Science Page: Investigating the role of the environment and the lactating sow in PRRSV infections during an outbreak (Part 1)

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, Dr. Carles Vilalta and Dr. Juan Sanhueza in collaboration with Dr. Montse Torremorell discussĀ the sensitivity and specificity of sampling the farrowing environment and lactating sows at processing to detect PRRSV in an infected farm.

Key Points:

  • Lactating sows and the farrowing environment can be sources of PRRS virus
  • Sampling the farrowing environment and the udder skin of lactating sows can be used to monitor for PRRSV although the sensitivity is lower than that of serum samples.
  • The farrowing environment and the lactating sow may serve as a source of infection for PRRSV.

Sampling started 2 weeks after a PRRSV outbreak was reported in a sow farm. Sampling was conducted from 10 litters every 3 weeks for a total of 24 weeks. Samples were collected at processing (~ 3 days of age) and included: surface wipes of farrowing crates, surface wipes of the udder skin of lactating sows, blood samples from all piglets within the selected litters.

PRRS sampling in the environment and on the sows.gif
Scatter plot of the individual RT-PCR Ct values in serum (all piglets) compared with those from surfaces (A) and udder skin (B).

PRRSV was detected in the farrowing crate environment and on the skin of the lactating sow at processing. The surface and udder skin wipes were less sensitive at detecting PRRSV than serum PCR at processing. However, in this study all pigs in the litter were bled which is not the standard practice in the field.

The results show that the environment and the lactating sow may serve as a source of
infection for PRRSV, indicating a need to further understand their roles to establish herd level stability.

Science page: Are patterns of spatiotemporal clustering of PRRSv consistent across years?

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 studied a subset of MSHMP participants located in the Midwest to test if some location/time combinations are more prominent during certain seasons across the years. Data from 358 farms in 10 management systems from 2011 to 2015 was compiled to look for clusters.

The clusters found by the SaTScanTM software are represented below. The red circles represent clusters identified in the time period from January to June, whereas blue ones are July to December. We can note that clusters were identified every year but that they varied with time.

Significant PRRS spatial cluster midwest
Significant spatial clusters for PRRSV in the Midwest between 2011 and 2015.

Key points

  • PRRS cases are recognized to be seasonal and aggregated by geographical space.
  • However, spatiotemporal patterns of PRRS clustering were not consistent across years.
  • Drivers of infection spread may vary over the years.

Future uses for this model can be found in the entire report

Science Page: Are the farms that broke with PED the same?

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 proud to introduce a new chart in the Morrison’s Swine Health Monitoring Project. This new addition will be able to answer a common question regarding PEDV outbreaks:

Are the farms currently breaking with PEDV the same than the ones which broke in the past?

To interpret the figure, follows these steps.

  • Horizontal axis represents all the farms that borke with PEDV during the season 2016/2017, with each tick representing an individual farm
  • Vertical axis shows the previous seasons with 2016-2017 on top and 2012-2013 at the very bottom.
  • The color of the cell (year : farm) represents the number of outbreaks experienced; darker blue meaning more outbreaks.

Here is the example of this chart presented this week:

MSHMP PEDV chart
Outbreak history of farms that broke during the 2016-2017 season.

Key points:

The farms that break with PEDV do not appear to have a history of PEDV infections in the prior season.

Of the farms that broke during the 2016/17 season, only 5 (6.5%) of them had outbreaks during the previous season and 43 (56.6%) of them had broken at some point since 2013.

Only one farm has had an outbreak every year since the beginning of the epidemic in the US (season 2013/14).

The full report is available.

Science Page: Detecting influenza virus with a portable device

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 are presenting today the work done in Dr. Cheeran’s lab on the detection of influenza virus in farms. The objective of their research project is to develop a portable diagnostic platform that is capable of performing on-site testing of influenza viruses in swine with minimum sample handling and laboratory skill requirements.

The device is usingĀ giant magnetoresistance (GMR) technology. In a nutshell, if influenza viruses are present in the sample, they will bind to sensors, cause a disruption in resistance, and create an electric signal in the device that will be able to wirelessly transmit the result to a smartphone or computer.

Key points from this week edition:

  • Portable, hand held device for detection of influenza A virus (IAV) based on giant magnetoresistance (GMR) biosensor has been developed.
  • Although in its developmental stage, if successful this test has the potential for rapid on-site testing of influenza viruses in swine.

The first sensitivity tests of the device look very promising!