Ontario Animal Health Network (OAHN) Swine Network Quarterly Industry Report

Disease and Survey Discussion

PORCINE EPIDEMIC DIARRHEA (PEDV) / PORCINE DELTACORONAVIRUS (PDCoV)

Jessica Fox, Manager at Swine Health Ontario reported the following cases in Q4:

Dec 02, 2021 Huron    PDCoV    Nursery

Nov 29, 2021  Huron    PDCoV    Farrow-to-wean

Nov 26, 2021  Huron    PED    Finisher

Nov 12, 2021  Oxford  PED    Finisher

Nov 04, 2021  Middlesex  PED    Finisher

Oct 13, 2021  Huron  PED    Nursery

There was 1 case of PEDV in a finisher in Lambton county in January 2022.  It appears that most of these cases may be associated with biosecurity issues related to transport or deadstock.

Dr. Christine Pelland reminded the group that the clinical signs associated with PDCoV are often much less severe than PEDV. Producers may assess this as a flair up of Rotavirus, E coli or Clostridial scours as opposed to coronavirus. If the level of scour is significantly increased, it is well worth checking with your herd veterinarian. If it is indeed identified as PDCoV steps can be taken to reduce the chances of spread to other herds. The PED and PDCoV Tracking map is available at the Swine Health Ontario website and shows current and annual cases by county. http://www.swinehealthontario.ca/Disease-Information/PED-PDCoV-Tracking-Map I

INFLUENZA A (IAV)

This has been a very busy quarter with respect to influenza. Sixty-six % of practitioners indicated that influenza activity had increased in Q4 vs Q3. This was supported by increased lab submissions reported at Animal Health Laboratory and Gallant Labs. Syndromic surveillance also detected signals of increased influenza activity especially towards the end of the quarter.

PORCINE CIRCOVIRUS 3 (PCV3)

Dr. Josepha Delay provided some direction on criteria that diagnosticians can use in determining the significance of PCV3 findings. Dr. Delay reviewed a recent paper that discusses PCV3- Associated Disease: Case Definition and Diagnosis.

Diagnosis of PCV3-Associated Disease (PCV3-AD) is becoming more common in North American swine. The frequency of diagnosis in Ontario herds is low, but PCV3-AD is a consideration in cases of reproductive loss and poor nursery pig performance.  Deciding that PCV3 is responsible for disease on a particular farm requires more than simply detecting the organism on a PCR test.

Clinical signs of reproductive or respiratory disease as well as microscopic evidence of tissue damage  as well as evidence of the virus in the affected tissues is required to confirm a diagnosis of PCV3. Your herd veterinarian will be able to submit the appropriate samples that will confirm or deny whether PCV3 is part of a herd disease problem. In summary, to reach a diagnosis of PCV3-AD, pigs must have appropriate clinical signs, specific pathologic lesions must be identified, and PCV3 must be identified in association with the lesions.

Reference: Saporiti V, G Franzo, M Sibila, J Segalés.  Porcine circovirus 3 (PCV-3) as a causal agent of disease in swine and a proposal of PCV-3 associated disease case definition.  Transboundary and Emerging Diseases.  2021.  68: 2936-2948.

EAR NECROSIS / FLANK NECROSIS

There were several questions for practitioners included with the clinical impressions survey in Q4. The respondents confirmed that ear necrosis and flank necrosis are not uncommon in Ontario herds and when they do occur they can be a welfare or production issue. Veterinarians reported that in some cases there is a response to management of temperature, humidity, draft control, stocking density, nutrition, water quality and quantity management. Sometimes treatment

with antibiotics or drying agents may help. Unfortunately, there still are many times where interventions do not seem to provide immediate relief and the condition can appear and disappear without explanation. There is some current research in progress in Western Canada.

SOW MORTALITY

One of the concerns raised as a potential emerging health issue was higher sow mortality. High sow mortality and pregnancy loss has in some instances been associated with a transition to loose housing. The problem can occur in both new and renovated construction but does seem to be a bit more common in renovated facilities. Many factors have been proposed and include : lack of skilled labour and management to manage loose housing; stall and flooring types in renovations; sow genotypes not developed for loose housing; lack of experience, knowledge and support for Electronic Sow Feeding systems. Other knowledge gaps in causes of sow mortality such as in the case of Pelvic Organ Prolapse and splenic rupture and other related spleen pathology. The old adage is that every solution can potentially create a new set of problems. As a supply chain we will need to ensure that this transition to loose housing goes as smoothly as possible. The link for the National Sow Housing Conversion Project site is www.groupsowhousing.com.

Ontario Veterinary College Research Update

Dr. Bob Friendship updated on some recent research activity on Post-weaning Diarrhea at Arkell research station. Each month 3 pens with 10 / pen were enrolled in a new replicate of treatments and control. Vaccines, proteobiotic and dietary changes are examined. Disease challenge is created by reducing sanitation and decreasing room temperature more or less like the real world. Vaccines have not shown benefits in these studies. Proteobiotics have shown some response at high levels. Reduced density diets did not provide control and made the pigs grow more slowly. One of the conclusions of these studies is that often the pathogen is necessary to have the disease but the presence of the pathogen is not necessarily sufficient to cause disease. Multiple etiological agents being concurrently present in the animals at the same time can make responses more variable.

