Science Page: African swine fever experience in a large commercial system in the Russian Federation

This is our Friday rubric: every week a new Science Page from the Bob Morrison’s Swine Health Monitoring Project. The previous editions of the science page are available on our website.

This week, we are sharing the experience Dr. Gustavo Lopez, a PhD candidate at the University of Minnesota, had dealing with African Swine Fever in Russia.

Key points:

  • Infected pigs can be asymptomatic carriers of African swine fever virus (ASFv)
  • Timely detection with diagnostic testing, strict biosecurity measures and rapid removal of the source of infection are key to limit the transmission of the virus within and between sites.

In December 2014, ASFv was detected in a finishing site of a multiplier herd from a large commercial pig company located in the Russian Federation. The region had multiple reports of ASFv in backyard pigs before the outbreak. The affected company consisted of 80,000 sows in 15 farms organized as a three-site production system with each sow farm having a dedicated nursery and two finishers. The multiplier herd supplied gilts from the finisher to the gilt development unit (GDUs) for each farm. Each sow farm had a quarantine within the farm to receive the gilts from the GDU .

A 3% mortality increase was reported in one room of the finishing site. A few pens in one of the rooms had pigs affected with fever, purple ear and mild scouring. The site was being monitored for ASFv on a weekly basis before gilt shipment, following local regulations and results always came back negative.

Samples collected from the affected pigs were negative for ASFv, Classical Swine Fever, PRRSv, and Salmonella so the decision was made to resume shipment of gilts from a room with no clinical signs to the GDU.

As the days progressed, the clinical signs in the affected room worsened and affected more pens. The GDU that had just received gilts reported similar clinical signs and diagnostics on samples collected then from the multiplier finisher and the GDU confirmed the presence of ASFv at both sites.

At that time, all pig movements were stopped and a 5km quarantine area was imposed around the two affected sites. Gilts that had been sent from the GDU to five commercial sow farms, and were in quarantine tested negative to ASFv. Nevertheless as a precaution, the decision was taken to sacrifice all the gilts in the quarantines.

Protocols mandated by the government were implemented in the ASFv positive multiplier finisher and GDU which consisted of euthanasia of all pigs within a 5km radius, destruction with burial and burning of all carcasses, strict movement restrictions for vehicles and people and exhaustive disinfection protocols inside the farm and its territory.

Transportation of infected non-symptomatic animals from the multiplier finisher was the most likely route of infection to the GDU. The source of infection to the multiplier finisher is unknown, although people are thought to have played a role given the presence of ASFv in backyard farms in the area. Events such as introduction of infected pork meat, lack of proper disinfection of 3rd party trucks or non-compliance with the shower-in policy of the farm could not be ruled out. The outbreak occurred in December when temperatures were below zero Celsius and wild pig-tick-domestic pig interaction was unlikely.

It is important to point out that 12 of the 16 rooms in the multiplier finisher remained negative to ASFv until the moment of euthanasia. The sow farm and nursery multiplier were monitored for ASFv during the quarantine period and until the moment of euthanasia 6 months later. During this time, they remained negative to ASFv, even though they were within close proximity to the affected farm. Our experience indicates that a timely detection of ASFv with testing, strict biosecurity measures and removal of the source of infection as soon as possible can limit the transmission of the virus between sites.

 

African Swine Fever information repository web page

The spread of African Swine Fever in China and in Europe has been raising concerns in the US swine industry. To answer the need of updated and relevant information, we created the webpage: z.umn.edu/AfricanSwineFever.

Among other resources you will find recording of the session of the 2018 Allen D. Leman Swine Conference, a link to the Swine Disease Global Surveillance reports, and preparedness checklists from the Pork Checkoff.
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The page is organized to answer the following questions:

  • What do we know about African Swine Fever virus?
  • What is the progression of African Swine Fever worldwide?
  • African Swine Fever in the field
  • What are the available diagnostic tests for African Swine Fever?
  • How to prepare for African Swine Fever
  • Is there a vaccine against African Swine Fever?
  • Is feed a concern?

