PRRSV – Page 17 – Swine in Minnesota

Studies on Heterologous Protection Between Japanese Type 1 and Type 2 Porcine Reproductive and Respiratory Syndrome Virus Isolates

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.

Dr. Iseki and colleagues from the National Institute of Animal Health (NIAH, Japan) present studies on heterologous protection between Japanese type 1 and type 2 porcine reproductive and respiratory syndrome virus (PRRSV) isolates. The level of cross-protection that a type 2-based PRRSV vaccine can confer against various type 1 PRRSV field strains is important because no type 1 PRRSV-based vaccine is commercially available in Japan. Find this work here as an advanced publication of the Journal of Veterinary Medical Science.

Key Points:

This study evaluated the cross-protective immunity between type 1 and type 2 PRRSV isolates in growing pigs.
Immunity induced by the type 1 infection may play a role in reducing viremia caused by the type 2 PRRSV.
The immunity induced by the type 2 may not contribute to cross-protection against the type 1.

Molecular detection of Porcine Reproductive and Respiratory Syndrome virus, Porcine Circovirus 2 and Hepatitis E virus in oral fluid compared to their detection in feces and serum

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.

Doctors Plut, Kamnikar-Ciglenecki and Stukeli from the University of Ljubljana (Slovenia) highlight the usefulness of pig oral fluid (OF) to detect Porcine Reproductive and Respiratory Syndrome Virus (PRRSV), Porcine Circovirus Type 2 (PCV2) and Hepatitis E virus (HEV) in different pig age categories. Read here the full article published in BMC Veterinary Research.

Key Points

OF, feces and serum were evaluated for the detection of PRRSV, PCV2 and HEV in six farms.
OF samples had good agreement with serum sample PCR results for the detection of all three viruses.
The study highlights that pooled samples can potentially be used to investigate viral presence on farms.

How much is the spread of 1-7-4-related PRRS viruses due to animal movement?

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.

Today, Dr. Makau and collaborators from the University of Minnesota provide insights into the role that repeated animal movements between farms play in the risk for Lineage 1A PRRS virus disease occurrence.

Keypoints:

Animal movements from 496 farms from a dense pig production area in the US, between 2014-2017, were analyzed.
Direct contact (through animal movements) and indirect contact with an L1A (Lineage 1A)-positive farm increased the likelihood of L1A occurrence, and occurrence of non-L1A PRRS virus one year prior decreased the likelihood of an L1A occurrence.
Outbreak risk increased for farms that engaged in more outgoing shipments.

Science Page: Prevalence comparison among different MSHMP cohorts

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.

This week, we are sharing a report from the MSHMP team regarding the differences in PRRS prevalence among various cohorts.

Key points:

Prevalence among cohorts does not differ.
Seasonal patterns can be seen in different cohorts located in different regions.

Prevalence PRRS status cohort A comparison from a prevalence standpoint between the cohort of farms belonging to the 13 systems participating at the start of the MSHMP (CS) and the cohort of farms from systems that joined the program later (CL), was performed with the objective of assessing whether the patterns between cohorts compare.

As seen in Figure 1–CS, there was a clear shift towards more use of MLV over LVI for sow herd stability purposes. The proportion of farms using LVI in the CS versus the CL is 5% and 10%, respectively. When assessing the proportion of farms in each AASV PRRS category (Holtkamp et al., 2011) both groups are comparable (Table 1). Also the temporal pattern of infection can be seen in both cohorts as described by Tousignant et al (2014).

In summary, both cohorts of farms (CS versus CL) yield similar results which continue to highlight the robustness of the program and the representativeness of the systems contributing to this program.

NHF: Processing fluids are effective for PRRSV diagnostics

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.