Survey Highlights Value of SHIC Disease Monitoring Reports to Swine Industry

This summer, SHIC requested industry input about usefulness and enhancements to the Swine Health Information Center’s monthly domestic and global swine disease monitoring reports. Comments and responses to the SHIC survey highlight the broad value and diverse ways in which reports are utilized. Made available through the SHIC e-newsletter and website, the survey covered both SHIC’s domestic and global reports, including questions on value, actionable content, use of data, additional pathogens, and opportunities for improvement.

Responses were received from the US, across 10 states, and internationally, with most individuals being private practice veterinarians, academics, pork producers, and federal government employees.

Respondents widely agreed that both reports are valuable, with 100% (domestic) and 91.4% (global) of participants responding yes when asked if the monitoring reports provided valuable information. Examples of comments provided about what was most valuable in the domestic report included “reliable information on time,” “keeps me up to date on new threats,” “concise report to reference when talking to producers and decision makers regarding domestic disease,” and “graphs allow for comparison of my clients’ herds to the nation.” Similarly, the global report comments on value included “trusted source,” “important to understand the movement and changes in global health issues,” “useful as a teaching tool,” and “good indication on what disease pressures are around the world.”

In addition to value, participants were asked if the reports were used as a tool by providing actionable content which affects their day-to-day decision making. Most respondents agreed, with 75% (domestic) and 55.9% (global) of participants responding they do. Examples of comments provided about what kind of decision-making is affected by the domestic report included “budgeting and forecasting for the business,” “if PRRS is trending up in an area, we may do additional testing,” “vaccinate or not,” “notification of regional risks to clients,” “helps me fine tune biosecurity,” and “rethink opportunities for area contamination or elimination.” Likewise, the global report comments on decisions included “utilize examples from this report to communicate the biosecurity message to producers and decision makers,” “is our research focused in right direction for emerging risks,” “allows me time to make informed risk management decisions,” and “awareness of where ASF is from a travel standpoint.”

Beyond decision-making, respondents report using the domestic and global reports for educating stakeholders, staying up to date on diseases affecting production and exports, understanding disease trends regionally and status of national herd, knowing pathogen variants, advising clients and producers, personal education, research purposes, staying up to date on regulatory diseases and reviewing protocols. Additional pathogens suggested by respondents to include were Erysipelas, Streptococcus equi, PCV3, coccidia, Brachyspira sp., Lawsonia sp., Escherichia coli, sapovirus, and Salmonella sp.

Respondents were also asked to provide SHIC with suggestions on how to improve the value of the reports. Potential improvements to the domestic report included adding an interpretation section for quotes that media could utilize, adding information about treatments, inclusion of the economic impact of diseases, increasing regional representation of data, and keeping the report brief with bullet points. Potential improvements to the global report included adding the economic impact of diseases, keeping the report brief, including relevant vaccine information, and increasing report frequency. SHIC is currently exploring the feasibility for implementation of suggested improvements.

SHIC, launched by the National Pork Board in 2015 solely with Pork Checkoff funding, continues to focus efforts on prevention, preparedness, and response to novel and emerging swine disease for the benefit of US swine health. As a conduit of information and research, SHIC encourages sharing of its publications and research. Forward, reprint, and quote SHIC material freely. SHIC is funded by America’s pork producers to fulfill its mission to protect and enhance the health of the US swine herd. For more information, visit http://www.swinehealth.org or contact Dr. Paul Sundberg at [email protected].

Dr. Evan Koep, Pipestone Veterinary Services, shared an overview of the challenge of endemic influenza on the farm, the system’s push for higher health, and desire to identify the cause of ongoing coughing. With a goal of eliminating influenza in sow herds within the Pipestone system, they hope to achieve a result of improved health and improved client satisfaction.

After two years, their influenza elimination program has a roughly 70% elimination success rate. Despite this success, some farms continue to have piglets coughing. This non-productive cough, at 20% to 60% prevalence, resembles influenza yet is confirmed not to be IAV via udder wipes, nasal swabs, and lung tissue testing.

