The Swine Health Information Center (SHIC) developed two systems for near real-time domestic and global swine disease monitoring. The information made available by these systems will help enable better, faster, and more effective response to endemic or foreign infectious production diseases. The June domestic report includes some noteworthy variation.
Background
In early 2018, the Swine Health Information Center (SHIC) started publishing monthly global and domestic disease monitoring reports from these programs to the SHIC website. Last month the global surveillance system expanded from surveillance of three tier-1 foreign swine diseases (ASF, CSF, FMD) to include other relevant diseases of swine such as porcine rotavirus, PEDV, and pseudorabies.
Domestic reports work to describe the dynamics of disease detection by pathogen or disease syndrome over time, specimen, age group, and geographical space. Featuring intuitive dashboards, predictive graphing works to estimate expected levels of percent positive cases considers the past three years’ data. Any variation above or below expected trends are discussed, noted, and given context by the reports’ advisory group. Veterinary diagnostic laboratory collaborators include Iowa State University and the University of Minnesota, with Kansas State University and South Dakota State University joining soon.
June Swine Disease Global Surveillance Report Highlights (To see full report, click here).
No relevant news was generated for porcine rotavirus, PEDV, and pseudorabies.
No significant change of status concerning ASF in the EU, but there was a new outbreak on a farm in South Africa outside that country’s ASF control zone.
June Domestic Swine Disease Reporting System Highlights (To see full report, click here).
PRRS
There has been an increase of cases testing positive for PRRSv RNA by rRT-PCR in wean to market pigs this winter. This coincides with field observations of pigs in higher swine density areas being more likely to become infected with PRRS during grow-finish.
During spring 2018 there was an increase in PRRS detection by PCR in sow farms. But processing fluid-based monitoring is more sensitive than individual pig serum-based monitoring schemes, increasing positives by 1.03 percent. The spike in PRRS detection coincides with a higher PRRSv incidence reported by the Morrison Swine Health Monitoring Project.
Corona Viruses
Delta corona virus (PDCoV) detection continues high relative to predicted values based on previous years.
But increased detection of PDCoV does not appear to be associated with increased outbreaks in sow farms at this time of the year. Sow farms were 9.48 percent positive during 2018 winter and 9.88 percent positive for 2018 spring.
CNS Disease
There was a 15.38 percent increase in the number of CNS case detections in 2018 compared to 2017 during the spring months. Streptococcus suis continues to be the main pathogen associated with the syndrome.
Conclusion
To implement infectious disease control and management, precise, science-based information is required. By funding these projects, SHIC helps the industry toward better swine health information to positively impact the long-term sustainability of pork production.
The Swine Health Information Center (SHIC) is watching porcine kobuvirus (PKV) as a possible emerging swine virus posing a valid threat to the US pork industry. Originally detected in 2008 in baby pigs in Hungary, PKV has been detected worldwide including in the US in 2013. SHIC-funded research conducted at Iowa State University resulted in the development and validation of a PKV real-time reverse transcriptase PCR (rRT-PCR) to detect strains of PKV circulating in US swine. The validation process of the PCR resulted in data that suggests PKV is widespread in US swine and additional research is needed to discern if pigs with or without diarrhea are infected with PKV or if different strains of the virus are more likely to cause diarrhea in swine.
PKV infection is most often a mild diarrheal disease with piglets of less than four weeks of age most likely to be infected. Prevalence in domestic pigs ranges from 13 to 99 percent and the virus has been isolated from both healthy and pigs with diarrhea. PKV is endemic in many countries and has been isolated worldwide.
In China, PKV was implicated as the cause of diarrhea, dehydration, and vomiting in piglets which resulted in morbidity of 80 to 100 percent and mortality of 50 to 90 percent, beginning in 2010. In the study summary, the authors say this suggests the emergence of PKV from different geographic regions is detectable using the targets based on the US strains of PKV.
No vaccines or anti-viral treatments have been developed for PKV infection in pigs. Proper sanitation and quarantine of ill pigs should help prevent and control possible outbreaks. This SHIC-funded study takes a critical step to identification of one of the viruses that might be threatening the US pork industry. As a result of this research, the swine industry has an assay able to detect Chinese strains of potentially pathogenic strains of PKV.
The frequency of swine movement in North America makes the industry vulnerable to disease spread. To explore how modifying movement patterns can reduce disease spread, the Swine Health Information Center (SHIC) recently sponsored research at the University of Minnesota (UMN) Department of Veterinary Population Medicine. The project looked at the question: Can we reduce the vulnerability of the US swine industry to disease spread by prioritizing surveillance and control on specific farms? The answer is yes.
The research was conducted by Kim VanderWaal, PhD, Amy Kinsley, PhD candidate, Andres Perez, DVM, PhD, and Meggan Craft, PhD, from UMN. The full study along with more information about analysis of pig movement data is awaiting publication in Preventative Veterinary Medicine.
Key Take Home Messages for Swine Veterinarians
Using SHIC support, the UMN team analyzed detailed swine movement data in three large production systems to measure the influence a specific farm has on disease spread throughout the system, which they quantified using several metrics. Specifically, they calculated:
The study found directing disease interventions towards farms based on their MIP can substantially reduce the potential for transmission of an infectious pathogen in the production system.
What are the take homes for swine veterinarians to start using today? When a disease strikes, a system may need to prioritize control strategies. The results of this work help identify which farms to target first. VanderWaal explained farms with high MIP scores can be targeted and prioritized for both monitoring as well as intervention or control. Since farms with high MIPs are more likely to break and spread disease, targeting monitoring at these locations makes sense.
Likewise, when the next disease epidemic comes, MIPs can help determine which sites may need to alter management strategies such as depopulation, transport segregation, switching from multiple to single source, and vaccinating, all of which could interrupt disease spread. Furthermore, in the event of an epidemic, the approach could help to selectively manage and monitor farms grouped on the estimated risk for disease, including zoning and compartmentalization strategies, which, if planned, may contribute to significantly mitigate the impact of an epidemic on a system
While production type did not significantly impact MIP, pig movement strategies did. For example, if a nursery barn received pigs from several sow farms and then had a movement event to multiple finisher barns, that barn would likely have a high MIP and could be called a “super-spreader.” Another example with a higher MIP is pulling gilts from a gilt development unit for multiple sow farms.
How is MIP calculated? It is a result of chains of farms connected via movements. Factors such as movement and pig sourcing and location all impact the number. At the end of the day, VanderWaal explains it is about incoming and outgoing contacts and the impact on risk.
For more information about analysis of movement data, identifying super-spreaders farms, and implications for disease control for farms in your system, contact Kim VanderWaal ([email protected]).
In cases of high or ongoing morbidity or mortality, where the cause is either not identified or diagnosis is questionable, SHIC may be able to help pay for further diagnostic work. There is risk of missing an emerging disease if a definitive diagnosis is not pursued diligently. SHIC recognizes limitations on resources may be a barrier and developed this program to assist at the production level for the benefit of the national herd.
Veterinarians and diagnosticians interested in pursuing diagnostic fee support will find required forms and information on SHIC’s website.
How Does the Process Work?
When questions are more plentiful than resources for diagnostic work, SHIC can help!
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