Science Page: Biosecurity screening tool; Benchmarking PRRSv biosecurity vulnerability using a short survey

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 by Dr. Linhares’ lab at Iowa State University. In this Science Page are the results of a study looking at biosecurity aspects associated with PRRS frequency.

Key Points

  • New methods allow estimation of the overall PRRS-vulnerability risk score by asking 20 or less questions.
  • This can help producers and veterinarians to (a) measure and benchmark key biosecurity aspects, and (b) toidentify sites at relatively higher (or lower) risk of PRRSv introduction.

Study Summary: This study aimed to identify a small set of biosecurity aspects that, when combined, have a strong association with the frequency of PRRSv introduction into swine breeding herds.

Parameters included in the 2 models (A and B) to predict the number of PRRS outbreaks in farms for the past 5 years.

Preliminary Results: A cross-sectional study assessed biosecurity aspects in 84 breeding herds from 14 production systems in 2017. Models were trained to predict whether a farm had or not reported a PRRS outbreak in the past 5 years, given a set of biosecurity aspects. Two methods were used, and both models were able to classify the herds with a great overall performance based on few biosecurity aspects (See figure). The variables used by both methods were related to the frequency of risk events in the farm, swine density around the farm, farm characteristics/ requirements to visitors, and operational connections to other sites.

Note: The Gini coefficient (or index) is a single number aimed at measuring the degree of inequality in a distribution. (Source: Wikipedia) The higher the number, the less equally distributed the farms will be.

When comparing the predicted positive value obtained by the models, they showed a strong positive correlation (0.7 and 0.76, respectively) with the frequency of past outbreaks.

Enroll on our follow-up study: Study farms will be asked to fill a short survey. Using the methods above, the PRRS-vulnerability risk score will be generated for each farm enrolled. The information will be collected via an Excel file and the name of the farms and production systems will be kept confidential.

To enroll or request additional information please contact: Gustavo Silva (gustavos-at-iastate.edu) or Daniel Linhares (linhares-at-iastate.edu) at Iowa State University.

Science Page: Protecting the Inevitable Risk; Biosecurity Evaluation at a Truck Wash

We hope you all had a great Thanksgiving! An ever increasing amount of you is visiting this blog every month so thank you, we appreciate your support!

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 by Megan Bloemer on biosecurity at a truck wash. Megan, a 3rd-year veterinary student from the University of Illinois, presented this project at the Leman Conference this year and won the Morrison Swine Innovator Prize.

Key points:

  • Monitoring cab cleaning and hot shot handle cleaning via Glo Germ Gel is simple and cost-effective.
  • Wiping down the cab interior with intervention wipes only adds around 5 minutes. These minor cost and time additions to truck wash procedures can help to prevent a million-dollar PRRS break.
  • Truck wash crew and trailer washers are often overlooked but perform a job that is essential in maintaining biosecurity and disease outbreak and therefore herd health.

The objective of this study was to assess overall biosecurity at the truck wash and identify potential areas of concern, measure and evaluate these areas of concern, and suggest solutions.

Potential Areas of Concern Identified

Cab Cleaning

Glo Germ Gel under a UV light when the door handle was not cleaned (left) and was wiped down (right).

The areas observed for cleaning included: steering wheel, dash, handles, climate control buttons, and radio. These areas were not being focused on; but are critical areas touched each time a driver is in the cab. In addition, it was difficult for monitors to tell if a cab had been cleaned or not by visual inspection alone.

Equipment Movement

After the three-day observation period, it became apparent that all equipment besides hot shots stayed in the dryers. Thus, hot shots were identified as the main equipment of concern. They were not returning with each trailer load, leading to biosecurity concerns.

Monitor Movement

Monitors inspect both PRRS positive and PRRS negative trailers throughout the day, before the wash crew is allowed to disinfect each trailer. Although monitors change boots and put on Tyvek before inspecting negative trailers, there is no true clean / dirty line where they change shoes.

Evaluation

Cab Cleaning

Steering wheel, dash, door handle, climate control buttons, and radio control buttons were evaluated on how well they were cleaned with a Glo Germ Gel product. The Glo Germ Gel was applied while the trucks were waiting in line to be cleaned. The assessment was performed using an UV light for any trace of the Glo Germ, indicating whether the surface had or had not been cleaned. The interior of cabs were not being cleaned as well as possible as evidenced by the amount of fluorescence that was detected in those five critical areas.

