Swine Veterinary Report – Q3 2022

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

Disease Surveillance Discussion

Porcine Epidemic Diarrhea (PEDV) / Porcine Deltacoronavirus (PDCoV)

There is a GOOD NEWS story to share in Q3 swine surveillance!  PED cases were down substantially in 2022 Q3. 

Jessica Fox, Manager at Swine Health Ontario reported the following cases in Q3:

Date County Name Disease Type Farm Type
11-July-22 Huron PED Nursery
13-Sept-22 Huron PED Finisher

There has been no additional cases in Q4 thus far.  The PED and PDCoV tracking map is available at the Swine Health Ontario website:  http://www.swinehealthontario.ca/Disease-Information/PED-PDCoV-Tracking-Map

African Swine Fever (ASF) Preparedness- Good News Stories

Dr. Christa Arsenault reported some good news stories that we wanted to share on ASF:

  • CanSpotASF testing continues in Ontario as a risk-based early detection testing program where testing is completed at the Animal Health Lab (AHL) in Guelph. Samples continue to be tested on any case submitted to the AHL where ASF is NOT suspected as the cause of disease and where eligibility criteria is met. We are excited to announce that CanSpotASF is now launched in both federally and provincially licensed and inspected processing plants within Ontario!
  • Vietnam is the only country to have a commercially licensed vaccine for ASF. There was a period where this vaccine license was pulled for an investigation into pig mortalities. The good news is that it was determined that the mortalities were associated with off-label use and the government is allowing the resumption of the vaccine with a target of 600,000 pigs to be vaccinated.
  • The USDA announced on October 13th, that it will increase ASF surveillance in the Caribbean. The USDA has a surveillance program in place in Haiti and the Dominican Republic as well as Puerto Rico. In Puerto Rico there is a plan to eliminate the feral pig population as well.

Influenza A (IAV)

All responding veterinarians to the clinical impression survey rated the frequency of IAV as common (64%) and very common (36%). The following Influenza genotypes were identified at the Animal Health Lab (AHL) in 27 submissions in Q3 2022: Subtype H1N1 classical= 1 total with 1 alpha, 0 beta, 0 gamma. Pandemic H1N1=1.  One H1N1 was too weak to type.  Subtype H3N2= 9 total. Subtype H1N2= 8 .Gallant Laboratories Ontario data indicated that there were no IAV isolates in Q3.


Laboratory Diagnostic Reports

Dr. Tim Pasma summarized findings from the AHL Syndromic Surveillance in Q3:

Influenza

2022 Q3 was a fairly active influenza season with signals based on both respiratory signs and mortality.

  • Week 30 (Jul 24)– 7 submissions- H3N2 (2), N2 (2), H1/N1/N2 (2), ELISA (1) (sow (2), nursery(1), grow finish (3)
  • Week 32 (Aug 7)– 3 submissions- H1N2, H1, N2, nursery (nursery (3)
  • Week 39 (Sep 25)- 4 submissions- H1N1 (2), N2 (1), ELISA (1) (suckling (1), nursery (2))

Over the last year H1N2 (36.3%) remains the dominant subtype but is followed closely by a very narrow margin by H3N2 (35.29%) and then H1N1 (25%).  The percentage of partial subtypes has increased since Q2.

Porcine Epidemic Diarrhea Virus (PED)

There had been a few detections of PEDV in Q3.  Positive submissions have been associated with monitoring.

Porcine Deltacoronavirus (PDCoV)

There were no PDCoV detections in Q3.

Syndromic Surveillance

There were no syndromic signals to report in Q3.

Animal Health Laboratory Diagnostic Reports

PATHOLOGY CASES  

Dr. Josepha DeLay and Dr. Jim Fairles reported that a total of 78 pathology cases were submitted to the AHL for 2022 Q3 originating from commercial swine herds of various sizes.  In addition, there were 2 meat inspection cases, and 3 pet pig cases.   Inclusion of PID for pathology submissions remains a weak link.  The PID inclusion rate for pathology cases from commercial herds was 59% (63% in Q2, 73% in Q1).  Age or commodity group was provided for 100% of all cases, and adequate clinical history was provided for 96% of the cases.   

