Porcine Epidemic Diarrhea Virus (PEDV)

Miles Beaudin

Current Status of Infection

PEDV Porcine Epidemic Diarrhea Virus

• Is not Zoonotic

•Which means that it does not affect

people or other animals

•Is not a food safety concern

• Is not a new disease

•PEDv looks like TGEv

Pathogenesis The pathogenesis of a disease is the mechanism that causes

the disease. The term can also describe the origin and

development of the disease and whether it is acute, chronic

or recurrent. The types of pathogenesis include microbial

infection, inflammation, malignancy and tissue breakdown.

• Replicates in the enterocytes on villi and the small

intestine.

•Degeneration/necrosis of enterocytes

A)Litter of pigs infected with this virus, showing watery diarrhea and emaciated bodies.

B) Emaciated piglet with yellow, water-like feces.

C)Yellow and white vomitus from sucking piglet.

D)Thin-walled intestinal structure with light yellow water-like content.

E)Congestion in the small intestinal wall and intestinal villi; shedded epithelial cells

from the intestinal villus.

F)Degeneration, necrosis, and shedding/peeling of cells of the intestinal villi

Subtitle

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The intestinal villi from a

normal neonatal pig. Note

that the villi are very long

(black arrow) with large

surface area to absorb

nutrients and water. The

crypts are where new cells

are produce which will

eventually slide up and

replace the cells on the villi.

Villi are long, covered with absorptive epithelium

(arrow)

PED infection in a neonatal pig. The brown staining is infected cells lining the

villi in a piglet roughly 8 hours after infection. All of the brown cells will die,

releasing billions of virus particles to infect more cells and more pigs.

Villi are covered with

infected epithelial cells

stained brown

Crypt epithelium is spared and will

be the source of new cell growth

Pathology

•Dehydration

•Intestine filled with yellow fluid.

Sow and Piglets

Nursery

Nursery

Nursery

Nursery

Nursery

Nursery

Growing Pigs

• –Extensive necrosis of back muscles.

• –Microscopically, villi in the small intestine

of piglets are atrophic (degeneration/decrease).

• Atrophic=A wasting away of the body, from

the defective nutrition.

Gross Signs Growing and Breeding Swine

Gross Signs Growing and Breeding Swine

•Feeders, finishers and adult swine have

–Diarrhea; much more subtle than TGE

–May move more slowly than TGE

–Low prevalence of vomiting

–Depression

–Anorexia

–Signs of abdominal pain

Sows

–Severe Diarrhea

•Morbidity may be high; affected animals are quite sick

•Mortality is rare; occasional sudden death

•

Clinical Signs – Sows Sows were fevered, lethargic and scouring

during late gestation or 2-3 days before

farrowing

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Clinical Signs – Sows Mastitis of sows contribute to high piglet

mortality

Clinical Signs – Sows

Risks Of Introduction Herd or System

• Transportation

•Dead Removal/Disposal

• Gilts

•People

•Feed

•Supplies

Cross Contamination Fecal Mater-Risk Areas Transportation

• Highest risk activity for movement of PED

• From processing and cull buying stations back to sites

• Truck

• Trailer

• Fomites (object or substance capable of carrying infectious organisms,

such as germs or parasites, and hence transferring them from one individual

to another. Skin cells, hair, clothing, and bedding are common hospital

sources of contamination.)

– Boots, clothing sort panes, transporter

– Mortality disposal-rendering

– Contract Washers, Manure pumpers

Risk Reduction of Fecal-Oral Spread

Transportation

Dedicated Trailers

• Cull sows

• Market pigs

• Premarket pigs

• weaners

Virus

• Virus is heat sensitive

– Any thermal processing method is going to reduce

infectivity such as pelleting.

– Sensitive to drying

Reduce the Risk of Fecal-Oral Spread

Transportation

1. All trailers are washed after movement

2. Wash, dry, disinfect all transport

3. Dry-increase temperatures to 140 degrees F

for 20 minutes

4. Survives at 122 degrees F but not 140 degrees

Reduce the Risk of Fecal-Oral Spread

Transportation

• Truck wash sanitation

– 3rd party audits truck wash

– Trailer inspection with Pass/Fail

– Wash floor between trailers

• Disinfect at end of day and dry

• Boots, clothing, hose, wand sanitation

• Transporter’s cab and supplies inspected

Reduce the Risk of Fecal-Oral Spread

Loading/Unloading Staff

Loading

– Establish a clean/dirty line from barn to the chute.

– Dedicated boots and coveralls in chute area

– Use plastic boots

After Completion of Load

- Wash and disinfect the chute

Clean/Dirty Line

Reduce the Risk of Fecal-Oral Spread

Dead Disposal • Review disposal procedures

• Rendering

• Risky activity

• No cross over traffic

• Separate drive ways

• Moves off site

• Equipment to transport dead pigs is washed after dropping at rendering

site.

Reduce the Risk of Fecal-Oral Spread

Isolation/Quarantine

• All replacement gilts are quarantined a

minimum of 28 days

• Careful observation of signs of diarrhea

– Diagnostics testing performed if any signs of

observed.

Feedback Material Formulation

• Piglet age not more than 5 days

• Only small intestine

• Take out put in plastic bag KEEP ON ICE

• 1 set of intestine per 10 sows

• 1 set per 250 ml fresh milk or Non chlorine

water

Results

• Diarrhea and mortality were not prevented in

litter of sows that received “feedback 1-2”

weeks before farrowing.

• Antibiotics, electrolytes, sow milk replacer and

colostrum replacer were of no help in

controlling PED

What to do now

• Breed to Wean

– Walk rows twice a day

– Mark each sow when clinical signs appear

(diarrhea, vomiting, anorexia, fever)

What to do now

• Wean to finish

-Walk barns and pens twice a day

-Mark each animal when clinical signs appear

(diarrhea)

Reality

• If a packer was to get PEDv

1 out of every 10 trucks that back up

to that facility would contract PEDv!