Slaughter Statistics

Federal Slaughter Statistic Summary (Q4 Aggregate)

Dr. Christine Pelland reported the following:

Carcass Condemnations

• Total number of hogs slaughtered in Q4 2021 = 1,077,968 with 2,231 carcasses condemned.
• Percent of carcasses condemned in Q4 2021 = 0.21% compared to Q1 2021 = 0.24%, Q2 2021 = 0.21% and Q3 2021 = 0.19%
• Abscesses, Peritonitis and Enteritis continue to be the 3 most common reasons for entire carcass condemnations.

Comment: Erysipelas is continuing to follow the seasonal patterns identified in 2019 and 2020 Once again condemnations for Erysipelas were highest in Q1 and Q4 2021 with Q2 and Q3 at lower levels.

Trim Demerit Condemnations

• Total number of carcasses that were subject to trim loss in Q4 2021 = 28,477 hogs. ( 2.64% of carcasses inspected in Q4 were subject to trim demerits. This compares to 2.67% of carcasses inspected in Q3 2021.)
• Total weight of trim in Q4 2021 = 154,982 kg with an average trim weight of 5.44 Kg / animal trimmed. Total weight of trim in Q3 2021 = 142,609 kg with an average trim weight of 5.2 kg/ animal trimmed.
• Total number of carcasses that were subject to trim loss due to abscess in Q4 2021 = 17346 carcasses with a total trim weight of 114,338 kg and an average trim weight of 6.59 Kg / animal trimmed.

CanSpotASF Surveillance Update

Drs Pasma and Fairles provided an update on CanSpotASF activity in Ontario.

These surveillance programs are important in early detection of ASF should it make its way to Canada. In addition, this type of surveillance helps to support a claim of freedom of ASF that supports international export of pork.

CanSpotASF is a risk-based early detection testing program that is available at approved Canadian animal health laboratories. There is no change for any case that arises where ASF is suspected. As always these cases must be immediately reported to the local Canadian Food Inspection Agency (CFIA) district office.

Approved laboratories that are part of the CAHSN network can now do ASF testing on cases, where you may want to rule-out ASF –just to be on the safe side. Until now, these types of cases have not been tested for ASF. This rule-out testing is targeted at herds with endemic diseases that could mask ASF and therefore delay detection. Both herd veterinarians and pathologists can initiate ASF rule-out testing. Practitioners can request rule out testing even if not submitting samples for histology. Some abattoir submissions to CanSpot are just starting.

What cases are eligible for risk-based early detection?

Certain diseases/conditions have been shown to mask the clinical signs associated with ASF and delay detection. Herds with a history of these diseases/conditions, or cases with a compatible clinicopathological presentation are eligible for testing. This could include a number of diseases that can look very much like normal endemic diseases that cause septicemia, multiorgan hemorrhage such as caused by E.rhusiopathiae; S.suis; S. zooepidemicus; A.suis; S. cholerasuis etc  and Porcine Reproductive and Respiratory Syndrome virus (PRRS), to name but a few.

International Disease Surveillance Topics

Dr. Al Scorgie commented on international disease surveillance reports.

Pseudorabies

In early September 2021, Colorado Parks and Wildlife officers confiscated three feral swine being raised on a small farm in El Paso County, Colorado.  The owner had illegally imported the feral swine from Texas.  The three pigs were euthanized.  Testing shows that the pigs were positive for pseudorabies. In 2005, Colorado State created a task force to eradicate feral swine.  Initially, the state tried to eradicate the feral swine through hunting.  The next step involved live trapping and euthanasia, using corral-like traps, some aerial hunting and a campaign to encourage the public to report sightings of feral pigs.  Parks and Wildlife officers were trained on identifying signs of feral pigs.  Data was gathered on locations, types of pigs and numbers.  USDA also collect water samples to test for the presence of DNA from wild pigs.  Trail cameras were also set up.  After 15 years, the state announced it had eradicated feral pigs. Although eradicated from the US domestic herd in 2005 Pseudorabies is still present in feral pigs in the USA. Ontario is in the fortunate position of still having a very low feral pig population and there are a number of initiatives such as the ban on hunting of pigs and farming Eurasian pigs in Ontario.

Source: Pork 01/06/22

ASF

Dr. Al Scorgie reported that on January 07th 2022, Italy reported a case of ASF in a wild boar found dead in the Piedmont region.  Since the first reported case, another 6 cases have been identified.  All cases are in the Piedmont region in Northwestern Italy.  Italy has established infected and surveillance areas.  Although the island of Sardina, which is part of Italy is endemic for genotype I, the genotype of the ASF found in the Piedmont region was genotype II.  The nearest region with an ASF genotype II case is 800km away in Germany.  The Piedmont region has a growing wild boar population. The ASF virus has continued its gradual march across Europe predominantly moving east to west.

How can producers engage in OAHN?

• Read our quarterly producer reports and let us know what you think!
• Discuss the material included in these reports with you herd veterinarian and other swine producers. Help us spread the word!

What to do if you see feral pigs in Ontario…

• OMAFRA is working with the Ministry of Natural Resources & Forestry (MNRF) to put together a wild swine strategy for Ontario. The first step will be to try to identify wild swine within Ontario.
• The MNRF has set up a page on iNaturalist at: www.inaturalist. org/projects/ontariowild-pig-reporting for residents to document any possible wild pigs in Ontario. Sighting information can also be emailed to MNRFSpeciesConservationPolicyBranch@ontario.ca.