Notable pathogens or disease syndromes detected, and apparent trends identified during 2022 Q3 are as follows:

  • Outbreak of lameness in 4% of pigs following transport to a finisher barn. Gross and histologic exam identified rickets. The rickets in this particular case was due to a phosphorus deficiency related to a feed formulation error that involved inappropriate phytase levels.
  • Congenital / neonatal tremors due to atypical porcine pestivirus. This is the first confirmed case identified at the AHL. Porcine astrovirus-3 was also detected in this submission, but the lesions were not consistent with Porcine astrovirus-3.
  • Bacterial pneumonia +/- septicemia, nursery pig – Klebsiella pneumoniae isolated
  • Brachyspira hyodyseneteriae was detected in 1 herd in which the organism was previously identified. Another pathogen that causes bloody diarrhea (Lawsonia intracellularis) was also detected in the group.
  • Necrotizing myositis, fasciitis, and dermatitis – Clostridium septicum – finisher pig
  • Possible Yersinia spp septicemia – co-isolated with S.suis
  • Three (3) pet pig cases: salt toxicity, pancreatitis, localized hyperplastic / dysplastic skin lesion

 NONPATHOLOGY CASES

There was nothing remarkable in Q3 with respect to non-pathology cases.

Gallant Custom Laboratory Diagnostic Reports

There were no swine submissions submitted to Gallant Labs from Ontario in Q3 2022.


Slaughter Statistics

Federal Slaughter Statistic Summary (Q3 Aggregate)

Dr. Christine Pelland along with assistance to compile the data by Gillian Greeves reported the following:

Carcass Condemnations

  • There were approximately six hundred more animals condemned in Q3 as compared to Q2.
  • Erysipelas condemnations declined to 2.4% of condemnations in Q3. This is consistent with a seasonal pattern of decline in Q3.
  • Abscesses and peritonitis continue to account for the largest proportion of condemnations.
  • Emaciation is a relatively minor reason for condemnations but there has been a trend to increasing numbers. Plans were to follow up with CFIA to see if there is any explanation for this

Trim Demerit Condemnations

  • No major changes in reasons for trim demerits.
  • Mammary trim appears in the trim demerit category. It is not clear why mammary glands would need to be trimmed in a plant that is slaughtering market hogs.

Ontario Provincial Slaughter Statistic Summary

Dr. Christine Pelland reported that the trends for the provincial slaughter statistics are for the most part unchanged.

  • Parasitic liver is consistently the most common trim reported
  • Condemnations due to abscess, arthritis and inflammatory conditions are the next most common.

CanSpotASF Surveillance Update 

Dr. Christa Arsenault provided an update on CanSpotASF activity in Ontario.  CanSpotASF is a risk-based early detection testing program that is available at approved Canadian Animal Health Surveillance Network (CAHSN) laboratories, which includes the Animal Health Lab (AHL) in Ontario. The CanSpotASF program is set up with the goal of early detection of ASF.  It is to be used when ASF is not a main rule-out diagnosis and where early clinical signs of ASF could be masked by other routinely diagnosed swine endemic viruses in CanadaIf ASF is suspected on a farm/premise, the Canadian Food Inspection Agency (CFIA) must be notified immediately.

This program works on the premise that early detection if ASF arrives in Canada will in turn limit the spread of this virus, leading to a faster and more efficient outbreak response.  Veterinarians and/or pathologists can initiate ASF rule-out testing for submissions that meet eligibility criteria.

There are many reasons why not all cases that are deemed eligible for CanSpotASF are tested including, but not limited to the following; missing information on submission form e.g. PID and missing tissues required to test for ASF.  To increase CanSpotASF submissions, an infographic providing a reminder to take and include the spleen with samples being submitted to the AHL was created and entitled “Make Spleen Routine”. Please download a copy and use this infographic as a visual reminder to indicate this on the lab submission forms for samples that meet the eligibility criteria for CanSpotASF:  https://www.oahn.ca/resources/infosheet-make-spleen-routine/

CanSpotASF Testing Summary

OAHN (Ontario) Period Number of Eligible Cases Number of Negative Cases Number of Positive Cases
2022 Q3 (Jul 1-Sep 30) 52 20 0
Cumulative 2021-2022 228 74 0
Cumulative 2020-2021 82 17 0

Ontario Veterinary College Research Update

Dr. Bob Friendship reported on the following activity:

The new Arkell pig barn is coming along and hopefully will have pigs by spring 2023.