Equipment Movement

All of the hot shot handles and prods were numbered in both the PRRS positive and PRRS negative equipment sheds on a Sunday. Every night for the next five days it was checked if each hot shot was present, which equipment shed it was in, and new ones were numbered as they appeared. Throughout the course of those five days hot shot handles and prods were not being returned on a consistent basis. However, the equipment was not switched between the PRRS positive and PRRS negative sheds.

Monitor Movement

Glo Germ Gel and Powder was applied to the shoes of monitors and on positive trailers before monitors inspected them. Although no Glo Germ was appreciated in the PRRS negative areas, it may still be a potential area of concern and should be further evaluated.

Interventions

Cab Cleaning

In order to ensure that the interior of cabs were being cleaned as well as possible,the truck wash crew was shown images of the cab interiors with the Glo Germ Gel comparing interiors that were wiped down and those that were not. Current protocols could be clarified, and the importance of cab cleaning should be emphasized. Glo Germ Gel also gives the monitors the ability to do random internal audits of cab cleaning.

Equipment Movement

In order to check hot shot handle and prod cleanliness Glo Germ can be applied at the same time monitors put Glo Germ in the cabs. To encourage returning hot shots the truck wash crew can continue to write down cull and gilt trailers that do not return with a hotshot. To stop any potential cross-contamination, the PRRS-positive hot shots could be painted red.

Monitor Movement

Although no Glo Germ was appreciated it is possible that monitor movement is still a potential biosecurity risk and should be further evaluated. It appears that the Glo Germ washed right off as the trailers were wet when the monitors inspected them.

Swine Influenza virus A: podcast 2/3

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Podcasts are perfect for summer! We are presenting you with a new series on swine influenza from “At The Meeting… Honoring Dr. Bob Morrison in collaboration with SwineCast.

If you missed it, click here to listen to the first episode from last week.

In this second episode,  Dr. Montserrat Torremorell, Dr. Adam Schelkopf (Pipestone Veterinary Services), Dr. Gordon Spronk (Pipestone Veterinary Services), and Dr. Tom Wetzell (Boehringer Ingelheim) continue the conversation on the challenges of IAV-S in day to day operation, the approaches to identifying infected pigs, and the processes that need to be put in place to reduce infection and increase survivability of pigs.

Click to listen to the entire recording (20min).

Swine Influenza virus A: podcast 1/3

microphone-2618102_1920

Podcasts are perfect for summer! We are presenting you with a new series on swine influenza from “At The Meeting… Honoring Dr. Bob Morrison in collaboration with SwineCast.

In this first episode,  Dr. Montserrat Torremorell (University of Minnesota), Dr. Marie Culhane (University of Minnesota), Dr. Gordon Spronk (Pipestone Veterinary Services), and Dr. Tom Wetzell (Boehringer Ingelheim), talk about the issues of influenza in humans and swine, the state of surveillance of influenza in pigs and humans, and the biosecurity needed to help prevent the spread of the influenza virus between human and pigs.

Click to listen to the entire recording (20min).

Can biosecurity measures prevent PEDV transmission?

Summary:

Porcine Epidemic Diarrhea virus is highly contagious.

The 2013 Porcine Epidemic Diarrhea virus’ (PEDV) outbreak in the USA taught the swine industry that the virus is highly contagious. This event forced producers and veterinarians to review and upgrade their biosecurity procedures.

Drs. Torremorell, Cheeran, and Goyal from the University of Minnesota evaluated some of these measures and how they can prevent PEDV transmission.

Changing Personal Protective Equipment (PPE) and showering before entering a new room prevented contamination.

Among the measures included in this study were the use and change of PPE as well as showering in and out of a facility. In the low biosecurity setting, personnel went from a room with PEDV positive pig straight to a room with naive pigs, contaminating them after the very first movement. In the medium biosecurity setting, personnel washed their hands and face and change their PPE before being in contact with the naive pigs. In this situation, pigs stayed negative for PEDV but  two personnel hair/face swabs came back positive for viral genetic material. On the contrary, personnel showered before getting in contact with the high biosecurity group. Those pigs as well as all personnel tests remained negative for PEDV during the study.

 

Torremorell PEDV biosecurity 2017

Abstract

Background:

The effectiveness of biosecurity methods to mitigate the transmission of porcine epidemic diarrhea virus (PEDV) via farm personnel or contaminated fomites is poorly understood. This study was undertaken to evaluate the effectiveness of biosecurity procedures directed at minimizing transmission via personnel following different biosecurity protocols using a controlled experimental setting.

