Salmonella and pigs

Posted on July 21, 2020 by Douglas Powell

Salmonella is one of the most important foodborne pathogens worldwide. Its main reservoirs are poultry and pigs, in which infection is endemic in many countries. Spain has one of the largest pig populations in the world. Even though Salmonella infection is commonly detected in pig farms, its spatial distribution at the national level is poorly understood.

Here we aimed to report the spatial distribution of Salmonella-positive pig farms in Spain and investigate the presence of potential spatial trends over a 17-year period. For this, data on samples from pigs tested for Salmonella in 2002–2013, 2015, 2017, and 2019 as part of the Spanish Veterinary Antimicrobial Resistance Surveillance program, representing 3,730 farms were analyzed. The spatial distribution and clustering of Salmonella-positive pig farms at the province level were explored using spatial empirical Bayesian smoothing and global Moran’s I, local Moran’s I, and the Poisson model of the spatial scan statistics. Bayesian spatial regression using a reparameterized Besag-York-Mollié Poisson model (BYM2 model) was then performed to quantify the presence of spatially structured and unstructured effects while accounting for the effect of potential risk factors for Salmonella infection at the province level. The overall proportion of Salmonella-positive farms was 37.8% (95% confidence interval: 36.2–39.4). Clusters of positive farms were detected in the East and Northeast of Spain. The Bayesian spatial regression revealed a West-to-East increase in the risk of Salmonella infection at the province level, with 65.2% (50% highest density interval: 70–100.0%) of this spatial pattern being explained by the spatially structured component. Our results demonstrate the existence of a spatial variation in the risk of Salmonella infection in pig farms at the province level in Spain.

This information can help to optimize risk-based Salmonella surveillance programs in Spain, although further research to identify farm-level factors explaining this pattern are needed.

Spatial trends in salmonella infection in pigs in Spain, 23 June 2020

Frontiers in Veterinary Science

Kendy Tzu-yun Teng^1*, Marta Martinez Avilés², Maria Ugarte-Ruiz¹, Carmen Barcena¹, Ana de la Torre², Gema Lopez³, Miguel A. Moreno^1,4, Lucas Dominguez^1,4 and Julio Alvarez^1,4

https://doi.org/10.3389/fvets.2020.00345

https://www.frontiersin.org/articles/10.3389/fvets.2020.00345/fulld

Risk of Hepatitis E from pigs or pork in Canada

Posted on October 11, 2016 by Douglas Powell

The role and importance of pigs and pork as sources of zoonotic hepatitis E virus (HEV) has been debated in Canada and abroad for over 20 years. To further investigate this question, we compiled data to populate a risk profile for HEV in pigs or pork in Canada.

We organized the risk profile (RP) using the headings prescribed for a foodborne microbial risk assessment and used research synthesis methods and inputs wherever possible in populating the fields of this RP. A scoping review of potential public health risks of HEV, and two Canadian field surveys sampling finisher pigs, and retail pork chops and pork livers, provided inputs to inform this RP. We calculated summary estimates of prevalence using the Comprehensive Meta-analysis 3 software, employing the method of moments.

Overall, we found the incidence of sporadic locally acquired hepatitis E in Canada, compiled from peer-reviewed literature or from diagnosis at the National Microbiology Laboratory to be low relative to other non-endemic countries. In contrast, we found the prevalence of detection of HEV RNA in pigs and retail pork livers, to be comparable to that reported in the USA and Europe. We drafted risk categories (high/medium/low) for acquiring clinical hepatitis E from exposure to pigs or pork in Canada and hypothesize that the proportion of the Canadian population at high risk from either exposure is relatively small.

Risk profile of Hepatitis E virus from pigs or pork in Canada

October 2016, Transboundary and Emerging Diseases, DOI: 10.1111/tbed.12582

https://www.researchgate.net/publication/308961418_Risk_Profile_of_Hepatitis_E_Virus_from_Pigs_or_Pork_in_Canada

Hep E? From pigs? In Corsica?

Posted on July 21, 2016 by Douglas Powell

To the Editor: In Western countries, human infection with hepatitis E virus (HEV) is mostly autochthonous and zoonotic through ingestion of contaminated food or direct contact with infected animals and very occasionally is imported from regions to which it is endemic to humans (tropical and subtropical areas) (1). Domestic pigs and wild boars are important zoonotic reservoirs of HEV worldwide (2).