In one study a graduate student is monitoring almost every farrowing at Arkell over the past year or so. She has recorded video of approximately three hundred plus farrowings. She is documenting information such as the duration of farrowing, pig to pig birthing intervals and the behavior of sows post farrowing. Currently she is focusing on identifying risks of stillbirth. It was hypothesized that sow anaemia may predispose to increased risk of stillbirths. Blood samples were taken from all sows just prior to farrowing at Arkell. Interestingly these Arkell sows were not anaemic. Subsequently no comparative analysis of sow anaemia as a risk factor for stillbirth could be undertaken. Could be, because the sows were not anemic it was not possible to do a comparative analysis of sow anaemia as a risk factor for stillbirth.. There are the usual risks such as sow parity with older parity sows having increased still births. Total born at Arkell is 15 pigs per litter on average with 1.5 still births per litter. Ten percent of pigs being still born still represents a significant economic loss.

Dr Friendship has been monitoring pigs for some viral pathogens that previously were a significant cause of disease in Ontario. Examples of this type of viral disease included Hemagglutinating Encephalomyelitis Virus (HEV) and Porcine Cytomegalovirus (the viral cause of Inclusion Body Rhinitis). In swabbing the tonsils of nursery pigs for diseases such as Porcine Cytomegalovirus it has been found that about fifty percent of the nursery pigs that have been swabbed are PCR positive for the virus. What is not clear is the reason that those viruses appear to be quite common and yet do not appear to be causing any significant clinical disease.


International Disease Topics Of Interest Summary

Dr. Al Scorgie provided a summary on some interesting international disease topics of interest for the OAHN Swine network members:

Carlos Pijoan SDEC Symposium- Biosecurity and Biocontainment in finishing pigs

At the recent 2022 Leman Conference, there was a seminar on biosecurity and finishing pigs.  Part of the reason that the seminar was held was because there have been several improvements in biosecurity on the sow side such as air filtration, transport, personnel entry etc., the average incidence of new PRRS breaks in sow herds has not changed much, usually over 20%.  In years where the incidence was less than 20%, that would be years such as 2013/2014 that the industry was concerned about PEDv or 2018/2019 when the industry was concerned about ASF.  Could finishing barns be contributing to breaks in sow herds?  Are there areas to improve biosecurity in finishing barns?

Dr. Montse Torremorell (UMN), shared that the diagnostic labs often start to see an increase in PRRS breaks in finishing barns in September that precedes sow breaks in October.

Dr. Paul Yeske (Swine Vet Center) presented a small study where he followed the PRRS breaks in a small number of sow herds and the downstream finishing.  Four of six PRRS breaks in the sow herds were linked to finisher sites.  Dr. Yeske also found that the majority of the finisher sites that broke with PRRSv had multiple breaks.

Dr. Derald Holtkamp (Iowa State), shared a study that followed 639 sites.  (The majority of the sites were wean-to-finish).  Of the 639 sites,

  • 23% (149) were PRRS negative at weaning and at marketing
  • 39% (243) were PRRS positive at weaning and marketing
  • 38% were PRRS negative at weaning but PRRS positive at marketing.

Dr. Holtkamp presented another study using GloGerm to access biosecurity risks during loading.  Derald wanted to look at loading risks because when finishing pigs are infected with PEDv in the last 4 weeks before marketing there is a reduction in ADG and an economic cost of over $2/pig.  Some of the barns were set-up with conventional loading and other barns had staged loading.  In staged loading there are people bringing the pigs up to a “dirty” zone who moves the pigs up to the demarcation line between the transport and the barn.  The person in the “dirty” zone does not leave that zone.  The study showed that staged loading significantly decreased the risk of material from the trailer being brought back into the barn.  Not all barns can be set-up for staged loading, but it is something to consider.

Dr. Jose Angulo (Zoetis) shared a trial where he did oral fluid (OF) sampling on 63 wean-to-finish sites from 10 production systems.  OFs were collected at 3, 8, 12, 16, 20 and 25 weeks after placement.  PRRS PCRs and ELISAs were run on the OFs.  If the OFs were PCR positive than sequencing was done.  A total of 134 PRRS sequences were done.  (One challenge was that on 95% of the sites the pigs were vaccinated with MLV PRRS vaccine).  Of the 134 sequences, 26% were wild type.  Vaccine-like PRRSv was found earlier post-placement, the peak was at 8 weeks.  Wild PRRSv was found later post-placement.  Dr. Angulo did a risk assessment and found that deadstock removal and the number of people coming onto the site were the biggest risk factors.

Dr. Lauren Glowzenski (Tri Oak Foods) presented a case of an APP serotype 15 outbreak in a finishing barn.  The production system was negative for APP serotype 15.  The finishing site was isolated and the chance of lateral spread from another site was unlikely.  This production system uses contracted load-out crews that work in other systems.  The load-out crews take sorting boards from site to site.  The APP break happened after the first pigs were shipped.  The sorting boards were the suspected source of APP.

