Further Evidence That Science-Based Biosecurity Provides Sustainable Prevention of Porcine Reproductive and Respiratory Syndrome Virus Infection and Improved Productivity in Swine Breeding Herds.

Porcine reproductive and respiratory syndrome virus (PRRSV) is a globally significant pathogen of pigs. Preventing the entry of PRRSV into swine breeding herds enhances animal health and welfare. A recently published retrospective cohort study reported significant differences in PRRSV incidence risk between breeding herds that practiced Next Generation Biosecurity (NGB) COMPLETE, versus herds that practiced a partial approach (NGB INCOMPLETE) over a 2-year period.

Improvements in swine herd biosecurity reduce the incidence risk of porcine reproductive and respiratory syndrome virus in breeding herds in the Midwestern United States.

Objective: Porcine reproductive and respiratory syndrome (PRRS) is a significant disease of swine. The purpose of this study was to determine whether application of a comprehensive, science-based approach to breeding herd biosecurity, known as next-generation biosecurity (NGB), could reduce PRRS incidence risk across a large commercial production company.

Animals: Pigs (381,404 sows across 76 breeding herds).

An assessment of enhanced biosecurity interventions and their impact on porcine reproductive and respiratory syndrome virus outbreaks within a managed group of farrow-to-wean farms, 2020-2021.

Introduction: Porcine reproductive and respiratory syndrome virus (PRRSV) has been a challenge for the U.S. swine industry for over 30 years, costing producers more than $600 million annually through reproductive disease in sows and respiratory disease in growing pigs.

Will swine veterinarians lead by meeting the next-generation needs of our industry?

The US swine industry is currently challenged by the potential of transboundary animal disease (eg, African swine fever) entry to the national herd and the relentless pressures of domestic diseases (eg, porcine reproductive and respiratory syndrome). The task of the swine veterinarian is to biosecure both the national herd and their customers' local farms to mitigate these risks. This Viewpoint raises 4 questions that swine veterinarians, including practicing (private and corporate), industry, research, academic, and regulatory (state and federal) veterinarians who spend a portion of their time controlling, treating, preventing, or eradicating diseases of swine, must answer to meet the needs of their farms to compete globally and survive.

An Assessment of Diagnostic Assays and Sample Types in the Detection of an Attenuated Genotype 5 African Swine Fever Virus in European Pigs over a 3-Month Period.

African swine fever virus causes hemorrhagic disease in swine. Attenuated strains are reported in Africa, Europe, and Asia. Few studies on the diagnostic detection of attenuated ASF viruses are available.

Evaluating the effect of temperature on viral survival in plant-based feed during storage.

Viruses of veterinary significance are known to survive for extended periods in plant-based feed ingredients imported into North America. To reduce the likelihood of virus introduction, high-risk ingredients, such as oil seed meals, are stored in designated facilities for extended periods under controlled environmental conditions to minimize viral infectivity prior to use in diets. While 30 days has become a standard storage period, the required ambient temperature to inactivate viruses during this time is not known.

A Molecular and Epidemiological Description of a Severe Porcine Reproductive and Respiratory Syndrome Outbreak in a Commercial Swine Production System in Russia.

Porcine reproductive and respiratory syndrome (PRRS) is an economically devastating disease of swine in many parts of the world. Porcine reproductive and respiratory syndrome virus (PRRSV) type 1 is endemic in Europe, and prevalence of the subtypes differ spatially. In this study, we investigated a severe PRRS outbreak reported in 30 farms located in eastern Russia that belong to a large swine production company in the region that was also experiencing a pseudorabies outbreak in the system.

Interventions to reduce porcine epidemic diarrhea virus prevalence in feed in a Chinese swine production system: A case study.

Research has shown that feed and feed ingredients can be one of the potential routes of transmitting viral pathogens into swine farms. In this short communication, we report two cases of Porcine Epidemic Diarrhea (PED) in two sow farms located in eastern China. Immediately after the outbreaks, extensive sampling and testing for genetic materials of PEDV was carried out on farms, and at the feed mill, in an effort to identify possible sources of infection based on field observations of local area viral spread and interventions already implemented to lower risk of this spread.

Evidence of viral survival in representative volumes of feed and feed ingredients during long-distance commercial transport across the continental United States.

The hypothesis that feed ingredients could serve as vehicles for the transport and transmission of viral pathogens was first validated under laboratory conditions. To bridge the gap from the laboratory to the field, this current project tested whether three significant viruses of swine could survive in feed ingredients during long-distance commercial transport across the continental US. One-metric tonne totes of soybean meal (organic and conventional) and complete feed were spiked with a 10 ml mixture of PRRSV 174, PEDV and SVA and transported for 23 days in a commercial semi-trailer truck, crossing 29 states, and 10,183 km.

Quantification of soya-based feed ingredient entry from ASFV-positive countries to the United States by ocean freight shipping and associated seaports.

