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In August, it was announced the Swine Health Information Center (SHIC) received a grant from the USDA Foreign Agricultural Service, with active support from the National Pork Producers Council (NPPC), to start a dialogue between the US and Asia, sharing veterinary knowledge and ways to prevent African swine fever (ASF) from further spreading. In September, SHIC Executive Director Dr. Paul Sundberg traveled to Vietnam as this process was launched. In this first phase, as key stakeholders were identified, collaboration and tours of ASF-affected farms in Vietnam gave Dr. Sundberg and strategic partners in the process a first-hand look at the disease’s impact. Dr. Sundberg notes it will be easy to mistake an ASF outbreak for porcine reproductive and respiratory syndrome (PRRS), salmonella septicemia, or any other herd-level disease. “Veterinarians need to communicate to producers that they can’t assume that what they see is what they’ve had in their barns before,” he explained. “Producers need to get a professional diagnosis every time they have a morbidity or mortality event on the farm, no matter if it is individual or multiple animals.”
During this initial visit to Vietnam, Dr. Sundberg and colleagues in the process met with staff from laboratories as well as producer companies to set up the infrastructure for implementation of the work outlined in the grant. A USDA/Vietnamese Department of Animal Health (DAH) meeting of “first responders” was an opportunity to listen to the government agencies talk about policies and communications.
On their visit to an ASF-affected farrow-to-finish farm, they noted mortality had been steady with one to several pigs dying every day. Staff on the farm did not describe a dramatic initial die-off. Pigs continue to get recruited into the disease and predictably die five to 10 days after they initially notice off-feed or fever. At the finishing farm toured, pigs ranged from 20 to 40 kg (44 to 88 pounds) bodyweight and were almost uniformly severely affected by ASF. Nearly all were extremely reluctant to rise and move, and when they did, generally just relocated and laid back down. By touch, most all pigs had easily detectable fever. There was some evidence of respiratory disease, but not as dramatic as on the first farm visited. Diarrhea was common in all pens; digested blood was apparent in the feces. Frank blood was easy to identify on the backs of pigs, walls of pens, and floors of pens but it was not obvious what the source of the blood was.
Dr. Sundberg emphasizes that the clinical picture of ASF is severe, however, could easily be assumed to be something else, for a few days or a week, if not investigated immediately. “I just heard the description that ASF is like lava from a volcano – it doesn’t move fast but it just keeps moving and it burns everything in its way,” he notes.
In the next steps of the project following this initial visit, ASF-related field projects will be implemented, including those helping to inform the U.S. pork industry about effective ASF preparedness and response. Key to the success of the overall mission will be these field projects in Vietnam, including analysis of pathways of entry onto the farms, collection and analysis of swine oral fluids, biocontainment of the virus after entry to the farms and cleaning, disinfection and repopulation trials, which will provide valuable data for all participants and US pork producers. In an additional phase of the grant-funded process, the strategic partners will train the Vietnamese veterinary workforce on ASF prevention and control, helping to build local veterinary capacity.
SHIC, NPPC, AASV and the National Pork Board are working closely with the USDA to first prevent ASF from entering the US swine herd but also to be prepared to respond should an outbreak occur. The industry is actively identifying and prioritizing critical research needs and working in collaboration with state and federal animal health officials to make sure that, at a national level, all appropriate biosecurity measures are being implemented.
Find ASF-related resources and information on the SHIC website.
Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) was isolated from two recent cases of high sow and feeder pig mortality in US assembly yards. While this organism is a sporadic cause of disease in multiple animal species, it has rarely been associated with disease outbreaks in US swine. Work completed by the Iowa State University Veterinary Diagnostic Lab (ISU VDL) since the initial diagnosis, with support from the Swine Health Information Center (SHIC), provides more details on current concerns.
See the initial report on this occurrence of S. zooepidemicus here.