In continental France, grouped cases of hepatitis E have been described after ingestion of Corsican specialties made with raw pig liver known as ficatelli, traditionally eaten grilled or raw after curing (3,4). A survey of French food products detected HEV RNA in 30% of ficatelli samples (5). A recent nationwide study of blood donors in France showed a high (>60%) HEV seroprevalence in Corsica, suggesting local hyperendemicity (6). Estimated prevalences of HEV RNA from wild boars and domestic pigs in Corsica were 2.3% and 8.3%, respectively (F. Jori, unpub. data). We aimed to evaluate, at a molecular level, the role of local wild boars and domestic pigs from Corsica in human infections or food contaminations.

We retrieved partial sequences of HEV open reading frame 2 capsid (7) from samples from 8 wild boars hunted during 2009–2013 and from 2 domestic pigs collected at a slaughterhouse in 2013 (F. Jori, unpub. data) and compared them with sequences available in GenBank. This genomic region is used frequently in phylogeny and reflects the diversity of HEV (8). After alignment with reference sequences for subtyping (9) and their closest sequences, we constructed a phylogenetic tree (Figure). All 10 sequences belonged to HEV genotype 3 and were distributed into 3 distinct clusters.

Cluster 1, subtype 3c, comprised 4 wild boar sequences (FR-HEVWB-1-91, FR-HEVWB-3-07, FR-HEVWB-7-114, FR-HEVWB-8-115) that had 96%–97% nt identity. These sequences were identified during 3 successive hunting seasons (2009, 2010, and 2013) in the same hunting area, suggesting that HEV sequences can be stable, with limited genetic variability, during at least 4 years in a local population of wild boars. These sequences were close to HEV wild boar sequences from Belgium (GenBank accession no. KP296177) and Germany (GenBank accession no. FJ705359; 3c reference sequence). A possible introduction of wild boars from northeast continental France into Corsica during the 1990s could explain such similarity (C. Pietri, pers. comm.). Two human cases reported in southeastern France (GenBank accession nos. GQ426997, KJ742841) in 2008 and 2009 also aggregated within this cluster (94%–95% nt identity), indicating possible zoonotic transmissions from wild boars to humans.

Cluster 2 comprised 2 wild boar sequences (FR-HEVWB-2-101 and FR-HEVWB-6-75) with 99.3% nt similarity, collected in 2009 and 2012 from the same geographic area (Haute Corse, <10 km apart). This cluster is distant from the subtypes assigned by Smith et al. (9) and shows <86.5% nt identity with reference sequences (Figure), indicating a possible local and stable evolution in space and time.

Cluster 3, subtype 3f, comprised sequences isolated from wild boars and domestic pigs from Corsica, humans from continental France, and 1 food sample from Corsica. The 2 domestic pig sequences (FR-SHEV-2B-1-182, FR-SHEV-2B-2-190) were 100% identical and shared 97.5% nt identity with a wild boar sequence (FR-HEVWB-4-104), suggesting transmission between domestic and wild pigs. These 2 swine sequences shared 96% nt identity with a sequence amplified in 2011 from a ficatellu sample (FR-HEVFIG-3; GenBank accession no. KJ558438) (5) from the same geographic area of Corsica (Haute Corse) and 96% nt identity with an isolate from a patient with acute hepatitis E recorded in France in 2009 (GenBank accession no. JF730424). In addition, the wild boar sequence in this cluster (FR-HEVWB-4-104) shared 96.4% nt identity with the same ficatellu sample and 97.1% nt identity with the same patient in France. This finding suggests that some locally produced ficatelli could be contaminated with HEV from local domestic pigs or wild boars. The human infection also suggests that zoonotic transmission might have occurred through contact with local pig or wild boar reservoirs or through ingestion of contaminated food products. No additional information is available about this human case that might attribute the contamination to 1 of the sources.

Also in cluster 3, another Corsican wild boar sequence (FR-HEVWB-5-117), isolated in 2011, shared 96.2% and 95.7% nt identity with 2 human sequences identified from continental France in 2013 (GenBank accession no. KR027083) and 2009 (GenBank accession no. JF730424 FR-HuHEV-09AL38). This finding again suggests a zoonotic origin for these human cases. Cluster 3 illustrates well a possible path of transmission between wildlife, domestic pigs, food, and human infection and the potential for dissemination of HEV outside Corsica.

