The first week-end of December was the Conference of Research Workers in Animal Diseases in Chicago. Several of the swine group graduate students were presenting their work and received an award.
First, Frances Shepherd received the award for best oral presentation in the Enteric Diseases category for her presentation titled Variability and bioinformatic analysis of porcine rotavirus B and C illustrate potentially important immunological sites. Frances’ advisers are Dr. Douglas Marthaler and Dr. Michael Murtaugh.
Then, Dr. Robert Valeris received the best poster award in the Veterinary Epidemiology and Preventative Medicine category for presenting Survival analysis of protocols for eradication of Mycoplasma hyopneumoniae in swine farms.
Join us in congratulating our students for their awards!
This month in the National Hog Farmer, Drs. Carles Vilalta, Juan Sanhueza, and Montse Torremorell share a project instigated by the late Dr. Bob Morrison regarding the use of processing fluids to make a PRRSV diagnosis.
The improvement of sampling and diagnostics techniques has made sampling on the farm an easier task with the use of pooled serums or oral fluids samples for example.
One of the ways to get cheaper, more sensitive and quicker techniques would be to use routine chores, such as piglet processing, since castration and tail docking are part of the regular procedures in sow farms.
The goal of this study was to evaluate the accuracy of the processing fluids (the liquid accumulated at the bottom of the pail when farmers collect tails and testicles during routine procedures) by real-time polymerase chain reaction to assess PRRSV status in a sow herd.
The key points from the studies were:
• Using processing fluids as a diagnostic tool can help us to detect lower PRRS prevalence in the herd.
• Testicles and tails should be collected in a pail as they are potential spreaders of PRRS in the farrowing room.
• We should target young parity sows for PRRSV sampling.
Each year approximately 3% of the sow farms have a PRRS outbreak during the summer.
The incidence of summer PRRS breaks has been constant over the last 9 years.
There are geographical areas with higher or lower risk of summer breaks.
A summer outbreak was defined as a PRRS case that happened between June 21st and September 21st of the year. The mean incidence of PRRS summer outbreaks was 3.2% between 2009 and 2017, ranging between 1.6% and 4.4%. The trend was stable among the years. (Figure 1) Not all areas are equal against summer outbreaks. Indeed, the region of Southern Minnesota – Northern Iowa is more at risk of outbreaks than others like Southern Iowa or Eastern North Carolina. (Figure 2)
Biosecurity measures against PRRSV should therefore be a concern all year round for swine producers!
The first week-end in December is usually the time of the North American PRRS symposium. This year did not upset the tradition but this time, the conference was in collaboration with the National Swine Improvement Federation.
The meeting was dedicated to our friend and colleague Dr. Bob Morrison. A memorial fellowship organized by Dr. Montse Torremorell (U of MN) and Dr. Joan Lunney (USDA) provided travel support to future scientists who wish to follow in his footsteps.
Stephen Gerike from the Pork Checkoff shared information on the state of pork products used in restaurant. Bacon represents 20% of products used but is still growing (+4% since last year).
Stephen Gerike shared the updated cooking recommendations for pork product.
Overall, 82% of restaurant customers eat the same or larger amount of pork which is a good trend for the industry. Mr. Gerike also shared the efforts done by Pork Checkoff to convince consumers to not overcook their pork. Reminder: 145F is safe. “Cook your pork like you cook your steak!”
The University of Minnesota was well represented during the conference. Dr. Montse Torremorell moderated the Saturday morning session on PRRS in the field. Drs. Cesar Corzo, Carles Vilalta and Juan Sanhueza shared the updates on the Morrison Swine Health Monitoring Program as well as regarding the studies that they are involved with. Take away messages:
MSHMP is now collecting information from 50% of the sows in the United States.
Based on this data, 58% of the farms breaking with PRRSV today will break again within a year.
PRRS summer outbreaks happen and vary based on location (see figure below).
Farms take a longer time to reach stability after a summer outbreak (median 41.5 weeks)
Processing fluids can be used as a monitoring method for PRRS.
After being introduced in 1999, PRRS was eradicated from the country in 2012.
In 2013 PRRS was again detected, sequence analysis suggested this was a new introduction to the country.
The Chilean swine industry and the Chilean Veterinary Services (SAG) expect to again eliminate the disease in the near future.
PRRS is a notifiable disease in Chile. It was first detected in 1999, and in 2000 both the swine industry and government joined efforts to eradicate the disease by a series of coordinated events including a mixture of herd closure and depopulation of infected premises. Vaccination was not allowed in the country to control PRRSV infection. The eradication program was completed in 2007 and as a result, Chile was declared PRRSV free in 2012. Nevertheless, on October 2013 clinical signs compatible with PRRSV were reported in a commercial sow farm. Since then, all commercial herds performed surveillance activities according to a risk score based on location and biosecurity measures. From October 2013 to October 2017, approximately 153,000 blood samples have been analyzed.
Viral sequences obtained during the 2013 outbreak were compared to sequences from the early 2000s outbreak in Chile. Results showed a large genetic difference between isolates from both outbreaks. Further analyses demonstrated that the Chilean virus was closely related to a virus circulating in the state of Indiana in the US at the time of introduction. These results suggested that the latest PRRSV outbreak in Chile was most likely due to a new introduction into the country rather than a reemergence of a strain previously detected in Chile.
By October 2017, the disease was restricted to approximately 45,000 animals in six commercial farms owned by two companies that currently have eradication programs in place. These six infected commercial sites are clustered in three areas. (See figure above)