Funeral Information for Dr. Michael Murtaugh

Michael Murtaugh
Dr. Mike Murtaugh

Professor Michael Murtaugh, PhD, passed away last Tuesday from complications related to his ongoing battle with pancreatic cancer. He was 67. A memorial service will be held Saturday, September 29 at 11 a.m. at Calvary Church in Roseville. Visitation is from 9 to 11 a.m. at the church.

Mike joined the college in 1985 and spent his University of Minnesota career in the Department of Veterinary and Biomedical Sciences. He was a consummate faculty member, excelling in teaching courses and conducting research and outreach. Mike authored more than 225 peer-reviewed journal articles, was the primary advisor for 30 Master’s and PhD students, and held three U.S. patents. At the time of his death, Mike was serving on the editorial boards of more than a dozen academic journals, and had successfully completed nearly 160 sponsored projects as a PI or co-PI.

He was an international leader in battling the porcine reproductive and respiratory syndrome virus (PRRSv) that costs U.S. swine producers alone nearly $500 million annually. Mike used molecular biology to first understand the PRRSv pathogen and immunology to evaluate the pig’s immune response. His lasting legacy is a generation of scientifically-trained swine health specialists.

Mike earned his BS in biology at the University of Notre Dame and then served as a Peace Corps volunteer in Venezuela. He earned a PhD in entomology at The Ohio State University. The University of Texas Medical School in Houston was his next stop—spending four years in a post-doctoral position in the departments of internal medicine and pharmacology—before arriving in St. Paul.

He will be remembered for his dry sense of humor, a character trait that he maintained even as his battle with cancer raged. Mike cared passionately about science and derived some of his greatest personal satisfaction working on the collegiate strategic plan and the International Conference on One Medicine and One Science. Mike cared deeply about science informing policy and saw the need for scientists to be more actively involved in communicating about their research. I am grateful to have known him, and stand in awe of the many contributions he made to our college.

Dean Trevor Ames
College of Veterinary Medicine
University of Minnesota

Megan Bloemer, U of Illinois student, receives the Morrison Swine Innovator Prize

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Megan Bloemer (right) receives the Morrison Swine Innovator Prize from Dr. Perle Boyer (left).

University of Illinois veterinary student Megan Bloemer has received the first-ever Morrison Swine Innovator Prize, a new award given to veterinary students who want to specialize in swine medicine. The award was presented at the annual Allen D. Leman Swine Conference in St. Paul, MN.

All North American veterinary students with an interest in swine health and production were eligible. Bloemer’s presentation on reducing the risks of disease transmission at truck washes helped her rise to the top among the seven student finalists.  The Bloomington, IL native says her project was an eye-opener.

“I didn’t know a lot about how truck washes worked and the amount of moving parts required prior to this project,” Bloemer says. “What was most interesting for me was the amount of hard work that goes into cleaning these trailers every day and just how critical they are for protecting herd health.”

Bloemer is a third-year veterinary student and hopes to find either a swine production company or swine veterinary clinic where she can add value by interacting with farm staff and improving herd health.

Bloemer received a cash award of $7,500 plus complimentary registration and travel costs to attend the Leman Swine Conference. The Morrison Swine Innovator Prize honors the legacy of the late Bob Morrison, DVM, PhD, MBA, who coordinated the conference for many years. The award is sponsored by leading swine producers, veterinary practices, and industry partners.

Science Page: Within farm PRRS time-to-stability differences in sow farms in the Midwest

This is our Friday rubric: every week a new Science Page from the Bob Morrison’s Swine Health Monitoring Project. The previous editions of the science page are available on our website.

This week, we are sharing a report by the MSHMP team regarding PRRS time-to-stability differences in sow farms.

Keypoints:

  • There is significant within farm PRRS time-to-stability variation.
  • Several factors contribute to PRRS time-to-stability variability; however, there is still a significant amount of unexplained variability.
  • The role of within farm management practices and internal biosecurity measures should be further explored.

