November 2018 – Page 2 – Swine in Minnesota

Cold plasma technology to clean swine barn air

Porcine reproductive and respiratory syndrome virus (PRRSv) costs the US swine industry more than $580 million each year. First described in North Carolina, Iowa, and Minnesota in the late 1980s, the virus rapidly spreads through swine barns and is one of the industry’s biggest game changers. Additionally, pigs infected with virulent strains exhales aerosols containing a large quantity of the virus.

Today, researchers in the Veterinary Diagnostic Lab at the CVM are looking to apply research they are doing on decontaminating foods in collaboration with the University of Minnesota College of Science and Engineering (CSE) to swine barn air filtration in an effort to further promote swine health and safety in the food industry at large.

Plasma, served cold

Plasma is defined as partially or fully ionized gases with neutral net charge. It consists of a cocktail of photons, ions, free radicals, molecules, and atoms—many of which are highly reactive, which allows for many applications, including water decontamination. Plasma sources can also be engineered to produce plasma at close to room temperature—often referred to as cold plasma—enabling the treatment of highly heat-sensitive surfaces, such as some foods.

2D- integrated coaxial micro hollow dielectric barrier plasma discharge array — Plasma (purple) is produced inside the holes of the array, through which air is blown. Pathogens are inactivated when they come into contact with the air coming through the holes in the array.

The United States Department of Agriculture is supporting Sagar Goyal, PhD, professor in the Department of Veterinary Population Medicine at the CVM; Peter Bruggeman, PhD, professor of Mechanical Engineering at the CSE; and their team of researchers in pursuing the use of cold atmospheric gaseous plasma technology for decontaminating food and food-processing surfaces.

The team is seeing success in the lab—bacteria and viruses stand little chance against the cold plasma they are making.

According to Goyal, the laboratory results look extremely promising. “If a surface is contaminated with viruses or bacteria, we can kill them,” says Goyal. “If food is contaminated—as early as during harvest by food handlers—our goal is to use cold plasma to kill the contaminants.”

A pig impact

“Meanwhile,” says Goyal, “swine farmers are already using air filtration systems to mitigate disease. But these are not foolproof, so if we can combine them with this cold plasma, it would be helpful in getting rid of any disease affecting swine that can be transferred by air.” This includes, but is not limited to, PRRSv. So, cold plasma could positively impact the food and agricultural industry in more ways than one.

Follow the link to read more about how cold plasma could be used in swine barns.

Science Page: Emerging enrofloxacin and ceftiofur resistance in E. coli isolated from US swine clinical samples

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 Dr. Shivdeep Singh Hayer from the STEMMA lab, on the emerging enrofloxacin and ceftiofur resistance in E.coli in swine.

Key points:

Nearly one-third of clinical E. coli isolates collected from swine samples were ceftiofur or enrofloxacin resistant
Genetic analysis revealed presence of rarely reported genes in antimicrobial resistant isolates
Most of the isolates were multi-drug resistant on both routine lab tests and genetic analysis

In a previous study, we analyzed the antimicrobial resistance in Escherichia coli isolates recovered from swine clinical samples from across USA during 2006-2016 at the University of Minnesota Veterinary Diagnostic Laboratory (UMN-VDL), and found a 47% annual increase in the prevalence of enrofloxacin resistance (from 1.5% in 2006 to 32% in 2016) while no trend was observed for the resistance to ceftiofur (that ranged between 32-39%). A follow-up study was conducted to evaluate the genetic basis of resistance against enrofloxacin and ceftiofur in E. coli isolates using whole genome sequencing (WGS).

153 swine clinical E. coli isolates collected in 2014-15 from 14 states across USA were selected and genes causing ceftiofur and enrofloxacin resistance were identified using WGS.

21 (out of 106) enrofloxacin-resistant isolates from 6 states harbored diverse plasmid mediated quinolone resistance (PMQR) genes (qnrB19, qnrB2, qnrS1, qnrS2 and qnrS15). The presence of PMQR genes alone was associated with clinical levels of resistance.

The most prevalent genes associated with ceftiofur resistance were blaCMY-2 (89/106, 84%). Moreover, 24 ceftiofur-resistant isolates harbored various blaCTX-M and blaSHV genes.