Our results provide evidence suggesting a dynamic exchange of HEV between domestic and wild swine reservoirs and possibly resulting in transmission from those reservoirs to humans through ingestion of infected food products. These animal reservoirs are common and abundant (http://www.oncfs.gouv.fr/IMG/file/mammiferes/ongules/ongules_sauvages/TCD/haute_corse_ongules_sauvages_tableau_departemental.pdf; http://draaf.corse.agriculture.gouv.fr/IMG/pdf/Chiffres_cles_Corse-2015_cle825d93.pdf) and represent a sustainable source of HEV exposure in Corsica.

Nicole Pavio , Morgane Laval, Oscar Maestrini, François Casabianca, François Charrier, and Ferran Jori

Author affiliations: ANSES (French Agency for Food, Environmental and Occupational Health and Safety); Maisons-Alfort, France (N. Pavio); INRA (National Institute for Agricultural Research); Maisons-Alfort (N. Pavio); University Paris 12, National Veterinary School, Maisons-Alfort (N. Pavio); INRA, Corte, France (M. Laval, O. Maestrini, F. Casabianca, F. Charrier); CIRAD (Agricultural Research for Development); Montpellier, France (F. Jori); Botswana University of Agriculture and Natural Resources, Gaborone, Botswana (F. Jori)

Acknowledgments

We are grateful to Gaël Stéphant for technical assistance in swine sample analysis. We thank Christian Pietri for sharing his knowledge on the origin of wild boar population in Corsica.

Part of the study including wild boar and domestic pig sample analysis was supported by the European Union Seventh Framework Program (FP7/2007-2013) under grant agreement no. 278433-PREDEMICS and grant agreement no. 311931 (ASFORCE).

References

1.Pavio N, Meng XJ, Renou C. Zoonotic hepatitis E: animal reservoirs and emerging risks. Vet Res. 2010;41:46. DOI PubMed

2.Thiry D, Mauroy A, Pavio N, Purdy MA, Rose N, Thiry E, Hepatitis E virus and related viruses in animals. Transbound Emerg Dis. 2015;n/a; Epub ahead of print. DOI PubMed

3.Colson P, Borentain P, Queyriaux B, Kaba M, Moal V, Gallian P, Pig liver sausage as a source of hepatitis E virus transmission to humans. J Infect Dis. 2010;202:825–34. DOI PubMed

4.Renou C, Roque-Afonso AM, Pavio N. Foodborne transmission of hepatitis E virus from raw pork liver sausage, France.[Erratum in: Emerg Infect Dis. 2015;21:384. ]. Emerg Infect Dis. 2014;20:1945–7.DOI PubMed

5.Pavio N, Merbah T, Thébault A. Frequent hepatitis E virus contamination in food containing raw pork liver, France.Emerg Infect Dis. 2014;20:1925–7. DOI PubMed

6.Mansuy JM, Gallian P, Dimeglio C, Saune K, Arnaud C, Pelletier B, A nationwide survey of hepatitis E viral infection in French blood donors. Hepatology. 2016;63:1145–54. DOI PubMed

7.Rose N, Lunazzi A, Dorenlor V, Merbah T, Eono F, Eloit M, High prevalence of hepatitis E virus in French domestic pigs.Comp Immunol Microbiol Infect Dis. 2011;34:419–27. DOI PubMed

8.Lu L, Li C, Hagedorn CH. Phylogenetic analysis of global hepatitis E virus sequences: genetic diversity, subtypes and zoonosis. Rev Med Virol. 2006;16:5–36. DOI PubMed

9.Smith DB, Simmonds P, Izopet J, Oliveira-Filho EF, Ulrich RG, Johne R, Proposed reference sequences for hepatitis E virus subtypes. J Gen Virol. 2016;97:537–42. DOI PubMed

Possible foodborne transmission of Hepatitis E virus from domestic pigs and wild boars from Corsica

Emerging Infectious Diseases; Volume 22, Number 12—December 2016; DOI: 10.3201/eid2212.160612

Pavio N, Laval M, Maestrini O, Casabianca F, Charrier F, Jori F.

http://wwwnc.cdc.gov/eid/article/22/12/16-0612_article

Emergence and spread of Salmonella Typhimuriam DT104

Posted on March 6, 2016 by Douglas Powell

Since it first emerged more than half a century ago, a particular strain of multidrug-resistant Salmonella has spread all over the world. Now researchers have figured out why this strain, Salmonella Typhimuriam DT104, has been so successful. This new knowledge could prove valuable in combating other successful pathogens, according to the authors. The study is published ahead of print March 4th in Applied and Environmental Microbiology, a journal of the American Society for Microbiology.