Dr. Koep sought a definitive diagnosis, with tests for IAV, PPIV, PHEV, PRCV, MHR, and other bacteria requested. He also submitted fixed and fresh lung, trachea, heart, spleen, liver, kidney and tonsil tissues. While these tests were all PCR negative for viruses, histopathology said, “Lesions in the trachea and upper airways are suggestive of an epitheliotropic virus.”

From this point, next generation sequencing on lung samples with lesions was the next step with porcine astrovirus 4 found and confirmed by follow-up PCR on past cases. PAstV4, an uncommon virus, is not well known nor is its association with the respiratory tract.

Dr. Hause shared there are five genotypes of porcine astrovirus. Historically, they are associated with gastroenteric disease though in 2015, PAstV4 was detected in multiple respiratory samples submitted for metagenomic sequencing at the Kansas State VDL. Genome sequencing identified a novel AstV in the PAstV4 lineage in those cases.

Testing at KSVDL compared Ct values for positive samples between nasal and fecal material. There were significantly lower Ct values (higher levels of PAstV4 genetic material) in nasal swabs. It suggests positive tests are indicative of a respiratory tropism. Dr. Hause’s presentation summary revealed astrovirus infections are common in pigs and extraintestinal infection in pigs includes the respiratory system.

Dr. Derscheid reviewed trachea physiology. While a non-collapsible passageway for air, the trachea includes cartilage rings and mucosal lining, regulating both temperature and humidity. The trachea protects and cleans columnar epithelium, goblet cells, and mucociliary apparatus. Dr. Derschied shared typical respiratory tissue VDL submissions and provided guidance for sampling the trachea for study.

In presenting a case history, Dr. Derschied shared initial results of testing which indicated typical respiratory issues, including IAV. When the producer submitted additional tissues due to ongoing coughing, including notes on negative IAV, porcine parainfluenza virus 1, and porcine respiratory coronavirus results, further tests were initiated, including NGS, PCR, and in situ hybridization. These results indicated tracheitis with and without bronchitis, not just for PAstV4. Porcine hemagglutinating encephalomyelitis virus and Mycoplasma hyopneumoniae causing persistent cilia damage were other viruses identified.

Dr. Derscheid said, “We don’t see what we don’t look for,” and recommended examination of the trachea, submitting fixed trachea and/or leaving a portion attached to fresh lung. And, she emphasized communication.

In a retrospective evaluation of bronchitis and tracheitis of unknown etiology, Dr. Rahe began with a case observation. The clinical report was of coughing in three-week-old pigs with multifocal to coalescing atelectasis, all of which are classic findings for influenza. However, the case was influenza PCR negative. The diagnostic code was respiratory – bronchitis, viral – non-specified. PAstV4 was identified via NGS.

Dr. Rahe then addressed the question, “How many cases of non-specific tracheitis/bronchitis are caused by non-influenza viral infections?” The review did identify some cases of PAstV4 associated tracheitis/bronchitis. Those tend to be limited to the trachea and bronchi but do not seem to extend into bronchioles, perhaps due to a lack of receptors. Cts over 25 in these cases were negative via RNA scope.

SHIC and AASV present webinars on topics of industry interest. ISU Swine Medicine Education Center conducts the webinars; previous webinars can be accessed here: https://www.swinehealth.org/podcasts/

SHIC, launched by the National Pork Board in 2015 solely with Pork Checkoff funding, continues to focus efforts on prevention, preparedness, and response to novel and emerging swine disease for the benefit of US swine health. As a conduit of information and research, SHIC encourages sharing of its publications and research. Forward, reprint, and quote SHIC material freely. SHIC is funded by America’s pork producers to fulfill its mission to protect and enhance the health of the US swine herd. For more information, visit http://www.swinehealth.org or contact Dr. Paul Sundberg at [email protected].