Additionally, bacteria carrying blaCTX-M and qnr genes also contained genes coding for resistance mechanisms against other antimicrobial classes and were commonly resistant against ampicillin, tetracyclines, gentamycin, trimethoprim and sulfonamides.

These genes (blaCTX-M, qnr) have been rarely reported from farm animals in USA and have been implicated as important genetic mechanisms behind extended spectrum cephalosporin and fluoroquinolone resistance in human and animal populations in several countries. These genes are present on plasmids, making their dissemination across bacterial populations faster by horizontal transfer.

The presence of multiple antimicrobial resistance genes on the same plasmids also makes mitigation of this problem more difficult because of the possibility that using one antimicrobial class will exert positive selection pressure for resistance against other antimicrobial classes.

Global trends in infectious diseases of swine

Dr. Kim VanderWaal and Dr. John Deen from the University of Minnesota co-authored a new publication available now in the Proceedings of the National Academy of Sciences of the United States of America.

The objectives of this study were to identify priority swine pathogens, characterize temporal and geographic trends in research priorities.

57,471 publications covering 40 swine pathogens, compiled from 3 major database searches and dating from 1966 to 2016 were included in this analysis.

The top 10 pathogens published on were:

Salmonella spp.
Escherichia coli
Influenza
Pseudorabies
Foot and Mouth Disease
Porcine Reproductive and Respiratory Syndrome
Classical Swine Fever
Actinobacillus pleuropneumoniae
Trichinella spp.
African Swine Fever

The number of publications on swine infectious diseases increased over time as the hog production intensified. However, 8 pathogens increased faster than expected, particularly in the past 15 years: hepatitis E virus, Nipah virus, influenza, Streptococcus suis, Lawsonia intracellularis, porcine circovirus 2, PRRS, and PED.

On the contrary, some diseases had a slower growth in number of publications than expected. These included pseudorabies, Pasteurella multocida, Actinobacillus pleuropneumoniae, Brachyspira hyodysenteriae, and transmissible gastroenteritis virus. All of these pathogens were production diseases whose importance to the industry had declined in recent decades due to better control or even regional eradication.

Differences among world regions were identified except for influenza virus which appeared in the top 5 in most regions of the world. Southern regions where extensive hog production may still be the norm, tended to focus more on parasitic infections compared to Northern areas. Western Europe centered more on pathogens related to zoonotic and foodborne concerns compared to Northern America.

Abstract

Pork accounts for more than one-third of meat produced worldwide and is an important component of global food security, agricultural economies, and trade. Infectious diseases are among the primary constraints to swine production, and the globalization of the swine industry has contributed to the emergence and spread of pathogens. Despite the importance of infectious diseases to animal health and the stability and productivity of the global swine industry, pathogens of swine have never been reviewed at a global scale. Here, we build a holistic global picture of research on swine pathogens to enhance preparedness and understand patterns of emergence and spread. By conducting a scoping review of more than 57,000 publications across 50 years, we identify priority pathogens globally and regionally, and characterize geographic and temporal trends in research priorities. Of the 40 identified pathogens, publication rates for eight pathogens increased faster than overall trends, suggesting that these pathogens may be emerging or constitute an increasing threat. We also compared regional patterns of pathogen prioritization in the context of policy differences, history of outbreaks, and differing swine health challenges faced in regions where swine production has become more industrialized. We documented a general increasing trend in importance of zoonotic pathogens and show that structural changes in the industry related to intensive swine production shift pathogen prioritization. Multinational collaboration networks were strongly shaped by region, colonial ties, and pig trade networks. This review represents the most comprehensive overview of research on swine infectious diseases to date.

Science Page: Illegal importation of meat derived food products through passenger airline carriers and possibility of disease introduction

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 an article by the MSHMP team regarding the impact of illegal meat product importation on disease introduction.