Based on review of past cases, ISU VDL learned the recent US strains are strikingly similar to the ATCC strain isolated from swine outbreak(s) of high mortality in China in the mid-1970s that reportedly involved the loss of more than 300,000 pigs (1, 2). These further characterization results suggest these recent case series for US assembly yards were related and caused by the same variant of S. zooepidemicus. Previous isolations of S. zooepidemicus from clinically ill pigs have been rather limited in the US. There is minimal information concerning the novelty of this particular variant of S. zooepidemicus, as compared to past findings in US swine.
Elevated swine mortalities in western Canadian assembly yards due to S. zooepidemicus were reported in the second quarter of 2019, per the Canadian West Swine Health Intelligence Network. More recently, an additional incident of elevated mortality and abortions caused by S. zooepidemicus in four related commercial sow farms located in Manitoba, Canada, occurred. The S. zooepidemicus isolate from the case series involving the four commercial sow farms in Manitoba was also reported to be genetically similar to the aforementioned ATCC strain of S. zooepidemicus associated with the high swine mortality event in Sichuan province in China in the 1970s(3).
These occurrences in the US and western Canada should spur increased pig farm biosecurity efforts, particularly related to transport and collection points.
SHIC will continue its efforts as further study is needed to better understand the relevance and prevalence of S. zooepidemicus in North American swine.
References
Porcine reproductive and respiratory syndrome (PRRS) continues to present challenges to producers. Using data generated by the Swine Health Information Center (SHIC) veterinary diagnostic lab standardization project and the resulting domestic disease monitoring report, Dr. Daniel Linhares of Iowa State University (ISU) and colleagues update current PRRS incidence and status. The Morrison Swine Health Monitoring Project (MSHMP) gives an opportunity to assess and prioritize biosecurity protocols to prevent PRRS. And a new project, again using MSHMP data, analyzes the predictability of porcine epidemic diarrhea virus (PED) outbreaks that could lead the way to also predicting PRRS infections.
In the October domestic disease monitoring report, authors monitored PRRS diagnoses in the major veterinary diagnostic laboratories. They found the number of cases tested for PRRSV doubled from 2010 to 2018. Apparent seasonal trends for the frequency of PRRSV detection were consistently observed with a higher percentage of positive cases occurring during fall or winter months. Read more detail in Dr. Linhares’s peer-reviewed paper on the topic here.
Information on prevention becomes more valuable to producers who wish to safeguard their herds from this disease. Dr. Gustavo Silva at ISU, and his team, devised a way to give farms a Biosecurity Vulnerability Score (BVS). Silva’s SHIC-funded research shows farms with higher BVS scores have broken more frequently with PRRS, adding validity to the scoring system. The most important categories of risk revealed by this study were those relating to swine movements, pickup/deliveries from/to premises, and people movement. The five most important events that occur in breeding herds related to PRRS introduction were breeding replacement animals, semen delivery, air transmission, weaned pigs transported from premises, and dead animal removal, respectively.
The BVS shows promise for assessing vulnerabilities on biosecurity protocols in order to reduce the frequency of PRRS outbreaks. And it may help producers and veterinarians prioritize investments in improving biosecurity practices over time. It can also be used to predict relative vulnerability of different farms within a production system and/or region based on frequencies of risk events since the probability of introduction of pathogens increases as the frequency of risk events increases.
Silva’s work continues with publication of an additional study done to evaluate the use of machine learning algorithms to identify key biosecurity practices and factors associated with breeding herds self-reporting (yes or no) a PRRS outbreak in the past five years. This study also explored the use of the positive predictive value (PPV) of these models as an indicator of risk for PRRSv introduction by comparing PPV and the frequency of PRRS outbreaks reported by the herds in the last five years.
Results of Silva’s newer work support the concept that there is correlation in biosecurity practices and factors of swine breeding herds. Findings indicate it is possible to identify the most relevant biosecurity practices and factors by asking fewer questions, and then to predict PRRSv risk of outbreak. In the study, Methods A and B have classified farms’ PRRS status as positive when diseases occurred with an accuracy of accuracy of 76% and 80%, respectively. This study allowed authors to develop the initial concept for a future tool with the capacity to help producers and veterinarians to measure and benchmark key biosecurity practices and factors more frequently, identify sites at relatively higher risk of PRRSv introduction to better manage the risk of virus introduction over time.