Transport Biosecurity, Bioexclusion and Biocontainment Highlight Planned Wean to Harvest Biosecurity Program

Dr. Paul Sundberg from Swine Health Information Center (SHIC) announced that a task force has been formed between SHIC, the Foundation for Food and Agricultural Research and the National Pork Board to focus on transport biosecurity and other bioexclusion and biocontainment practices for wean to harvest.

Dr. Sundberg said that analysis of health data shows that finishers infected with PRRS, or PED can be a source of infection for the breeding herd.  Dr. Sundberg commented that when the US eradicated pseudorabies that had to be vaccination of finishing because the finishing pigs were a source of infection for the breeding herd.(Farmscape.ca – 2022/10/03)

Senecavirus A Transmission Via Soy

Dr. Scott Dee, Pipestone Applied Research, recently commented about a case of Senecavirus A (SVA) that he was consulted on. The case was in another country. The national herd of this country had been historically negative for SVA. A pork production company had imported 40,000 tonnes of soy from multiple countries. Some of these countries were endemically infected with SVA. The soy was fed to multiple farms and multiple farms were breaking with SVA. The company sampled the remaining soy and found SVA in the feed. The production company and the country’s veterinarians believe that the contaminated feed was the source of SVA that infected the pigs. This case is important for several reasons.

  • research has demonstrated that viruses such as SVA, FMD or ASF can survive in certain feed ingredients but this is an actual case
  • since the country has been historically negative for SVA, and the feed tested positive for SVA it helped establish contaminated feed as the cause.  Fortunately, this was SVA and not FMD. (Jennifer Shike, Pork, 2022-09-13)

Porcine Reproductive Respiratory Virus (PRRS)- Severe Outbreaks in Spain

There are reports of a new PRRSv clade causing severe outbreaks in Spain. The first outbreak from this new PRRS strain were reported in Catalonia. Veterinarians reported that the outbreaks had high abortion rates, up to 50%, the abortions lasted for several weeks. The high abortion rate was seen even in vaccinated herds. Sow mortality rates of up to 15%. High mortality in nursing pigs and nursery pigs (20-50%). Poor growth in the surviving pigs. The new PRRS strain has spread to other regions.  Lab analysis had shown that the new PRRS strain contains parts of a high virulent strain of PRRSv reported from Italy from 2017. The new strain also combined with segments of other PRRS strains. (UMNSwineNews 2022-09-09)

African Swine Fever (ASF)

Vietnam – In August 2022 the Vietnamese government temporarily suspended the use of the ASF vaccine.  The reason for the suspension was high mortality in vaccinated pigs. The government stated an investigation. The vaccine was developed at Plum Island in the US. Initial trials were promising. Vaccinated pigs did not show clinical signs of ASF and it “appeared” vaccinated pigs did not shed ASF.  The vaccine was being used on a small scale in Vietnam to further evaluate vaccine efficacy and safety in the field.   The Vietnamese released the findings of the investigation in October.  Where mortalities occurred, the vaccine was being used extra-label. In some cases, an inappropriate dose was given or the wrong age of pigs were being vaccinated.  The vaccine is labelled for pigs 8-10 weeks of age. The government is allowing the resumption of the vaccine with a target of 600,000 pigs to be vaccinated. (Vincent ter Beek, Pig Progress, 2022-08-24, National Hog Farmer, 2022-10-25)

Caribbean – The USDA announced on October 13th, that it will increase ASF surveillance in the Caribbean.  ASF was detected in the Dominican Republic in July 2021 and in Haiti in September 2021.  The USDA has a surveillance program in place in both countries as well as Puerto Rico. In Puerto Rico there is a plan to eliminate the feral pig population. During Hurricane Maria in 2017, pet pigs escaped or were released and started a breeding population. The USDA has already eliminated feral pigs in the US Virgin Islands. The USDA had made plans to eliminate feral hogs in the Dominican Republic and Haiti but now says that is not possible at this time. With the political, humanitarian and environmental crises in Haiti, the Haitian government has no funding to put towards ASF.  Communication is difficult in Haiti. APHIS has started an outreach and information program about ASF in Puerto Rico. (Ann Reus, Feed Strategy, 2022-10-25)

How can you Participate in OAHN?

Look for the 2022 Q4 veterinary clinical impression survey that will come out the second of January via an email through the OASV listserv.

The survey takes less than 10 mins time to complete!

Report 33

JUL-SEP

2022

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