PEDv)”