Results:
PEDV RNA was detected from rectal swabs of experimentally infected (INF) and sentinel pigs by real-time reverse transcription polymerase chain reactio n (rRT-PCR). Virus shedding in INF pigs peaked at 1 day post infection (dpi) and viral RNA levels remained elevated through 19 dpi. Sentinel pigs in the low biosecurity group (LB) became PEDV positive after the first movement of study personnel from the INF group. However, rectal swabs from pigs in the medium biosecurity (MB) and high biosecurity (HB) groups were negative during the 10 consecutive days of movements and remained negative through 24 days post movement (dpm) when the first trial was terminated. Viral RNA was detected at 1 dpm through 3 dpm from the personal protective equipment (PPE) of LB personnel. In addition, at 1 dpm, 2 hair/face swabs from MB personnel were positive; however, transmission of virus was not detected. All swabs of fomite from the HB study personnel were negative.
Conclusions:
These results indicate that indirect PEDV transmission through contaminated PPE occurs rapidly (within 24 h) under modeled conditions. Biosecurity procedures such as changing PPE, washing expose d skin areas, or taking a shower are recommended for pig production systems and appear to be an effective option for lowering the risk of PEDV transmission between groups of pigs.

Link to the full text

Air samples successful in detecting on-farm PRRSV, PEDV, and high-path avian influenza virus

Reducing the likelihood of a piglet reservoir when dealing with influenza in swine herds

Drs. White, Torremorell and Craft from the University of Minnesota recently published an article in Preventative Veterinary Medicine regarding practices that can decrease the likelihood of creating an endemic piglet reservoir in the case of an infection by swine influenza. Indeed, a stochastic model was developed considering that the pigs were in one of the following categories: Susceptible, Exposed,  Infectious, Recovered, or Vaccinated. Loss of immunity over time and differences between naturally infected and vaccinated animals were taken into account. Several scenarios were evaluated regarding their impact on piglet prevalence: timing of gilt introductions, gilt separation, gilt vaccination upon arrival, early weaning, and sow vaccination strategies.

In this model, homologous mass vaccination and early weaning were the most efficacious interventions. By combining frequent homologous mass vaccination, early weaning, gilt separation, gilt vaccination and longer periods between gilt introductions reduced endemic prevalence overall by 51% relative to the null scenario and the endemic prevalence in piglets by 74%.

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Abstract: Recent modelling and empirical work on influenza A virus (IAV) suggests that piglets play an important role as an endemic reservoir. The objective of this study is to test intervention strategies aimed at reducing the incidence of IAV in piglets and ideally, preventing piglets from becoming exposed in the first place. These interventions include biosecurity measures, vaccination, and management options that swine producers may employ individually or jointly to control IAV in their herds. We have developed a stochastic Susceptible-Exposed-Infectious-Recovered-Vaccinated (SEIRV) model that reflects the spatial organization of a standard breeding herd and accounts for the different production classes of pigs therein. Notably, this model allows for loss of immunity for vaccinated and recovered animals, and for vaccinated animals to have different latency and infectious periods from unvaccinated animals as suggested by the literature. The interventions tested include: (1) varied timing of gilt introductions to the breeding herd, (2) gilt separation (no indirect transmission to or from the gilt development unit), (3) gilt vaccination upon arrival to the farm, (4) early weaning, and (5) vaccination strategies of sows with different timing (mass and pre-farrow) and efficacy (homologous vs. heterologous). We conducted a Latin Hypercube Sampling and Partial Rank Correlation Coefficient (LHS-PRCC) analysis combined with random forest analysis to assess the relative importance of each epidemiological parameter in determining epidemic outcomes. In concert, mass vaccination, early weaning of piglets (removal 0–7 days after birth), gilt separation, gilt vaccination, and longer periods between introductions of gilts (6 months) were the most effective at reducing prevalence. Endemic prevalence overall was reduced by 51% relative to the null case; endemic prevalence in piglets was reduced by 74%; and IAV was eliminated completely from the herd in 23% of all simulations. Importantly, elimination of IAV was most likely to occur within the first few days of an epidemic. The latency period, infectious period, duration of immunity, and transmission rate for piglets with maternal immunity had the highest correlation with three separate measures of IAV prevalence; therefore, these are parameters that warrant increased attention for obtaining empirical estimates. Our findings support other studies suggesting that piglets play a key role in maintaining IAV in breeding herds. We recommend biosecurity measures in combination with targeted homologous vaccination or vaccines that provide wider cross-protective immunity to prevent incursions of virus to the farm and subsequent establishment of an infected piglet reservoir.

Link to the full article