Work on other swine disease pathogens also yields valuable information in the battle with PRRS. PED is among the most impactful endemic swine pathogens in the US, yet risk factors that drive viral circulation at regional levels are still not completely understood. This is partly because risk is dynamic and changes rapidly both spatially and temporally. Utilizing a subset of data from MSHMP containing weekly PED status, Dr. Kim VanderWaal and her team are developing predictive machine-learning models that estimate the probability of a PED break each week. The forecasting model uses data on pig movements, geolocations of farms, environmental, and weather factors to predict the probability that a sow farm will become infected two weeks in advance. The model’s positive predictive value (PPV) is ~70%, meaning that the model is quite accurate in the advance warning it provides.
Current efforts for this project include developing a software platform that is integrated with the MSHMP database. Thus, farm-level forecasts for two weeks in the future can be updated as new data emerges each week. These two-week projections will be delivered each week to participating production systems, allowing ample time to mitigate the risk or minimize the impact. The platform can also be readily applied to other diseases, such as PRRS. Ongoing analysis suggests that PRRS breaks are more difficult to predict, and that the importance of animal movements versus spatial proximity between farms is dependent on the particular strain. The expected roll-out of the forecasting platform for currently participating production systems is fall 2019. Ultimately, the near real-time estimation of forecasts will provide tools for data-informed actions by producers and practitioners to control outbreaks.
Following the annual meeting of the US Animal Health Association (USAHA) last month, resolutions will be sent to the USDA Animal and Plant Health Inspection Service – Veterinary Services (APHIS-VS) to convey the importance of pork industry issues from the organization’s membership. The US swine industry was well represented on USAHA committees affecting pork production and offering the resolutions, including Transmissible Diseases of Swine, Animal Emergency Management, Animal Welfare, One Health, and National Animal Health Laboratory Network. African swine fever (ASF) was the main topic addressed by several committees with swine industry experts sharing information and was the focus of the keynote address given by Dr. Juan Lubroth, chief veterinary officer for the United Nations Food and Animal Organization. The Swine Health Information Center (SHIC) contributed by providing background and support of the science behind proposed resolutions. The approved resolutions are intended to protect the health of the US swine herd.
RESOLUTION: Adequate Funding for National Animal Vaccine and Veterinary Countermeasures Bank
USAHA urges USDA and State Animal Health Authorities to support a total of $92 million for the National Animal Vaccine and Veterinary Countermeasures Bank (NAVVCB), with a minimum of $20 million for each of the first four years and $12 million in the fifth year, of the funding established in the 2018 Farm Bill to provide adequate number of doses of foot-and-mouth disease vaccine and surge capacity. This $92 million for NAVVCB is to include a reasonable stockpile of foreign animal disease testing kits/reagents needed for outbreak response.
Additionally, the 2018 Farm Bill prevention funding the National Animal Disease Preparedness and Response Program (NADPRP) should not be used to fund current USDA APHIS activities with the states nor should it inhibit full appropriation of the National Animal Health Laboratory Network (NAHLN) laboratory authorization within USDA, National Institute of Food and Agriculture, Food and Agriculture Defense Initiative and APHIS budgets.
RESOLUTION: African Swine Fever/Classical Swine Fever Surveillance Program and Tissues for Official ASF Testing in National Animal Health Laboratory Network Laboratories
USAHA urges USDA APHIS to validate and approve the items listed below. Collectively, these efforts aim to enhance the cost-effectiveness, sustainability, and breadth of coverage provided by the ASF/Classical Swine Fever (CSF) Surveillance Program.
The USDA APHIS ASF/CSF Surveillance Program at USDA NAHLN laboratories shall:
Foreign animal disease (FAD) diagnostic capabilities and capacities at USDA NAHLN laboratories shall:
RESOLUTION: Valid Sampling Methods and Protocols for Feed and Feed Inputs
USAHA urges the Food and Drug Administration Center for Veterinary Medicine and USDA APHIS-VS to work with the US pork industry to develop valid sampling methods and protocols to detect pathogens in foreign feed and feed inputs that can be applied at the point of embarkation to the US or upon arrival at the port of entry.