Introduction

Porcine reproductive and respiratory syndrome (PRRS) stability is reached when no evidence of infection is observed in wean-age piglets. Sample size to detect PRRS virus in wean-age piglets usually involves blood sampling of 30 piglets, at least four times, 30 days apart (Holtkamp et al., 2011). The cumulative time from the intervention (i.e. whole herd exposure, herd closure) to PRRS stability is usually referred to as time-to-stability (TTS).

Here we summarize differences in TTS in MSHMP participating farms located in the Midwest that have had at least two PRRS outbreaks.

Methods

Six systems that are similar in the way they test to classify a herd as stable were selected for inclusion in the study. PRRS outbreaks reported from 2011 to 2017 were used for analysis.

TTS was defined as the time period from the date of outbreak reporting to the date when PRRS stability was reported (last consecutive negative PCR result). To assess the variability in TTS, only farms that had at least two PRRS outbreaks were selected.

Results

Overall, 133 PRRS outbreaks in 53 farms were recorded withtwo, three, four and five outbreaks in 35, 11, 5, 2 farms, respectively. The median TTS standard deviation of PRRS outbreaks within the same farm was 12 weeks (minimum = 0 weeks, maximum=88 weeks).

After accounting for the effect of the intervention using MLV or FVI, the RFLP pattern of the virus associated with the outbreak and previous PRRS outbreaks in the farm, the PRRS time-to-stability correlation of outbreaks in the same farm and system was only 1.2%.

In other words, TTS of two given outbreaks in the same farm were not correlated indicating that TTS within farm is highly variable.

Conclusion

There is a high TTS variability after a PRRS outbreak within the same farm that is not accounted for by the effect of the intervention used, the virus (i.e RFLP), previous PRRS outbreaks in the farm and system.

ASF update: Swine Disease Global Surveillance bi-monthly report

This report was published by the Swine Health Information Center and prepared by the University of Minnesota.

Epidemiological Situation

Belgium

On September 14th, the OIE official report of the 1st ASF case in Belgium was released, confirming our previous report. On Saturday, 15th, the Federal Agriculture minister confirmed three new cases in the same area of the initial report, identified in wild boars found dead in the city of Etalle (Luxembourg province), near the border with France.

On Friday evening, a multisectoral meeting took place in Belgium, where the farming, meat and animal feed sectors asked for priority measures against the spread of African Swine Fever to be in place. In the joint statement coming from that meeting, they draw up five possible critical needs/measures to mitigate the disease spreading: a European plan to define and maintain the affected zone; the creation of a committee dedicated to the export of meat and pork products; a regulated slaughtering and butchering method for pigs in the area which is under tight surveillance; a realistic and feasible plan to reduce the boar population in the country; and finally the creation of a crisis communication committee.

Arrangements are being done to ban the movement, hunting and feeding of wild boars in the region to control the spread of the disease by human interaction. An investigation and monitoring program is being implemented, with the support of European experts.

China

With the reporting of two new outbreaks today (September 14th), unofficially, there have been 21 ASF outbreaks reported in China. The last two reported outbreaks included (a) 16 hogs with sudden death in the Inner Mongolian Province, and (b) a farm in Henan Province, with 148 infected pigs and 43% fatality rate. Officially, however, the OIE WAHIS platform still reports only 19 outbreaks in six provinces (Figures 1 and 2). Although the cause of ASF introduction into China remains unclear, in March, 2018, FAO alerted for the risk of introduction of ASF into the country by illegal introduction of animals or food. There are also concerns that, similarly to what has been reported in Europe, wild boars may play a role in the spread of the disease.