African swine fever virus (ASFV) can survive in soya-based products for 30 days with T ½ ranging from 9.6 to 12.9 days in soya bean meals and soya oil cake.

An evaluation of additives for mitigating the risk of virus-contaminated feed using an ice-block challenge model.

The role of animal feed as a vehicle for the transport and transmission of viral diseases was first identified during the porcine epidemic diarrhoea virus (PEDV) epidemic in North America. Since that time, various feed additives have been evaluated at the laboratory level to measure their effect on viral viability and infectivity in contaminated feed using bioassay piglet models. While a valid first step, the conditions of these studies were not representative of commercial swine production.

Use of a demonstration project to evaluate viral survival in feed: Proof of concept.

In 2014, the hypothesis that feed ingredients could serve as vehicles for the transport and transmission of viral pathogens was proposed and evaluated by multiple investigators under laboratory conditions. In an attempt to validate these data, we used a demonstration project to test whether three significant viruses of swine could survive in feed ingredients under real-world shipping conditions. Samples of soya bean meal (organic and conventional), lysine, choline and vitamin A were spiked with a mixture of PRRSV 174, PEDV and SVA and transported for 21 days in the trailer of a commercial transport vehicle, encompassing 14 states and 9,741 km.

The risk of viral transmission in feed: What do we know, what do we do?

The role of animal feed as a vehicle for the transport and transmission of viral diseases was first identified in 2014 during the porcine epidemic diarrhoea virus epidemic in North America. Since the identification of this novel risk factor, scientists have conducted numerous studies to understand its relevance. Over the past few years, the body of scientific evidence supporting the reality of this risk has grown substantially.

Correction: Survival of viral pathogens in animal feed ingredients under transboundary shipping models.

[This corrects the article DOI: 10.1371/journal.pone.

Correction: Survival of viral pathogens in animal feed ingredients under transboundary shipping models.

[This corrects the article DOI: 10.1371/journal.pone.

Survival of viral pathogens in animal feed ingredients under transboundary shipping models.

The goal of this study was to evaluate survival of important viral pathogens of livestock in animal feed ingredients imported daily into the United States under simulated transboundary conditions. Eleven viruses were selected based on global significance and impact to the livestock industry, including Foot and Mouth Disease Virus (FMDV), Classical Swine Fever Virus (CSFV), African Swine Fever Virus (ASFV), Influenza A Virus of Swine (IAV-S), Pseudorabies virus (PRV), Nipah Virus (NiV), Porcine Reproductive and Respiratory Syndrome Virus (PRRSV), Swine Vesicular Disease Virus (SVDV), Vesicular Stomatitis Virus (VSV), Porcine Circovirus Type 2 (PCV2) and Vesicular Exanthema of Swine Virus (VESV). Surrogate viruses with similar genetic and physical properties were used for 6 viruses.

Modeling the transboundary risk of feed ingredients contaminated with porcine epidemic diarrhea virus.

Background: This study describes a model developed to evaluate the transboundary risk of PEDV-contaminated swine feed ingredients and the effect of two mitigation strategies during a simulated transport event from China to the US.

Results: Ingredients imported to the USA from China, including organic & conventional soybeans and meal, lysine hydrochloride, D-L methionine, tryptophan, Vitamins A, D & E, choline, carriers (rice hulls, corn cobs) and feed grade tetracycline, were inoculated with PEDV. Control ingredients, and treatments (ingredients plus a liquid antimicrobial (SalCURB, Kemin Industries (LA) or a 2% custom medium chain fatty acid blend (MCFA)) were tested.

Evaluation of the long-term effect of air filtration on the occurrence of new PRRSV infections in large breeding herds in swine-dense regions.

Airborne transmission of porcine reproductive and respiratory syndrome virus (PRRSV) is a risk factor for the infection of susceptible populations. Therefore, a long‑term sustainability study of air filtration as a means to reduce this risk was conducted. Participating herds (n = 38) were organized into 4 independent cohorts and the effect of air filtration on the occurrence of new PRRSV infections was analyzed at 3 different levels from September 2008 to January 2012 including the likelihood of infection in contemporary filtered and non-filtered herds, the likelihood of infection before and after implementation of filtration and the time to failure in filtered and non-filtered herds.

Comparative infection efficiency of Porcine reproductive and respiratory syndrome virus field isolates on MA104 cells and porcine alveolar macrophages.

Isolation of Porcine reproductive and respiratory syndrome virus (PRRSV) on MA104 or MARC-145 cells is frequently used in PRRS diagnosis. However, the ability of recent field isolates to grow on these established simian cell lines has not been determined. The aim of this study was to characterize the growth of PRRSV field isolates on primary porcine alveolar macrophages (PAMs) and MA104 cells in comparison with the growth of the laboratory-adapted strain VR-2332.