In order to construct the history of this strain, the investigators performed whole-genome sequencing of samples of DT104 that had been collected from patients over more than 40 years, from 1969 to 2012, in 21 countries, on six continents. Very tiny changes in the genome that took place over time enabled them to construct the strain’s family tree. The sequences have also made it easy to estimate roughly when the pathogen acquired the resistance genes.

DT104’s success was due in no small part to its resistance to at least five antibiotics, including ampicillin, chloramphenicol, streptomycin, sulphonamide, and tetracycline, said corresponding author, Pimlapas Leekitcharoenphon, PhD.

Further abetting its spread, unlike other strains of DT Salmonella, DT104 was able to infect numerous livestock species, including cattle, poultry, pigs, and sheep, said Leekitcharoenphon. “Having multiple hosts increases the chances of dissemination,” she explained. Leekitcharoenphon is a postdoctoral researcher at the Research Group for Genomic Epidemiology, National Food Institute, Technical University of Denmark, Lyngby.

Using a program that took into account the rate of mutations in DT104, the investigators estimated that it first emerged in 1948 as an antibiotic susceptible pathogen. It is not clear exactly when DT104 first acquired the multidrug resistance-containing transposon. Transposons are mobile genetic elements that can carry antibiotic resistance genes, and that can jump from one genome to another. In the case of DT104, transposons have been identified as the sources of the resistance genes. The study suggests that the first acquisition of antibiotic resistance may have happened in 1972. However, multidrug-resistant DT104 was first reported in 1984 in the United Kingdom.

The new results also illuminated, for the first time, the results of a program in Denmark to eradicate all pigs infected with DT104, which had begun in 1996, but was stopped in 2000 due to financial pressures. It turns out that program was quite successful.

“If we know and understand the past, we might be able to solve the current resistance problems and prevent future ones,” said Leekitcharoenphon.

It’s the best scene from Snatch: Oregon farmer convicted of killing men, feeding to pigs

Posted on April 22, 2015 by Douglas Powell

Jurors spent only about an hour deliberating Tuesday before convicting an Oregon woman of killing two handymen and feeding their corpses to her pigs.

The Jackson County jury found Susan Monica guilty of murdering two men about a year apart, then abusing their corpses by feeding them to the animals at her farm, The Medford Mail Tribunereported.

Circuit Judge Tim Barnack immediately sentenced Monica to a minimum 50 years in prison.

“You shot two people and fed them to your pigs,” the judge told Monica, 66. “I don’t know how else I can put it. You valued pigs more than you value people.

170 sick with trichinosis in Argentina

Posted on February 8, 2015 by Douglas Powell

The National Health Service and Food Quality (SENASA) implemented bans and controlled performed tasks for the health operative in response to the outbreak of trichinosis detected in Pehaujó, Buenos Aires.

There are an estimated 170 people have been affected and 504 pigs sent to slaughter in the area involved.

The origin of the outbreak was due to the consumption of sausages unmarked from a butcher in that city, which was not authorized by local authorities, or hatcheries and farms of which got the pork that marketed the premises.

Before the fact, SENASA authorities acted in conjunction with the Ministry of Land Affairs of the Province and the Municipality of Pehuajó, from the initial seizure of the goods at the butcher until bans and controlled delivery job of confiscated animals. According to the results of diagnostic tests in the cold, many of these animals were positive.

Trichinosis or trichinellosis is a zoonotic disease that may be present in raw or undercooked meat from pigs and certain game animals such as wild boar and pumas. People get sick when they eat raw, sausages or sausage meat without proper sanitary control.

Pigs can get trichinosis when raised in unhygienic conditions with rodents and fed with trash or debris inadequate food. Parasitized pigs have no symptoms and characteristics of their meat is not altered.