Key Points:

Commercial airplane passengers bring illegal food imports
These illegally imported food products are an overlooked but important disease introduction source
The illegal importation by commercial travelers happens more frequently then generally assumed

Illegally imported products are a likely source of disease introduction

The recent African Swine Fever (ASF) outbreaks in China have created concern in the US swine industry over the possible introduction of the disease into the US, thus making Foreign Animal Disease (FAD) a primary topic of concern. One of the most pressing concerns about FADs in general, and ASF in particular, is what are the likely sources of entry, and how the associated risks can be mitigated. Illegally imported products, carried by commercial air passengers are often overlooked as a minor introduction source. Several studies around the world show that commercial air passengers do represent a likely source of disease introduction. Outbreaks of ASF, Classical Swine Fever (CSF) and Foot and Mouth Disease (FMD) have been attributed to feeding imported waste meat to domestic pigs (Falk, et al., 2013).

Thousands tons of illegal food products are found at airports

It is difficult to estimate the total amount of illegal food products entering a single country each year. A study conducted in Germany in 2015 at two major airports tracked seizures for three months, including an intensive 10 days of special controls where higher numbers of passenger luggage was searched. Based upon that data they estimated that each year 2,800 tons of illegal food products were brought in via the Frankfurt airport alone. The most commonly imported foods were meat and meat products, including raw, home cooked, preserved, and packaged foods (Beutlich, et al., 2015).

Another study, conducted in Switzerland estimated that the total volume of non-intercepted meat products were 8.6 tons for bush meat, and 1,013 tons for other meat products (Falk, et al., 2013).

Illegal food products contain pathogens; airports are risky ports of entry

A key point to understand the risk of improperly imported foods is knowing how often they contain pathogens and whether these have the capability of remaining infectious. In the German study, out of 474 samples tested, 5% of them contained food borne pathogens (Beutlich, et al., 2015). In a similar study conducted in Spain 67 out of 122 samples tested at an airport contained human noroviruses, and hepatitis E (Rodriguez-Lazaro, et al., 2015).

A modeling study focused on estimating the risk of introduction of ASF and CSF into the US using airport and customs data. The study identified specific airports (i.e.Washington-Dulles, George Bush-Houston, JFK-Queen, Warwick, Sanjuan, West Palm Beach, Charlotte, Ft. Lauderdale, Newark and Cleveland) as ports of entry with the highest risk for both ASF and CSF introduction. This work also identified the months of May through July as the months with the highest risk (Jurado, Paternoster, Martínez-López, Burton, & Mur, 2018).

Only a fraction of illegal imports are intercepted

It is estimated that only between 10-50% of improperly imported products are intercepted at customs (Jurado, Paternoster, Martínez-López, Burton, & Mur, 2018).One study’s sensitivity analysis showed that for both ASF and CSF, the likelihood of detecting illegal products was highly correlated with the final risk of disease introduction.This means that an increase in customs detection of products brought by commercial passengers largely reduces the risk of a CSV or ASF introduction into the US (Jurado, Paternoster, Martínez-López, Burton, & Mur, 2018).

Pork products were seized recently in the USA and Japan

Recently, on October 15th, 2018 a customs and border protection beagle found a whole roasted pig in the luggage of a traveler from Ecuador(Lieu, 2018) at the Hartsfield-Jackson Atlanta airport. Ecuador as any other South American country is ASF negative, but CSF continues to be present in the country. It is unknown whether the smoked pig has been tested for CSF, but the case is a perfect example of the variety of products that are being transported to the US.

On October 1st, Japanese customs officials confiscated a pork sausage from a Beijing traveler. The sausage tested positive for ASF (Reuters). African Swine Fever has also been found at a South Korean airport in pork products brought in a commercial passenger airline from China (Reuters). All of these examples highlight the reality of the risk illegally imported products carried by commercial travelers play in FAD introduction.

It is important for the swine community to be aware of these risks, to be aware of what food products are being brought to their sites by people, and to push for effective prevention methods. It also highlights the need of the swine community to communicate this risk to the non-swine community to raise awareness and thus contribute to protecting the industry. By using research that helps identify where the highest risks lie spatially and temporally, as well as flights from which countries represent risk, better prevention methods can be developed and implemented.

What if African Swine Fever came to Minnesota?

The Center for Food Animal Health and Food Safety at the University of Minnesota released a new video on African Swine Fever and what the consequences would be if it ever came to Minnesota. Dr. Marie Culhane from the University of Minnesota and Dr. Beth Thompson, executive director of the Minnesota Board of Animal Health discuss how the state prepared for this eventuality.

Click on the video to listen to their exchange. (14:56 min)