In lieu of the Science Page today, we are bringing you our most popular articles on the blog this past year: a publication by Dr. Maria Pieters, head of the MycoLab called Sample and diagnostic types for early detection of Mycoplasma hyopneumoniae.
Mycoplasma hyopneumoniae is the causative agent enzootic pneumonia, an economically significant disease in pigs. In this study published by Drs. Pieters and Rovira from the University of Minnesota, pigs experimentally inoculated with M.hyopneumoniae were sampled 0, 2, 5, 9, 14, 21, and 28 post-inoculation.
Different sample types were compared:
Using different diagnostic tests:
ELISA IgG anti M.hyopneumoniae
ELISA Ig M anti M.hyopneumoniae
ELISA C-reactive protein
Laryngeal swab samples tested by PCR were highly sensitive for detection of Mycoplasma hyopneumoniae in live pigs. Various commercial ELISA kits for detection of Mycoplasma hyopneumoniae antibodies showed similar sensitivity. Oral fluids showed a low sensitivity for detection of Mycoplasma hyopneumoniae in experimentally infected pigs.
Usually, vitamins A and E are added to swine diets at up to 4 times the recommendation made by the National Research council. This is due in part to the variability of requirements in swine. However, a system-wide approach could help the industry to cope with the increase in price and the limited supply.
A wide range of alternatives are proposed to make up for the shortage:
Rely on body reserves
Add ingredients with high levels of vitamins
Remove vitamins A and E from finishing diets 35 days before harvest (it has no effect on their performances)
Minimize storage time to avoid degradation
Avoid low-quality oils to increase vitamin E absorption by the liver
Polyphenols and carotinoids can be used as alternatives
Strategically use injectable form
In addition to those strategies, farm personnel needs to be vigilant and look for signs of deficiency like impaired reproductive performances and Mulberry Heart Disease.
In the event of a Foreign Animal Disease outbreak it is required for all swine premises to have a Premises Identification Number
Having correct location data associated with PINs is imperative for responding to an FAD at a farm or large scale level
Validating and correcting information associated with PINs is an important step in FAD preparedness
What is a PIN?
A federal swine Premises Identification Number (PIN) is a unique, seven character ID, allocated to a premises where swine are produced, kept or moved through.The PIN is a key component in identifying and tracking swine as they move through the United States.The USDA APHIS PIN allocator generates a PIN once a premise has been registered through a state’s animal health official.
What is it used for?
PINs are essential for continuity of business (COB) during a Foreign Animal Disease (FAD) event.Any premises wishing to move pigs during an FAD event must have a PIN.
Unfortunately, there are two common problems in the industry, creating poor PIN information:
incorrect address linked to a site
two geographically distinct sites sharing the same PIN
It is important to find and correct these or other issues that are identified for an existing
PIN. An easy way to identify issues is to validate the locations associated with aPIN using a mapping site such as Google Maps to check the accuracy of the address and coordinates.
To correct these errors it will be necessary to apply for a new PIN via the state’s animal health official.
We launched a new series on the blog in October. Once a month, we are sharing with you a presentation given at the 2017 Allen D. Leman swine conference, on topics that the swine group found interesting, innovative or that lead to great discussions.
Our fourth presentation is by Dr. Pete Thomas from Iowa Select Farms on antibiotic injection of piglets, how it needs both veterinary oversight and justification of use but also how we need to re-evaluate its necessity regularly.
To listen to this talk, please click on the picture below.
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.
We will remember 2017 for the loss of Dr. Morrison, in whose honor the program us now named. Dr. Andres Perez led the transition of the program and now Dr. Corzo, the new Leman Chair in Swine health and Productivity is leading the project.
MSHMP acknowledges and thanks all participants for their willingness to share their data to support the US industry.
The Swine Health Information Center (SHIC) has been instrumental for the execution of this project.
Four new participants joined MSHMP increasing the representativeness of the project by adding 64 sow farms accounting for 220,000 sows.
The weekly report capturing the changes in incidence and prevalence of important pathogens has been shared to participants (n=33) and non-participants (n=185). Now we report on PRRS, PEDv, SVA and novel viruses associated with atypical central nervous system disease.
The weekly science page featured authors from 18 institutions who explained cutting edge research findings, recent publication summaries, and breakdowns of MSHMP data.
168 genomes from Canadian swine influenza A viruses,
5 genomes from highly under-represented US states (Alabama, Arkansas, Kentucky, Maryland and Montana),
648 genomes from US and Canadian swine influenza A viruses (GenBank).
In total, these data represented 29 US states and 5 Canadian provinces.
Genetic diversity of influenza A viruses
In Canada, H1α viruses were the most frequently identified H1 viruses. In contrast, H1α viruses died out long ago in US herds, and have only been identified sporadically following new viral introductions from Canada. Notably, the two dominant H1 viruses in the United States, H1γ and H1δ-1, were not observed in any Canadian province during 2009–2016. In contrast to H1, H3 viruses are found in both the United States and Canada, with evidence of frequent cross-border transmission.
Sources of viral diversity
The study shows that the source of influenza viruses is aligned with pig movements. Indeed, Iowa and Minnesota receive around 87% of Manitoba swine exports. Therefore, the patterns of swine influenza viruses in those 2 US states correlate with the ones in Manitoba.
Similarly, viral gene patterns found in Illinois, Michigan, Wisconsin, or Ohio are influenced by the ones found in Ontario. Indeed, it only takes 3 hours to transport pigs from Ontario to Michigan. However, North Carolina and Virginia are the largest source of viruses for this region.
Swine are a key reservoir host for influenza A viruses (IAVs), with the potential to cause global pandemics in humans. Gaps in surveillance in many of the world’s largest swine populations impede our understanding of how novel viruses emerge and expand their spatial range in pigs. Although US swine are intensively sampled, little is known about IAV diversity in Canada’s population of ~12 million pigs. By sequencing 168 viruses from multiple regions of Canada, our study reveals that IAV diversity has been underestimated in Canadian pigs for many years. Critically, a new H1 clade has emerged in Canada (H1α-3), with a two-amino acid deletion at H1 positions 146–147, that experienced rapid growth in Manitoba’s swine herds during 2014–2015. H1α-3 viruses also exhibit a higher capacity to invade US swine herds, resulting in multiple recent introductions of the virus into the US Heartland following large-scale movements of pigs in this direction. From the Heartland, H1α-3 viruses have disseminated onward to both the east and west coasts of the United States, and may become established in Appalachia. These findings demonstrate how long-distance trading of live pigs facilitates the spread of IAVs, increasing viral genetic diversity and complicating pathogen control. The proliferation of novel H1α-3 viruses also highlights the need for expanded surveillance in a Canadian swine population that has long been overlooked, and may have implications for vaccine design.
The Exponential Weighted Moving Average (EMWA) is a statistical method that averages data over time, continually decreasing the weight of data as it moves further back in time. An EWMA chart is particularly good at monitoring processes that drift over time and is used to detect small shifts in a trend.
In our project, EWMA is used to follow the evolution of the % of farms at risk that broke with PRRSV every week. EWMA incorporates all the weekly percentages recorded since the beginning of the project and gives less and less weight to the results as they are more removed in time. Therefore, the % of farms at risk that broke with PRRSV last week will have much more influence on the EMWA than the % of farms at risk that broke with PRRSV during the same week last year.
Key Points of the report:
Different states continue to have different EWMA patterns.
Even though winter is the high risk season, biosecurity measures should be enhanced during the whole year.
The state of Minnesota suffered two unusual peaks, one in spring and another one during the summer.