Wild Boar population explodes in Germany: Plenty of bacon to go around

Posted on December 6, 2009 by Michelle Mazur

The New York Times reports “the wild boar is multiplying and less lovable.” I’m pretty sure the closest boars got to lovable was in the Lion King, and even then: not so lovable (and not a terrific singer either). Germany has its hands full with the wild boar population. Normally, the worst thing one of Germany’s wild boars will do is ruin a field of corn, which is one of their favorite foods. Lately, however, as their population has exploded scientists estimate that it increased by 320 percent in Germany in the last year alone — the pigs have been having more and more encounters with humans. Wild boars cause extensive damage to crops and property, but also have the potential be deadly to people that come upon them. But if they don’t kill you immediately, they could be carrying bugs that will get you later. Wild hogs are carriers of diseases such as anthrax, brucellosis, pseudorabies and tuberculosis.

If they don’t eat all of the crops while scavenging, they could be leaving behind E. coli in their feces, which was the likely situation in 2006 when contaminated spinach from California took three lives and made over 200 ill. These buggers are so destructive that fencing off crops is useless; the pigs plow right through them. I’d love to see if there’s any data out there correlating E.coli cases in Germany with the increasing populations of wild boars.

Currently an estimated 2 million to 2.5 million boars roam the forests, suburbs and maize fields of Germany. No national program seems to be set up to eradicate this problem, but local hunters do their best by enjoying a roasted leg of wild boar once in awhile.

Egypt kills pigs to stop a virus that moves person-to-person

Posted on May 1, 2009 by Casey Jacob

Egypt began culling its roughly 300,000 pigs on Wednesday and, Reuters reported,

“The move is not expected to block the H1N1 virus from striking, as the illness is spread by people and not present in Egyptian swine. But acting against pigs, largely viewed as unclean in conservative Muslim Egypt, could help quell a panic.”

The next day, according to the Associated Press, the World Organization for Animal Health said, "there is no evidence of infection in pigs, nor of humans acquiring infection directly from pigs," and the World Health Organization announced, "Rather than calling this swine flu … we’re going to stick with the technical scientific name H1N1 influenza A."

These organizations recognized that Egyptians aren’t getting the whole story.

The World Health Organization has raised the alert on the H1N1 flu virus to phase 5, which assistant director-general Dr. Keiji Fukuda said is reserved for situations in which the likelihood of a pandemic “is very high or inevitable.” The move reflects the need for countries to take the virus seriously, and Egyptian leaders appear to be doing just that. However, costly culls that act against current evidence are sending inaccurate messages to the public about the risks present and the ways in which they can be effectively controlled.

Egyptian pig farmers are outraged. The remaining citizens feel a bit safer now. But they will all feel terribly betrayed when the H1N1 flu infiltrates their borders in the form of an infected human.

Using pigs as bug control in an orchard?

Posted on March 4, 2008 by Ben Chapman

Today the Associated Press reports that a farmer in Michigan has been using more than two dozen pigs in his organic apple orchards in his quest to control the plum curculio:

Jim Koan has gone hog-wild in his battle against a beetle that threatens his 120-acre organic apple orchard. [The] porkers patrol his orchard, gobbling down fallen, immature apples containing the beetle’s larvae. After a successful trial run late last spring, he and some researchers at Michigan State University are preparing for year two of the experiment at AlMar Orchards & Cidery in eastern Michigan.

They hope their work will someday help fruit growers throughout the world reduce the use of pesticides while diversifying their agricultural operations, as he is doing. He plans to periodically sell off the offspring of his four original hogs, keeping only what he needs.

Interesting move, definitely thinking outside the box, as organic producers must, when it comes to pest control. I wonder if there is a segment of the research that looks at the microbiological differences between the fresh apples (and the drops) on his farm and other producers not using the hogs. This pest reduction plan might be introducing new food safety risks that weren’t there before.

Feral pigs seemed to play a part in the the 2006 spinach outbreak. Last March the FDA said: "Potential environmental risk factors for E.coli O157:H7 contamination at or near the field included the presence of wild pigs, the proximity of irrigation wells used to grow produce for ready-to-eat packaging, and surface waterways exposed to feces from cattle and wildlife."

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