RESOLUTION: Efficient Diagnostic Sample Validation and Approval for Foreign Animal Diseases of Swine
USAHA urges the USDA APHIS-VS to work with US pork industry to validate and approve swine oral fluids, swine processing fluids, and meat juice for detection of antigen and antibody for CSF, ASF, and foot-and-mouth disease (FMD).
RESOLUTION: Foreign Animal Disease Prevention
USAHA urges the Department of Homeland Security (DHS), United States Customs and Border Protection (CBP) to 1) on a quarterly basis, provide interdiction metrics to pork industry representatives, 2) work with the FMD Cross-Species Team to develop education designed to increase awareness for passengers that are in transit from foreign ports into the US on the importance of protecting agriculture and being truthful on the US Customs Declaration form, 3) work with the FMD Cross-Species Team to develop biosecurity education for travelers diverted for secondary screening after declaring they have been on a farm or in contact with animals in a foreign animal disease positive nation, and 4) modify the US Customs Declaration form to include language regarding a traveler’s proximity to packing and processing plants, live and/or wet markets, research facilities, laboratories, or any other location where there is a likelihood that cross-contamination could occur directly or indirectly between the traveler and animals, fresh animal products, or animal excretions.
RESOLUTION: Evaluating and Recognizing Compartments
USAHA urges USDA APHIS-VS to host a meeting with the US pork industry and State Animal Health Officials to discuss the proposed criteria that will be used to evaluate and recognize livestock/livestock products compartments domestically and internationally.
RESOLUTION: Stop Movement – Criteria for Implementing and Releasing
USAHA urges USDA APHIS-VS to work with the United States pork industry and state animal health officials to develop criteria for implementing and releasing national movement standstills due to the occurrence of a trade and commerce limiting foreign animal disease of swine.
From the keynote speaker’s presentation to discussion at many committee meetings, African swine fever (ASF) was a significant focus at the US Animal Health Association (USAHA) Annual Meeting in late October. In an article prepared by USAHA at the conclusion of the event, they pose the question, “Is the Pork Industry Ready for African Swine Fever?” While rhetorical in nature, it does lead to examination of completed and still needed work in the areas of prevention, preparedness, and response.
Is the Pork Industry Ready for African Swine Fever?
(The following article comes from the US Animal Health Association following their Annual Meeting the week of October 28.)
If an outbreak of African swine fever (ASF) were to occur in the U.S. is the pork industry ready? Many parties are working to make sure it’s as ready as possible, but there may be more questions than answers. Dr. Sarah Tomlinson, Associate Deputy Administrator of the Strategy and Policy Unit within USDA’s Animal and Plant Health Inspection Service (APHIS), Veterinary Services, gave an update on the four ASF exercises that have been conducted this year to help the industry prepare. She spoke during a meeting of state veterinary officials, held in conjunction with the 2019 U.S. Animal Health Association annual meeting, in Providence, Rhode Island, this week.
The exercises involved veterinary officials from 14 pork-producing states, APHIS, state and national pork associations and private sector companies. Each exercise built upon the previous, to provide successive levels of preparedness.
The goal of the final exercise was to conduct a combination of functional exercises and drills over a four-day period with participation from federal, state and local agencies along with industry representatives. It took place in September and focused on the following major activities:
Day 1: Conduct a foreign animal disease (FAD) investigation and subsequent communication, coordination and engagement of the National Veterinary Services Laboratory’s Foreign Animal Disease Diagnostic Laboratory, and the appropriate laboratories in the National Animal Health Laboratory Network.
Day 2: Respond to and support a state, regional, or national movement standstill, depending on the pig population infected.
Day 3: Implement the planning and resource coordination associated with depopulating and disposing of infected and exposed swine.
Day 4: Implement a system to allow for continuity of business for non-infected operations within a control area.