Control Activities

Approximately 40,500 pigs have been culled since the beginning of the epidemic, with mortality rates that varied between 0 and 23.17% (Figure 1). The Chinese government reported checking pigs in thousands of sites, which may have resulted in the increase of the identification of new outbreaks. In an attempt to contain the spread of the disease, all transport of live animals from infected provinces is restricted, feed policy is being adjusted to the current scenario, and the logistics of the industry and the Chinese market are being reviewed. On September 13th, the use of food waste and pig blood as feed for pigs in ASF-infected and neighboring provinces was banned. Also, testing pig feed to ASF will be required, and positive samples will trigger destruction of the whole batch of feed.

Disease Impact

China is considering to import meat from other markets, including the European Union, that in 2017 faced an intense decline in pork exports. US hog market is also currently facing a low price market, however with expansion in number of sows and pork produced. International trade is at risk once ASF is spreading rapidly into consolidated markets like Europe and China, and concerns are growing around the globe.

 

Figure 1: Summary of outbreaks of African Swine Fever in China. Nineteen outbreaks were reported to OIE, in 6 provinces: Lianoning, Henan, Jiangsu, Zhejiang, Anhui, Heilongjiang (Source: OIE – WAHIS).

 

Figure 2: Chinese provinces with reported ASF outbreaks (Lianoning, Henan, Jiangsu, Zhejiang, Anhui, Heilongjiang). The intensity of the green shade depicts the number of culled animals, with the Province of Liaoning (darkest green) showing the highest cull rate.

 

 

Passing of Dr. Mike Murtaugh, colleague and friend

Tribute from the National Hog Farmer.

Michael MurtaughThe swine industry is grieving today after the loss of one its most profound scientists in PRRS research. Mike Murtaugh, a professor of virology and immunology at the University of Minnesota College of Veterinary Medicine, passed away Tuesday morning, following a battle with pancreatic cancer.

Murtaugh was also recognized today as the 2018 Allen D. Leman Swine Conference recipient of the Pijoan Lecture for his 30-year research into the PRRS virus and how his work on such a devastating disease has become a model for advancing progress in the industry.

“The Pijoan lectureship is not my honor and this is not my talk,” says Michael Rahe, a 2017 graduate under Murtaugh who filled in to give the keynote lecture at the Leman conference. “That honor and this talk belong to a man I have the highest regard for, my former adviser Dr. Mike Murtaugh.”

Murtaugh, who held a doctorate in entomology from Ohio State University, based his research program at the University of Minnesota on

the molecular mechanisms of disease resistance in pigs. His contributions to science has made many significant advances in fundamental porcine immunobiology related to immune protection and immunomodulation; porcine antiviral immunity, including lymphocyte memory and mechanisms of protection; and molecular virology, evolution and discovery sciences to elucidate viral origins and evolution as a means to understand genetic diversity and immunological challenges.

“Mike Murtaugh is a scientist and not a veterinarian. His goal as a faculty member has always been to better understand the mechanisms of disease resistance in swine,” Rahe says. “The tools which Mike has used toward PRRS are molecular biology and immunology. He has used molecular biology to understand the PRRS virus pathogen, since you must first know the pathogen to assess the immune response and then immunology to assess the quality of immune response.”

Murtaugh significantly advanced the field of knowledge of PRRS, PCV2 and PED viruses’ evolution, pathogenesis and immunity, and his work will continue to impact the U.S. and global swine industries.

“Getting out of the comfortable confinements of the academic laboratory was essential for this and without the support of students, colleagues, veterinarians and producers nothing … would have been accomplished,” Rahe says. “Part of Mike’s legacy will be the next generation of scientifically-trained swine health specialists.”

The Pijoan lecture is named in honor of Carlos Pijoan for his work in the area of swine respiratory disease and the influence of swine production systems on the dynamics of microorganism, such as porcine reproductive and respiratory syndrome virus, Haemophilus parasuis, Streptocococcus suis and Mycoplasma hyopneumoniae. In 1982, he joined the University of Minnesota College of Veterinary Medicine, where he was the founder and director of the Swine Disease Eradication Center and a professor in the Veterinary Population Medicine department. Pijoan passed away Jan. 9, 2007, after a three-year battle with pancreatic cancer.