In addition to U.S. government and industry representatives, interested parties from Australia, Denmark, and the Canadian Food Inspection Agency also took part.
Action items identified
Participants learned a great deal by going through the exercises. As a result of the final exercise, several conclusions became evident.
National movement standstill
Many states and pig companies support a national-movement standstill at the start of an ASF outbreak if the disease is detected in commercial pigs in order to determine where the disease is and control immediate spread. Participants recognized the need for updates to the existing “Initial Movement Standstill” guidance to include the start/stop time criteria, the grace period for pigs in transit and those in livestock markets. APHIS will be working on this request with the stakeholders and will also determine the appropriate regulatory mechanism for a national movement standstill, should it be needed.
Indemnity policy
Compensation for animals that are depopulated during an outbreak is an important issue. States and the private sector have requested 100% fair market value payment for ASF-infected or exposed swine that are depopulated in order to prevent and control ASF spread. Currently, regulations allow for 50% of fair market value for animals and materials that are destroyed/depopulated, with the Secretary of Agriculture having the discretion to authorize up to 100%, Tomlinson said. APHIS supports the 100% fair market value; however stakeholders acknowledge the fair market value for pigs may change rapidly in an outbreak situation. APHIS has committed to clarify what indemnity payment percentage is available, and what, if any, actions are needed at the start of an outbreak to implement it.
Rapid depopulation
ASF is a disease that moves very quickly – and can affect many pigs in a short amount of time. Stopping the spread of the disease involves depopulating affected and exposed animals.
“During the exercise, some our state and industry partners asked us to provide guidance on what methods of rapid depopulation APHIS will support and how that would vary during the outbreak – whether APHIS would only support rapid depopulation at the start of an outbreak or throughout its duration,” Tomlinson said. “APHIS has committed to review the available information and make a decision to share with the states and industry.”
National surveillance and diagnostics
The ability to accurately detect the presence and absence of a disease is essential. In the event of an ASF detection, the states and the private sector want assurances their companies and networks are uninfected from ASF and may request wide-scale surveillance and pre-movement testing by company, network, or jurisdiction at the start of an ASF outbreak. APHIS is working with states and industry to further develop surveillance capabilities, including validation of multiple sample types (e.g., pooled whole blood, oral fluids) for use in an outbreak and prioritization criteria for testing samples to have ready for immediate implementation at the start of an outbreak.
Virus elimination
During any animal disease outbreak, cleaning and disinfection with the goal of eliminating the virus from infected areas is very important. States, the private sector, and APHIS will work together for better information and knowledge on defining adequate ASF virus elimination in different premises and environments, Tomlinson said. Additionally, APHIS was asked to provide details on how flat-rate virus elimination reimbursement will be calculated.
The exercises were valuable, and provided an important foundation for follow-up procedures and mechanisms to help the industry deal with an FAD outbreak.
The USAHA addresses topics ranging from zoonotic diseases, to regulations, to specific diseases in cattle, horses, sheep, cervids, poultry and pigs, and much more. Leaders from government, industry and academia gather with producers to find solutions to health issues that help animal agriculture thrive.
Porcine reproductive and respiratory syndrome (PRRS) positive cases were up in October over September in all age categories, per seasonal expectations. Porcine epidemic diarrhea virus (PEDV) and porcine delta corona virus (PDCoV) detection in October also increased as expected. Mycoplasma hyopneumoniae (MHP) positive cases were slightly higher than expected for October. From September 1 to October 19, there was an increased number of cases diagnosed with Influenza virus A at the Iowa State University Veterinary Diagnostic Lab, though it is not associated with more severity of the disease.
In this month’s report, learn about the World Organization for Animal Health’s alarming statement regarding about the global pig population and African swine fever (ASF). There’s increasing global concern regarding smuggled meat products from infected countries. The first ASF was confirmed in wild boars of South Korea. The media has reported ASF cases in Indonesia. In Mexico, the first outbreak of Aujeszky’s disease virus since 2015 has happened. And new outbreaks of Classical swine fever (CSF) in Brazil diagnosed close to the free zone.
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